1. No category

BIMATE
BiMatE was held at the Polymer Technology College in Slovenj Gradec, Slovenia. The conference started
on Wednesday, 15 April 2015, and finished on Friday, 17 April 2015.
Conference topics
 Biopolymer synthesis and modifications
 Biopolymer composites and nanotechnologies
 Biopolymer processing
 Biopolymer characterisation
 Polymer biodegradation
 Biopolymer recycling
 Advanced applications of biopolymers
 Life cycle assessment
 Innovations and biopolymer industry
The Organising Commitee
 Irena Pulko, Polymer Technology College, Slovenj Gradec, Slovenia
 Silva Roncelli Vaupot, Polymer Technology College, Slovenj Gradec, Slovenia
 Gašper Gantar, College of Industrial Engineering, Celje, Slovenia
 Cvetka Ribarič-Lasnik, Institute of the Environment and Spatial Planning, Celje, Slovenia
 Valerij Dermol, International School for Social and Business Studies, Celje, Slovenia
 Andrej Kržan, National Institute of Chemistry, Ljubljana, Slovenia
The Scientific Commitee
 Majda Žigon, National Institute of Chemistry, Ljubljana / Polymer Technology College, Slovenj
Gradec, Slovenia
 Vojko Musil, Polymer Technology College, Slovenj Gradec, Slovenia
 Irena Pulko, Polymer Technology College, Slovenj Gradec, Slovenia
 Matjaž Kunaver, National Institute of Chemistry, Ljubljana, Slovenia
 Aleš Hančič, Tecos, Slovenian Tool and Die Center, Celje, Slovenia
 Ema Žagar, National Institute of Chemistry, Ljubljana, Slovenia
 Peter Krajnc, University of Maribor, Slovenia
 Thomas Lucyshyn, Montanuniversität Leoben, Leoben, Austria
 Jiří Kotek, Institute of Macromolecular Chemistry, Academy of Sciences, Prague Checz Republic
 Primož Rus, Polymer Technology College, Slovenj Gradec, Slovenia
 Stephan Laske, Montanuniversität Leoben, Leoben, Austria
The conference was organized within operation Creative Core VŠTP.
The operation is partially co-financed by European Union, European Regional Development Fund. The
operation is executed within the framework of Operative Programme for Strengthening Regional Development
st
Potentials for Period 2007-2013, 1 development priority: Competitiveness of the companies and research
excellence, priority aim 1.1.: Improvement of the competitive capabilities of companies and research
excellence.
2
ORGANISER
The Polymer Technology College (VŠTP) was founded in year 2006, based on the needs of the
polymer industry in Slovenia. It is the only institution in the country which educates engineers and
master engineers of polymer technology. Its graduates have excellent chances for employment,
because the area of polymer materials and technologies is one of the most rapidly growing industries
in Europe and world, and the knowledge from this area is crucial for its further development.
Development goals of VŠTP are related to continuous rise of the study process quality and to
development of research & development activities, with emphasis on applied research projects for
companies. It has rich laboratory equipment, which is constantly being supplemented, upgraded and
modernized. With this, it allows the students to do quality laboratory work and get acquainted with
research work, whereas the researchers are well equipped for research activities.
By status VŠTP is an independent and private college. Besides the programme of Polymer
Technology, it has also accredited two 1st cycle study programmes, namely Interactive Information
Systems and Sustainable Engineering. With its unique approach and small groups the Polymer
Technology College can pride itself with high successfulness of its students.
Moreover, it also participates in numerous national and international projects in which it successfully
cooperates with different partners.
3
MEDIA SPONSOR OF THE CONFERENCE
CRATIVE CORE VŠTP
Title
KREATIVNO JEDRO VŠTP, projekt št. 3330-13-500034
(CREATIVE CORE VŠTP, project No. 3330-13-500034)
Napredni polimerni materiali iz obnovljivih virov in tehnologije
(Advanced polymer materials from renewable resources and technologies)
Duration of the
project
2,5 years
Project management
/project office
Responsible person of the applicant: Dr. Silva Roncelli Vaupot
Project leader: Assist. Prof. Dr. Irena Pulko
Value of the project
999.999,60 EUR
The public tender is partially funded by the European Union through the
European Regional Development Fund (ERDF). The Slovenian participation
share of funds is 15 %.
Purpose of the
project
The main purposes of the project are: (i) to obtain a critical mass of
knowledge in the area of biopolymers, based on own research as well as on
collaboration with foreign institutions; (ii) to implement the knowledge into
the pedagogical process; and (iii) knowledge transfer to the industry.
Expected results
-
-
Research hours in the extent of 4 FTE
Five research & development projects:
- Blends and composites from renewable resources
- Integrated processing of polymer materials
- Recycling and innovative products from recycled plastics
- LCA and studies of environmental impacts
- Marketing and commercialization
Patent applications
Release of publications and relevant bibliographic citations according to
the criteria of the Slovenian Research Agency
Agreements with foreign research organizations
Additional training of researchers abroad
Hosting foreign guest lecturers
Publications of contributions at conferences
Organization of a conference with international participation
Organization of research days for younger population
Inventions or innovations
New R&D projects funded within the EU research program HORIZON 2020
Implementation of new knowledge into pedagogical process
Supervisor of the operation at the
Ministry of Education, Science and
Sport
Petra Žagar (by 7. 8. 2013)
Luka Živić
4
PROCEEDINGS OF THE CONFERENCE BIOPOLYMER MATERIALS AND ENGINEERING
Biopolymer Materials and Engineering
15 – 17 April 2015, Slovenj Gradec, Slovenia
www.bimate.si
[email protected]
Publisher:
Polymer Technology College, Ozare 19, SI-2380 Slovenj Gradec
www.vstp.si
Editor:
Irena Pulko
Majda Žigon
Design:
Andrej Knez
Mateja Poročnik
Type of publication:
Conference Proceedings
E-publication
Place and year of publishing:
Slovenj Gradec, 2015
Available at:
http://www.vstp.si/1/predstavitev/knjiznicavstp/zalozniska-dejavnost.aspx
and
www.bimate.si/Proceedings
5
CIP - Kataložni zapis o publikaciji
Narodna in univerzitetna knjižnica, Ljubljana
66.095.26(082)(0.034.2)
CONFERENCE Biopolymer Materials and Engineering (2015 ; Slovenj Gradec)
Biopolymer materials and engineering [Elektronski vir] : [proceedings of the Conference Biopolymer
Materials and Engineering, 15-17 April 2015, Slovenj Gradec, Slovenia] / [editor Irena Pulko, Majda Žigon].
- El. knjiga. - Slovenj Gradec : Polymer Technology College, 2015
ISBN 978-961-6792-09-7 (pdf)
1. Gl. stv. nasl. 2. Pulko, Irena, 1980279943680
© Polymer Technology College, 2015
TABLE OF CONTENTS
BIMATE ............................................................................................................................................... 2
ORGANISER ......................................................................................................................................... 3
MEDIA SPONSOR OF THE CONFERENCE ................................................................................................ 3
CRATIVE CORE VŠTP ............................................................................................................................ 4
PLENARY LECTURES ............................................................................................................................. 8
BECKER, MATTHEW L.: FUNCTIONAL DEGRADABLE NANOFIBERS FOR REGENERATIVE MEDICINE ................. 8
KERN, WOLFGANG: FUNCTIONALIZATION OF POLYMERS, FILLERS AND FIBERS – STRATEGIES TOWARDS
ADVANCED APPLICATIONS ................................................................................................................................ 9
INVITED LECTURES ............................................................................................................................. 10
BUDTOVA, TATIANA: BIO-AEROGELS.............................................................................................................. 10
KHOSRAVI, EZAT: FUNCTIONALIZATION AND GRAFTING OF CARBOHYDRATES VIA CLICK REACTION AND
SYNTHESIS OF TEMPERATURE RESPONSIVE POLYMERS .................................................................................. 11
KOLLER, MARTIN: PRODUCTION OF POLY(HYDROXYALKANOATE) (PHA) BIOPOLYESTERS FROM AGROINDUSTRIAL WASTE- AND SURPLUS STREAMS: CLOSING THE MATERIAL CYCLES........................................... 13
KRAJNC, PETER: CREATING DIFFERENT LEVELS OF POROSITY WITH EMULSION TEMPLATING AND LAYER BY
LAYER PHOTOPOLYMERISATION ..................................................................................................................... 16
LASKE, STEPHAN: THERMAL STABILIZATION OF PLA ...................................................................................... 17
SINNER, EVA-KATHRIN: SYNTHETIC PROTEINS IN SYNTHETIC MEMBRANE ASSEMBLIES ............................... 17
LECTURES .......................................................................................................................................... 18
BOLKA, SILVESTER: STUDY OF COLD CRYSTALLIZATION BEHAVIOR OF POLY(LACTIC ACID) ........................... 18
CORTÉS-ZÁRATE, JOSUÉ: INTERNATIONAL COLLABORATION FOR THE IDENTIFICATION AND
CHARACTERIZATION OF BIOPOLYMERS FROM MARINE OR AGRICULTURAL SOURCES (WASTE) WITH
POTENTIAL OPHTHALMOLOGICAL APPLICATIONS: THE BIOPMAT NETWORK ................................................ 23
EFIMOVA, ANNA A.: MULTI-LIPOSOMAL CONTAINERS BASED ON BIODEGRADABLE POLYLACTIDE PARTICLES
STABILIZED BY POLYETHYLENEGLYCOL CHAINS ............................................................................................... 24
GANTAR, GAŠPER: INJECTION MOLDING OF BIOPOLYMERS IN INDUSTRIAL ENVIRONMENT ........................ 25
HABERMANN, CHRISTOPH: GREEN METAL? A HOLISTIC COMPARISON OF COMPOSITES BASED ON THE
BIOCONCEPT CAR ............................................................................................................................................ 28
HARTMANN, TOBIAS: TPE-MODIFICATION OF WOOD PLASTIC COMPOUNDS FOR ADVANCED RHEOLOGICAL
AND IMPACT PROPERTIES ............................................................................................................................... 32
HOLOBAR, ANDREJ: OPTIMIZATION OF OPTICAL PROPERTIES OF RUTHENIUM OXYGEN SENSORS IN
POLYMER MATRIX AND OXYGEN PERMEATION MEASUREMENTS FOR PHARMACEUTICAL PACKAGING ...... 41
HUSKIĆ, MIROSLAV: GRAFTING OF CAPROLACTONE ON HYPERBRANCHED POLYESTER ............................... 43
HUŠ, SEBASTJAN: EFFECT OF BIO-DEGRADABLE COMPATIBILIZER ON MECHANICAL PROPERTIES OF PLABASED COMPOSITES ........................................................................................................................................ 46
MAHENDRAN, ARUNJUNAIRAJ: NANOSTRUCTURED FLY ASH AS REINFORCEMENT IN A PLASTOMER-BASED
COMPOSITE: A NEW STRATEGY TO REDUCE GREEN HOUSE EMISSION FROM THERMAL POWER STATION
SOLID WASTE ................................................................................................................................................... 48
OSTAFIŃSKA, ALEKSANDRA: MORPHOLOGY AND RHEOLOGY OF TPS/TIO2 AND PCL/TIO2 COMPOSITES ..... 51
PERZ, VERONIKA: CUTINASES FOR ALIPHATIC-AROMATIC POLYESTER BIODEGRADATION............................ 53
POVERENOV, ELENA: NANOTECHNOLOGIES IN BIOPOLYMER COMPOSITES TO PREPARE ACTIVE
BIODEGRADABLE FILMS FOR FOOD PACKAGES AND COATINGS ..................................................................... 55
SAMYN, PIETER: CRYSTALLIZATION BEHAVIOUR AND THERMAL PROPERTIES OF BIO-BASED PHB/NFC
NANOCOMPOSITE BLENDS .............................................................................................................................. 56
6
SIMNETT, ROSE E.: SYNTHESIS OF BIOCOMPATIBLE NVP-BASED MATERIALS WITH DESIGNED ARCHITECTURE
......................................................................................................................................................................... 58
ZABOROVA, OLGA: BIOCOMPATIBLE pH-SENSITIVE CARRIERS BASED ON ANIONIC LIPOSOME-POLYCATIONIC
PARTICLE COMPLEXES ..................................................................................................................................... 61
ZEPNIK, STEFAN: EXTRUSION FOAMED EXTERNALLY PLASTICIZED CELLULOSE ACETATE FOR
THERMOFORMED TRAYS ................................................................................................................................. 62
POSTERS ........................................................................................................................................... 65
BLACKWELL, CATHERINE: DEGRADATION OF THERMOSETTING MATERIALS VIA ACID HYDROLYSIS – A
TRANSITION TO THERMOPLASTICS.................................................................................................................. 65
BOZSÓDI, BRÚNÓ: THE EFFECT OF COUPLING ON THE STRUCTURE, INTERFACIAL INTERACTIONS AND
MECHANICAL PROPERTIES OF POLYPROPYLENE/LIGNIN BLENDS ................................................................... 65
BRZESKA, JOANNA: COMPOSITES OF CROSSLINKED POLYURETHANES WITH CHITOSAN .............................. 67
ČEPIN, MARJETA: ANTIBACTERIAL PROPERTIES OF AMINO-FUNCTIONALISED NANOSIZED ZINC OXIDE ....... 70
DERMOL, VALERIJ: ARE ENVIRONMENTALLY FRIENDLY BEHAVIOUR AND ATTITUDES TOWARDS THE
ENVIRONMENT DEPENDED ON DEMOGRAPHIC CHARACTERISTICS? .............................................................. 71
DZIOB, DANIEL AND KOŁODZIEJ, TOMASZ: ELASTIC POLYMER SUBSTRATES FOR CELL MIGRATION RESEARCH
......................................................................................................................................................................... 72
ĐORĐEVIĆ, NENAD: CHARACTERIZATION OF MODIFIED NANOCELLULOSE ................................................... 73
GLAVAN, GAŠPER: ABSORPTION OF WATER IN NATURAL AND SYNTHETIC TEXTILE FIBERS STUDIED BY
OPTICAL POLARIZATION MICROSCOPY ............................................................................................................ 73
GORDOBIL, OIHANA: CHEMICAL MODIFICATION OF ORGANOSOLV EUCALYPTUS LIGNIN WITH FATTY ACIDS
......................................................................................................................................................................... 76
HAAS, CORNELIA: HIGH CELL-DENSITY PHB PRODUCTION IN A MEMBRANE BIOREACTOR ........................... 79
HAERNVALL, KAROLINA: ENHANCED ENZYMATIC MODIFICATIONS OF POLYESTERS BY MODULATION OF
ENZYME ADSORPTION ..................................................................................................................................... 80
HAERNVALL, KAROLINA: FUNCTIONALIZATION OF POLY(L-LACTIC ACID) FILMS VIA A TWO-STEP ENZYMATIC
PROCESS .......................................................................................................................................................... 82
HUŠ, SEBASTJAN: PLA-BASED BIOCOMPOSITES WITH EXCELENT TRIBOLOGICAL PROPERTIES ...................... 83
JOVANOVSKI, VASKO: SYNTHESIS OF NANOCRYSTALLINE ZNO DECORATED WITH IONIC LIQUID MOIETIES
AND THEIR ANTIMICROBIAL ACTIVITY ............................................................................................................. 86
JÓZÓ, MURIEL: SYNTHESIS OF CARBON AEROGEL PRECURSOR POLYMERS IN DEEP EUTECTIC SOLVENT
MEDIA .............................................................................................................................................................. 87
KÁRPÁTI, ZOLTÁN: INTERFACIAL INTERACTIONS IN POLYLACTIC ACID/LIGNOCELLULOSIC COMPOSITES...... 88
KUN, DÁVID: POLYMER/LIGNIN BLENDS: STRUCTURE, INTERACTION, PROPERTIES ...................................... 90
OLEWNIK-KRUSZKOWSKA, EWA: THE INFLUENCE OF OZONE ON DEGRADATION PROCESS OF PLA – MMT
COMPOSITES .................................................................................................................................................... 92
PUTIĆ, SLAVIŠA: DETERMINATION OF ACID VALUE AND MICROMECHANICAL ANALYSIS OF MODIFIED
NANOCELLULOSE ............................................................................................................................................. 95
STAMENOVIĆ, MARINA: LIFE CYCLE OF BIODEGRADABLE POLYMERS AND THEIR IMPACT ON THE
ENVIRONMENT ................................................................................................................................................ 95
SZABÓ, GÁBOR: IONOMER/LIGNOSULFONATE BLENDS: INTERACTION, STRUCTURE, PROPERTIES ............... 96
VECCHIATO, SARA: BIOPOLYMER BASED DIAGNOSTICS FOR DETECTION OF WOUND INFECTION ................ 98
VECCHIATO, SARA: MODIFICATION OF LIGNOSULFONATES BY LACCASE ..................................................... 100
The scientific and grammatical contents of abstracts within this publication are the responsibility of
submitting authors.
7
PLENARY LECTURES
PL1
BECKER, MATTHEW L.: FUNCTIONAL DEGRADABLE NANOFIBERS FOR REGENERATIVE
MEDICINE
1
1
1
1
1
1
1
Jukuan Zheng , Gina M. Policastro , Fei Lin , Shan Li , Yaohua Gao , Erin P. Childers , Matthew L. Becker *
1
Department of Polymer Science, The University of Akron, 170 University Ave, Akron, OH 44325
*[email protected]
1. Summary
Polymeric nanofibers have been studied extensively for applications in wound healing and
regenerative medicine.1 Most polymers can be fabricated into nanofibers via melt or electrospinning with
highly tunable size and morphology by manipulating various experimental parameters.2 Nanofibers have
been found to influence cell function in a number of ways including morphology, confinement via contact
guidance, and mechanical properties.3, 4 While there have been several reports of methods for placing
bioactive groups on nanofibers,5-8 degradable polymers present some significant limitations with regard
to conjugation chemistry. To preserve the structural and morphological integrity of the nanofibers, any
conjugation method must be compatible with a solvent system orthogonal to the solubility parameters of
the polymer. One strategy to overcome this limitation has been to introduce the bioactive species prior to
electrospinning.9, 10 While some have successfully utilized this approach, it is inefficient in that a
significant fraction of the bioactive species are buried in the nanofiber, and as such, are not bioavailable
to the target cell population. The lack of control over surface functionality severely complicates any
manufacturing process and regulatory strategy when trying to advance these materials to clinical
applications. There have been several demonstrations of peptide-modified nanofibers in biomedicine
including bone,11 neural12-14 and vascular applications15, 16. We will discuss our recent innovations in
creating platform scaffolds that can be derivatized post-fabrication with multiple bioactive species using
highly controlled techniques.
Acknowledgements
We are grateful for funding from The National Institutes of Health, The National Science Foundation
and The Akron Functional Materials Center for enabling this work.
References
[1] Ma, Z.; Kotaki, M.; Inai, R.; Ramakrishna, S., Potential of Nanofiber Matrix as Tissue-Engineering
Scaffolds. Tissue Eng. 2005, 11, 101-109.
[2] Reneker, D. H.; Yarin, A. L., Electrospinning jets and polymer nanofibers. Polymer 2008, 49, (10),
2387-2425.
[3] Lim, S. H.; Liu, X. Y.; Song, H.; Yarema, K. J.; Mao, H.-Q., The effect of nanofiber-guided cell alignment
on the preferential differentiation of neural stem cells. Biomaterials 2010, 31, (34), 9031-9039.
[4] Subramony, S. D.; Dargis, B. R.; Castillo, M.; Azeloglu, E. U.; Tracey, M. S.; Su, A.; Lu, H. H., The
guidance of stem cell differentiation by substrate alignment and mechanical stimulation.
Biomaterials 2013, 34, (8), 1942-1953.
[5] Kim, T. G.; Park, T. G., Biomimicking Extracellular Matrix: Cell Adhesive RGD Peptide Modified
Electrospun Poly(D,L-lactic-co-glycolic acid) Nanofiber Mesh. Tissue Eng. 2006, 12, (2), 221-233.
8
[6] Yoo, H. S.; Kim, T. G.; Park, T. G., Surface-functionalized electrospun nanofibers for tissue engineering
and drug delivery Adv. Drug Delivery Rev. 2009, 61, 1033-1042.
[7] Mattanavee, W.; Suwantong, O.; Puthong, S.; Bunaprasert, T.; Hoven, V. P.; Supaphol, P.,
Immobilization of Biomolecules on the Surface of Electrospun Polycaprolactone Fibrous Scaffolds for
Tissue Engineering. ACS Appl. Mater. Interfaces 2009, 1, (5), 1076-1085.
[8] Tischer, T.; Rodriguez-Emmenegger, C.; Trouillet, V.; Welle, A.; Schueler, V.; Mueller, J. O.; Goldmann,
A. S.; Brynda, E.; Barner-Kowollik, C., Photo-Patterning of Non-Fouling Polymers and Biomolecules on
Paper. Adv. Mater. 2014, 26, (24), 4087-4092.
[9] Yu, J.; Lee, A.-R.; Lin, W.-H.; Lin, C.-W.; Wu, Y.-K.; Tsai, W.-B., Electrospun PLGA Fibers Incorporated
with Functionalized Biomolecules for Cardiac Tissue Engineering. Tissue. Eng. Pt. A. 2014, 20, (13-14),
1896-1907.
[10] Yang, Q.; Wu, J.; Li, J.-J.; Hu, M.-X.; Xu, Z.-K., Nanofibrous Sugar Sticks Electrospun from
Glycopolymers for Protein Separation via Molecular Recognition. Macromol. Rapid. Comm. 2006, 27,
(22), 1942-1948.
[11] Jang, J.-H.; Castano, O.; Kim, H.-W., Electrospun materials as potential platforms for bone tissue
engineering. Adv. Drug Delivery Rev. 2009, 61, (12), 1065-1083.
[12] Shaw, D.; Shoichet, M., Toward spinal cord injury repair strategies: peptide surface modification of
expanded poly(tetrafluoroethylene) fibers for guided neurite outgrowth in vitro. J. Craniofac. Surg.
2003, 14, (3), 308-316.
[13] Cho, Y. I.; Choi, J. S.; Jeong, S. Y.; Yoo, H. S., Nerve growth factor (NGF)-conjugated electrospun
nanostructures with topographical cues for neuronal differentiation of mesenchymal stem cells. Acta
Biomater. 2010, 6, (12), 4725-4733.
[14] Low, W. C.; Rujitanaroj, P.-O.; Lee, D.-K.; Messersmith, P. B.; Stanton, L. W.; Goh, E.; Chew, S. Y.,
Nanofibrous scaffold-mediated REST knockdown to enhance neuronal differentiation of stem cells.
Biomaterials 2013, 34, (14), 3581-3590.
[15] Ma, Z.; Kotaki, M.; Yong, T.; He, W.; Ramakrishna, S., Surface engineering of electrospun
polyethylene terephthalate (PET) nanofibers towards development of a new material for blood
vessel engineering. Biomaterials 2005, 26, (15), 2527-2536.
[16] Ma, Z.; He, W.; Yong, T.; Ramakrishna, S., Grafting of Gelatin on Electrospun Poly(caprolactone)
Nanofibers to Improve Endothelial Cell Spreading and Proliferation and to Control Cell Orientation.
Tissue. Eng. 2005, 11, (7-8), 1149-1158.
PL2
KERN, WOLFGANG: FUNCTIONALIZATION OF POLYMERS, FILLERS AND FIBERS –
STRATEGIES TOWARDS ADVANCED APPLICATIONS
Wolfgang Kern*
Chair in Chemistry of Polymeric Materials, Montanuniversität Leoben, A-8700 Leoben, Austria
Polymer Competence Center Leoben (PCCL), A-8700 Leoben, Austria
*[email protected]
1. Summary
Functionalized polymers and their surfaces are important in numerous fields, among them electronics,
coatings technology, analytical chemistry as well as biochemistry. In a similar way, the proper adaptation
of the surface properties of inorganic fillers and fibers is a prerequisite to obtain compatibility between
the polymer matrix and the dispersed phase (particles, fibers). In recent years, the formation of covalent
bonds at the interface between the polymer matrix and dispersed particles (or fibers) has become an
important technology to adjust the properties and the durability of composite materials.
9
The lecture will present several methods that can be used to activate and modify the properties of
surfaces. Regarding polymers, corona and plasma activation techniques, as well as methods based on UV
light will be presented. Such activation reactions can be combined with a designed follow-up chemistry at
the surface, e.g. by covalent immobilization of functional monomers, to confer hydrophilic or hydrophobic
properties onto the surface.
Physico-chemical methods that are frequently used in the characterization of modified surfaces will be
presented. Such methods comprise spectroscopic techniques (e.g. infrared spectroscopy and X-ray
photoelectron spectroscopy), electrokinetic methods (zeta potential) as well as contact angle testing and
tensiometry to assess the surface energy. Typical examples will be given which show the potential but
also the limitation of the individual methods.
Moreover, ways to functionalize the surface of inorganic components by reaction with functional
silanes, thiols and phosphonates will be presented, with a look on strategies to obtain optimal adhesion
between different phases. Examples for the functionalization of nano-scaled fillers will be given as well,
considering particular challenges related to the functionalization of nano-materials. Selected applications
of polymer nano-composites e.g. in the field of electrical insulation will be discussed.
Regarding novel and unconventional approaches, it will be demonstrated how photochemical
transformations can be performed in thin molecular surface layers, and how coupling of functional
molecules in the irradiated zones of the surface (e.g. a polymer or an inorganic material) can be achieved.
Both organic molecules (e.g. dyes and DNA sequences) as well as inorganic nano-particles can be
immobilized after UV induced “activation” of organic surfaces. Finally, an example for nanoparticles
equipped with a photoreactive shell will be presented. The radiation induced reaction of such particles
with polymer matrices and polymer surfaces will be highlighted, and potential technological applications
are discussed.
Acknowledgment
Part of the present research was performed within the K-Project “PolyComp” at the Polymer
Competence Center Leoben GmbH (PCCL, Austria) within the framework of the COMET-program of the
Federal Ministry for Transport, Innovation and Technology and the Federal Ministry of Economy, Family
and Youth Funding is provided by the Austrian Government and the State Government of Styria.
INVITED LECTURES
IL1
BUDTOVA, TATIANA: BIO-AEROGELS
1
1
1
1
2
2
Cyrielle Rudaz , Arnaud Demilecamps , Georg Pour , Margot Alves , Arnaud Rigacci , Christian Beauger ,
3
4
1
Hebert Sallée , Gudrun Reichenauer and Tatiana Budtova *
1
MINES ParisTech, Centre de Mise en Forme des Matériaux (CEMEF),
UMR CNRS 7635, CS 10207, 06904 Sophia Antipolis, France
2
MINES ParisTech, Centre procédés, énergies renouvelables et systèmes énergétiques (PERSEE),
CS 10207 06904 Sophia Antipolis Cedex, France
3
CSTB, 25 rue Joseph Fourier, 38400 Saint Martin d’Hères, France
4
Bavarian Center for Applied Energy Research, Am Galgenberg 87, 97074 Würzburg, Germany
*[email protected]
10
1. Summary
Aerogels are highly porous, ultra-light (density around 0.1 g/cm3) nanostructured materials. One of
their most extraordinary properties is thermal super-insulation, i.e. thermal conductivity below that of air:
0.015 vs 0.025 W/(m.K) in ambient conditions. However, classical silica aerogels are extremely fragile and
organic/synthetic (resorcinol-formaldehyde) aerogels may include toxic components, which hinders their
wide application.
Bio-aerogels are a new generation of aerogels made from biomass-based polymers, mainly
polysaccharides. We prepared aerogels from cellulose (“Aerocellulose” /1, 2, 3/) and pectin (“Aeropectin”
/4/) via polymer dissolution, coagulation and drying with super-critical CO2. Their density varies from 0.05
to 0.2 g/cm3 and specific surface area is around 200-300 m2/g. Bio-aerogels are mechanically strong
materials, with Young’s moduli from 1 to 30 MPa and plastic deformation without breakage up to 60-70%
strain.
The thermal conductivity of Aeropectin is around 0.015 – 0.020 W/(m.K) making it the first thermal
super-insulating fully biomass-based aerogel reported. The thermal conductivity of Aerocellulose is rather
“high”, around 0.030-0.035 W/(m.K), due to the presence of large macropores. We demonstrate that by
using cellulose functionalization and making polymer-silica interpenetrated aerogel networks the specific
surface area increases to 800-900 m2/g and thermal conductivity decreases below that of the air.
Bio-aerogels open up many new applications of polysaccharides: in engineering (as thermal
superinsulators), medical and pharmaceutical (as scaffolds, matrices for drug controlled release) and
electro-chemical when pyrolysed (batteries, fuel cells).
Acknowledgements
This work was funded within the 7th EU Framework Program, (FP7/2007-2013), under grant
agreement no. 260141, “AEROCOINS” project; by French National Research Agency (ANR), “NANOCEL”
project ANR-09-HABISOL-010 and by ADEME, France, “SILICA-CELL” project.
References
[1] R. Gavillon, T. Budtova, Biomacromolecules, 9, 269 (2008).
[2] R. Sescousse, R. Gavillon, T. Budtova, Carbohydrate Polymers, 83, 1766 (2011).
[3] A. Demilecamps, C. Beauger, C. Hildenbrand, A. Rigacci, T. Budtova, Carbohydrate Polymers, 122, 293
(2015).
[4] C. Rudaz, R. Courson, L. Bonnet, S. Calas-Etienne, H. Sallee, T. Budtova, Biomacromolecules, 15, 2188
(2014).
IL2
KHOSRAVI, EZAT: FUNCTIONALIZATION AND GRAFTING OF CARBOHYDRATES VIA CLICK
REACTION AND SYNTHESIS OF TEMPERATURE RESPONSIVE POLYMERS
Ezat Khosravi
Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom
[email protected]
1. Summary
The lecture describes a novel and versatile method for the modification of 2-hydroxyethyl cellulose
(HEC). The process of Click reactions involving azide-alkyne cycloaddition was used to impart neutral
(ester) and ionic (carboxylic acid and 1ry amine) functionalities on HEC, Figure 1.
11
Cu(II)SO4 / Na Ascorbate
DMSO
24 hr, 70o C
1
R = H or
R = H or
G=
2
3
4
Figure 1.
Sequential Click reactions were also used to successfully synthesize polydimethylsiloxane (PDMS)
grafted HEC containing neutral (ester) and ionic (carboxylic acid and 1ry amine) functionalities.
Furthermore, The Click Coupling technique was utilized for grafting onto HEC; PLA (as hydrophobic
segments) and PEG (as hydrophilic segments), Figure 2.
12
Figure 2.
AFM analysis revealed that the PLA grafted HEC exhibited a brushlike architecture indicating that the
HEC backbone is likely in an extended conformation with the PLA side chains stretching outward. The
extended wormlike structures were not observed for other functionalised HEC prepared via Click reaction,
Figure 3.
Figure 3.
The lecture will also discuss the synthesis and characterisation of a novel temperature responsive
water-soluble glycopolymer via copper wire-catalysed click-polymerisation, Figure 4. The investigation of
the cloud point of the aqueous solution of glycopolymer by optical microscopy and UV-Vis spectroscopy
will also be discussed. The LCST of the glycopolymer was found to be within physiological range of about
39 oC, known as fever temperature. The full characterisation of all the products as well as the
intermediates by NMR, MS, IR, SEC, TGA and DSC will be presented.
AcO
N3
AcO
N
O
AcO
N
O
H N
AcO
OAc OAc
O
AcO AcO
OAc
N3
THF/water
Cu-wire
60oC,
O
O
O
OAc OAc
O
N
24 hrs
N
nO
N
OAc
H
O
O
O
x
n
Figure 4.
References
[1] A.M. Eissa, E. Khosravi, European Polymer Journal, 2011, 47, 61-69.
[2] A.M. Eissa, E. Khosravi, A.L. Cimecioglu, Carbohydrate Polymers, 2012, 90, 859-896.
IL3
13
KOLLER, MARTIN: PRODUCTION OF POLY(HYDROXYALKANOATE) (PHA) BIOPOLYESTERS
FROM AGRO-INDUSTRIAL WASTE- AND SURPLUS STREAMS: CLOSING THE MATERIAL
CYCLES
1,2
1
2
Martin Koller *
Institute of Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28, 8010 Graz, Austria
ARENA (Association for resource efficient and sustainable technologies), Inffeldgasse 21/B, 8010 Graz, Austria
*[email protected]
1. Introduction
The paper demonstrates the value-added, bio-mediated conversion of (agro)industrial waste streams
towards microbial biopolyesters: Poly(hydroxyalkanoates) (PHA) (generic chemical structure see Fig. 1).
PHA can be used to manufacture biodegradable “green plastics”. Two case studies are presented: The
utilization of lipid-rich waste streams from slaughtering and rendering industry and of carbohydrate-rich
waste from dairy industry. The viability of these processes is demonstrated based on experimental results
and economic appraisals. In addition, the article details strategies for the recycling of waste streams of
the PHA production process itself.
2. Theory
In order to satisfy mankind’s enormously increasing consumption of safe and convenient packaging
materials and other plastic-based items, an annual quantity of 300 million tons of highly recalcitrant
plastics is produced globally [1]. Well-established plastic production techniques classically are based on
the conversion of limited fossil resources. Provoked by environmental concerns arising from the resulting
piles of plastic waste (landfill crisis, greenhouse gas emissions, global warming) and the ongoing depletion
of fossil feedstocks, we contemporarily witness a tremendously emerging biopolymer market. Critically
analysing various commercialized “green plastics” often reveals severe shortcomings regarding the
attributes “biobased”, “biodegradable”, “compostable”, and “biocompatible” that have to be fulfilled
according to strict standards, norms and certificates [2].
Poly(hydroxyalkanoates) (PHAs) are accumulated as intracellular carbon- and energy reserves by a
variety of prokaryotic species (Fig. 2). They entirely conform to the four above attributes, thus justifying
their classification as “green plastics”. The molecular composition, material properties and performance
of these biopolyesters is pre-defined at statu nascendi during biosynthesis. Dependent on the length of
their monomeric building blocks, PHAs are classified as short chain length PHA (scl-PHA) or medium chain
length PHA (mcl-PHA). In contrast to recalcitrant petrol-based plastics, PHAs are based on renewable
resources and undergo complete biodegradation during composting. Possible implementations
encompass compostable packaging, formulations for medical and pharmaceutical purposes,
biodegradable latexes, generation of novel nano-particles, electronic construction components, or
hydrolysis to generate chiral synthons for organo-chemical synthesis of fine chemicals. Low-quality PHA
can even be converted to biodiesel-like fuels or other green energy carriers [3,4].
Like all biopolymers, PHA must compete with their petro-chemical opponents both in terms of
material performance AND economically. Up to now, PHA production is based on expensive feedstocks of
nutritional value, thus contributing to the contemporary “plate-vs.-plastic” controversy. Replacing such
precious feedstocks by carbon-rich waste-streams of (agro)industrial processes alleviates industrial
disposal problems, preserves food resources, and enhances PHA production economically [3,4].
14
Figure 1. Generic structure of PHA [1]
Figure 2. STEM-picture of Cupriavidus necator cells
harbouring PHA granules as intracellular inclusions
3. Our Case Studies
Availability of suitable carbon-rich feedstocks defines the location of an envisaged industrial-scale PHA
production facility. Processes developed in our recently performed R&D projects (acronyms ANIMPOL and
WHEYPOL), both financed by the European Commission (5th and 7th FP), resort to waste streams which
accrue in Europe at enormous quantities:
3.1 ANIMPOL project: Surplus lipids from slaughterhouses (annual quantities in Europe: 500,000 tons)
can be converted to crude glycerol phase (CGP) and fatty acid esters (FAEs, biodiesel) (see Fig. 4).
Saturated FAEs (SFAE) counteract the applicability of biodiesel as fuel, but can be converted to PHAs at a
price below 2 €/kg, if integrating PHA production into existing biodiesel facilities (Fig. 3). Both SFAE and
CGP constitute precious carbon feedstocks to produce rather crystalline, thermoplastic scl-PHA [5]. By
using special microbial production strains from the pseudomonad’s group, SFAE can also be converted to
highly elastic, amorphous mcl-PHA that can be used in niche-fields of the plastic market [6,7].
Figure 3. ANIMPOL process: From slaughterhouse
waste to PHA
Figure 4. Mass balances of ANIMPOL
3.2 WHEYPOL project: In Europe, surplus whey from dairies accrues at annual quantities exceeding 13
Mt (Fig. 5), causing increasing environmental and economic alarm. Especially in the north Italian region,
where numerous huge dairy companies and cheese manufacturers are located, a quantity of around 1
million litres of whey has to be disposed of daily; this is often accomplished just by pouring this liquid of
high (bio)chemical oxygen demand into the sea! WHEYPOL profited from the fact that lactose, whey´s
main carbohydrate, acts as substrate in various bioprocesses. Inter alia, PHA production can be
accomplished based on whey lactose. Using whey lactose or its hydrolysis products (glucose and
galactose), thermoplastic scl-PHA can be produced. Here, cost-assessment indicates a tentative
production price below 3 €/kg [5,8].
15
Figure 5. WHEYPOL process: Available quantities of surplus whey and theoretical amounts of PHA
accessible thereof [8]
3.3 Recycling: In addition to the application of waste streams as raw materials, it is pivotal to close all
material cycles of the fermentative PHA production process itself and of the subsequent downstream
processing for recovery of PHA from the surrounding biomass [9]. This is especially valid in the case of
PHA production from waste materials using extremely halophile microbial production strains. Such
extremophiles require highly saline fermentation media that, after harvest of PHA rich biomass, leaves
over highly saline spent fermentation broth and salty cell debris. Recently accomplished recycling
experiments demonstrate that these two waste streams can successfully be returned to subsequent
fermentation batches as microbial salt- and nutrient source, thus considerably contributing to the
lowering of the overall PHA production costs, and elevating the environmental burdens [10]. The positive
effect of these recycling efforts is demonstrated by accomplished Life Cycle Assessment (LCA) studies;
using the Sustainable Process Index (SPI) as a tool to assess to compare PHA production from industrial
waste streams, the superiority of such novel processes compared to the life cycle of plastics of fossil origin
is clearly demonstrated [11-13].
4. Conclusions
The case studies demonstrate the achievability of economically competitive AND sustainable PHA
production by closing material cycles. Doubtless, the demand for real biopolymers with plastic-like
properties will strongly increase in the next future. If successfully implementing the presented strategies
on industrial scale, these seminal materials will not (as today!) have to be allocated from running
manufacturing plants in global regions, where PHA synthesis competes with nutrition, and frequently
lacks environmental considerations and acceptable human working conditions [3,4].
Acknowledgements
The author appreciates the support of the EC for the projects WHEYPOL (“Dairy industry waste as
source for sustainable polymeric material production”; 5th FP project GRD2-2000-30385) and ANIMPOL
(“Biotechnological Conversion of Carbon Containing Wastes for Eco-Efficient Production of High-Value
Products”; 7th FP project Grant no. 245084). The STEM picture of C. necator, used for Fig. 2, was provided
with courtesy by Dr. E. Ingolić, FELMI-ZFE; Graz.
References
[1] M. Koller, Appl. Food Biotechnol. 2014, 1, 3
[2] A. Kržan, S. Hemjinda, S. Miertus, A. Corti, E. Chiellini, Polym. Degrad. Stab. 2006, 91, 2819
[3] M. Koller, A. Atlić, M. Dias, A. Reiterer, G. Braunegg, in: Plastics from bacteria (pp. 85-119). Springer,
2010
[4] M. Koller, A. Salerno, M. Dias, A. Reiterer, G. Braunegg, Food Technol. Biotechnol. 2010, 48, 255
[5] M. Koller, A. Salerno, A. Muhr, A. Reiterer, G. Braunegg, Mater. Tehnol. 2013, 47, 5
[6] A. Muhr et al. (2013). React. Funct. Polym. 2013, 73, 1391
[7] A. Muhr, E. M. Rechberger, A. Salerno, A. Reiterer, A., K. Malli, K. Strohmeier, M. Koller, J. Biotechnol.
2013, 165, 45
[8] M. Koller, P. Hesse, R. Bona, C. Kutschera, A. Atlić, G. Braunegg, Macromol. Biosci. 2007, 7, 218
[9] M. Koller, H. Niebelschütz, G. Braunegg, Eng. Life Sci. 2013, 13, 549
[10] M. Koller, Int. J. Polym. Sci. 2015, 2015, article ID 370164
[11] M. Titz, K.-H. Kettl, K. Shahzad, M. Koller, H. Schnitzer, M. Narodoslawsky, Clean Technol. Env. Pol.
2012, 14, 495
[12] K. Shahzad, K.-H. Kettl, M. Titz, M. Koller, H. Schnitzer, M. Narodoslawsky, Clean Technol. Env. Pol.
2013, 15, 525
[13] M. Koller, D. Sandholzer, A. Salerno, G. Braunegg, M. Narodoslawsky, Res. Cons. Rec. 2013, 73, 64
IL4
KRAJNC, PETER: CREATING DIFFERENT LEVELS OF POROSITY WITH EMULSION
TEMPLATING AND LAYER BY LAYER PHOTOPOLYMERISATION
1
1
1,2
3
4
1
Peter Krajnc , Maja Sušec , Robert Liska , Jürgen Stampfl , Urška Sevšek , Irena Pulko5
University of Maribor, Faculty of Chemistry and Chemical Engineering, PolyOrgLab, Smetanova 17, 2000 Maribor, Slovenia
2
Centre of Excellence PoliMaT, Tehnološki park 24, 1000 Ljubljana, Slovenia
3
Vienna University of Technology, Institute of Applied Synthetic Chemistry, Getreidemarkt 9/163, 1060 Vienna, Austria
4
Vienna University of Technology, Institute of Materials Science and Technology, Favoritenstraße 9-11, 1060 Vienna, Austria
5
Polymer Technology College, Ozare 19, 2380 Slovenj Gradec, Slovenia
1. Summary
A combination of high internal phase emulsion templating and additive manufacturing technology via
layer by layer photopolymerisation will be presented. Emulsion templating enables the creation of macro
pores within a polymeric material in the range of a few micrometers while layer by layer
photopolymerisation procedure, coupled with a computer guided setup, can build threedimensional
objects on a milimeter scale. Combined, the two approaches enable creation of porous objects with an
16
internal porous structure on a micrometer level, as a result of the polymerisation of the continuous phase
of a high internal phase emulsion.
IL5
LASKE, STEPHAN: THERMAL STABILIZATION OF PLA
1,*
1
2
Stephan Laske , Wolfgang Ziegler , and Clemens Holzer
1
Department of Polymer Engineering and Science, Polymer Processing, Montanuniversität Leoben, Leoben, Austria
2
Department of Polymer Engineering and Science, Chemistry of Polymeric Materials, Montanuniversität Leoben,
Leoben, Austria
1. Summary
Polymers, which are based on renewable resources and biodegradable, play nowadays an important
role in the packaging sector. These so-called biopolymers are both CO2-efficient and resource saving. Their
most common representative is polylactic acid (PLA). However, some material properties limit the field of
applications, decelerate the development of plenty of products such as microwave-ready or hot beverage
packaging as well as endangers products by possible temperature peaks (e.g. shipping container internal
temperature exceeds 80°C) during transport or usage (e.g. car dashboard heated by sun).
The aim of this study was the development of a PLA compound with an operating temperature above
100 °C. Therefore different formulations (e.g. stereocomplex of PLLA and PDLA, cross-linking or
commercial additives) were identified and processed compounds tested regarding their thermal and
mechanical properties. The results showed clearly possible routes for improving the thermal properties of
PLA. Using such compounds respectively processing routes and additives helps to overcome one of the
most significant problems when using PLA and will lead to a wider field of application regarding operating
temperature and possible shipping hazards.
17
IL6
SINNER, EVA-KATHRIN: SYNTHETIC PROTEINS IN SYNTHETIC MEMBRANE ASSEMBLIES
Eva-Kathrin Sinner*
Universität für Bodenkultur, Wien, Austria
*[email protected]
http://www.nano.boku.ac.at/synthbio.html
1. Summary
Proteins embedded in the cell membrane are a crucial means by which cells sense and adapt to the
environment. For this reason, many pathological conditions arise when these protein species are downregulated or become defective, which makes membrane proteins important pharmaceutical targets.
Our goal is to develop synthetic membrane mimetics for robust and quantitative membrane proteinbased assay developments. By restoring functional membrane proteins into cells, we can probe
functionality of those functional membrane-protein assemblies. We could show already, that membrane
proteins can be embedded into biocompatible polymer assemblies for functionaly analysis.
To demonstrate this concept, we present the synthesis of a membrane protein species, such as the
dopamine receptor, using a cell-free cotranslational-insertion. This reaction will be augmented by the
addition of polymeric scaffolds mimicking the lipid bilayer structure of the cell membrane. Here, we
present the in principle studies of synthetic amphiphiles, serving as membrane surrogates for stable
incorporation of membrane proteins. We are optimistic, that this technology would ultimately allow the
development of cell- like assay systems for membrane protein research and ultimately - allow the
treatment of notoriously difficult membrane protein deficiencies/diseases by targeted cell-specific
implantation of polymer-embedded synthetic proteins into living cells serving as intracellular, molecular
implants.
Figure 1. Graphical Image of cell free protein synthesis into polymeric membrane mimicking architectures
LECTURES
L1
BOLKA, SILVESTER: STUDY OF COLD CRYSTALLIZATION BEHAVIOR OF POLY(LACTIC ACID)
S. Bolka
Polymer Technology College, Ozare 19, 2380 Slovenj Gradec, Slovenia
[email protected]
1. Introduction
The understanding of cold crystallization behavior is crucial for understanding the surface crack
formation in injection moulded parts. PLA is a typical representative of materials that exibit crystallization
after injection moulding. This study focuses on higher mold temperature at injection moulding as the
important parameter for preventing crack formation of PLA-based molded parts.
The effect of different ageing temperatures on the injection moulded parts was examined using fast
differential scanning calorimetry, Flash DSC. The samples were taken from the surface and from the
interior of the 4 mm thick injected moulded part. The aging temperature of 60 °C for the time period of 4
days raised the crystallinity of the surface, while the crystallinity of the interior remained the same. The
behavior was characterized also with the 600 s long cold crystallization period by Flash DSC between 80
and 140 °C. Above 120 °C, the rapid decrease of crystallinity at all aging temperatures was observed. The
aging temperature of 60 °C for 4 days showed almost constant degree of crystallinity between 80 and 120
°C for the surface samples, while the samples from interior showed rapid rise of the crystallinity from 90
to 100 °C and also the constant increase of crystallinity. Samples aged at room temperature and at 40 °C
showed similar behavior. The melting peaks of the aged samples at 60 °C for 4 days were lower in
18
comparison to the samples kept at room temperature up to 130 °C, at 130 °C and 140 °r. The same effect
was also observed at melting onset temperatures. To confirm the results obtained by Flash DSC, the rise
of crystallinity was monitored also by DMA, TGA and ATR FT-IR.
Keywords: poly(lactic acid), Flash DSC, cold crystallization
2. Experimental
Injection molding of the parts
The PLA (producer Nature Work, grad Ingeo 2003D, batch CE2928B121) parts (Figure 1) were injection
moulded on the Haitian HTF 86X, with the screw diameter of 36 mm. The temperatures from the hopper
to the nozzle were form 165 °C to 194 °C. The mould temperature was set to 20 °C. The cold crystallization
was monitored at three different temperatures: 25, 40 and 60 °C. After that period, the samples for Flash
DSC were cut form the surface of the part and from the interior of the thickest, 4 mm thick bottom area of
the cup (shown on Figure 1 with red arrow). For DMA, TGA and ATR FT-IR measurements the samples
were taken form the plain area (shown on Figure 1 with red rectangle).
Figure 1. Injection molded part
Methods
The Flash DSC measurements were performed using Mettler Toledo Flash DSC 1 attached to a Huber
intracooler TC45. The samples were purged with nitrogen at a flow rate of 20 ml min-1. The sample mass
was estimated by comparing the measured heat-capacity increment on a fully amorphous sample at the
glass transition temperature with the mass specific heat-capacity increment of 0.5 Jg-1K-1, measured on
the same sample with the Mettler Toledo DSC 1. [1]
The sample mass was between 6 and 70 ng. The samples were heated rapidly with the rate of 1000 °C
s-1 from 20 to aging temperature (80 – 140 °C), then kept at aging temperature for 6000s, rapidly cooled
with the rate of 1000 °C·s-1 to 20 °C and heated with 500 °C·s-1 to 195 °C to estimate the melting behavior
of PLA. [2] The second heating was taken for the sample mass estimation. The samples were taken from
the surface and from the interior of the 4 mm thick injected moulded part.
DMA measurements were performed using Perkin Elmer DMA 8000. Single cantilever tests at the
frequency 1 Hz, amplitude 1 micro m and heating rate of 2 °Cmin-1 were performed. Test specimens were
cut with the width app. 4 mm and the thickness of 1.3 mm.
TGA measurements were performed using Perkin Elmer TGA 4000. Test specimens with the mass
between 10 and 20 mg were heated with 10 °Cmin-1 from 40 °C to 500 °C in N2 atmosphere with the flow
rate of 20 ml min-1.
ATR FT-IR measurements were performed using Perkin Elmer Spectrometer Spectrum 65. Test
specimens were positioned onto ZnSe crystal and measured from 600 to 4000 cm-1 wave number.
19
3. Results and discussion
Results of sample crystallinity for those samples, aged at room temperature (RT), 40 °C and 60 °C, are
presented in Figures 2-5.
Figure 2. Crystallinity for the samples aged at room temperature
20
Figure 3. Crystallinity for the samples aged at 40 °C
Figure 4. Crystallinity for the samples aged at 60 °C
Figure 5. Flash DSC curves for the interior of
moulded part aged at 60 °C
The aging temperature of 60 °C for the time period of 4 days raised the crystallinity of sample surface,
while the crystallinity of ample interior remained the same. At aging temperatures higher than 120 °C, the
rapid decrease of crystallinity was observed. The aging temperature of 60 °C for 4 days showed almost
constant degree of crystallinity between 80 and 120 °C for the sample surface, while the sample interior
showed a rapid rise of crystallinity in the region from 90 to 100 °C and also the constant increase of
crystallinity. Samples aged at room temperature and at 40 °C showed similar behavior. Aging at room
temperature gave the same crystallinity for the sample surface and interior at 80 °C, while from 90 to 100
°C the increase in crystallinity is different for sample surface and interior. The crystallinity of sample
surface increased rapidly and, after reaching a certain degree of crystallinity, it stayed almost constant,
while it rise only slowly for sample interior up to 100 °C and then decreased constantly up to 130 °C.
These differences can be the reason for crack formation on the sample surface and could be minimized by
using different tempering temperatures.
Melting temperatures of the samples (Table 1) are in close correlation with the aging temperatures
used for measurements by Flash DSC. The aging temperature of 60 °C causes uniformly increasing melting
temperatures of the samples surfaces and interiors, which can be connected with more uniform
distribution of formed crystals in the PLA matrix.
Table 1. Melting temperatures of the PLA injection moulded samples
Aging 4 days [°C]
25
25
25
25
25
25
40
40
40
40
40
40
40
60
60
60
60
60
60
60
Aging 600s, Flash DSC [°C]
80
90
100
110
120
130
80
90
100
110
120
130
140
80
90
100
110
120
130
140
Surface
127,3
145,3
144,6
161,6
162,7
162,1
131,9
140,8
146,6
156,6
164,8
186,5
123,1
139,2
138,0
159,6
162,6
179,6
180,4
Interior
127,9
139,7
149,7
157,0
163,5
170,4
126,4
140,2
147,7
155,5
160,4
172,7
127,1
137,7
147,9
155,0
161,7
168,5
174,7
Higher crystallinity was observed also by DMA (Figure 6). The E modulus is higher for the higher aging
temperatures and also the glass transition temperature is higher for the higher aging temperatures.
21
Figure 6. DMA curves for the samples aged at 60 °C (dash line), 40 °C (dash-dot line) and room
temperature (dot line)
The increase in crystallinity at higher aging temperature was observed also at ATR FT-IR spectroscopy.
The bands of carbonyl groups at 1082 cm-1 on an ATR FT-IR spectrum for the higher aging temperatures
shifted to the higher wavenumber for about 2 cm-1.
The decomposition temperatures as determined by TGA were practically the same for the aged sample
at RT, 40 C and 60 C: at RT the decomposition temperature was 363.4 C, at 40 C it was 363.7 C and at
60 C it was 364.0 C.
4. Conclusion
The crystallinity of the PLA injection moulded samples at higher aging temperatures increased,
especially on the surface, meanwhile, the difference in melting temperatures between sample surface
and interior was lower. The difference in crystallinity on the surface and in the interior of the specimen
coud be the reason for higher tension and, consequently, generation of cracks first on the surface and
then throughout the whole specimen. The experiment showed that higher moulding temperatures could
help in preventing crack formation for products made of PLA.
Acknowledgements
Research made within operation »Creative Core VŠTP«. The operation is partially co-financed by
European Union, European Regional Development Fund. Operation is executed within framework of
operative Programme for Strengthening Regional Development Potentials for Period 2007-2013, 1st
development priority: Competitiveness of the companies and research excellence, priority aim 1.1.:
Improvement of the competitive capabilities of companies and research excellence.
References
[1] R. Androsch, E. Zhuravlev, C. Schick. Solid-state reorganization, melting and melt-recrystallization of
conformationally disordered crystals (α´-phase) of poly (L-lactc acid). Polymer. 2014. 55. 4932-4941.
[2] P. Badrinarayanan, R. K. Ko, C. Wang, B. A. Richard, M. R. Kessler. Investigation oft he effect of clay
nanoparticles on the thermal behavior of PLA using a heat flux rapid scanning rate calorimeter.
Polymer Testing. 2014. 35. 1-9
22
L2
CORTÉS-ZÁRATE, JOSUÉ: INTERNATIONAL COLL ABORATION FOR THE ID ENTIFICATION
AND CHARACTERIZATION OF BIOPOLYMERS FROM MARINE OR AGRICULTURAL SOURCES
(WASTE) WITH POTENTIAL OPHTHALMOLOGICAL APPLICATIONS: THE BIOPMAT
NETWORK
1,2
J. Cortés-Zárate*, A.M. Gómez
2
Basic Sciences Institute / University of Veracruz, 91000, Xalapa, Veracruz, Mexico
*[email protected]
1. Summary
Biopolymeric materials are renewable, biodegradable and biocompatible, reason why their future and
present applications are only limited by our imagination. Some applications are: adhesives, packages,
adsorbents, lubricants, soil conditioners, cosmetics, fabrics, structural materials, computer information
storage hardware, and implants.
Biopolymeric Materials Engineering (BIOPMAT), is a project that circumscribes within the world trends
denominated "Green Chemistry" and the one known as "Engineering for life". Also, using the agricultural
and marine waste to pruduce biopolymers yields two expected outcomes in a developing country
economy like Mexico: 1) the development of high value-added materials which are an alternative to
petroleum-based polymers, and 2) the solution to a highly complex environmental problem such as
agricultural and marine wastes. The project main objective is the identification and characterization of
biomaterials from marine or agricultural sources (waste, mainly) with potential innovating applications.
The project BIOPMAT has attracted an international group of scholars interested or already working in the
field of biopolymers, an area that we consider of great importance for the sustainable future of our
country. This is now the: BIOPMAT NETWORK. This paper will present a network model intended to
integrate and promote efficient interaction of the key elements of innovation in developing countries:
Universities, R&D Centers and Businesses, to build research capacities in Mexico in the field of
biopolymers assisted by international partners. The BIOPMAT NETWORK, is celebrating its third
international meeting, this year in early september, in the beatiful city and port of Veracruz, Mexico,
willing to identify ways of further collaboration. We thank the authorities of the University of Veracruz,
for the economical support provided since the beginning of this project.
References
[1] BIOPMAT. Proc. of 2nd International Conference on Biopolymers (Biopolymers: sources,
transformation, produc on and innova ng applica ons), edited by A. G mez. Editor (Editoriales FESI,
Xalapa, Ver, 2010).
[2] BIOPMAT. Proc. of 1st International Conference on Biopolymers (Biopolymers: sources,
transformation, production and innovating applications), edited by A. G mez. Editor (Editoriales FESI,
Xalapa, Ver, 2008).
[3] V. FERRARO, I. B. CRUZ, J. R. FERREIRA, F. X. MALCATA, M. E. PINTADO and CASTRO, P. M. L.
Valorisation of natural extracts from marine source focused on marine by-products: A review. Food
research International Rev, 43, 9, p. 2221- 2233 (2010).
23
L3
EFIMOVA, ANNA A.: MULTI-LIPOSOMAL CONTAINERS BASED ON BIODEGRADABLE
POLYLACTIDE PARTICLES STABILIZED BY POLYETHYLENEGLYCOL CHAINS
1
1
1
2
2
A. A. Efimova *, A. V. Sybachin , A. A. Yaroslavov , S. N. Chvalun , A. I. Kulebyakina , E. V. Kozlova
2
1
M.V.Lomonosov Moscow State University, Department of Chemistry,
Leninskie Gory 1-3, 119991 Moscow, Russian Federation
2
National research centre "Kurchatov Institute",
Acad. Kurchatov sq., 1, 123182, Moscow, Russian Federation
*[email protected]
1. Introduction
Liposomes are widely used for delivery of biologically active substances. Multi-liposome assembly, for
example via immobilization of several liposomes on a nano-sized colloid particle, can increase the efficacy
of liposome interaction with cells and therapeutic effect of a liposomal drug. However, liposomes binding
with a solid carrier is usually accompanied by their destruction and uncontrolled release of encapsulated
agents. Several examples of successful intact liposome immobilization, as described in literature, include
pre-modification of liposomes and of the surface. Thus, there is a need for a drug carrier devoid of the
disadvantages mentioned above.
In the present work we describe multi-liposomal containers (MLC) based on complexes of liposomes
with biodegradable polylactide (PLA) particles stabilized by polyethyleneglycol (PEG) chains. Liposomes
have been adsorbed electrostatically on the PLA particle surface. It is known that polylactide is destructed
in the presence of hydrolytic enzymes.
2. Results and discussion
Biodegradable PLA particles were used for constructing MLC. The average size of PLA particles was
found to be equal to 170 nm; electrophoretic mobility (EPM) to -0.6 (μm/s)/(V/cm). Liposomal containers
were prepared from a mixture of anionic and negatively charged lipids with a molar fraction of anionic
head-groups equal to 0.1. To make anionic liposomes capable of binding to the negative PLA particles,
they were modified by a cationic polymer, polylysine.
It was shown that resulting PLA-polylysine-liposome complex bears number of liposomes forming
multiliposomal container. The integrity of liposomes in the ternary complex was controlled by means of
conductometry. It was found that liposomes involved in the complex formation keeps their untegrity
within 3 hours.
In the PLA-polylysine-liposome ternary complex all components are biodegradable that allows its
decomposition in biological environment. In our study the decomposition was initiated by addition of a
proteolytic complex Morikrase to a suspension of the ternary complex. Morikraze are capable of cleaving
ester bonds in PLA and lipid molecules and amide bonds in polylysine. A process was controlled by
measuring a size of particles in the suspension. It was shown that the particle size decreased and became
undetectable 100 hours after Morikrase addition.
3. Conclusions
Biodegradable multi-liposomal containers composed of PLA core and electrostatically adsorbed
liposomes are obtained. The integrity of liposomes involved in the container formation remains
unchanged that allows their use for encapsulation of bioactive compounds. PLA-polylysine-liposome
containers eventually decompose being attacked by hydrolytic enzymes. This makes described above
multi-liposomal containers promising in the field of drug delivery.
24
Acknowledgements
This work was supported by Russian Science Foundation (project 14-13-00255). The authors are
grateful to Professor Galina N. Rudenskaya (Lomonosov Moscow State University, Russia) for the
Morikrase sample and stimulating discussions.
L4
GANTAR, GAŠPER: INJECTION MOLDING OF BIOPOLYMERS IN INDUSTRIAL
ENVIRONMENT
1,2
1
1,3
Gašper Gantar *, Andrej Glojek , Boštjan Šmuc
1,3
Polymer Technology College, Ozare 19, 2380, Slovenj Gradec, Slovenia
College of Industrial Engineering, Mariborska 2, 3000, Celje, Slovenia
3
TECOS, Kidričeva 25, 3000, Celje, Slovenia
*[email protected]
2
1. Introduction
Biopolymers attract a growing market interest. When it comes to processing them, injection moulders
face many difficulties.The paper deals with injection moulding process of an industrial case study. The first
aim of the research is to understandthe influence of processing parameters onthe quality of products. The
second aim is to develop numerical models for prediction of injection moulding processes of biopolymers
and to evaluate their reliability.
2. Experimental
A glass, which is currently produced of Polypropylene, was used as a case study (see Figure 1). In the
presented research the injection moulding process for producing the same product from PLA
Natureworks 3251D on the existing equipment was studied.
Figure 1. Case study and measured dimensions
In the first part of the paper the recommenced range of processing parameters (melt temperature,
mould temperature, ejection temperature etc.) was found in the literature [1-3]. Based on
recommendations from the literature Design of Experiments (DOE) was selected to study the influence of
five processing parameters on the properties of products (see Table 1). Additional runs (run 9-13 with low
melt temperature) were inserted into standard DOE with eight runs to closely evaluate the danger of wall
slip effect, which was observed in previous testing and reported in the literature. Temperature of the
cooling water was kept constant between 13-15°C in order to keep the temperature of the mould below
the recommended 40°C.
25
Table 1. Design of experiments
Run
Injection time Melt
ti (sec)
temperature
Tmelt (°C)
1
1,6
180
2
0,8
175
3
1,1
210
4
1,2
210
5
3,4
175
6
2,3
180
7
3,0
210
8
3,0
210
9
1,6
180
10
0,5
180
11
0,4
180
12
0,5
180
13
6,4
180
Packing
time
tp (sec)
6
12
4
12
4
10
4
12
6
4
4
6
6
Packing
pressure
pp (bar)
300
600
200
600
600
300
600
200
600
200
200
600
600
Cooling
time
tc (sec)
7
6
15
7
12
6
7
6
6
6
8
10
10
The experiments were performed on a toggle machine Battenfeld with the clamping force 2100kN. For
each run from DOE the production was kept running for several shots after the change of process
parameters to achieve a new steady state. Only the last 5 produced test pieces were used for
measurements. Test pieces were visually inspected and their weight and dimensions were measured. A
visual inspection showed that around the gate some material was left attached tothe bottom of the test
pieces due to inappropriate hot nozzle. The scale was used for measuring of weight, and ATOS measuring
equipment for measuring of dimension. The results of the measurements are presented on the left hand
side of Table 2.
In the second stage, a numerical model was developed in Autodesk Simulation Moldflow Insight 2015
software. A dual domain mesh and 3D mesh were used. For the modelling of material properties, an
integrated database was used.
Figure 2. Numerical model and prediction of shrinkage
26
Numerical simulations were calculated with the same processing parameters as the previously
performed experiments. Calculated injection pressure, final weight and shrinkage of the test pieces were
compared to experimentally measured results. The summary of the results is presented in Table 2.
Table 2. Comparison of measured results and results predicted by numerical simulations (for 3D mesh).
Run
Experimentally measured
Injection Part
Shrinkage
pressure weight
of height H
pp (bar)
(g)
(%)
Shrinkage
of
diameter
D (%)
1
850
72,90
0,37
0,22
2
1199
74,27
0,19
0,11
3
520
72,91
0,39
0,27
4
630
74,50
0,3
0,24
5
728
73,74
0,26
0,18
6
693
73,09
0,28
0,33
7
700
73,15
0,44
0,27
8
545
72,84
0,37
0,25
9
850
73,80
0,29
0,14
10
1244
72,51
0,44
0,27
11
1170
72,50
0,64
0,29
12
1255
73,42
0,20
0,22
13
722
74,00
0,41
0,22
Difference between measurements and simulations
Average:
Min:
Max:
Results of numerical simulations
Injection Part
Shrinkage
pressure weight
of height H
pp (bar)
(g)
(%)
689
823
583
557
711
663
457
460
689
909
980
942
827
68,51
69,73
67,04
70,27
69,47
68,75
68,54
68,81
67,90
66,85
66,78
69,35
70,30
1,00
0,73
1,23
0,55
0,75
0,99
0,96
0,98
1,29
1,46
1,50
0,79
0,48
Shrinkage
of
diameter D
(%)
0,76
0,38
0,83
0,26
0,49
0,82
0,59
0,86
1,25
1,19
1,18
0,35
0,64
17,9%
-34,7%
14,5 %
7,1%
-9,7%
-6,0%
2,3%
0,1%
7,6%
1,9%
0,1%
3,5%
3. Conclusions
Testing in the industrial environment was short because the machine was not available for long term
testing. The measurement of final dimensions of test pieces was challenging due to deformation of test
pieces after ejection from the machine but nevertheless the following conclusions can be given.
Conclusion regarding testing in the industrial environment
- With the appropriate settings of the processing parameters it is possible to set stabile and reliable
processing of the biopolymers made of PLA in the industrial environment on a standard injection
moulding machine with a standard screw;
- It is important to process biopolymers made of PLA on injection moulding machine with an
appropriate size of screw due to danger of material degradation;
- Hot nozzle for injection moulding of Polypropylene is not suitable for injection moulding of
biopolymers made of PLA since PLA is more sensitive to the drop of the melt temperature on the
gate;
- During opening of the mould the hot nozzle constrained the ejection of the test pieces from the
mould which caused the deformation of the test pieces;
- Biopolymers made of PLA poses a narrower processing window;
- With the appropriate setting of mould temperature it is possible to avoid the wall slip effect.
Conclusions regarding reliability of numerical model:
- Numerical simulations can predict the characteristics of products made of biopolymers made of
PLA and for optimisation of injection moulding process;
- Reliability of numerical models with 3D and dual domain are comparable (numerical model with
27
dual domain mesh was better in predicting the injection pressure);
- Prediction of injection pressure can vary up to 35% compared to experimentally measured values;
- Predicted weight of the product is always too low and can vary up to 10% compared to
experimentally measured values;
- Predicted shrinkage is too high in the majority of tested runs and can vary up to 7,6% compared to
experimentally measured values;
- The reliability of numerical simulations is higher if value and time of packing pressure are high.
Acknowledgements
This contribution was made within operation »Creative Core VŠTP«. The operation is partially cofinanced by European Union, European Regional Development Fund. Operation is executed within
framework of operative Program for Strengthening Regional Development Potentials for Period 20072013, 1st development priority: Competitiveness of the companies and research excellence, priority aim
1.1.: Improvement of the competitive capabilities of companies and research excellence.
References
[1] M. Knights, Injection Molding Biopolymers: How to Process Renewable Resins, Plastics Technology,
April 2009.
[2] S. Pilla, Processing and Characterization of Biobased Plastics, Ph.D. thesis, University of Wisconsin,
2010.
[3] Tehnološki list materialaTDS_NatureWorks LLC Ingeo™ PLA 3001D.
L5
HABERMANN, CHRISTOPH: GREEN METAL? A HOLISTIC COMPARISON OF COMPOSITES
BASED ON THE BIOCONCEPT CAR
1
1
Christoph Habermann , Hans-Josef Endres
2
M. Eng. Christoph Habermann, born in 1986, is junior researcher at IfBB- Institute for Bioplastics and Biocomposites,
Hanover University of Applied Sciences and Arts
2
Prof. Dr.-Ing. Hans-Josef Endres, born in 1966, is a professor of environmental engineering at Hanover University of
Applied Sciences and Arts and director of the IfBB, Heisterbergallee 12, 30453 Hanover, Germany
Phone: +49-(0)-511-9296-2269; [email protected]
1. Introduction
The advantages of glass and carbon fiber-reinforced plastics (GRP/CRP) have so far been valued and
utilized mainly for lightweight design layout. But other criteria such as cost, ecological compatibility or
disposability of a material are also becoming increasingly important. In terms of these aspects, the
potential of natural fiber-reinforced plastics becomes evident in the “Bioconcept Car” project.
2. Theory
There are different motives for increasing applications with CRP (carbon fiber reinforced plastics), but
the production of carbon fibers demands much energy and resources. Hence the development of
sustainable materials for making new products is a necessary step toward a ready-for-the-future mobility.
This is the main incentive for IfBB (Institute for Bioplastics and Biocomposites, University of Hanover,
Germany) to engage in a cooperation with the race driver Smudo (a well-known celebrity in Germany as a
singer of the German hip-hop group “Die Fantastischen Vier”) and the Four Motors Racing Team. Funded
by the Agency for Renewable Resources (FNR Fachagentur Nachwachsende Rohstoffe e.V.) on behalf of
28
the German Federal Ministry of Food, Agriculture and Consumer Protection, this joint endeavour is
focused on the development of bio-based materials and sustainable parts for the automotive industry.
Bioplastics and biocomposites in this context are defined as fully or partially bio-based materials or as
composites with bio-based reinforcement fibers and/or bio-based matrices.
With increasing use of bio-based components in its construction, the Bioconcept Car is well equipped
to stand the strain of competitive long-distance races such as the VLN Endurance Championship or the
ADAC 24 hour races on the famous Nürburgring circuit. So the Bioconcept-Car sets out a path for a change
toward sustainable materials not only in racing but also in normal traffic. There is growing evidence that
bio-based materials can well be applied in modern technical constructions which are exposed to heavy
strains like automotive parts.
3. Experimental
Different natural and non-natural fabrics with variable weight and variable weave were produced and
tested to achieve the necessary quality/character in terms of stability or processing properties (see table
1) and to ensure the desired results in combination with the resin. In order to attain the properties of the
natural fibers in the composites, they are laminated with a resin (“Epoxidharz L” with “Epoxidhärter GL2”
by “R&G Faserverbundwerkstoffe GmbH”).
Table 1. Fabrics overview, [based on manufacturer's data]
Textile
Weave
Grammage [g/m2]
Glassfiber-Fabric
Carbonfiber-Fabric 1
Viscosefiber-Fabric
Flaxfiber-Fabric 3
280
285
190
238
Plain weave
Twill weave
Satin weave
Twill weave
The used test samples (Type „1B“ l: 115,0 ± 0,2mm, b: 10,0 ± 0,2mm h: according to quantity layer) are
milled from the composites. They are produced by means of a vacuum bag process on a steel plate
(370x370 mm) which was coated with a priming wax and a form release agent. The different layers are
laminated by hand before they are cured at 70°C for 24h under vacuum. The mechanical parameters are
determined after DIN EN ISO 527_4 by means of a universal testing machine Zwick/Roell type
„Zmart.Pro“.
4. Results and discussion
A comparison of potential lightweight materials reveals the advantages and disadvantages of the
different fibers.The advantage of carbon fibers lies in their construction performance; however, this
comes at a price – both economically and environmentally. Glass fibers are certainly less costly but more
heavy-weight and have some ecological disadvantages similar to those of carbon fibers. Viscose fibers
have advantages because of their light weight and better ecological and acoustic properties, but they lack
the higher mechanical performance of carbon or glass fibers. Even flax fibers do not reach these levels but
come out well in terms of weight, splitting behavior, cost, ecology and acoustics. Considering their very
low needed energy for production (and CO2), it is in fact a viable and ecology option to increase their use
for those parts where they already meet the requirements regarding mechanical performance.
Viewing on figures 1 and 2 (calculated with formula 1), which show the energy und CO2 emissions
specific mechanical values, this will be clear. In order to get the same mechanical properties you need
much more CO2 emissions to produce carbon fiber for structural elements in comparison with materials
based on biogenic resources.
29
Formula 1. Specific properties
30
Figure 1. Carbon Dioxide Specific Tensile Strength
Figure 2. Carbon Dioxide Specific Tensile E-Modulus
5. Conclusions
To increase the proportion of renewable raw materials in the vehicle (see Figure 3), bio-based resin
instead of petro-based resin is used for the components of the Bioconcept car. The raw materials for a
bio-based epoxy resin can be different vegetable oils which are suited to achieve the necessary
properties, e.g. hardness, viscosity, a quick curing time, or the ability to combine well with natural fibers.
A new bio-based resin is currently being used in the tailgate of the Bioconcept Car.
Furthermore, other parts with more complex shapes - for example components under the hood and
the interior part of a car - are designed with injection-moulded bio-based plastics or biocomposites.
31
Figure 3. Renewable raw materials BCC [7]
Using natural fibers as reinforcements for thermoset resins is a sustainable option for lightweight car
bodies and is even successful under extreme stress situations during racing. Even though alternative parts
are currently being developed specifically for motor sports, these parts are well suited to be included in
the series production of standard cars as well.
References
[1] Baillie C.: Green Composites - Polymer composites an the enviroment, Woodhead Publishing, p. 245,
Cambrige 2004.
[2] KOHLER & WEDLER 1996 and Kennwerte von Faserwerkstoffen nach BOBETH, Link in:
http://www.inaro.de/Deutsch/ ROHSTOFF/indus- trie/FASER/mechkenn.htm, access date: 26. April
2013.
[3] N-Fibre-Database: http://www.n-nibrebase.net/nfibrebase_faser/matdb/matdb.php?sLg=de, access
date: 26. April 2013.
[4] Mohanty, A. K.; Misra, M.; Drzal, L. T.: Natural fibers, biopolymers, and biocomposites, Taylor &
Francis Group, p. 39, Boca Raton 2005.
[5] Belgacem, M. N.; Gandini, A.: Monomers, Polymers and Composites from Renewable Resources,
Elsevier, Amsterdam 2008, p. 405.
[6] Manufacturer's data R&G Faserverbundwerkstoffe GmbH.
[7] Based on: Four Motors GmbH.
[8] Manufacture’s data AALCO METALL AMARI Metall GmbH, EN AW-6262A (AlMg1SiSn)PE International
GaBi6 2013 und Ecoinvent V2.2.
L6
HARTMANN, TOBIAS: TPE-MODIFICATION OF WOOD PLASTIC COMPOUNDS FOR
ADVANCED RHEOLOGICAL AND IMPACT PROPERTIES
1
1
1
1
T. Hartmann *, S. Bürgermeister , R. Rinberg , Lothar Kroll
1
Department of Lightweight Structures and Polymer Technology, Technische Universität Chemnitz,
09126, Chemnitz, Germany
*[email protected]
1. Introduction
The market for Wood Plastic Composites (WPC) shows a steady growth within the last decades, due to
their advantages for certain applications in comparison to classical polymer and wood materials. On the
one hand, WPCs surpass synthetic plastics, in case of their natural image, lower price and technical
properties (higher stiffness, lower thermal expansion coefficient). On the other hand, they outperform
classical wood materials regarding their unrestricted formability, moisture resistance and higher durability
and longevity.[1,2] Because of these specific features, WPCs are used in Germany especially for decking
boards in outdoor areas and for car interiors in the automotive industry.[3] WPC products are processed
by extrusion as well as by compression and injection molding. Depending on the processing technology,
the wood fiber content could vary up to 80 wt% for extrusion of profiles. For injection molding, a natural
fiber content between 30 and 50 wt% is typical and increases up to over 90 wt% for compression
molding.[4,5] Currently in the automotive industry, injection molding applications of WPCs are far behind
those of compression molding. This fact is surprising taking several benefits of injection molding process
into account such as high volume production, approachability of complex structures and structural
lightweight (in comparison to frequently used talcum filling). WPCs possess a decisive disadvantage with
respect to their impact properties which prohibits a wide range use of injection molded WPCs in
automobile applications.[6]
According to K. Oksman and C. Clemons [7] there are several ways to improve impact properties of
fiber-reinforced composites: 1) increase the matrix toughness; 2) optimize interface filler/matrix with
compatibilizers; 3) optimize filler-related properties (content, particle-size and dispersion); 4) length-todiameter ratio and orientation. The investigation of PP/WF from K. Oksman and C. Clemens is mainly
focused on the optimization of fiber-matrix-compatibilization while increasing the polymer matrix PP as a
targeted side effect. Several combinations of PP-g-MA, ethylene/propylene/diene terpolymers (EPDM) as
well as maleated EPDM (EPDM-MA) and maleated SEBS (SEBS-MA) were tested (all 40 wt% WF). The top
performance is reported for a composite composition containing both PP-g-MA and SEBS-MA. The trend
of these results regarding enhanced impact strength are confirmed by Kim and Pal[8] for use of PP-g-MA,
SEBS-MA as well as neat SEBS which was also tested. Moreover in this context the rheological properties
were investigated. The reported plots show, that shear viscosity is largest for SEBS-MA, followed by SEBS
and PP-g-MA. In other words the considered impact modifications worsened the flow behavior of WPC
melts. Beside the referred disadvantage above with respect to impact properties, the poor processability
of WPCs is an frequently mentioned topic. According to L. Haijun and L. Shiang [9] the viscosity of the melt
is one of the most important characteristics to be considered when designing any industrial process for
WPCs besides mechanical properties of finished component.
The approach of processability enhancement in this investigation is deduced from the general
32
methodology of TPE processing. In case of SEBS, due to its poor processing properties, the copolymers are
never used in their pure form and must be compounded with oils, fillers and other polymers. Through the
addition of small amounts of PP and high amounts of processing oil is common practice. The resulting
SEBS/oil/PP blends have an improved processability and stiffness and are commercialized since the early
1990s.[10-12] Transferring this methodology on WPC processing, the reported compatibility of SEBS, oil
and PP offers new possibilities by changing the ratios of components to PP with modifier SEBS/oil. Against
this background an investigation of PP/WF with SEBS/oil modification appears promising with respect to
advanced impact and rheological properties. The addition of SEBS/oil modificator was realized as dryblend (DB) and as basis for modification a system of PP/WF (40 wt% WF) with PP-g-MA as compatibilizing
agent with 3 wt% was selected. The amount of compatibilizer was determined by earlier investigations,
with a maximum for tensile strength and simultaneously no deterioration of impact properties which was
caused by amounts above 3 wt%. [13]
2. Experimental
Materials
Matrix polymer was Slovnaft's PP homopolymer Tatrene HG1007 (bulk density 0.55 kg/dm³. melt flow
index MFI 10 g/10min at 230 °C and 2.16 kg, ISO 1133). WF (Jeluxyl WEHO 500S) was provided by JELUWERK Josef Ehrler GmbH & Co. KG. Rosenberg (bulk density 0.27 kg/dm³, L/D ratio 3.36). According to the
manufacturer, WF was not pre-treated or modified with chemicals. Used PP-g-MA compatibilizer was
SCONA TPPP 8112GA from BYK Additives&Instruments. Wesel; it had a MA-content of 1.4 wt% (bulk
density 0.45-0.55 kg/dm³). Tested modificator mixes consisted of two components. Component 1 was a
linear high molecular weight styrene-ethylene/butylene-styrene block copolymer (SEBS with
butadien/styrenic-ratio BD/SM of 67/33) and a low molecular weight oily component 2. Total
Compositions of various PP/WF composites are shown in Table 1.
Table 1. Composition of the various PP/WF composites
Composite composition [wt%]
Sample
PP
PP-g-MA
WF
Code
0
57
3
40
1a
47
3
40
1b
37
3
40
2a
47
3
40
2b
37
3
40
3a
47
3
40
3b
37
3
40
4a
47
3
40
4b
37
3
40
DB-1
DB-2
DB-3
DB-4
untreated
10
20
10
20
10
20
10
20
Processing
At first Component 1 (SEBS) and 2 (low molecular weight oil) were dry blended before the
compounding process in compositions of component-ratios 1 to 2 of 90/10, 75/25, 65/35 and 45/55. Used
DB compositions are shown in Table 2. Then all WPC samples were compounded by a co-rotating twin
screw extruder (Noris Plastics ZSC 25/40D. screw diameter 32 mm, barrel temperature 180°C, screw
speed 200 rpm, material output of 10 kg/h) equipped with atmospheric and vacuum degassing. A self developed screw configuration for fiber-reinforced composites was used (screw-development during
33
project FENAFA1. The degassing extruder section removes effectively the residual moisture, therefore no
pre-drying step was implemented before compounding. Such approach meets best industrial conditions
where no pre-drying step is performed for wood flour, due to time and energy efficiency. The extruded
strands were cooled in a water slide system and pelletized. Pelletized WPC samples were then dried 4
hours at 80°C in a dry-air-dryer (Werner Koch Maschinentechnik GmbH). Injection mold processing was
performed on an ARBURG Allrounder 370A/600-170 (processing temperature profile 185-205°C and mold
temperature 40°C) into standard test specimens DIN EN ISO 3167 type A.
Mechanical testing
Tensile testing of specimens was performed according to DIN EN ISO 527 on a Zwick/Roell Z010 TN
ProLine material test machine. Crosshead speed was 2 mm/min for E-modulus and 10 mm/min for tensile
strength and elongation at break. 10 test specimens of each composition were tested.
Impact testing was performed using a CEAST Resil Impactor according to DIN EN ISO 179 Charpy
impact method. The unnotched impact energies were determined for 10 test specimens of each
composition at room temperatures and at -20°C.
Rheological testing
The melt flow rate MFR was determined on testing machine MeltFlow@on plus from KARG. Conditions
for the compound were according to DIN EN ISO 1133-1 at a temperature of 190°C and a mass of 21.6kg
by multiple determinations (at least three repeat measurements).
The flow spiral tests were performed on an ARBURG Allrounder 370A/600-170 at a processing
temperature of 190°C with an flow spiral AIM Test Mould System from Axxicon, Specimen dimensions:
1150 x 5 x 3 mm) at a mold temperature of 40°C. The spiral length was determined for at least 5 test
specimens on molding pressures of 300, 900, 1200 and 1800 bar.
3. Results and discussion
Characterization DB
The dry-blends were characterized by size exclusion chromatography (SEC). Results of SEC
measurements are shown in Table 2. The results are put in context to theoretically approach of
composition. For all further calculations and figures the actual composition determined by SEC were used.
Table 2. Compositions of dry-blends*
SEBS
theoretical
Oily component
Sample Code
DB-1
[%]
90
practical*
Area
Mw
[%]
[103 g/mol]
89
DB-2
75
71
DB-3
65
66
DB-4
45
47
260
theoretical
[%]
10
practical*
Area
Mw
[%]
[103 g/mol]
11
25
29
35
34
55
53
0.4
*)
SEC determination (eluent: THF, flow rate: 1.00 ml/min, column Set: 3x PL gel mixed B 900mm x 7.5mm, detector: DRI
(differential refractometer), temp.: 40°C)
1
„Ganzheitliche Bereitstellungs-, Verarbeitungs- und Fertigungsstrategien von Naturfaserrohstoffen“ funded by Fachagentur für
nachwachsende Rohstoff e.V. (FNR)
34
Mechanical Properties
The mean values and standard deviation of the mechanical properties of PP/WF samples with
different content of DB are summarized in Table 3. These results are presented in separate figures to ease
an interpretation and point out effects of single component variations.
Table 3. Mechanical properties of PP/WF samples (± values are standard deviations)
Tensile Properties
Charpy Impact Properties
Elongation
Unnotched - Unnotched Strength
E-Modulus
at break
at RT*
at -20°C
Sample Code
[MPa]
[GPa]
[%]
[kJ/m²]
[kJ/m²]
0
39.2 ± 0.3
4.3 ± 0.06
2.5 ± 0.2
13.0 ± 1.2
10.1 ± 1.1
1a
32.0 ± 0.3
3.3 ± 0.04
4.8 ± 0.3
18.3 ± 1.0
14.4 ± 1.0
1b
24.6 ± 0.1
2.3 ± 0.02
11.3 ± 0.6
28.9 ± 1.7
23.4 ± 2.1
2a
32.4 ± 0.2
2.9 ± 0.01
5.6 ± 0.3
23.0 ± 1.7
17.8 ± 1.4
2b
26.2 ± 0.1
2.4 ± 0.02
7.6 ± 0.4
26.4 ± 2.2
21.2 ± 2.1
3a
32.4 ± 0.1
2.9 ± 0.03
5.3 ± 0.3
22.6 ± 2.3
17.7 ± 1.3
3b
21.3 ± 0.1
1.8 ± 0.02
9.5 ± 0.9
29.8 ± 3.0
26.1 ± 2.3
4a
30.7 ± 0.1
2.6 ± 0.03
5.5 ± 0.2
22.9 ± 2.1
18.5 ± 1.8
4b
20.4 ± 0.2
1.6 ± 0.02
9.1 ± 1.4
26.2 ± 1.4
23.4 ± 2.4
*)
room temperature
Figure 1 provides an overview of percentage changes of mechanical properties relating to the
unmodified test sample 0 for test series a) (with 10 wt% DB) as Figure 2 for test series b) (with 20 wt% DB).
Whereas the numbers of test samples represent the different DBs used (cf. Table 2). The values of
standard deviation were included and interpreted in that way, that bars show the absolute minimum of
percentage changes in case of positive and the absolute maximum in case of negative percentage changes
for all values according to Table 3. All samples in Figure 1 and Figure 2 show in general a decline of tensile
strength and E-Modulus and an increase of stiffness and impact strength. The addition of 10 wt% DB
affects the percentage changes of mechanical properties less than the addition of 20 wt% DB.
A maximum of overall mechanical properties with 10 wt% DB (cf. Figure 1) was determined for sample
2a with an increase of Charpy impact strength at room temperature by 50% and of elongation at break by
98% along with a decrease of tensile strength by 18% and E-Modulus of 34%. A minimum of properties
was determined for sample 1a (with the highest content of SEBS within this series), while Charpy impact
strength was improved by 22% and tensile strength was decreased by 20%. Taking all results within test
series a) in evaluation there are some remarkable developments. The reduction of tensile strength
remains almost constant at very low level until sample 3a, regardless of variation of SEBS/oil ratio
(reduction from 8.1 to 1.9 in total composition) only when reducing the SEBS/oil ratio to 0.89 tensile
strength went down from 18 to 23%. But in the same range from 1a to 3a there is a distinguishable
change in elongation at break (from 65 to 98%) and Charpy impact (from 22 to 50%) behavior. For further
reduction of SEBS/oil content these properties remain at this high level while tensile strength decreases.
In Figure 2 the maximum of overall properties was sample 1b with an increase of 296% for elongation
at break and 92% for Charpy impact strength while E-modulus is reduced by 49% and tensile strength by
38%. In contrast to test series a), the test sample 1b has the highest content of SEBS (17.8 wt% in total
composition) is the best performing sample related to overall properties (cf. test series a), test sample
with highest SEBS content shows poorest mechanical properties). Regarding the effect of SEBS/oil ratio on
mechanical properties in test series b) the reduction of tensile strength can be observed between samples
2b and 3b (SEBS/oil ratios of 2.4 to 1.9) within a quite close range. In test series b) remarked trends for EModulus, impact strength and elongation at break are less distinctive but still identifiable.
35
85%
100%
95%
98%
120%
65%
80%
43%
46%
46%
49%
E-modulus
50%
46%
60%
Tensile strenght
22%
19%
40%
20%
Elongation at break
0%
Charpy Impact
Strength (-20 C)
-41%
-34%
-23%
-18%
-18%
-34%
-40%
-25%
-20%
-20%
Charpy Impact
Strength
-60%
1a
2a
3a
4a
296%
Figure 1. Percentage changes of mechanical properties for addition of 10 wt% DB related to unmodified
sample
330%
165%
230%
185%
216%
280%
80%
75%
87%
71%
71%
92%
90%
130%
Tensile strenght
89%
112%
180%
Elongation at break
Charpy Impact
Strength
30%
-20%
Charpy Impact
Strength (-20 C)
-65%
-49%
-61%
-46%
-47%
-34%
-49%
-38%
-70%
E-modulus
-120%
1b
2b
3b
4b
Figure 2. Percentage changes of mechanical properties for addition of 20 wt% DB related to
unmodified sample
A competitive evaluation of maxima from test series a) (sample 2a; 7.1 wt% SEBS; 2.9 wt% oil) and test
series b) (sample 1b; 17.8 wt% SEBS; 2.2 wt% oil) is delivering following noticeable facts. A factor of 2.4
regarding the wt% of SEBS in total composition increases elongation at break by a factor of 3.0 (from 98%
to 296%), Charpy impact strength by a factor of 1.8 (from 50% to 92%), while decreasing tensile strength
by a factor of 2.1 (from -18% to -38%) and E-modulus by a factor of 1.4 (from -34% to -49%).
To check the apparent effects of variation of SEBS and oil content in total composition and to discuss
the results basing on a different perspective than the SEBS/oil ratio. The mechanical properties are
36
interpreted regarding changing SEBS content (by constant oil-content) and changing oil-content (by
constant SEBS content) as follows. Figure 3 shows the total composite composition of test samples 2b and
4a. The oil contents remain almost constant for test sample 2b with 5.8 wt% and 4a with 5.3 wt%,
whereas the SEBS content in total composition varies from 4.7 wt% for test sample 4a to 14.2 wt% for test
sample 2b. The trends were determined for mechanical properties E-modulus, elongation at break, tensile
and Charpy impact strength related to the mean values, but standard deviations are included as well.
Tensile strength shows a falling tendency for higher amounts of SEBS. E-modulus is almost unaffected and
the elongation at break behavior shows a rising tendency. The trends of Charpy impact strength are
difficult to determine because the standard deviation areas are overlapping. For the mean values impact
behavior shows a rising tendency. At the background of literature this fact is partially unexpected.
According to Kim and Pal[8] higher SEBS contents are related with negative effects on tensile strength and
E-modulus and positive effects on impact strength. The determined results within this study confirm the
decrease of tensile strength related to higher SEBS contents but the expected increase in Charpy impact
strength just in terms.
E-modulus [GPa]
100
35
Charpy impact strenght [kJ/m2]
Tensile strength [MPa]
Charpy impact strenght (-20 C) [kJ/m2]
Elogation at break90[%]
30
90,00
70
80,00
composition [wt%]
35
25
30
60
70,00
20
oily comp.
15
40
50,00
40,00
20
PP + PP-g-MA
15
30
30,00
10
10
20
5
20,00
10
5
10,00
30
90,00
WF
25
50
60,00
100,00
SEBS
25
80,00
composition [wt%]
80
composition [wt%]
100,00
70,00
20
60,00
50,00
15
40,00
10
30,00
20,00
5
10,00
0
0,00
4a
0
0
2b
Sample Code
2b
Sample Code
0,00
0
4a
2b
Sample Code
Figure 3. Change of tensile and impact properties related to SEBS content exemplified by comparison
of sample 2b (SEBS 14.2 wt%; oil 5.8 wt%) and sample 4a (SEBS 4,7 wt%; oil 5.3 wt%)
Figure 4 shows the total composite composition of test samples 1a and 4b. The SEBS content remains
almost constant for test sample 1a with 8.9 wt% and 4b with 9.4 wt%, whereas the oil contents in total
composition varies from 1.1 wt% for test sample 1a to 10.6 wt% for test sample 4b. The trends were
determined for mechanical properties E-modulus, elongation at break, tensile and Charpy impact strength
related to the mean values, but are standard deviations are included as well. Tensile strength and Emodulus show a falling tendency for higher amounts of oil. The elongation at break and Charpy impact
behavior shows a rising tendency (also including the standard deviation range). Taking the increase of
impact strength by constant matter of SEBS while rising oil content into account one possible
interpretation is provided by G. Holden.[12] The high compatibility of the system PP/SEBS/oil could lead to
a better distribution of the SEBS phase within the PP matrix which rises the elastomeric impact on overall
mechanical properties according to the enlargement of surface area.[10] Clarification of the observed
effect could be provided in further morphological characterizations.
37
E-modulus [GPa]
Tensile strength [MPa]
Elogation at break [%]
100
100
90
90
Charpy impact strenght (-20 C) [kJ/m2]
35
35
30
30
25
25
100
60
50
40
30
70
60
SEBS
20
50
40
30
15
20
10
10
0
20
WF
15
PP + PP-g-MA
10
10
20
oily comp.
5
1a
Sample Code
70
20
60
50
15
40
10
30
20
5
5
0
1a
0
4bSample Code
0
25
80
composition [wt%]
70
30
90
80
composition [wt%]
composition [wt%]
80
Charpy impact strenght [kJ/m2]
10
0
0
1a
4b
Sample Code
Figure 4. Change of tensile and impact properties related to oily content exemplified by comparison of
sample 1a (oil 1.1 wt%; SEBS 8.9 wt%) and sample 4b (oil 10.6 wt%; SEBS 9.4 wt%;)
Rheological Properties
Conclusions on the rheological behavior during the compounding process of the PP/WF were provided
by temperature and pressure sensors within the compounder. Processing parameters of rotary current,
the processing melt temperature and pressure (both directly at the nozzle) were monitored.
For discussing values of MFR measurements of WPCs there exist different stances. Experts like
Geißle[14] reported about the deficits of MFR measurement with respect to test equipment, measurement
process and underlying flow function, which finally lead to higher calculated shear viscosities from MFR
then the apparent viscosity. Hansmann and Laufer[15] confirmed this result, but mentioned that the
deviation is very small and reported that MFR measurements especially for WPC melts show a very good
correlation with measurements by an extrusion slit capillary rheometer.
Without a doubt MFR is the most important parameter for describing the flow behavior of a plastic
melt for the plastics processing industry and quality assurance. Therefore within this investigation the
MFR value is discussed as an one-point measurement of shear viscosity by an indirect proportional
correlation. All samples were tested at the same testing machine under equal conditions by one single
person and the results will be discussed only relatively to each other and only in combination with
additional data like melt pressure of compounding process and the results of flow spiral tests.
Table 4 shows the processing parameters recorded under stable processing conditions at constant
screw speed (200 rpm). The observed values show an overall down trend regarding rotary current, melt
pressure and temperature for both test series (with 10 wt% DB in part A and 20 wt% DB in part B)
according to higher oil-contents from samples 0 to 4. The observed decrease of melt temperature
indicates a reduction of frictional heat within the compounding process.
Being more specific, related to the value of test sample 0, the samples 1a and 2b show global maxima
for the melt pressure. This can be considered as an effect of high SEBS and low oil-contents of these
samples. That effect was expected and is reported in literature [8] as well. In addition the determined
results of MFR measurements of the test series b) (with 20% DB) are shown in Table 4 part B. The
observed trends for test series b) are accompanied by the results of MFR measurements which show an
indirect proportional trend and confirm conclusions of the discussion of processing parameters which is
emphasized in Figure 5.
38
Table 4. Processing parameters during compounding and MFR results of test series b)
A)
B)
Compounding parameter
Sample
Code
Compounding parameter
Rotary
current
Melt
Temp
Melt
Pressure
[A]
[°C ]
[bar]
Sample
Code
0
30.1 - 31.6
181
22.2 - 23.6
0
1a
2a
3a
4a
27.1 - 30.4
25.0 - 26.1
24.0 - 25.6
20.9 - 22.4
182
180
178
177
24.2 - 26.9
21.7 - 23.2
18.4 - 20.4
17.3 - 19.2
1b
2b
3b
4b
MFR
Rotary
current
Melt
Temp
Melt
Pressure
[A]
[°C ]
[bar]
[g/10min]
181
22.2 - 23.6
120.3
182
179
177
175
24.2 - 26.9
25.7 - 28.2
18.8 - 19.9
14.7 - 15.5
55.3
117.4
158.5
459.2
30.1
31.6
26.8 - 29.0
21.7 - 23.8
21.2 - 22.3
17.5 - 19.0
In Figure 5 the results of MFR measurements are shown in order of size (smallest to largest) in context
of composite composition. Sample 1b with the smallest value of MFR has the highest content of SEBS and
just a small oily content and lies even beyond sample 0 (without modification). So the high SEBS-content
worsens the melt flow behavior regarding to untreated sample 0. In case of sample 2b and 3b, there is
shown the effect of the oily component, which reduces the weaken effect of SEBS on the flow behavior. In
sample 4b the effect of the oily component exceeds completely the TPE effect.
100
600
500
80
70
400
60
50
300
MFR [g / 1 0 mi n]
co mpo si ti o n [wt%]
90
oily Comp.
SEBS
PP+PP-g-MA
40
200
30
WF
MFR (190 C/21,6kg)
20
100
10
0
0
1b
0
2b
3b
4b
Sample Code
Figure 5. MFR related to different composite compositions
In addition to the above discussed flow behavior during compounding, practice-oriented flow spiral
tests were performed for conclusions on the flow behavior regarding injection molding process. These
measurements of spiral flow offer a comparative analysis of a material's ability to fill a part with a
constant injection pressure. The spiral flow test is performed by injecting a material into a spiral mold.
The distance the material travels in the spiral mold is measured in cm and is an indication of the flow
behavior of the melt. The results of the test-series b) (20% DB) are shown in Table 5. The spiral length was
determined on injection pressures of 300, 900, 1200 and 1800 bar and put in context to the obtained MFR
results. The trends of flow spiral length regarding decreasing SEBS and increasing oily contents confirm
conclusions of the discussion of rheological properties.
39
Table 5. Flow spiral tests with injection molding conditions (temperature 190°C) and MFR results
Length of the flow spiral [cm]
MFR
Sample Code
300 bar
900 bar
1200 bar
1800 bar
[g/10min]
0
14.6
32.3
37.3
55.4
120.3
1b
16.8
38.7
40.7
53.3
55.3
2b
17.0
40.7
49.7
68.5
117.4
3b
12.4
43.7
58.1
79.8
158.5
4b
25.5
62.4
78.2
103.5
459.2
4. Conclusions
The objective of this study was to investigate the effects of different SEBS/oil DB on the mechanical
properties of PP-g-MA compatibilized PP/WF. The DBs were added in amounts of 10 and 20 wt%. The top
performing test sample within test series a) was observed with 10 wt% DB-2. An increase of Charpy
impact strength at room temperature of 50% and elongation at break by 98% was observed along with a
decrease of tensile strength by 18% and E-modulus by 34%. Top performing test sample of test series b)
with 20 wt% DB-1 shows a 92% improvement regarding Charpy impact strength and 296% for elongation
at break and a decrease of tensile strength of 38% as E-modulus of 49% but also the worst result related
to flow behavior.
Analysis regarding SEBS/oil ratio for test series a) shows a range from 8.1 to 1.9 where tensile strength
and E-modulus reduction remains at low levels in combination with oscillating values for impact strength
and elongation at break behavior. For test sample series b) these range was quite closer. The point of
inversion of this range for sample series b) could be defined more precisely between 2.4 and 1.9, whereas
this point for test sample series a) lies between 1.9 and 0.89. Results regarding influences of rising SEBS or
oil contents in total composition deliver also interesting results. The investigation shows that the increase
of SEBS by a factor of 3 with constant oil content could not affect the impact properties. In contrast to
that, varying the oil content by a factor of 9 with constant SEBS contents shows an increase of Charpy
impact strength. Especially the last observation raises the question for further investigations with respect
to distributional effects within the system PP/SEBS/oil by morphological characterization.
The rheological characterization showed that there is a negative effect of SEBS on the relative flow
behavior of PP/WF compound in case of high SEBS/oil ratios. This relative effect could be reversed dealing
with slightly higher oil contents. The relative flow behavior within compounding and injection molding
could be improved related to the measured data. However, these relative trends and results have to be
confirmed by additional characterization methods as capillary rheometry, plastographic monitoring or
extrusion slit capillary rheometer measurements.
References
[1] A.K. Bledzki, J. Gassan. "Composites reinforced with cellulose based fibres". Prog. Polym. Sci. Vol. 24,
(2), pp. 221-274, 1999.
[2] M. N. Ichazo, C. Albano, J. Gonzales, R. Perera, M. V. Candal. "Polypropylene/wood flour
composites: treatments and properties". Compos. Struct. 54 (2-3), pp. 789-797, 2001.
[3] Hansen, E. "Market and innovation considerations in development of natural/wood fibre
composites". Properties and Performance of Natural-Fibre Composites. pp. 356, 2008.
40
[4] A.K. Bledzki, M. Letman, A. Viksne. "A comparison of compoundingprocesses and wood type for
fibre-PP composites". Composites A. Vol. 36(6), pp. 789-797, 2005.
[5] Z.-Y. Sun, et al. "Mechanical Properties of Injection-molded Natural Fiber-reinforced Polypropylene
Composites: Formulation and Compounding Processes". J. Reinf. Plast. Compos. 29 (5), pp. 637-649,
2010.
[6] Bledzki, A. K., Faruk, O. and Sperber, V. E. Macromol. Mater. Eng. 2006.
[7] K. Oksman, C. Clemons. "Mechanical Properties and Morphology of Impact ModifiedPolypropyleneWood Flour Composites". J. Appl. Polym. Sci. 67, pp. 1503-1513, 1998.
[8] Pal, J. K. Kim and K. "Recent Advances in the Progresing of Wood-Plastic Composites". Heidelberg:
Springer-Verlag, 2010.
[9] L. Haijun, L. Shiang, S. Mohini. "Process Rheology and Mechanical Property Correlationship of WoodFlour-Polypropylene Composites". J. Reinf. Compo. 23, pp. 1153-1158, 2004.
[10] H. M. Tiggemann, D. Tomacheski, F. Celso, V. F. Riberio, S. Nachtigall. "Use of wollastonite in a
thermoplastic elastomer composition". Polymer Testing. 32, pp. 1373-1378, 2013.
[11] W. F. Sengers, M. Wübbenhorst, S. J. Picken, A. D. Gotsis. "Distribution of oil in olefinic
thermoplastic elastomer blends". J. Polymer. 46, pp. 6391-6401, 2005.
[12] Holden, G. "Applied Plastics Engineering Handbook". 2011.
[13] E. Sykacek, H. Frech, N. Mundigler. "Eigenschaften hochgefüllter Holz-Polypropylen-Composites mit
unterschiedlichen Haftvermittlern". Österr. Kunststoff-Zeitschrift. 38, pp. 12-15, 2007.
[14] Geißle, W. "Influence of the Measuring Apparatus and Method on the Value of Melt Index".
Rheology. pp. 13, 1994.
[15] Hansmann, H. and Laufer, N. Rheology: Characterization of WPC Melts. Kunststoffe international. 2,
pp. 27-29, 2013.
[16] Yeh, S.-K., Kim, K.-J. and Gupta, R. K. Synergistic Effect of Coupling Agents on Polypropylene-Based
Wood-Plastic Composites. J. Appl. Polym. Sci. 127 (2), pp. 1047-1053, 2013.
41
L7
HOLOBAR, ANDREJ: OPTIMIZATION OF OPTICAL PROPERTIES OF RUTHENIUM OXYGEN
SENSORS IN POLYMER MATRIX AND OXYGEN PERMEATION MEASUREMENTS FOR
PHARMACEUTICAL PACKAGING
1
1
Andrej Holobar *, Polona Brglez
1
ECHO, d.o.o., Stari trg 37, SI-3210, Slovenske Konjice, Slovenia
*[email protected]
1. Introduction
Optical oxygen sensor based on 4.7 - diphenyl - 1, 10 - phenanthroline ruthenium(II) dichloride
complex – (Ru(dpp)3) in polymer matrix and different polymer support were tested to improve optical
features and response of a sensor. Research of sensor features was carried out with an emphasis on
various techniques of making sensors, modification of dye concentration, application of different
polymeric supports, influence of the interference effect, and an emphasis on implementation of
nanoparticles. Application for measuring oxygen transfer rate in plastic pharmaceutical ethylene vinyl
alcohol (EVOH) bottles was also tested.
2. Theory
Different techniques of sensor solutions applications (»spin coating« technique, using device for a thin
layer and mechanical application) were used in order to make an optical oxygen sensor. The purpose was
to prepare the most homogeneous sensor solution and sensor with optimal characteristics. Applying
sensor´s solutions with mechanical application is simple and the most cost advantageous technique.
However, this technique has not proven to be the most appropriate, because it is difficult to ensure a
homogeneous coating over the entire sensor surface.
We found out that the main advantage of using a spin-coating technique is its velocity, simplicity and
its suitability for application of smaller volumes. It also enables a production of various series of sensors
with different features and minimal reagent use. The spin coating method has proven to be efficient when
applying sensor solutions in laboratories, but it does face a few difficulties when it comes to preparation
of homogeneous coating. Figure 1 and figure 2 shows an optical oxygen sensor.
Figure 1. Description of optical oxygen sensor
Figure 2. Optical fiber oxygen measuring
instrument HandO2
The most suitable method of applying sensor solutions presents a thin layer device where the thickness
of sensor solutions was between 10-50 µm. Such method enables the most homogeneous application of
sensor solution; it is fast, simple, and enables production of the sensors with reproducible properties. By
adding various metal nanoparticles and Triton - X - 100 characteristics of the sensors were improved.
Application of sensor in the permeation of packaging materials has been of importance to food,
packaging and pharmaceutical engineers for decades. Oxygen transmission rate (OTR) is one of the most
important of the gas transmission properties. OTR is the measurement of the amount of oxygen gas that
passes through a packaging within a certain time at a certain temperature and partial pressure of oxygen.
The factory sealed bottle was placed in a permeation cell, which was purged with oxygen deficient gas
(nitrogen). We measured the oxygen concentration in the permeation cell, which is a result of diffusion of
oxygen from the bottle to the permeation cell. Oxygen transfers through the EVOH bottle and accumulate
over time. The rate of oxygen accumulation was measured and converted into OTR measurement for the
EVOH bottles.
3. Experimental
We measured OTR of EVOH bottles with dynamic accumulation method using optical oxygen sensor.
This method allows oxygen to transfer through EVOH bottle and accumulate in a given volume. The test
volume incorporates an optical fluorescence oxygen sensor. Optical fluorescence oxygen sensor provides
the ability to non-destructively measure oxygen concentration within EVOH bottles. Figure 3 shows
example of measuring diffusion of oxygen through EVOH bottle.
Figure 3. Measuring diffusion of oxygen through EVOH bottle
42
4. Results and discussion
Table 1 shows that the concentration of oxygen in 27 hours was increased approximately by 14 ppm.
The linear area the average diffusion rate was 12 ppm O2/day which is equivalent to 0.0021 mL of O2/day.
Table 1. OTR measurements EVOH bottle
OTR (ppm O2/day)
Measurement
1
17
2
14
3
12
Average
14
OTR (mL O2/day)
0,0029
0,0024
0,0021
0,0024
5. Conclusions
The advantages of the optical oxygen sensors are the following: no oxygen consumption during
measurements, enables measurements in liquid or gas phase, measuring in explosion atmosphere and
measuring under high pressure. Specially designed measuring set-up enables construction of different
measuring devices for various applications, for example presented system for measuring oxygen
transition rate of packaging.
References
[1] P. Brglez, A. Holobar, A. Pivec, M. Kolar, Materials and technology, 2013, 48, 2, p.181-188.
[2] P. Brglez, A. Holobar, A. Pivec, M. Kolar. Optimization of optical oxygen sensor's properties based on
4.7-diphenyl-1,10-phenanthroline ruthenium(Ii) dichloride complex. V: 20. jubilejna konferenca o
materialih in tehnologijah, 17.-19. oktober 2012, Portorož, Slovenija. GODEC, Matjaž (ur.), et al.
Program in knjiga povzetkov = Program and book of abstracts. Ljubljana: Inštitut za kovinske
materiale in tehnologije, 2012, str. 151.
[3] B. Welt, A. Abdellatief, Packag. Technol. Sci., 2012.
L8
HUSKIĆ, MIROSLAV: GRAFTING OF CAPROLACTONE ON HYPERBRANCHED POLYESTER
1
M. Huskić
1,2,3
*, I. Pulko
2
National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
Polymer Technology College, Ozare 19, 2380 Slovenj Gradec, Slovenia
3
TECOS, Slovenian Tool and Die Development Centre, Kidričeva 25, Celje 3000, Slovenia
*[email protected]
2
1. Introduction
Polycaprolactone (PCL) is an aliphatic, semicrystalline polyester, which can be used as implantable
biomaterial, for drug delivery, as a scaffold for tissue repair etc. [1-3] PCL is biodegradable from microbes
and enzymes, whereas it cannot be degraded enzymatically in the body [4]. PCL is miscible with PVC and
acts as a plasticiser [5].
There is an increasing interest in the synthesis of star-shaped, and hyperbranched (HB)
polycaprolactone polymers and copolymers [6,7]. Star polymers have better solubility, and lower
viscosity, lower melting temperature, and degree of crystallization than their linear analogues.
PCL and its block copolymers are prepared by ring-opening polymerization of caprolactone (CL) using
various catalysts i.e. various metal-based, enzymatic, organic amines and acids as well as inorganic acids.
43
Many catalysts work only in the presence of initiator, which are mostly alcohol, amine or water [4]. Water
can initiate but also terminate polymerization reaction and therefore, CL and all other chemicals, usually
have to be thoroughly dried. On the other hand, there are several examples of CL polymerization and
copolymerization in the presence of water, using 4-dimethylamino pyridine [8], metal triflates [9] or
Brønsted acids [10] as a catalyst.
This work focuses on a simple synthesis and characterization of multi-arm PCL star shaped graft
copolymers based on commercial HB polyester BoltornTM H40 (BH40), with theoretically 64 -OH functional
groups. This type of polymers was already synthesized [11, 12]. The authors used much higher reactant
ratio and Sn(Oct)2 as an initiator. They also performed heavy drying of both BH40 and caprolactone. The
goal of this research was to synthesize multi-arm graft copolymers, i.e. hyperbranched polyester BH40-gPCL without CL drying.
2. Experimental
Grafting of PCL on BH40 was performed in the bulk at 145 °C in nitrogen atmosphere. The BH40 and CL
were weighed in a ratio that corresponds to a molar ratio of –OH groups to CL of 1:1 (BH40-g-1PCL) and
1:10 (BH40-g-10PCL). The reaction time was 3 h to 24 h, depending on the ratio of reactants and was
longer at higher ratios.
Differential scanning calorimetry (DSC) was performed on a Mettler Toledo DSC-1 calorimeter. The
samples were heated/cooled/heated with heating and cooling rates of 10 °C/min. 1H NMR spectra were
recorded in DMSO-d6 solution at a concentration of 10 mg/g on a on a Varian Unity Inova-300
spectrometer. The absolute molar mass averages were determined by SEC-MALS using successively
connected pre-column, PLGel 103 Å column and Mesopore column. The nominal eluent (THF) flow rate
was 0.8 mL/min and the sample concentration was typically 0.01g/mL.
3. Results and Discussion
Block copolymers BH40-g-PCL were transparent viscous liquids after the synthesis. BH40-g-10PCL
crystallized on cooling, while all others crystallized and turned into white soft solids after a few hours or
even weeks. All copolymers were soluble in non-polar solvents like toluene and chloroform and in polar
solvents like DMSO and acetone. They were also soluble in warm methanol and ethanol.
The mechanism of grafting is monomer activation of CL by acid groups and initiation with the terminal
-OH group of BH40. The hydroxyl groups in the linear repeat units stay almost untouched. Decreased
intensity of linear -OH groups signal was only observed on a spectrum of BH40-g-10PCL. The activator is ptoluenesulfonic acid (p-TSA), which was used as a catalyst in BH40 synthesis.
Molar masses as well as dispersity increase with increasing reactant ratio, which confirms the grafting
and is in agreement with previous findings.
BH40 is amorphous polymer with the glass transition temperature (Tg) of 31 °C. Grafting of short PCL
chains decreases Tg to -60 °C which is characteristic for PCL. Crystallization can only be observed in
samples with high PCL content (BH40-g-4PCL to BH40-g-10PCL). The melting temperature was usually in a
temperature range 30-50 °C.
44
Figure 1. NMR spectrum of BH40-g-5PCL
4. Conclusions
Simple and efficient method for the synthesis of multiarm star-shaped graft copolymers of
polycaprolactone and hyperbranched polyester Boltorn H40 is presented. Contrary to previously
published data, graft copolymers can be prepared without the addition of catalyst and without time
consuming drying of caprolactone. The p-toluenesulfonic acid, which is presented in BH40 in trace
amounts, acts as a catalyst for CL grafting, and it is very much insensitive to the presence of water in CL.
Acknowledgements
The work »Grafting of caprolactone on hyperbranched polyester« was carried out within operation
»Creative core VŠTP«. The operation is partially co-financed by European Union, European Regional
Development Fund. Operation is executed within framework of operative Programme for Strengthening
Regional Development Potentials for Period 2007-2013, 1st development priority: Competitiveness of the
companies and research excellence, priority aim 1.1.: Improvement of the competititve capabilities of
companies and research excellence.
References
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[2]
[3]
[4]
[5]
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[8]
[9]
[10]
T. Dash, V. Konkimalla, J. Controlled Release 2012, 158, 15.
M. Yong, S. Saifzadeh, G. Askin, R. Labrom, D. Hutmacher, C. Adam, Tissue Eng., Part C 2014, 20, 19.
N. Asvadi, N. Dang, N. Davis-Poynter, A. Coombes, J. Mater. Sci.: Mater. Med. 2013, 24, 2719.
M. Labet, W. Thielemans, Chem. Soc. Rev. 2009, 38, 3484.
A. Mamun, V.H. mareau, J. Chen, R.E. Prud’homme, Polymer 2014, 55, 2179.
L. Mou, N. Chen, K. Zhu, Y. Chen, X. Luo, Polym. Adv. Technol. 2012, 23, 748.
N. Nguyen, K. Trechet, S. Howdle, D. Irvine, Polym. Chem. 2014, 5, 2997.
H. Feng, C.M. Dong, J.Polym. Sci. 2006, 44, 5353.
R. Scullion,P. Zinck, Polym. Bull. 2012, 69, 757.
N. Stanley, G. Bucataru, Y. Miao, A. Favrelle, M. Bria, FStoffelbach, P. Woisel, P. Zinck, J. Polym.
Sci.Part A, Polym. Chem. 2014, 52, 2139.
45
[11] M. Trollsas, C. Hawker, J.Remenar, J. Hedrick, M. Johansson, H. Ihre, A. Hult, J. Polym. Sci.Part A,
Polym. Chem. 1998, 36, 2793.
[12] W. Xia, G. Jiang, W. Chen, J. Appl. Polym. Sci. 2008, 109, 2089.
L9
HUŠ, SEBASTJAN: EFFECT OF BIO-DEGRADABLE COMPATIBILIZER ON MECHANICAL
PROPERTIES OF PLA-BASED COMPOSITES
1
1
1
Sebastjan Huš *, Silvester Bolka , Irena Pulko
1
Polymer Technology College, Ozare 19, 2380 Slovenj Gradec, Slovenia
*[email protected]
1. Introduction
With increasing production and use of plastic materials there is also increased risk of disposal of waste
at landfills or marine environments.[1,2] Good alternative are bioplastics, materials that are bio-based
and/or bio-degradable and do not affect the environment to such extent as conventional plastics.
Especially interesting are bio-composites which are prepared by incorporating various natural fillers to the
polymer matrix.[3-5] Natural fillers have high specific strength-to-weight ratio, low-density and cause less
abrasion to machinery compared to mineral fillers [6] but usually affect mechanical properties in negative
way and this is why compatibilization is necessary. The simplest way to achieve good adhesion between
matrix and fillers is to add coupling agent to the mixture of polymer and filler.[7-12] Since most of the
used coupling agents are nondegradable they reduce the degradation rate of the prepared composite.
This is why our goal was to produce compatibilizer that is both bio-based and bio-degradable and does
not affect the degradation rate of the prepared bio-composites. In this work we present the impact of
novel bio-compatibilizers on mechanical properties and thermal stability of the prepared PLA-based
composites.
2. Experimental
For the composite preparation following materials were used: poly(lactic acid), PLA, Ingeo Biopolymer
2003D was supplied by NatureWorks LCC, nanocrystalline cellulose was supplied by the University of
Maine, microcrystalline cellulose Arbocel UFC M8 was supplied by JRS GmbH, wood flour, coconut flour,
paper pulp and hemp fibre and coir were supplied by local companies as waste materials. Natural fillers
were dried in the oven for 4 h at 80 °C, grinded into fine powder, sieved trough 1000 µm and dried again
in the oven for 4 h at 80 °C. L-lactide (Sigma Aldrich), triazabicyclodecene – TBD (Sigma Aldrich),
dichloromethane – DCM (Sigma Aldrich) and methanol (Sigma Aldrich) were used as received.
Bio-compatibilzers, namely graft copolymers made of cellulosic fillers grafted with PLA, were
synthesized according to Chung et al. who used lignin as a cellulosic material. We used previously
mentioned fillers for lactide grafting instead of lignin.
Composites were prepared by mixing 90 wt% of PLA and 10 wt% of filler with sufficient amount of
DCM. In case where biocompatibilizers were used, 5 wt% of filler was substituted with the filler and PLAbased compatibilizer. Compositions of samples are presented in Table 1. Mixture was left for 24 h on
magnetic stirrer to achieve homogenous solution, afterwards it was degassed to remove air bubbles and
casted into foils using doctor blades with dimensioned slits of 400 μm.
Composites were characterized using ATR-FTIR Spectrum 65 (PerkinElmer). Mechanical properties of
the prepared composites were analysed on a testing machine AG-X plus (Shimadzu) using a stress-strain
test ISO 527. Thermogravimetric analysis was performed on a TGA 4000 (PerkinElmer) in a nitrogen
atmosphere at the rate of 10 °C/min from 40 °C to 650 °C.
46
Table 1. Mechanical properties and thermal stability of prepared composites
Sample
Composition
S0
100% PLA 2003D
Young modulus
[GPa]
Tensile strength
[MPa]
114,3 ± 6,1
6,2 ± 0,9
Ɛ at break [%]
Td [°C]
266,3 ± 18,6
353,8
145,6 ± 18,4
352,2
134, 4 ± 12,7
356,1
142,6 ± 23,7
342,4
39,4 ± 9,1
353,6
290,5 ± 29,1
354,8
200,8 ± 14,1
355,3
69,5 ± 6,4
367,6
175,9 ± 17,7
373,8
S1
90% PLA + 10% cellulignin
211,6 ± 12,1
4,9 ± 0,2
S1.1
90% PLA + 5% cellulignin + 5% comp.
344,6 ± 25,8
5,1 ± 0,3
S2
90% PLA + 10% wood flour
238,3 ± 23,8
6,8 ± 0,4
S2.2
90% PLA + 5% wood flour + 5% comp.
408,0 ± 22,5
5,2 ± 1,0
S3
90% PLA + 10% MCC
131,4 ± 10,3
8,9 ± 1,0
S3.3
90% PLA + 5% MCC + 5% comp.
193,0 ± 9,5
7,0 ± 0,6
S4
90% PLA + 10% NCC
472,7 ± 17,3
5,3 ± 0,1
S4.4
90% PLA + 5% NCC + 5% comp.
569,6 ± 32,7
7,7 ± 0,7
S5
90% PLA + 10% paper pulp
139,2 ± 13,2
9 ± 1,1
14,1 ± 5
358,0
S5.5
90% PLA + 5% paper pulp + 5% comp.
354,9 ± 16,7
7,7 ± 1,8
32,2 ± 5,1
342,3
S6
90% PLA + 10% hemp fibre
467,9 ± 15,1
11 ± 0,0
12 ± 1,7
330,3
S6.6
90% PLA + 5% hemp fibre + 5% comp.
959,6 ± 181,5
11,4 ± 0,7
7,4 ± 2,5
361,4
S7
90% PLA + 10% hemp coir
349,7 ± 22,9
7,3 ± 0,4
10,8 ± 4,9
345,3
S7.7
90% PLA + 5% hemp coir + 5% comp.
582,0 ± 13,8
8,7 ± 0,3
7,1 ± 1
358,0
4. Results and discussion
Thermal properties of compatibilized samples were measured and compared to those of
uncompatibilized samples and to neat PLA. As it can be seen from Table 1, the addition of natural fillers
usually reduces thermal stability as compared to neat PLA but when used in combination with
compatibilizers, the thermal stability improved significantly. It can be also seen that compatibilizers
improve mechanical properties as well. With the addition of natural fillers biocomposites exhibited higher
Young modulus which additionally increased when compatibilizers were used. The prepared composites
were consequently stiffer as compared to neat PLA. In some cases, both Young modulus and elongation at
break improved when using compatibilizers, which indicated that composites with compatibilizator were
tougher as compared to composites without compatibilizer.
5. Conclusions
In this study we investigated the effect of synthesized bio-compatibilizers on thermal and mechanical
properties of the prepared PLA-based bio-composites. Efectiveness of bio-compatibilizers depends on
their composition: it is important that the same material, which is used as a filler, is also used as a raw
material for the synthesis of bio-compatibilizator. The addition of bio-compatibilizers in most cases
improves the mechanical properties such as Young modulus and tensile strength as well as thermal
stability as compared to composites without bio-compatibilizers. In some cases, the addition of biocompatibilizers also improves flexibility and consequently the toughness of PLA-based composites which
broadens the range of their applications.
47
Acknowledgements
This contribution was made within operation »Creative Core VŠTP«. The operation is partially cofinanced by European Union, European Regional Development Fund. Operation is executed within
framework of operative Programme for Strengthening Regional Development Potentials for Period 20072013, 1st development priority: Competitiveness of the companies and research excellence, priority aim
1.1.: Improvement of the competitive capabilities of companies and research excellence. Authors wish to
thank R. Bobovnik for technical support.
References
[1] Plastics - The Facts 2013 - An analysis of European latest plastics production, demand and waste
data. 2013, Plastics Europe.
[2] EPA, United States Environmental Protection Agency 2000.
[3] J. Y. Jang, T. K. Jeong, H. J. Oh, J. R. Youn, Y. S. Song, Thermal stability and flammability of coconut
fiber reinforced poly(lactic acid) composites, Composites Part B: Engineering (2012), vol. 43, str.
2434-2438.
[4] M.J.A. van den Oever, B. Beck, J. Müssig, Agrofibre reinforced poly(lactic acid) composites: Effect of
moisture on degradation and mechanical properties, Composites Part A: Applied Science and
Manufacturing, 2010;41:1628-1635.
[5] N. Graupner, A. S. Herrmann, J. Müssig, Natural and man-made cellulose fibre-reinforced poly(lactic
acid) (PLA) composites: An overview about mechanical characteristics and application areas,
Composites Part A: Applied Science and Manufacturing, 2009;40:810-821
[6] G. Radonjič, V. Musil Kompatibilizacija propilenskih mešanic / Compatibilization of polypropylene
blends, Kovine, zlitine, tehnologije, 30, (1996) 75-78
[7] Xie Y, Hill CAS, Xiao Z, Militz H and Mai C, Silane coupling agents used for natural fiber/polymer
composites: A review. Composites Part A: Applied Science and Manufacturing, 2010. 41(7): p. 806819.
[8] Imre B and Pukánszky B, Compatibilization in bio-based and biodegradable polymer blends.
European Polymer Journal, 2013. 49(6): p. 1215-1233.
[9] Rasal RM, Janorkar AV and Hirt DE, Poly(lactic acid) modifications. Progress in Polymer Science, 2010.
35(3): p. 338-356.
[10] Cheng Y, Deng S, Chen P and Ruan R, Polylactic acid (PLA) synthesis and modifications: a review.
Frontiers of Chemistry in China, 2009. 4(3): p. 259-264.
[11] Chow WS, Leu YY and Ishak ZAM, Effects of SEBS-g-MAH on the properties of injection moulded
poly(lactic acid)/nano-calcium carbonate composites. eXPRESS Polymer Letters, 2012. 6(6): p. 503–
510.
[12] Chun K, Husseinsyah S and Osman H, Mechanical and thermal properties of coconut shell powder
filled polylactic acid biocomposites: effects of the filler content and silane coupling agent. Journal of
Polymer Research, 2012. 19(5): p. 1-8.
L10
MAHENDRAN, ARUNJUNAIRAJ: NANOSTRUCTURED FLY ASH AS REINFORCEMENT IN A
PLASTOMER-BASED COMPOSITE: A NEW STRATEGY TO REDUCE GREEN HOUSE EMISSION
FROM THERMAL POWER STATION SOLID WASTE
1
1
2*
1
Akshata G. Patil , Arunjunairaj Mahendran , S. Anandhan , Herfried Lammer
2
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka,
48
2
Mangalore-575025, Karnataka, India
Kompetenzzentrum Holz GmbH, Wood Carinthian Competence Center, A-9300 St. Veit/Glan, Austria
*[email protected]
1. Introduction
Class-F fly ash (FA) from a coal-fired thermal power station was subjected to high energy ball
millinginduced mechanochemical activation aided by a surfactant. Subsequently, ethylene-octene
copolymer/mechanochemically activated FA (EOC/MCA-FA) composites were prepared by solution
casting. The surface modification of FA was confirmed from contact angle measurements and FTIR
spectroscopy, which accounts for a good interaction between MCA-FA and the polymer matrix. X-ray
diffraction reveals that the crystalline size of quartz phase present in FA got reduced, while the relative
lattice strain on it increased during milling. Morphological studies revealed that interfacial adhesion
between the polymer and MCA-FA is good and this accounts for the improvement in mechanical
properties of the composites even at the minimum filler loading. Flame retardance of the matrix polymer
is improved by the addition of either fresh FA or MCA-FA. The results imply that FA is a valuable
reinforcing filler for ethylene-octene copolymer and its mechanochemical activation is an effective
strategy for its future use.
2. Theory
Fly ash (FA) is one of the residues left during the combustion of pulverized coal in coal-fired power
plants and is an air, water and soil pollutant. Nano-fly ash, when used as reinforcement in polymer matrix
composites could reduce the consumption of the other commonly used mineral fillers, such as silica
thereby reducing the green house emissions. Even at low loading of nano-filler, the entire nanocomposite
would consist of interfacial polymer, with majority of polymer chains residing in close contact with the
filler surface. Ongoing research on valorization of FA has found many potential applications in different
fields, which reduce environmental pollution and add value to new product(s). Fly ash has been used
widely as reinforcement in polymer matrix composites and it was earlier used in various polymers, such as
polyetheretherketone , polypropylene , epoxy, poly(vinyl alcohol) , and high density polyethylene (HDPE)
and ethylene-octene copolymer (EOC).
EOC, a relatively new random copolymer of ethylene and 1-octene is a commercially available polyolefin
plastomer, which possesses the flexibility and mechanical properties of a synthetic rubber and the melt
processability of thermoplastics. EOC has high filler loading capability, excellent electrical properties and
weathering resistance. It is used in general purpose thermoplastic vulcanizates, wires and cables, and
automobile applications Therefore, in this work, an attempt has been made to modify the surface of the
FA mechanochemically by high energy ball milling in the presence of toluene and an anionic surfactant
and the resultant FA was used as a nano-structured reinforcement in ethylene-octene copolymer (EOC)
matrix. The mechanical, morphological, thermal properties along with crystallization behavior and
flammability of the EOC/FA and EOC/mechanochemically activated FA (MCA-FA) composites were studied
and the findings are reported in this work.
3. Experimental
The as received FA was washed in distilled water and the carbon that creamed up during washing was
removed. The magnetic separation was carried out manually to remove the magnetic impurities and the
FA obtained in this method are mentioned as fresh FA. Another method is mechanochemical activation
(MCA) of fresh FA which was achieved by using a high-energy planetary ball mill and the milling was
carried out for 30 h and 60 h in the toluene medium along with 1 % w/w of sodium lauryl sulfate to
reduce agglomerations of FA particles. Three sets of composites with 1, 3 and 5 % w/w of fresh FA and FA
mechanochemically activated for 30 and 60 h (MCA-FA), were prepared by a solution casting method. A
transmission electron microscope was used for the analysis of particle morphology as well as surface
texture of the MCA-FA. Dynamic contact angle analyser was used to determine the wettability of fresh FA
and MCA-FA pellets obtained by using a hydraulic press. The hydrodynamic sizes and size distributions of
49
fresh FA and MCA-FA fly ash particles in aqueous or glycerol media were measured by a dynamic light
scattering (DLS) instrument. X-ray diffraction measurements were carried out to find the crystallite size
and lattice strain of the quartz phase of fresh FA and MCA-FA. SEM was used to evaluate the texture and
morphology of fresh FA, MCA-FA and their composites with EO. A universal testing machine was used to
determine tensile strength, elongation at break and stresses at 100 % and 300 % strains. FTIR was utilized
to examine the functional group present in the composites and the flame retardancy of the composites
was determined using limited oxygen index (LOI) method. The change in crystallinity of the composites
was evaluated using differential scanning calorimetry.
4. Results and discussion
TEM measurements revealed that the particles attained irregular shape with rough surface. The size of
a single particle is typically in nanometer range with narrow crystalline needle-like shape, which plays a
significant role in the reduction of agglomeration of particles in the fabrication of composite films; this
means that the intimate contact areas of MCA-FA particles with the polymer matrix will be high due to
enhanced mechanical interlocking between the polymer chains and the surfaces of the MCA-FA particles.
The results of wettability study showed that structure of the MCA-FA can look like an inverse micelle in
which the FA particle surrounded by the ionic heads form the core and the non-polar tails for the outer
core and the proposed model is shown in Scheme 1. It is also found that, during the mechanochemical
activation of FA, appreciable changes happen not only in the morphology and size of FA, but, also in its
surface wettability characteristics. The results of contact angle measurement imply that MCA-FA can be
easily wet by the EOC solution, which can lead to a good interaction between the MCA-FA particles and
the polymer matrix.
50
Scheme 1. Mechanochemical activation of FA
The X-Ray diffraction patterns of fresh FA and MCA-FA showed a lower degree of crystallinity for fresh
FA and few numbers of crystalline peaks in the diffraction pattern. In all the diffraction patterns, an
amorphous hump was observed between 2θ values of approximately 14° to 35°, which is due to the
presence of amorphous glassy materials. Morphological studies of the composites using SEM revealed
that MCA-FA particles are of irregular shapes with rough surfaces. It can be observed that due to the
smooth surface and spherical shape of fresh FA, its particles are poorly wet by the matrix resulting in
segregation. But on the other hand, MCA-FA demonstrates an efficient wetting of the particles of MCA-FA
by the matrix along with minimal amounts of interstitial voids or porosities. In term of mechanical
properties, neat EOC exhibits a tensile strength value of 9.7MPa. In EOC/FA composites, there is no much
improvement in tensile strength at 1 % w/w and 3 % w/w of filler loading, but, at a loading of 5 % w/w,
the tensile strength exhibits a value of 11.3 MPa (% enhancement =16.5). For the EOC/30 h MCA-FA
composites, the tensile strength attains the maximum value (% enhancement = 29) at a filler loading of 1
% w/w of and then decreases at higher filler loading. The optimum filler content for EOC/30 h MCA-FA
composite is 1 % w/w, which enables a relatively high interfacial bonding between the filler and EOC. The
good distribution of the filler particles throughout the matrix inhibits crack propagation and thereby
improves the mechanical properties. The irregularly shaped, rough textured, surfactant-wrapped particles
of MCA-FA form a strong interface with the polymer matrix due to mechanical interlocking combined with
dispersion and van der Waals forces. From flammability point of view, it seems that a still higher filler
loading is necessary to improve the flame retardance of EOC. Due to the multi-layer build-up, these EOC
composites exhibit several melting peaks. It is clear that the crystallization peaks of EOC shifted to higher
temperature with fresh FA content and to lower temperature with MCAFA. The observed effects can be
attributed to the nucleating effect of filler in EOC crystallization process, the crystallization peak shifts to
lower temperature as the filler content increases.
5. Conclusions
One of the principal problems that occurred whenever FA has been used as filler in polyolefin
polymers the interface formation between the polymer and FA has been a challenge. In this work, an
attempt was made to improve the compatibility between the non-polar EOC matrix and the polar filler by
modifying the surface of the FA by mechanochemical treatment. Surface modification and better
interaction of filler and polymer matrix were determined by contact angle measurement. The crystallite
size of quartz phase present in the fresh FA was 56 nm, which got reduced to 33.6 nm and 28 nm after 30
h and 60 h of milling, respectively. The relative lattice strain of the quartz phase was also increased from
0.23 % to 0.33 % after 60 h of milling. Morphological studies revealed that interfacial adhesion between
EOC and the MCA-FA is good resulting in an improvement in the mechanical properties MCAFA/EOC
composites even at very low filler loading compared with that of FA/EOC composites. Flame retardance of
EOC is enhanced by the addition of FA and MCA-FA. The improvement in physico-mechanical and
flammability of these composites is encouraging as this strategy could help eliminate environmental
pollution due to FA in a very profitable manner.
L11
OSTAFIŃSKA, ALEKSANDRA: MORPHOLOGY AND RHEOLOGY OF TPS/TiO 2 AND PCL/TiO 2
COMPOSITES
A. Ostafińska*, D. Michálková, J. Mikešová, M. Nevoralová, J. Kratochvíl, I. Fortelný, M. Šlouf
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic,
Heyrovského nám. 2, 162 06 Prague, Czech Republic
*[email protected]
1. Introduction
In our research we focused on an influence of titanium dioxide particles on morphology and rheology
of melt mixed matrices, thermoplastic starch (TPS) and poly(ɛ-caprolactone) (PCL). The microscopy
techniques were used to evaluate phase structure of TPS/TiO2 and PCL/TiO2 composites. The thermal,
mechanical and rheological properties were used for further characterization of the systems.
2. Theory
Biopolymers are attractive materials due to their biodegradability and biocompatibility [1]. One of
cheap natural polymers is starch. Because of its processability, it is required to transform a native granular
starch into a thermoplastic starch (TPS) [2]. An improvement of TPS properties can be realized by an
51
addition of micro-/nanoparticles [3]. Recently, a distinct attention is paid to titanium dioxide (TiO2)
particles due to their anti-bacterium properties, antistatic behavior and photocatalytic activity [4]. The
micro- and nanoparticles can improve mechanical and rheological properties as well as influence the
morphology, crystallinity and degradability.
Next well-established method for improving properties of polymers is preparation of blends [5].
Nowadays, more and more from TPS starch-based heterogeneous materials with improved properties are
produced. For instance, TPS is blended with poly(ɛ-caprolactone) (PCL). PCL is a biodegradable polymer
with excellent deformability and impact properties. The combining of TPS with PCL and TiO2 seems to be a
promising way how to optimize mechanical performance and biodegradability of both polymers.
3. Experimental
TPS/TiO2 composites with different content of filler (1, 2, 3 %wt) were prepared by solution casting
method [6] of wheat A-starch with TiO2 as filler. In the next step, TPS/TiO2 were melt-mixed, which
resulted in more homogeneous dispersion of the filler. PCL/TiO2 composites (with filler content 2.5 and 5
wt.%) were obtained by single-step melt mixing. All systems (TPS/TiO2, PCL/TiO2) were studied by
microscopy techniques in order to evaluate homogeneity, dispersion of fillers and phase structure. We
used a light microscope (LM) and a scanning electron microscope (SEM) with secondary electrons
(SEM/SE) and back-scattered electrons imaging (SEM/BSE). The rheological and mechanical properties of
TPS/TiO2 systems were examined. The rheology and crystallization kinetics (using differential scanning
calorimetry and in-situ observation of the crystallization process by means of polarized light microscopy)
of PCL/TiO2 systems were studied.
4. Results and conclusions
The present study was focused on determination of the effect of titanium dioxide particles on
morphology and properties of TPS and PCL matrix. We managed to prepare TPS/TiO2 [7] and PCL/TiO2
composites with very good and homogeneous dispersion of TiO2 in the polymer matrix (Fig. 1). The
results were confirmed by higher-resolution SEM/BSE micrographs.
52
Figure 1. The LM micrographs of thin sections of (a) TPS/TiO2 (2 wt.%) and (b) PCL/TiO2 (2.5 wt.%)
composites.
In TPS/TiO2 composites, we observed enhancement of complex viscosity with addition of TiO2
particles. The mechanical properties evaluation confirmed enhancement of TPS stiffness with increasing
filler content.
In PCL/TiO2 composites, our experiments proved that the process of crystallization was not initiated by
the particles, but occurred in entire volume of sample. Rheology measurements (frequency sweep)
showed that complex viscosity decreased with increasing TiO2 content, which indicated a moderate
degradation of the PCL matrix due to previous melt-mixing in the presence of titanium dioxide. On the
other hand, PCL/TiO2 composites showed the slight crosslinking during the time sweep rheological
measurements, when the shear forces were lower than during the melt-mixing.
Our results indicated that TPS/TiO2 and PCL/TiO2 are promising materials for preparation of
multicomponent blends, as they have very good filler dispersion. Our aim is obtaining the TPS/TiO2/PCL
blends with controlled morphology, biodegradation rate and properties. The addition of TiO2 to the
TPS/PCL blends will help us to control the properties and biodegradability of the blends. The preliminary
results show that melt-mixed blends of TPS/PCL/TiO2 exhibit fine structure and good dispersion of the
filler, like the original individual components – TPS/TiO2 and PCL/TiO2.
Acknowledgements
The authors would like to thank the Grant Agency of the Czech Republic (P108/14-17921S) for the
financial support.
References
[1] B. Imre, B. Pukanszky, Eur. Polym. J., 2013, 49, 1215-1233.
[2] P.M. Visakh, P.A. Mathew, K. Oksman, S. Thomas, Starch-based bionanocomposites: processing and
properties. In: Habibi, Y., & Lucia, L.A. (Eds.), Polysaccharide building blocks: A sustainable Approach
to the Development of Renowable Biomaterials, John Wiley & Sons. 2012.
[3] F. Xie, E. Pollet, P.J. Halley, L. Averous, Prog. Polym. Sci., 2013, 38, 1590-1628.
[4] J. Mikešová, M. Šlouf, U. Gohs, D. Popelková, T. Vacková, N. H. Vu, J. Kratochvíl, A. Zhigunov, Polym.
Bull., 2014, 71, 795-818.
[5] Z. Horák, I. Fortelný, J. Kolařík, D. Hlavatá, A. Sikora, Polymer blends, In: J. Kroschwitz, ed.
Encyclopedia of Polymer Science and Technology. Indianapolis: John Wiley & Sons, 2005, 1–59.
[6] I. Kelnar, L. Kaprálková, L. Brožová, J. Hromádková, J. Kotek, Ind. Crops. Prod., 2013, 46, 186-190.
[7] A. Ostafińska, J. Mikešová, D. Michálková, J. Kredatusová, I. Fortelný, M. Šlouf, Carbohydr. Polym.,
2015, submitted.
L12
PERZ, VERONIKA: CUTINASES FOR ALIPHATIC-AROMATIC POLYESTER BIODEGRADATION
1
1
2
3
3
Veronika Perz *, Karolina Haernvall , Julian Ihssen , Carsten Sinkel , Ulf Kueper ,
3
1
4
Melanie Bonnekessel , Doris Ribitsch , Georg M. Guebitz
1
ACIB GmbH, Konrad Lorenz Strasse 20, 3430, Tulln, Austria
Laboratory for Biomaterials, Empa, Swiss Federal Laboratories for Biomaterials Science and Technology,
Lerchenfeldstrasse, 5, CH-9014 St. Gallen, Switzerland
3
BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen, Germany
4
Institute of Environmental Biotechnology, IFA Tulln, University of Natural Resources and Life Sciences, Vienna, Konrad
Lorenz Str. 20, 3430 Tulln, Austria
*[email protected]
2
1. Introduction
One of the primary goals of polymer development was to design materials of high stability and
durability. Today, these features lead to major environmental problems. That is why society is confronted
with the need to reduce packaging waste as well as to find and enhance polyesters that are biodegradable
and show required material properties. Generally spoken, aliphatic polyesters exhibit better
biodegradability than aliphatic-aromatic ones but they sometimes lack the required thermal and
53
mechanical properties. In contrast to that, aromatic polyesters like polyethylene terephthalate (PET) show
good material properties but are hardly biodegradable.
Several studies have clearly demonstrated the biodegradability of the aliphatic-aromatic copolyester
PBAT (poly(butylene adipate-co-butylene terephthalate)) under composting conditions. Nevertheless,
there is a lack of information about the enzymes that play the major role during PBAT hydrolysis. In this
study we present enzymes from typical soil and compost inhabitants that hydrolyze PBAT efficiently.
2. Theory
PBAT (poly(butylene adipate-co-butylene terephthalate)) is an aliphatic-aromatic copolyester short
[P(BAda-co-BTa)]) that contains adipic acid (Ada), 1,4-butanediol (B) and terephthalic acid (Ta) (Figure 1).
The ratio of adipic acid:terephthalic acid is approximately 50:50.
O
O
O
O
O
O
nO
O
m
Figure 1. Chemical structure of PBAT, with BTa and AdaB subunits
Beside PBAT, several polymeric PBAT model substrates with modified Ada:Ta ratios were tested
concerning their degradability. The Ada:Ta ratios were ranging from 0 mol% BTa (mono(4-hydroxybutyl)
terephthalate) (Ada100_Ta0) to 50 mol% BTa (Ada50_Ta50)) Apart from those polymeric model
substrates also oligomeric model substrates were systematically designed with variations of the chain
length of the alcohol and the acid as well as with varying content of the aromatic constituent terephthalic
acid (Ta)
3. Results and discussion
The enzymatic degradation pattern of three different hydrolases was tested on the polymeric and
oligomeric PBAT model substrates. The substrate specificities of a bacterial cutinase from Thermobifida
cellulosilytica (Thc_Cut1), a fungal cutinase from Humicola insolens (HiC) and a polyhydroxyalkanoate
depolymerase (ePhaZmcl) from Pseudomonas fluorescens was evaluated. The degradation process was
followed over time and hydrolysis products were analyzed and quantified via HPLC-MS. The difference
between the temperature where the degradation takes place and the melting temperature (Tm) of the
polymer was reported to be a crucial factor for enzymatic hydrolysis [1,2]. Consequently a TG-DSC
(Thermogravimetry and Differential Scanning Calorimetry) analysis was performed for PBAT and all tested
model substrates and melting temperature (Tm) values were taken into account during the evaluation of
the degradation results. It is notable that the enzymes show a distinct mechanism for the model
substrates and for PBAT.
4. Conclusions
The bacterial cutinase from Thermobifida cellulosilytica and the fungal cutinase from Humicola
insolens hydrolyzed PBAT as well as oligomeric and polymeric PBAT model substrates. It was clearly seen
that higher concentrations of aromatic building blocks (i.e. BTa) lowered the enzymatic hydrolysis rates.
Moreover, the influence of the Tm values on the enzymatic degradability was confirmed. We can learn
important principles of enzyme degradation by comparing the hydrolysis process of different polyester
model substrates. These findings will help to improve polyester degradation and modification procedures.
Acknowledgements
This work has been supported by the Federal Ministry of Science, Research and Economy (BMWFW),
the Federal Ministry of Traffic, Innovation and Technology (BMVIT), the Styrian Business Promotion
54
Agency SFG, the Standortagentur Tirol and ZIT - Technology Agency of the City of Vienna through the
COMET-Funding Program managed by the Austrian Research Promotion Agency FFG.
References
[1] E. Marten, R.-J. Müller, and W.-D. Deckwer, “Studies on the enzymatic hydrolysis of polyesters I. Low
molecular mass model esters and aliphatic polyesters,” Polym. Degrad. Stab., 2003, 80, no. 3, pp.
485–501.
[2] Z. Gan, K. Kuwabara, M. Yamamoto, H. Abe, and Y. Doi, “Solid-state structures and thermal
properties of aliphatic–aromatic poly(butylene adipate-co-butylene terephthalate) copolyesters,”
Polym. Degrad. Stab., 2004, 83, no. 2, pp. 289 300.
L13
POVERENOV, ELENA: NANOTECHNOLOGIES IN BIOPOLYMER COMPOSITES TO PREPARE
ACTIVE BIODEGRADABLE FILMS FOR FOOD PACKAGES AND COATINGS
Elena Poverenov*, Hadar Arnon
Food Quality and Safety Department, Agricultural Research Organization The Volcani Center, Bet Dagan, 25050, Israel
*[email protected]
1. Summary
Biopolymers, carboxymethyl cellulose (CMC) and chitosan (Chi) were utilized to prepare active edible
coatings. Addition of coating was performed using the Layer-by-Layer (LbL) technique, which is based on
electrostatic deposition of oppositely charged CMC and chitosan layers. The efficacy of the developed
CMC-Chi coatings was evaluated on four different citrus fruit species: 'Or' and 'Mor' mandarins, 'Navel'
oranges and 'Star Ruby' grapefruits after 4 weeks of storage at the optimal temperature for each variety
and 5 more days at shelf life conditions at 20°C. The results showed that adding an external layer of
chitosan increased the fruit gloss and firmness in a concentration dependent manner.
Nanoemulsions were utilized to incorporate food sourced citral, sensitive and liphophilic active agent
into a coating matrix. Water was utilized as a solvent, organic solvents and synthetic additives were
avoided. The properties and functionality of the nano-emulsified active edible films were compared to
those of the coarse-emulsified films. Average droplet diameter of the citral emulsions was found to be
4000-5000 nm for coarse emulsions and 100-200 nm for nanoemulsions. The nano-emulsified films
demonstrated improved mechanical properties (tensile strength, elongation at break and Young modulus)
as compared to the corresponding coarse-emulsified films. The effect of active edible coatings on quality,
storability and microbial safety of the food products was examined on fresh-cut melon model. Active
coatings demonstrated improvement of physiological parameters of the fruit and reduction of the
bacterial growth.
55
L14
SAMYN, PIETER: CRYSTALLIZATION BEHAVIOUR AND THERMAL PROPERTIES OF BIOBASED PHB/NFC NANOCOMPOSITE BLENDS
1
1
1
1
Vibhore K. Rastogi , Tilmann Herberger , Pieter Samyn *
University of Freiburg – Freiburg Institute for Advanced Studies (FRIAS) – Chair for Bio-based Materials Engineering,
Werthmannstrasse 6, D-79085 Freiburg (Germany)
*[email protected]
1. Introduction
The formulation of novel bio-based composite blends has become challenging in many application
areas, especially for packaging coatings and films. A homogeneous distributive / dispersive mixing and full
compatibility of additives is required to fully benefit from the reinforcing capacity of the composite.
Nanofibrillated cellulose (NFC) is a favourable additive to improve the mechanical strength and barrier
properties of polymer blends, however, its mixing properties may also influence the crystallization kinetics
of the polymer blend as it acts as a nucleating agent. Therefore, the processing properties of
nanocomposite blends may strongly differ from the unfilled polymer and require adaptation of the
processing parameters. In this work, the effects of blending NFC into polyhydroxybutyrate (PHB) is
evaluated. The PHB is a semi-crystalline polyester and exists in different grades with variable mechanical
properties from flexible to stiff. As a main disadvantage, PHB is relatively brittle and should be processed
with care under slow temperature rates as it has a very slow crystallization rates. The maximum
crystallization rates occur at temperatures between 60°C and 70°C. If cooling times after processing are
very short, the polymer will only crystallize to a very small extend. So, it is rather recommended to allow
long cooling times at molding temperatures of 60°C. If cooling times cannot be extended because of the
fast cycle rates and economic production cost, the mold has to be colder. In addition, similar problems
occur with the dimensional stability of PHB at temperatures slightly above room temperature, where the
polymer becomes too flexible if it is exposed to moderately high temperatures. After processing
operations and drawing, especially, the non-stretched segments of a part are at risk of being to flexible.
Already stretched amorphous parts shrink back when heated over a certain temperature. The stretched
regions are oriented and crystallized by orientation and have therefore stiffer mechanical properties than
the non-oriented segments. This is even more obvious when the cooling time is short, because then there
is not enough time for crystallization.
In conclusion, the main drawbacks in processing PHB have to do with controlling the crystallization
properties. A way of counteracting these drawbacks is the use of nucleating agents as additives, which
control the type and the rate of crystallization by inducing the formation of a homogenous structure with
small crystals. It further can be assumed that the nucleating agents amplify the crystallization effect of the
orientation by drawing. The nucleating agent should just increase the rate of crystallization, but not the
amount of crystallinity. Besides different commercial nucleating agents, the role of nanofibrillated
cellulose (NFC) as biodegradable and bio-based additive and effect as nucleating agent should be known.
Therefore in this work NFC fibers are compounded with PHB. The blending of PHB and NFC fibers can have
potential interests for thermoforming, barrier coating applications, or structural nanocomposites. This
work presents a manufacturing process for compounding PHB with NFC fibers and clarifies which NFC
ratios are inducing the favourable crystallization rates.
2. Experimental
Different PHB grades are combined with different concentrations of NFC. The commercial PHB grades
Mirel M2100, Mirel 4100 (delivered by Metabolix) and a 50/50 blend of M4100 and M2100 each are
mixed with 0 %, 0.25 %, 0.5 %, 0.75 % and 1 % softwood NFC (delivered by VTT Finland) or 2 % of an
established nucleating agent (delivered by Metabolix). The M4100 grade is more stretchable and should
therefore be more suitable for thermoforming. Pure M2100 has a higher crystallinity than pure M4100,
56
therefore it is expected that the effect of NFC fibers can more easily be seen on M2100. A blend of both
grades is expected to have intermediate material properties.
The following method for production of PHB/NFC blends was followed. First, the PHB was purified and
dissolved in propylene carbonate (PC). Next, the aqueous NFC suspension was mixed with polyethylene
glycol (PEG) and added to the solution of PHB/PC. The amounts of required NFC per blend were calculated
as weight percentages and added appropriately. The PHB/PC solution was heated up to 140°C for 20
minutes and was stirred with a magnetic stirrer at 600rpm until the PHB was fully dissolved. Then, the
NFC/PEG solution was added. The viscous mixture was further manually stirred until a homogenous
mixture without agglomerations was obtained. The viscous mixture was pressed through a sieve into a
glass with 500 ml °C cold water and thereby formed noodle-like shapes. The blends were cleaned by
subsequently heating and quenching in cold water, allowing for gradual diffusion of PC and PEG. The
cleaning steps were repeated three and the material was finally dried under vacuum conditions at 70°C
for about 16 hours.
The blends were subsequently characterized by standard techniques including TGA (Pyris 1, Perkin
Elmer), DSC (DSC 8500, Perkin Elmer) and FTIR (Spectrum 65, Perkin Elmer). For DSC, a sample weight of
about 5 mg was heated over two cycles from -40 to 200 ºC at a heating rate of 10 °C/min and cooling rate
of 30°C/min. For FTIR, the spectra were measured at 4000-550 cm-1 wavelengths with a resolution of 4
cm-1 averaged over 32 scans. The FTIR measurements were done three times for every sample. The TGA
and DSC measurements were done three times for one sample and one time for the other samples. The
several measurements on one sample provide statistically consistent results.
3. Results and discussion
The DSC curves for PHB (M2100) blends are shown in Figure 1a. In the cooling step, the earliest
crystallization occurs with 0.75% NFC, followed by 0.5 % NFC, 0.25 % NFC, 1 % NFC and the 2 %
commercial nucleating agent. The native PHB shows no crystallization during cooling. PHB with
commercial nucleating agent has the earliest peak for cold crystallization, followed by unmodified PHB.
The main melting temperatures of all blends are 5 to 10°C lower temperature than native PHB, while the
nanocomposite blends with NFC have an additional small melting peak at lower temperature. The batches
with NFC are generating a small additional amount of different crystals. The blending process is promoting
a slight increase in crystallization, even if no nucleating agent or NFC is added: in that case, a small
amount of remaining PC (detected by FTIR) may induces some crystallinity. For 0.25 to 0.5 % NFC, the
crystallization is favoured and rates are proportional to the NFC content. The 1% NFC content is too high
and does not promote the crystallization optimally, as high NFC contents to block molecular
arrangements in the polymer matrix. In contrast, the commercial nucleating agent is only slightly
increasing the crystallinity. Based on weight percentages, NFC more efficiently controls crystallization
than a commercial nucleating agent.
The variation in crystallinity for the different blends were further confirmed by FTIR, shown in Figure
1b. All spectra were baseline corrected and normalized on the 1380 cm-1 absorption band, corresponding
with CH3 conformations that are not related to crystalline or amorphous regions. The absorption bands at
1276 cm-1 and 1227 cm-1 are characteristic for crystallinity, while a band at 1178 cm-1 indicates amorphous
structures. The small peak at 1804 cm-1 reflects only a small amount of PC that is left after blending. The
highest intensity for crystalline absorption bands occurs in presence of 0.75 % NFC, followed by 0.5 %
NFC, 0.25 % NFC, 1.0 % NFC and native PHB. The PHB blends with M2100 show higher crystallinity and less
amorphous structures compared with other blends of M4100. This can most likely be related to a
different molecular structure of M4100 with a more spacious structure so the added NFC fibers are not
blocking the structural rearrangements during crystallization. Similarly, the NFC fibers act as a nucleating
agent and induce crystallinity. For M4100, the NFC contents below 1% are too low for inducing the
crystallization effects and higher amounts are needed for those blends.
57
(a)
(b)
0.75 % NFC
0.50 % NFC
0.25 % NFC
Absorbance (a.u.)
Heat flow (endo up)
commercial
00
1 % NFC
native PHB
00
PHB
0.50 % NFC
commercial
1 % NFC
0.25 % NFC
0.50 % NFC
0.75 % NFC
-30
0
40
80
120
Temperature
(°C)
160
200
1325
1300
-1
1275 Wavenumber
1250
1225
(cm ) 1200
1175
Figure 1. Characterization of PHB (M2100)/NFC blends with 0 to 1 % NFC together with a 2 %
commercial nucleating agent, (a) DSC curves, (b) FTIR spectra
4. Conclusions
Successful compounding of PHB and NFC is demonstrated and confirmed by FTIR, TGA and DSC. The
FTIR spectra present an increase of hydrogen bonding in the compounds indicating good interaction
between the NFC and PHB. The expectation to measure an induced crystallization by NFC fibers is fulfilled
and desirable NFC ratios for the different grades are defined: DSC data show that this ratio is at around
0,75% for the grade M2100, at least 1% for the grade M4100 and at around 0,75 % for a mix between the
grades M2100 and M4100. Based on the weight-percentage, the use of NFC as nucleating agent is more
efficient that available commercial nucleating agent. Two of drawbacks of PHB, i.e. the high brittleness
and the low thermal stability can be improved by a homogenous and fast crystallization in presence of
NFC. As such, NFC fibers have the potential to induce desired crystallinity. In future applications, we are
considering these blends as protective barrier coatings on paper, improving hydrophobicity and oxygen
barrier properties.
Acknowledgements
We thank the Robert-Bosch Foundation for financial support of the Juniorprofessorship (2011-2016:
“Foresnab”-project) and the State of Baden-Württemberg for support in the Juniorprofessorenprogram
(2012-2015: “NaCoPa” – project).
L15
SIMNETT, ROSE E.: SYNTHESIS OF BIOCOMPATIBLE NVP-BASED MATERIALS WITH
DESIGNED ARCHITECTURE
Rose E. Simnett*, Iain J. Johnson, and Ezat Khosravi
Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom
*[email protected]
58
1. Introduction
PNVP is industrially important as it
possesses a number of unique
chemical and biological properties. It is
a
nontoxic
polymer
that
is
biocompatible with living tissue and
soluble in water as well as organic
solvents. Therefore, it is of great
interest for the use in medical,
cosmetic, and food industries. Hence,
our interest here is to develop novel
RAFT agents for RAFT polymerization
to produce NVP-based polymeric
materials with high conversions,
Figure 1. Structures of RAFT1-5
controlled molecular weights, and
complex architectures. The work presented here describes the synthesis of a number of novel xanthate
RAFT agents, RAFT1–5 (Fig. 1) to prepare a range of novel NVP-based polymeric materials with linear and
star architectures via RAFT polymerization [1].
2. Experimental
The syntheses of RAFT1-4 were carried out in THF unless otherwise stated. RAFT1 was synthesised by
reaction of N-bromoethylpyrrolidone with potassium O-ethyl xanthate. The reaction of Nhydroxyethylpyrrolidone, trimethylamine and 2-bromopropionyl bromide produced the intermediate 2(2-oxopyrrolidin-1-yl)ethyl 2-bromopropanoate which was reacted with potassium O-ethyl xanthate to
give RAFT2. RAFT3 was produced by reaction of N-hydroxyethylpyrrolidone, trimethylamine and αbromoisobutyrylpropionyl bromide, potassium O-ethyl xanthate was added to the intermediate in ethanol
to afford the product. N-hydroxyethylpyrrolidone, potassium phosphate tribasic, carbon disulphide were
reacted in chloroform to give an intermediate which was reacted with methyl 2-bromopropionate to give
RAFT 4. RAFT5 was synthesised using an adapted procedure [2], di(trimethylolpropane), 2bromopropionyl bromide in chloroform to give the intermediate. Potassium O-ethyl xanthate was added
and the product purified.
Typical procedure for homopolymerizations with RAFT1–4 NVP, RAFT2, 4,4’-azobis(4-cyanovaleric acid)
(ACVA) in 1,4 dioxane at 70 oC for 8 h.
3. Results and discussion
Ethyl pyrrolidone moiety was included in the structures of the xanthates as a part of R (RAFT1-3) or Z
group (RAFT4) to evaluate their effect on the polymerization and to impart homogeneity in the resulting
products. The xanthates were designed to fragment to give primary (RAFT1), secondary (RAFT2 and 4),
and tertiary radicals (RAFT 3) allowing evaluation of their effect on polymerization. RAFT5 was designed to
produce polymeric materials with four-arm architectures (Figure 1).
(i)
(ii)
Figure 2. SEC traces (refractive index) (i) and molar mass distribution (ii) for the polymerization of
NVP in the presence of RAFT4: (a) 1 h, (b) 2 h, (c) 4 h, (d) 8 h, and (e) 16 h
59
Homopolymers of NVP as well as linear and 4-arm star co-polymers PNVP-ran-PVAc, and 4-arm star copolymers of PNVP-block-PVAc were prepared. The results of the kinetic study indicate that the
incorporation of ethyl pyrrolidone moiety in both R and Z groups in the RAFT2-4 allows the synthesis of
NVP-based materials with high conversion and high level of control. Moreover, the incorporation results
in the placement of pyrrolidone as chain end groups, which is anticipated to lead to NVP-based materials
with greater homogeneity. For homopolymerisation of NVP with RAFT2 and 4, a good linear correlation
for log[([M]o/[M])] against time was observed, with no apparent inhibition period in the polymerization
reaction, Mn increased in a linear fashion with increasing conversion and Ð remained narrow. The
progression of the SEC traces and the molar mass
distributions for polymerisation with RAFT4 are shown
in Figure 2.
The four-arm star of PVAc was synthesised and
used as a macroCTA for the RAFT polymerization of
NVP to synthesize a four-arm star of PVAc-block-PNVP
(Figure 3). The morphology of aggregates formed by
the amphiphilic four-arm star block copolymer of
PVAc-block-PNVP was investigated by TEM (Figure 4).
The resulting micrograph clearly showed that the
Figure 3. Structure of PVAc-block-PNVP
block copolymer formed a phase consisting of
spherical micelles with an average diameter of about
60 nm.
4. Conclusions
Novel xanthate RAFT agents containing ethyl pyrrolidone moiety as part of R (RAFT1–3) and Z group
(RAFT4) were successfully synthesized and used to prepare linear PNVP homopolymers. RAFT1 showed
comparable characteristics to conventional free radical polymerization due to the formation of unstable
primary radical species upon fragmentation. RAFT2 and 4 gave
polymerizations with living/controlled characteristics as the result
of the combination of the formation of stable secondary radical
species upon fragmentation and incorporation of ethyl pyrrolidone
moiety as the R and Z group, respectively. Furthermore, the
resulting NVP-based materials would be anticipated to have a
greater homogeneity in comparison to those obtained via nonpyrrolidone-containing RAFT agents. Four-arm star homopolymers
of PNVP and PVAc as well as linear and four-arm star PNVP-ranPVAc exhibited monomodal distributions with narrow Ð and
molecular weights close to the theoretical values. TEM of four-arm
star PVAc-block-PNVP showed a phase consisting of spherical
micelles.
Figure 4. TEM image of assemblies
formed by four-arm star PVAcblock-PNVP
Acknowledgements
The authors gratefully acknowledge the financial support from Ashland Inc. for I.J. Johnson and R.E.
Simnett.
60
References
[1] I. J. Johnson, E. Khosravi, O. M. Musa, R.E Simnett, J. Polym. Sci. Part A Polym. Chem., published
online 31st Dec. 2014, DOI: 10.1002/pola.27502.
[2] J. Bernard, A. Favier, L. Zhang, A. Nilasaroya, T. P. Davis, C. Barner-Kowollik, M. H. Stenzel,
Macromolecules, 2005, 38, 5475–5484.
L16
ZABOROVA, OLGA: BIOCOMPATIBLE p H-SENSITIVE CARRIERS BASED ON ANIONIC
LIPOSOME-POLYCATIONIC PARTICLE COMPLEXES
1
1
2
Olga Zaborova *, Andrey Sybachin , Vyacheslav Samoshin , Alexander Yaroslavov
1
1
Lomonosov Moscow State University, Leninskie Gory, 1, 119991, Moscow, Russia
2
University of Pacific, 3601 Pacific Ave., CA 95211, Stockton, USA
*[email protected]
1. Summary
Use of spherical monolamellar bilayer lipid vesicles (liposomes) as containers for delivery was
suggested after their discovery in the middle of previous century [1]. Due to unique structure, liposomes
are used for encapsulation of different substances for improving their physical, chemical and operational
characteristics. This makes liposomal containers promising for encapsulation and delivery of various
therapeutic, diagnostic and cosmetic agents.
Liposomes immobilized on suitable surfaces can act as more capacious depots for pharmaceutical
active compounds, and remain stable until they reach the target side. Unfortunately, due to liposomesurface and liposome-liposome interactions, fusion and rupture events are common during adsorption
particularly at higher coverage.
We suggest to use spherical polycationic brushes – colloidal particles with a condensed core and a
shell of grafted linear polycationic chains – as carriers for liposomes. Anionic liposomes effectively adsorb
on the cationic brush surface and retain their integrity. This allows one to concentrate dozens of
liposomes with entrapped bioactive compounds within a rather small volume. In this work we
demonstrate the simple way of preparation of multi-liposomal compositions of vesicles bearing different
substances in desired proportions – the key to creation of multi-target drug.
A special problem of liposomal containers is to force liposomes to release a content at a target site for
enhancing therapeutic effect of drugs. It has been shown that a decrease in pH value (increase of acidity)
is typical for pathological physiological pathways, e.g. inflammation, solid tumor progression, ischemic
injuries of heart and brain tissues, etc [2,3]. Thus, the change in pH can serve as an attractive stimulus to
trigger a drug delivery system.
Incorporation of pH-triggerable lipid (flipid) [4], capable to change conformation with decrease in pH,
in membrane of anionic liposomes allowed us to control release of hydrophilic substances from multiliposomal containers.
Stability of liposomes/brush complexes towards dissociation in physiological media, their rather low
toxicity and pH-controlled release of encapsulated substances make these structures promising for use as
nanocontainers for delivery of biological active compounds.
This work was supported by Russian Science Foundation project № 14-13-00255.
61
References
[1] Bangham A.D., Hill M.W., Miller N.G.A. /Methods in Membrane Biology. Ed. by E.D. Korn. New York:
Plenum Press, 1974.
[2] Karanth H., Murthy R.S.R. pH-Sensitive liposomes - principle and application in cancer therapy. J.
Pharm. Pharmacol. 2007, 59, 469-483.
[3] Allen T.M., Cullis P.R. Drug delivery systems: entering the mainstream. Science. 2004, 303, 18181822.
[4] Brazdova B.; Zhang N., Samoshin V.V., Guo X. trans-2-Aminocyclohexanol as a pH-sensitive
conformational switch in lipid amphiphiles. Chem. Commun. 2008, 4774-4776.
L17
ZEPNIK, STEFAN: EXTRUSION FOAMED EXTERNALLY PLASTICIZED CELLULOSE ACETATE
FOR THERMOFORMED TRAYS
1,2
3
3
1
2
Zepnik, S. *, Hendriks, S. , Hopmann, C. , Kabasci, S. , Radusch, H.-J. , van Lück, F.
4
1
Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT,
Osterfelder Straße 3, 46047, Oberhausen, Germany
2
Center of Engineering Sciences, Martin Luther University Halle-Wittenberg, 06099 Halle/Saale, Germany
3
Institute of Plastics Processing (IKV) at RWTH Aachen University, 52056 Aachen, Germany
4
AIXtrusion Consulting, Grünstraße 31, 41564, Kaarst, Germany
*[email protected]
1. Introduction
Today, polystyrene (PS) is the predominant polymer for producing extruded foams for thermoformed
trays. However, PS is derived from petrochemicals and is not biodegradable. The use of renewable
resources, the reduction of packaging waste, and the minimization of emissions is becoming more
important. PS does not comply with these requirements. Consequently, lots of research has been
conducted on foaming bio-based polymers, e. g. thermoplastic starch (TPS) or poly(lactic acid) (PLA) [1-4].
With respect to thermoformed trays for hot food contents, these biopolymers exhibit several drawbacks
such as limited heat resistance for PLA and insufficient moisture resistance for TPS. Cellulose acetate (CA),
as an organic cellulose ester, is one of the oldest bio-based and biodegradable polymers. Thermal,
rheological, and mechanical properties of thermoplastic CA compounds are comparable to those of PS.
Therefore, CA is a promising bio-based polymer for replacing PS in certain foam applications including
extrusion foamed trays for packaging [5,6]. This contribution shows recent results of externally plasticized
CA (plCA) extrusion foams and their potential for producing thermoformed trays.
2. Experimental
Externally plasticized CA was obtained as granules from FKuR GmbH. Trans-1,3,3,3-tetrafluoropropene
(HFO 1234ze) from Honeywell Fluorine Products B.V. was used as physical blowing agent with zero ozone
depletion potential and global warming potential of six. Table 1 shows typical properties of HFO 1234ze.
Ethanol was added as co-blowing agent with 0.4 wt.%. Talc was used as nucleating agent having platelet
geometry with a specific surface area of 9.5 m2 g-1 and a median particle size d50 of 2 µm. Talc was first
melt compounded with plCA to obtain a 30 wt.% masterbatch. This talc masterbatch was then added to
the foam extrusion process with 0.5 wt.%.
62
Table 1. Typical properties of HFO 1234ze
Molar mass Boiling point Vapour pressure at 25 °C
[g mol-1]
[°C]
[kPa]
114.0
-19.0
450.0
Liquid density at 20 °C Vapour density at 20 °C
[kg m-3]
[kg m-3]
1194.2
22.3
A 60 mm single screw foam extruder of Barmag Oerlikon Textile GmbH & Co. KG with a length to
diameter ratio L/D = 40/1 was used. The extruder is equipped with a mixing screw optimized for the foam
extrusion process. The last 11 D of the extruder length are temperature controlled with oil in order to cool
the polymer melt. The blowing agent was compressed and injected into the extruder barrel through a
pressure hole at 16 D using a metering system equipped with a diaphragm pump. By means of mixing
elements on the screw, the blowing agent is dispersed in the melt.
Film thickness, blow up ratio, density, and density reduction of the extruded foam sheets were
measured. The blow up ratio is defined as the ratio of the annular die diameter to the cooling mandrel
diameter. The morphology was analysed by scanning electron microscopy (SEM). Mechanical properties
were investigated by means of tensile test in machine and transverse direction according to DIN EN ISO
527. Thermoforming behaviour of the extruded foam sheets was tested on an industrial thermoforming
machine BN 500 from BN-Sondermaschinen.
3. Results and discussion
Table 2 compares typical characteristics of the extruded plCA foam sheet with an extruded PS foam
sheet from Inde Plastik Betriebsgesellschaft mbH. As can be seen, the density is close to an industrially
produced PS foam sheet. However, the blow up ratio is still lower and thus the extruded plCA foam sheet
is thicker.
Table 2. Physical properties of extruded plCA foam sheet in comparison to extruded PS foam sheet from
Inde Plastik Betriebsgesellschaft mbH. Density of unfoamed plCA is 1310 kg m-3 und of unfoamed PS
1050 kg m-3
Density [kg m-3] Density
reduction Film thickness [mm] Blow up ratio [-]
Property
[%]
PS foam sheet
88.0
91.6
1.5
5:1
plCA foam sheet
115.5
91.2
2.4
3:1
The extruded plCA foam sheet has a fine and homogeneous foam morphology with polyhedral closed
cells, as shown in figure 1. It is similar to that of extruded PS foam sheet. However, the lower blow up
ratio results in a less homogeneous stretching of the plCA foam sheet. Thus, slightly higher cell orientation
is observed for the plCA foam sheet.
Figure 1. Foam morphology of extruded plCA foam sheet (left) and extruded PS foam sheet (right)
Table 3 compares the specific stiffness and strength of the extruded plCA foam sheet with the
standard PS foam sheet from Inde Plastik Betriebsgesellschaft mbH. The stiffness of the plCA foam sheet
is comparable to that of the PS foam sheet, while the strength of the standard PS foam sheet is noticeably
higher in both directions, MD and TD. Additionally, the ratio between MD and TD is lower for the standard
63
PS foam sheet due to the higher blow up ratio, which leads to stronger and more homogenous stretching
and consequently resulting in lower anisotropy of the foam structure (see figure 1).
Table 3. Mechanical properties in machine direction (MD) and transverse direction (TD) of extruded plCA
foam sheet in comparison to extruded PS foam sheet from Inde Plastik Betriebsgesellschaft mbH.
Specific modulus [(MPa)/(kg m-3)]
Specific strength [(kPa)/(kg m-3)]
Property
MD
TD
MD/TD
MD
TD
MD/TD
PS foam sheet
0.89
0.76
1.17
36.4
34.1
1.07
plCA foam sheet
0.89
0.61
1.46
28.7
21.6
1.33
Figure 2 shows two types of trays thermoformed from the extruded plCA foam sheet. Especially for flat
trays such as plates and dishes the haptic and optical properties are very similar to thermoformed trays
from an industrial extruded PS foam sheet. However, trays having a high drawing depth such as cups or
food boxes show limited product quality, mainly in the corners.
Figure 2. Thermoformed trays based on extruded plCA foam sheet
4. Conclusions
Externally plasticized CA (plCA) was successfully extruded to foam sheets using a mixture of
HFO 1234ze and ethanol as blowing agent. The foam density and density reduction are in the range of a
standard PS foam sheet, while the blow up ratio is still lower. The foam morphology of the extruded plCA
foam sheet is similar to that of a standard PS foam sheet. A fine and homogeneous morphology with
closed cells is obtained. Due to the lower blow up ratio, anisotropy is slightly higher in case of the
extruded plCA foam sheet leading to higher MD/TD ratios.
The plCA foam sheets can be successfully thermoformed to different packaging trays. The product
quality is similar to that of trays produced from standard PS foam sheets, especially in case of flat trays
such as plates. The results show that plCA is a promising biopolymer for extrusion foaming and can be a
suitable alternative to PS.
Acknowledgements
The authors thank the BMBF (German federal ministry of education and research) and the PtJ (project
management Jülich) for funding the project.
References
[1] J.-F. Zhang, X. Sun, J. Appl. Polym. Sci. 2007, 106, 857-862.
[2] J. Reignier, R. Gendron, M.F. Champagne, Extrusion foaming of Poly(lactic acid) blown with CO2:
Toward 100% green material. 8th International Conference on Blowing Agents and Foaming
Processes, Munich, 16-17 May 2006, Paper 8.
[3] Y. Nabar, R. Narayan, Polym. Eng. Sci. 2006, 46, 438-451.
[4] S.-T. Lee, C.B. Park, N.S. Ramesh, Polymeric foams: science and technology; Chapter 8, CRC Press,
2007, 165-204.
[5] S. Zepnik, S. Hendriks, S. Kabasci, H.-J. Radusch, J. Mat. Res. 2013, 28, 2394-2400.
[6] S. Zepnik, S. Kabasci, R. Kopitzky, H.-J. Radusch, T. Wodke, Polymers 2013, 5, 873-889.
64
POSTERS
P1
BLACKWELL, CATHERINE: DEGRADATION OF THERMOSETTING MATERIALS VIA ACID
HYDROLYSIS – A TRANSITION TO THERMOPLASTICS
C. Blackwell* and E. Khosravi
Department of Chemistry, Durham University, DH1 3LE, UK,
*[email protected]
1. Summary
Thermosets are an important class of materials due to their good adhesive strength and high
temperature stability [1]. However they are not degradable, reworkable and recyclable which is of great
significance for both environmental and economic considerations. The intractability of thermosets is a
particular problem for manufacturers requiring the disassembly of products at end of use to facilitate
detaching and recycling.
Ring opening metathesis polymerization (ROMP) initiated by Grubbs well-defined ruthenium initiators
has been used to synthesise well-defined polymers with controlled architectures, molecular weights,
dispersities and terminal functionalities [2, 3].
This poster reports the first example of acid-catalyzed degradation of ROMP thermosetting materials
based on norbornene dicarboximide moieties containing an acetal ester linkage. The degradation process
was monitored by 1H NMR and rheological analysis. The insoluble cross-linked materials were subjected
to acid-catalyzed hydrolysis using green acids such as acetic and citric as well as hydrochloric acid,
resulting in the materials becoming completely soluble in dichloromethane. 1H NMR performed on
materials after acid-catalyzed hydrolysis revealed the structure of a linear polymer confirming the
cleavage of crosslinks upon degradation and established that cross-linked polymers were degraded into
linear polymers. Rheological analysis performed on cross-linked materials after hydrolysis showed
characteristics indistinguishable to that of the linear analogues.
The results of 1H NMR and rheological studies confirm the breakdown of the acetal ester linkages by
acid-catalyzed hydrolysis allowing the transition from cross-linked to linear thermoplastic polymers. This is
anticipated to facilitate the recycling and reworking.
References
[1] Malik, J.; Clarson, S. J. Int. J. Adhes. Adhes. 2002, 22, 283.
[2] Khosravi, E.; Iqbal, F.; Musa, O. M. Polymer 2011, 52, 243.
[3] Khosravi, E.; Musa, O. M. Eur. Polym. J. 2011, 47, 465.
P2
BOZSÓDI, BRÚNÓ: THE EFFECT OF COUPLING ON THE STRUCTURE, INTERFACIAL
INTERACTIONS AND MECHANICAL PROPERTIES OF POLYPROPYLENE/LIGNIN BLENDS
1
1
1
1
Brúnó Bozsódi *, Péter Dénes , Dávid Kun , Béla Pukánszky
1,2
Laboratory of Plastics and Rubber Technology, Budapest University of Technology, H-1521 Budapest, P. O. Box 91, Hungary
65
2
Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences, H-1519 Budapest, P.O. Box 286,
Hungary
*[email protected]
1. Introduction
Lignin (LS) is produced as a by-product during cellulose production and it is often used as fuel due to
its high energy density. However, burning is disadvantageous since it produces a significant amount of
carbon-dioxide and a lot of raw material is lost. Blending LS with polymers could be a solution to the
problem. LS is a polar biopolymer, thus its compatibility with polypropylene (PP) is poor. This problem
may be eliminated by coupling agents, such as maleic anhydride-grafted polypropylene (MAPP).
Accordingly the goal of our research was the preparation of PP/LS and PP/MAPP/LS blends and the
investigation of the effect of coupling on structure and interfacial interactions.
2. Background
Interfacial interactions can be estimated quantitatively from the composition dependence of tensile
properties [1, 2]. One of the applied equations describes the composition dependence of tensile strength:
 T   T 0  n 
1
 exp B 
1  2.5
(1)
where σT and σT0 are the true tensile strength (σT = σλ and λ = L/L0) of the blend and the matrix polymer, n
is a parameter expressing the strain hardening tendency of the matrix, φ is the volume fraction of lignin in
the blend and B is a parameter related to the load-bearing capacity of the lignin, i.e to interaction. If n is
known, Equation (1) can be rearranged:
 1  2.5 1 
n T
   n  Tred   n  T 0   B
1   n 

(2)
According to Equation (2) the ln(σTred) vs. φ plot must give a straight line, the slope of which is equal to
parameter B.
3. Experimental
The materials used in our experiments were the Tipplen H 649 FH (TVK, Hungary) PP homopolymer,
the Orevac CA100 (Arkema, USA) MAPP coupling agent and the Bretax SRO2 (Burgo, Italy) lignosulfonate.
Blends were prepared with different lignin contents from 0 to 60 vol%. MAPP/LS ratio was 0.20.
Components were homogenized in a Brabender W 50 EHT internal mixer for 10 min at 190 °C, 42 rpm.
The blends were compression moulded into 1 mm thick plates at 190 °C using a Fontijne SRA 100 machine
and then specimens were cut for tensile testing with a Charlyrobot Charly 4U CNC milling machine. The
mechanical properties of the blends were determined by tensile testing (Instron 5566). During the tensile
tests, the acoustic emission (AE) of the blends was monitored by a Sensophone AED 40/4 apparatus, since
micromechanical deformation processes often result in acoustic signals. We applied scanning electron
microscopy, SEM (JEOL JSM 6380 LA) to study morphology and differential scanning calorimetry, DSC
(Perkin Elmer DSC 7) to determine the crystallinity of the matrix.
4. Results and discussion
Lignin enhances the stiffness of the blends, while the extent of crystallinity does not change
significantly. The strength of PP/LS blends decreases with increasing lignin content, while the strength of
PP/MAPP/LS has a maximum at 40 vol% lignin content. This represents stronger interfacial interactions in
the presence of MAPP. According to the AE results, micromechanical deformation processes are initiated
at larger stresses in the case of coupling. Furthermore, SEM micrographs show that lignin particles are
66
smaller in the PP/MAPP/LS blends. All of these facts prove that coupling results in stronger interfacial
adhesion between the components. As Fig. 1 shows the B values of the blends differ considerably, which
also indicates that coupling is an effective method to increase the strength of interfacial adhesion in PP/LS
blends.
5.5
PP/MAPP/LS
B = 3.40
2
R = 0.976
5.0
ln(Tred)
4.5
4.0
3.5
PP/LS
B = 1.05
2
R = 0.866
3.0
2.5
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Volume fraction of lignin, 
Figure 1. Determination of parameter B
5. Conclusions
According to the results, MAPP increases the strength of interfacial adhesion in PP/LS blends resulting
in smaller lignin particles and larger reinforcement. Furthermore, micromechanical deformation processes
are initiated at larger stresses in case of coupling, which also indicates stronger adhesion between the
components.
Acknowledgements
The research was financed by the National Scientific Research Fund of Hungary (OTKA Grant No.
K101124) and the Forbioplast FP7 project of EU (212239). The authors would like to thank Burgo Cartiere
SpA for donating the lignin sample.
References
[1] B. Turcsányi, B. Pukánszky, F. Tüdős, J. Mater. Sci. Lett. 1988, 7(2), 160-162.
[2] B. Pukánszky, Composites 1990, 21(3), 255-262.
P3
BRZESKA, JOANNA: COMPOSITES OF CROSSLINKED POLYURETHANES WITH CHITOSAN
1*
1
1
2
2
J. Brzeska , K. Albecka , W. Sikorska , M. Kowalczuk , M. Rutkowska
1
Gdynia Maritime University, Department of Chemistry and Industrial Commodity Science,
83 Morska Str., 81-225 Gdynia, Poland
2
Polish Academy of Sciences, Centre of Polymer and Carbon Materials,
34 Curie-Sklodowska Str., 41-819 Zabrze, Poland
*[email protected]
67
1. Introduction
Polyurethanes (PUR) are material whose properties can be programmed by selecting the suitable
substrates for their synthesis. For material designing for a particular purpose the appropriate
oligomeroles, isocyanates and chain extenders have to be chosen. Degradable material may be obtained
by introducing of oligoester (eg. poly([R,S]-3-hydroxybutyrate and polycaprolactone) into the structure of
soft segments. If isocyanate and the chain extender are also nontoxic and degradable that polyurethane
would be environmental friendly. Polyhydroxyacids are one of the most important biodegradable
compounds. Synthetic, almost amorphous R,S-PHB oligomer, obtained by anionic ring-opening
polymerization (R,S)-β-butyrolactone, degrades under the influence of the environment conditions [1].
In addition to the traditional applications the crosslinked polyurethanes can be using as modern
coatings and membranes, polymers with the shape memory and materials for medical application [2].
The properties of polyurethanes can be modified by physically mixing with natural polymers, such as
proteins or saccharides [3,4]. Chitosan is a natural amino polysaccharide with the unique properties - is
non-toxic, biocompatible, biodegradable and antimicrobial material [5].
It seemed to be interesting to obtain composites of crosslinked polyurethanes (synthesized with
degradable subtracts) with chitosan. The oil and water sorption and water vapor permeability were
estimated for obtained composites.
2. Experimental
Synthesis of polyurethanes and their composites with chitosan
Synthesis of polyurethanes was carried out in a two-step reaction, with molar ratio of NCO:OH = 4:1 on
prepolymer step, in way similar to synthesis of linear polyurethanes [6]. The hard segments of obtained
new polyurethanes were synthesized with aliphatic 4.4'-methylene dicyclohexyl diisocyanate (H12MDI,
Aldrich) and 1,4-butanediol (1,4-BD, Aldrich). The soft segments were built of polycaprolactonetriol (PCLtriol, Mn 900, Aldrich) and synthetic R,S-PHB (Mn 1700) in weight ratio of 90:10 or 70:30. R,S-PHB was
obtained by anionic ring opening polymerization of (R,S)--butyrolactone initiated by 3-hydroxybutyric
acid sodium salt/18-crown-6 complex at room temperature and terminated with 2-bromoethanol [7]. The
prepolymer was obtained in mass and next dissolved in dimethylformamide.
Chitosan (Mη 171000, deacetylation degree 97%), previously grounded in the mortar to the small
particles, was added to polyurethane solution at the end of prepolymer chains extension. Blend of
polyurethane with chitosan was mixed and poured on Teflon plates. After the DMF evaporation the
PUR/Ch composite was annealing in vacuum drier for reaction completing.
The composition of linear polyurethane (PURlin.) with chitosan was obtaining for comparison of
properties.
Table 1. Substrates used for soft segments synthesis of PUR and composition of PUR/Ch composites
Substrates used for hard
Substrates used for soft
Composite of PUR/Ch
Materials
segments synthesis
segments synthesis
[wt.%]
PUR 0
100% PCL-triol
100/0
PUR 10
100/0
10%R,S-PHB + 90%PCL-triol
PUR 10/Ch
97.5/2.5
H12MDI+1,4-BD
PUR 30
100/0
30%R,S-PHB + 70%PCL-triol
PUR 30/Ch
97.5/2.5
PURlin./Ch
10%R,S-PHB + 90%PCL-diol
97.5/2.5
3. Methods
The oil sorption of obtained polyurethanes was estimated by immersing of polymer samples in
sunflower oil at 37 ºC for 24 hours and next their weighting after cleaning with filter paper [8]. For water
sorption measurement the samples were immersed in deionized water for 3 days at 37 ºC. After the
68
appropriate time the swollen samples were gently blotted with filter paper and weighted [9]. Water vapor
permeability of samples was estimated, using Radwag balance equipped with adapter for water vapor
permeability measuring, according to procedure of producer [10].
4. Results and discussion
Results of measuring of water vapor permeability and sunflower oil sorption by polyurethanes and
their composites with chitosan are presented in Table 2.
Table 2. The water vapor permeability and the oil sorption by polyurethanes and their composites with
chitosan
The samples mass changes after oil
Water vapor permeability
Sample
sorption [wt.%]
[mg/cm2·h]
PUR 0
0.8
1.3
PUR 10
0.5
1.0
PUR 10/Ch
1.0
2.4
PUR 30
0.7
PUR 30/Ch
0.6
1.4
PURlin./Ch
0.2*
2.3
*
data presented in paper send to publication in Polimery
the mass changes [%]
The obtained polymers minimally absorbed vegetable oil, indicating hydrophilicity of polyurethanes
and their composites. The presence of chitosan in the structure of composites did not affect their ability
to absorb oil. Crosslinked polyurethanes absorbed higher amount of oil than PURlin/Ch which was
expected because of the existing free volume in the network of crosslinked polyurethanes. The water
vapor permeability through the samples of polyurethanes and their composites was low.
16
PUR 0
PUR 10
14
PUR 30
PURlin./Ch
PUR 10/Ch
69
12
10
8
6
4
2
0
0
0,5
1
1,5
2
2,5
3
3,5
time [days]
Figure 1. The weight changes of the polyurethanes and their composites after incubation in deionized
water
Introducing of R,S-PHB into polyurethane structure increased the amount of absorbed water. The
sample mass of PUR 0 (without R,S-PHB) increased only for 2.9 wt.% after 3 days of incubation in water
whereas PUR 30 (with 30 wt.% of R,S-PHB in soft segments) – for 8.2 wt.%. Blending of crosslinked
polyurethane with chitosan caused higher water sorption (4.5 wt.% for PUR 10 whereas 13.9 wt.% for PUR
10/Ch). The mass changes of composite of linear polyurethane with chitosan PURlin/Ch after incubation in
water increased only for 3.5 wt.%.
5. Conclusion
The crosslinked polyurethanes with different amount of synthetic polyhydroxybutyrate were
synthesized and next blended with chitosan. They were absorbed a small amount of sunflower oil. The
water vapor permeability through their samples was low.
The water sorption by samples of polyurethanes increased after introduction of R,S-PHB into soft
segments and after blending of PUR with chitosan. Crosslinked polyurethanes with R,S-PHB absorbed
more water than linear polyurethane.
Acknowledgements
Authors thank to Dr. Anna Wojtasz-Pająk from MIR Gdynia for kindly support of chitosan.
References
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
K. Sudesh, H. Abe, Y. Doi, Progress in Polymer Sci. 2000, 25, 1503.
H. Janik, A. Balas, Polimery 2009, 54, 3.
C. Wong, S. Patel, R. Chen, O. Amal, M. Yos, J. of Mech. in Med. and Biol. 2010, 10 (4), 563.
J. Kuciñska-Lipka, I. Gubañska, H. Janik, Polimery. 2013, 58(9), 678
A. Qurashi: “Handbook of Bioplastic and Biocomposites Engineering Applications”, In Srikanth Pilla
(ed); John Wiley & Sons, 2011, p. 357.
J. Brzeska, P. Dacko, H. Janik, M. Kowalczuk, M. Rutkowska, Biodegradowalne poliuretany i spos b
ich wytwarzania, 2012, PL Patent No. 212763.
H. Arslan, G. Adamus, B. Hazer, M. Kowalczuk, Rapid Commun Mass Sp. 1999, 13, 2433.
A. Szelest-Lewandowska, B. Msaiulanis, Elastomery, 2002, 6, 3.
H. Yeganeh, P. Hojati-Talemi, Polym. Deg. and Stab. 2007, 92, 480.
www.radwag.pl
P4
ČEPIN, MARJETA: ANTIBACTERIAL PROPERTIES OF AMINO-FUNCTIONALISED NANOSIZED
ZINC OXIDE
Marjeta Čepin, Vasko Jovanovski, Zorica Crnjak Orel*
Kemijski inštitut, Hajdrihova 19, 1000 Ljubljana, Slovenija
*[email protected]
1. Introduction
Antibacterial properties of zinc oxide are largely depended on its size and particle morphology. This
particular metal oxide is used in, creams, medical supplies, solar cells, chemical sensors, catalysts, UV
shielding, bioimaging and other applications. ZnO nanoparticles are very pertinent as antimicrobial agent
for various microorganisms and fungi. The biggest advantage of this inorganic material over organic
agents is in its long-term activity and stability. It is also relatively nontoxic and environmentally friendly
material.Surface modifications with amino groups or polymers incorporating amino groups can greatly
improve properties of materials against bacterial colonization [2].
2. Experimental
Structure, morphology and particle size of prepare new ZnO [2] before and after modification were
examined with scanning electron microscopy (SEM) that reveals increasing integration of particle into
aggregates in some cases. Functionalisation of particles was evaluated with zeta potential measurements
and the IR spectroscopy. Research confirmed the successful binding of functional groups onto ZnO and
modification of their surface properties. X-ray diffraction unveiled highly crystalline structure of
70
nanoparticles. DLS was used to monitor particle size in water suspension and showed increased particle
size from 80 nm up to 130 nm which is associated with particle agglomeration. Antibacterial activity
measurements were performed using E. coli and S.aureus by tracking growth rate which was measured
with optical density at 600 nm [1].
3. Conclusions
From the gathered data we can confirm that studied surface modifications with selected amino
silanes, significantly improve antibacterial properties of ZnO, exhibiting up to 100 % improvement
compared to unmodified ZnO. Obtained result show exhibited improved antibacterial properties in
comparison with commercially available antibacterial agent comprising silane group.
Acknowledgements
The authors gratefully acknowledge the financial support from the Slovene research agency (Programs
P1-0030 and P1-0034).
References
[1] M. Čepin, G. Hribar, S. Caserman, Z. Crnjak Orel, Mat. Sci. Eng. C 2015, 204-211
[2] M. Čepin, V. Jovanovski, M. Podlogar, Z. Crnjak Orel, J. Mater. Chem. B 2015, 3, 1059.
P5
DERMOL, VALERIJ: ARE ENVIRONMENTALLY FRIENDLY BEHAVIOUR AND ATTITUDES
TOWARDS THE ENVIRONMENT DEPENDED ON DEMOGRAPHIC CHARACTERISTICS?
Valerij Dermol
Polymer Technology College, Ozare 19, 2380 Slovenj Gradec, Slovenia
International School for Social and Business Studies, Mariborska cesta 7, 3000 Celje, Slovenia
[email protected]
1. Summary
The paper is based on the assumption that the attitude towards the environment and environmentally
friendly behaviour significantly affect the buying behaviour of modern consumers and their decisions
about green products' purchase. Attitude towards the environment is reflected in attitudes about the
possibilities of life harmonised with the nature, necessity of natural balance, scarcity of natural resources,
human rights to modify the environment, the occurrence of environmental degradation as a result of
human actions, etc. On the other hand, the environmentally friendly behaviour means either (i)
purchasing behaviour, which leads to purchases of products manufactured by environmentally
responsible companies, manufactured and packaged in recycled or environmentally friendly materials,
with instructions that expose their environmentally friendly characteristics, (ii) environmentally friendly
behaviour by recycling various materials , the use of environmentally friendly materials and devices, etc.,
as well as (iii) the potential volunteering and donation activities.
In an empirical study which is based on the use of descriptive and bivariate statistical methods, we
determine to what extent the inhabitants of Slovenia show a positive attitude towards the environment,
and the extent to which they demonstrate environmentally friendly behaviour. In the analysis, we are
particularly interested in the study of the dependence of the two aforementioned variables on gender,
level of education, employment status, and geographic region from which individuals derive.
The results of the analysis will be able to help marketing departments in companies in defining the
targeting strategy and defining the attempts to promote the purchases of green products.
71
P6
DZIOB, DANIEL AND KOŁODZIEJ, TOMASZ: ELASTIC POLYMER SUBSTRATES FOR CELL
MIGRATION RESEARCH
1
1
1
Daniel Dziob *, Tomasz Kołodziej **, Justyna Nowak, Zenon Rajfur
2
Jagiellonian University, Institute of Physics, Reymonta 4, 30-059 Krakow, Poland
*[email protected], ** [email protected]
1. Introduction
Cell migration is one of the most fundamental of biological processes. Motility of cells is inherently
connected with the proper functioning of immune system and embryonic development. It also plays an
important role in pathological processes, such as tumor metastasis and arthritis. It has been proven that
cells transmit forces generated by the actomyosin system through cell adhesions and interact with the
substrate. This type of interaction was called cell tractions and it can be measured by employing elastic
substrate method, in which deformation of the substrate is translated to the cell traction map.
2. Theory
Adherent migrating cells exert forces on the substrate. It was shown that basic parameters of
migration, like cell velocity, directional persistence or even call shape, changed depending on substrates
with different mechanical properties. It seems that cellular response can be especially driven by the
elasticity of the substrate (2,3). In this work the systematic study has been performed to prove how
migration parameters of fish keratocytes depend on the elasticity of the substrate.
3. Experimental
Elastic substrate preparation (1,4): the preparation of acrylamide substrates was based on the radical
polymerization reaction, in which acrylamide was a monomer and bis-acrylamide was a crosslinking agent.
N,N,N´,N´- tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) were catalysts. Specific
elasticity of the polymer was achieved by varying the acrylamide to bis-acrylamide molar ratio.
Cell migration assay: epithelial fish keratocytes were used as a model migrating cells. They were
prepared according to the standard procedures: single Molly fish scales were incubated sandwiched
between two coverslips, then after 48h migrating keratocytes were separated from the cell sheet by short
incubation in the PBS buffer. Afterwards, time lapse of single migrating cells was recorded and migration
parameters were calculated from images.
4. Conclusions
There are clear differences between basic set of keratocyte migration parameters like migration
velocity, directional persistence and cell shape depending on the mechanical properties of a substrate.
We had also observed a significant change in actin cytoskeleton in cells cultured on different elastic
substrates. Future works will determine the detailed biophysical mechanism of interactions between
migrating cell and the substrate
Acknowledgements
All experimental work was done in prof. Jozef Moscicki lab. This work was supported by VENTURES
grant 2012-9/3 from Polish Science Foundation.
References
[1]Damljanovic V., Lagerholm C.B., Jacobson K. Bulk and micropatterned conjugation of extracellular
matrix proteins to characterized polyacrylamide substrates for cell mechanotransduction assays.
Biotechniques. 2005 Dec;39(6):847-51.
72
[2] S. F. Gilbert, Ed., Developmental Biology (Sinauer, Sunderland, MA, ed. 7, 2003)
[3] Ridley AJ, Schwartz MA, Burridge K, Firtel RA, Ginsberg MH, Borisy G, Parsons JT, Horwitz AR. Cell
migration: integrating signals from front to back. Science. 2003;302:1704–1709.
[4] Tse J.R., Engler A.J.. Preparation of Hydrogel Substrates with Tunable Mechanical Properties. Current
Protocols in Cell Biology 10.16.1-10.16.16, June 2010
[5] Roy P., Rajfur Z., Jones D., Marriott G., Loew L. and Jacobson K. Local photorelease of caged thymosin
β4 in locomoting keratocytes causes cell turning. Journal of Cell Biology, 2001;153;1035-1047
P7
ĐORĐEVIĆ, NENAD: CHARACTERIZATION OF MODIFIED NANOCELLULOSE
1
2
3
Nenad Đorđević , Aleksandar Marinković , Marina Stamenović , Slaviša Putić
4
1
College of Vocational Studies Belgrade Polytechnic, Belgrade, Serbia
Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
3
College of Vocational Studies Belgrade Polytechnic, Belgrade, Serbia
4
Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
2
1. Summary
Nanocelluloses or nanofibrillated celluloses (NFCs) have attracted increasing attention as new,
biobased, and highly crystalline nanofibers because NFCs are not only environmentally compatible but
also have unique characteristics as nanomaterials. The process for isolating the nano-crystalline cellulose
from cellulose fibers is based on acid hydrolysis. This paper presents the results of characterization
nanocellulose (obtained from cotton, acid hydrolysis using sulfuric acid mass fraction of 64%) modified
maleic anhydride, recording FTIR spectra and TGA analysis. FTIR spectroscopy shows that samples that are
modified nanocellulose anhydrides show typical strip to a carbonyl group of the ester of maleic anhydride,
and ester C-O vibration. For samples of modified nanocellulose is noticeably decrease the intensity of the
tape due to O-H vibrations. Based on the results obtained and TGA curves for unmodified and modified
nanocellulose concludes that show great similarity, which also reveals that the thermal degradation takes
place in three stages.
KEYWORDS: nanocellulose, acid hydrolysis, maleic acid, FTIR, TGA
P8
GLAVAN, GAŠPER: ABSORPTION OF WATER IN NATURAL AND SYNTHETIC TEXTILE FIBERS
STUDIED BY OPTICAL POLARIZATION MICROSCOPY
1
2
3,4
5,4
5,4
G. Glavan *, M. Devetak , U. Maver , Z. Peršin , K. Stana Kleinschek , I. Drevenšek Olenik
1
Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
2
Hella Saturnus Slovenija d.o.o., Letališka cesta 17, SI-1001 Ljubljana, Slovenija
3
Faculty of Medicine, University of Maribor, Slomskov Trg 15, 2000, Maribor, Slovenia
4
Member of Centre for Open Innovations and Research UM (CORE@UM), Slovenia
5
Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, 2000, Maribor, Slovenia
6
J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
* [email protected]
1. Introduction
1,6
73
The capacity of textile materials to absorb water-based liquids and the rate of the associated liquid
sorption and desorption processes play very important role in clothing, medical, sanitary, cosmetic and
other applications of textiles. These properties are conventionally investigated on a macroscopic level by
analysing fabric samples with typical size of several square centimetres. Such samples consist of a mesh of
a large number of single fibres and the observed properties are a convolution of the intrinsic processes
taking place within single fibres and cooperative processes going on in the areas between the fibres. To
resolve the characteristics of both contributions, separate investigations on single fibre samples need to
be performed.
2. Theory
Practically all textile fibres exhibit a relatively strong optical birefringence that is a consequence of
directional alignment of polymer chains generated during spinning and drawing processes. Due to the
symmetry of these processes, the induced anisotropy is usually uniaxial, which means that the fibre
exhibits only two different principal refractive indices: a principal refractive index for light polarized along
the fibre axis (nII) and a principal refractive index for light polarized perpendicular to the fibre axis (n) [1].
Optical birefringence of the fibres n=( nII–n) can be conveniently probed by polarization optical
microscopy (POM) in crossed polarizer and analyser configuration. Thereby, the sample is illuminated with
linearly polarized monochromatic light and the intensity of transmitted light with polarization
perpendicular to the incident polarization is measured. The transmitted intensity depends on the optical
retardation  between the normal modes of light propagation (eigen-waves)
 = 2d / 
(1)
where d is the material thickness and  the optical wavelength. For a fibre oriented at 45 with respect to
the axes of the polarizer and the analyser, the intensity of transmitted light is given as

(2)
where is the intensity of incident light. Typical values of n for different types of fibres are in the range
0.01<n<0.1 and the values of d are between 10 to 50 m. Consequently, for 0.5 m,  spans a
broad range from =0.4 to =20 and the
associated transmittance T=( / ) can exhibit
values in a full range between T=0 and T=1.
Despite the fact that liquids are optically
isotropic (non-birefringent), incorporation of a
liquid into the fibre structure can cause
modification of its birefringence, because it
modifies the internal stress present in the fibre.
This
consequently
induces
directional
(orientational) redistribution of polymer chains.
Due to this n is modified and in the same time
due to up-take of the liquid volume also d is
changed 2.
According to Eq. (2), modifications of the
product (dn) can be monitored by measuring the fibre transmittance T during the liquid up-take. This
provides a very convenient method to obtain information on the kinetics of the sorption process on the
level of a single fibre (Figure 1). With a subsequent analysis of the microscopy images, modifications of d
can be resolved directly from the images and subsequently also modifications of n can be calculated, so
separate information on both parameters is obtained.
74
Figure 1. POM image (crossed polarizers configuration) of a dry viscose fibre mesh (a), and the same fibre
mesh soaked with water (b). Absorption of water causes strong increase of intensity of light transmitted
through the fibres.
3. Experimental
A single fibre pulled out from a selected fabric (alginate, PES) was fixed onto the microscopy object
glass by gluing its edges to the glass surface. Then it was covered by the cover glass and the assembly was
fixed together by two metallic clamps providing constant mechanical stress during the sorption process.
The sample was placed on the microscope (Nikon Optiphot2-pol, crossed polarizers configuration) and the
fibre was oriented at 45 with respect to the polarizers. A selected liquid was introduced into the gap
between the glass plates via the capillary action. During the liquid up-take process video-microscopy
imaging was performed. Image analysis in MatLab was performed to deduce modifications of transmitted
intensity and image analysis in ImageJ to resolve modifications of fibre diameter d.
Fibres were wetted with water, because water is a usual solvent for medical substances. The desribed
methodology was to our best knowledge not used before for this purpose and therefore simulated
physiological fluids, regularly used in wound dressing assessment, would most likely raise more questions,
especially due to presence of the drug [2][3]. In terms of the type of fibre materials, we used viscose,
alginate and PET, since they are among the most abundant materials used for preparation of wound
dressings. The field of wound care can certainly greatly benefit from such novel fibre evaluation
approaches. On one hand the findings can lead to optimization of the desired therapeutic intervention
(through understanding of swelling and drug release from single fibres, the added dose of the drug can be
optimized), and on the other hand to rationalization of wound dressing development costs (laboratory
optimization is always far cheaper than optimization in a larger (industrial) setup, also less incorporated
drug means a cheaper final product).
4. Results and discussion
Figure 2 shows modifications of relative transmitted intensity obtained for alginate and polyester
fibres soaked with water and with water/diclofenac mixture. The sorption process starts at t=0. One can
notice profound differences between sorption kinetics of various samples. As a large part of these
differences originates from diversity between dimensions and structure of fibres taken from the same
starting material, statistical analysis performed on a large number of fibre samples is necessary to resolve
significant differences between different
fabrics.
Figure 2. Modifications of relative transmitted
intensity for (a) alginate (from ref. 3) and
(b) polyester fibres. The black curve in (a)
corresponds to pure alginate and the red curve
to the alginate with pre-adsorbed diclofenac.
The two curves in (b) correspond to two
different regions of the same polyester fibre.
Figure 3 shows modifications of the diameter d of the polyester
fibre during water sorption. One can notice a profound correlation
between the behaviour of d(t) and It(t). However, the increase of
fibre diameter (10%) is significantly lower than the increase of
transmitted intensity (50%). Further experiments with calibrated
measurements of It are necessary to be able to resolve
birefringence changes n(t) from the obtained data.
75
Figure 3. Modification of polyester fibre diameter during water sorption. The two curves correspond to
two different regions of the same fibre.
5. Conclusions
Our experiments demonstrate that polarization optical video-microscopy combined with an
appropriate image analysis is a very convenient tool to investigate effects related to sorption of liquids
into single textile fibres. Many further improvements with respect to the methodology described above
are still possible. For instance, the use of a fast camera can provide information on sorption kinetics with
time resolution of milliseconds, which would be beneficial for synthetic fibres that typically exhibit very
rapid sorption. Calibration of the setup in purpose to be able to determine optical retardation  is the
next necessary step. Besides this, some additional experiments should be performed to distinguish
between intensity modifications related to the retardation and modifications due to scattering. These
improvements are the aim of our future investigations and will possibly lead to determination of
quantitative variations of n induced by liquid absorption into the fibre. Quantitative data are
prerequisite for theoretical modelling of the observed effects on the level of a single fibre as well as for
their comparison to the macro-scale sorption properties of the woven fabrics.
Acknowledgements
We acknowledge financial support in the framework of the Slovenian research program P1-0192 “Light
and Matter” as well as the support from the national funded project L2-5492 (C) “Development of the
functional textiles used for the treatment of diabetic foot (malum perforans)”.
References
[1] S. J. Eichhorn, J. W. S. Hearle, M. Jaffe, T. Kikutani, Handbook of textile fibre structure, Vol. 1,
Fundamentals and manufactured polymer fibres; Woodhead Publishing in Textiles, 2009.
[2] Z. Peršin, M. Devetak, I. Drevenšek-Olenik, A. Vesel, M. Mozetič, K. Stana-Klainschek, Carbohydr.
Polym. 2013, 97, 143.
[3] M. Devetak, Z. Peršin, K. Stana-Klainschek, U. Maver, Microsc. Microanal. 2014, 20, 561.
P9
GORDOBIL, OIHANA: CHEMICAL MODIFICATIO N OF ORGANOSOLV EUCALYPTUS LIGNIN
WITH FATTY ACIDS
Oihana Gordobil, Itziar Egüés, Jalel Labidi*
Chemical and Environmental Engineering Department, University of the Basque Country,
Plaza Europa, 1, 20018, Donostia-San Sebastián, Spain
* [email protected], tel.:+34-943017178; fax: +34-943017140
1. Introduction
Nowadays most of the plastics materials are made from petroleum. Their use creates many potential
problems due to their non-renewable nature and ultimate disposal. Therefore, is necessary to develop
biodegradable materials based on renewable sources with comparable properties to synthetic polymers
and at equivalent cost. For this purpose, the use of lignocellulosic biomass is an attractive alternative due
to their renewable origin, the biodegradability of their components and their non-human food
application. Lignin, one of the main structural components of lignocellulosic biomass and the second most
abundant macromolecule in nature, can offer a large amount of organic material that could be used in the
76
production of biopolymers. It is a complex amorphous and heterogeneous polyphenol material. It
basically consists of various types of phenylpropane units called p-hydroxyphenyl (H, from coumaryl
alcohol), guaiacyl (G, from coniferyl alcohol) and syringyl (S, from sinapyl alcohol), which are bound to
each other via aryl ether or carbon-carbon linkages. The most common linkage is -O-4 followed by others
like -O-4, -5, 5-5, 4-O-5, 1, and - [1]. In general, softwood lignins are mainly composed of G-units
whereas hardwood lignins are based on guaiacyl (G) and syringyl (S) units present in different ratios. Nonwoody plants are hydroxyphenyl/guaiacyl/syringyl-type (HGS) [2, 3]. Although it is very heterogeneous
molecule, its structure and abundance makes it a good alternative to use as a raw material in the polymer
industry. Moreover, chemical modification of functional groups presents in lignin molecule like phenolic
hydroxyl groups and aliphatic hydroxyl groups at the C-α and C-γ positions on the side chain, is a good
alternative to increase the range of applications in the polymer industry area [4, 5]. The esterification of
lignin also allows increase hydrophobicity of lignin and its solubility in organic solvents. However, lignin
also possesses many advantages like its brittleness, poor film forming ability and difficulty of processing
[6]. The natural condensed structure and strong intermolecular hydrogen bonding interactions in lignin
restrict the thermal mobility and result in its high Tg [7]. It is well known that when the lignin is modified
by esterification, hydroxyl groups were replaced by ester substituent [8] and thus, reduce the number of
hydrogen bonding and lead an increased free volume in the molecule and thus the mobility of the chains
[9]. So, esterification is a potential route to lower the glass transition point of lignin and increase its
thermoplasticity [6].This study was focused on the isolation, structural and thermal characterization and
chemical modification of lignin from Spruce wood. The main objective was obtaining a decrease in glass
transition temperature and increase lignin thermoplasticity by esterification with fatty acyl to be
processed.
2. Experimental
2.1 Lignin isolation
Spruce (softwood) was used as raw material for lignin extraction. The treatment was carried out in a 4
L pressure (20Ba) stainless steel batch reactor with constant stirring (EL0723 Iberfluid) with electronic
control unit for pressure and temperature control. Spruce was treated with a mixture of ethanol-water
(50/50 w/w) at 180 °C for 60 min. H2SO4 was used as catalyst (1.2% w/w). The solid to liquid ratio was 1:7
(w/w). Dissolved lignin was isolated by precipitation with four volumes of cold water. The lignin was
recovered by filtration, washed until neutral pH and then was dried al 50°C.
2.2 Esterification with fatty acids
0.5 g of lignin was dissolved into 15 mL of DMF and 0.75 mL of trietylamine in a two-necked flask with
a magnetic stirrer. Pyridine (2.75 mL) was used as a catalyst and dodecanoyl chloride was added (0.9 mL).
The reaction was then conducted at ambient temperature at different times (2 and 6 h). After that, the
solution was poured into 650 mL of 2% ice-cold hydrochloric acid. The precipitate was filtered and washed
with excess distilled water and ethanol. The samples were then dried in vacuum at 35 °C overnight.
3. Results and discussion
Physico-chemical properties of isolated lignin (OS) are shown in Table 1. FTIR spectra confirmed that
the estherification process was successful at both studied conditions. Isolated lignin presented typical
lignin spectra with a wide absorption band at 3400 cm-1 indicated the presence of O-H stretching
vibrations in aromatic and aliphatic O-H groups. Bands around 2930 and 2840 cm-1 can be assigned to C-H
77
stretching in -CH2- and -CH3 groups. The peaks at 1595 and 1510 cm-1 are due to C=C of aromatic skeletal
vibrations. Spruce lignin did not present any peak associated to syringyl units. This result agrees with 31P
NMR results. So, it can be said that Spruce lignin is formed only by guaiacyl units. In both modified lignin
samples appeared a new intense peak at 1760 cm-1 corresponds to a carbonyl vibration of the aromatic
ester group formed in the reaction. Also, both estherificated lignins showed a great increase of bands at
2930 and 2840 cm-1 due to introduced long chain during esterification process. But, only modified lignin
during 6 h showed that the signal around 3400 cm_1 was completely reduced. The absence of the
characteristic bands of dodecanoyl chloride around 1800 cm-1 showed that the modified lignins do not
contain traces of unreacted dodecanoyl chloride. The ratio A1760/A1510 can be used to give an indication on
the degree ofsubstitution (DS) of hydroxyl groups afetr modification. Indeed, the greater these ratios, the
greater the DS [10]. The ratio value were 1.49 and 1.62 for EOS 2h/20°C and EOS 6h/20°C, respectively.
Table 1. Physico-chemical properties of Spruce
organosolv lignin
a
b
31
Calculated from P NMR
13
Calculated from 3.00-I123-106 in C NMR spectra
Figure 1. FTIR spectra of isolated and
estherificated Spruce lignin samples
4. Conclusions
The isolation and physicochemical characterization of isolated Spruce lignin was performed. The
modification was successful in both cases at ambient temperature, but with an increase in the reaction
time higher DS has been achieved.
Acknowledgments
The authors thankful for the financial support from the University of the Basque Country and the
Department of Education, Universities and Investigation of the Basque Government through project
IT672-13.
References
[1] S. Laurichesse, L. Avérous, Chemical modification of lignins: Towards biobased polymers, Prog Polym
Sci. 39 (2014) 1266-1290.
[2] O.Y. Derkacheva, Estimation of aromatic structure contents in hardwood and softwood lignins from
IR absortion spectra, J Appl Spectrosc. 80 (2013) 670-676.
[3] D. Schorr, P.N. Diouf, T. Stevanovic, Evaluation of industrial lignins for biocomposites production, Ind
Crop Prod. 52 (2014) 65-73.
[4] S. Kim, S. Oh, J. Lee, N. Ahn, H. Roh, J. Cho, B Chun, J. Park, Effect of Alkyl-chain-modified Lignin in the
PLA Matrix. Fiber Polymer 15 (2014) 2458-2465.
[5] A. Awal, M. Sain, Characterization of soda hardwood lignin and the formation of lignin fibers by melt
spinning, J Appl Polym Sci. 129 (2013) 2765-2771.
78
[6] E.Hult, J. Ropponen, K. Poppius-Levlin,T. Ohra-Aho, T. Tamminen, Enhancing the barrier properties of
paper board by a novellignin coating, Ind Crop Prod50 (2013) 694-700.
[7] Chung, Y., Olsson, J.V., Li, J.R., Curtis W.F., Waymouth, R.M., Billington, S.L., Sattely, E.S., 2013. A
Renewable Lignin−Lactide Copolymer and Application in Biobased Composites. Sustainable Chem
Eng. 1, 1231-1238.
[8] Cachet, N., Camy, S., Benjelloun-Mlayah, B., Condoret, J., Delmas, M., 2014. Esterification of
organosolv lignin under supercritical conditions. Ind Crop Prod. 58, 287-297.
[9] Lispeguer, J., Perez, P., Urizar, S., 2009. Structure and thermal properties of lignins: characterization
by infrared spectroscopy and differential scanning calorimetry. J. Chil Chem Soc. 54,460-463.
[10] Cachet, N., Camy, S., Benjelloun-Mlayah, B., Condoret, J., Delmas, M., 2014. Esterification of
organosolv lignin under supercritical conditions, Ind Crop Prod. 58,287-297.
P10
HAAS, CORNELIA: HIGH CELL-DENSITY PHB PRODUCTION IN A MEMBRANE BIOREACTOR
1
1
1
1
Cornelia Haas *, Lukas Burgstaller , Marina Smerilli , Markus Neureiter
1
BOKU University of Natural Resources and Life Sciences, Konrad Lorenz Straße 20, 3430, Tulln, Austria
*[email protected]
1. Introduction
Agricultural residues with a high carbon content such as molasses are already intensively used as
fermentation substrates. Residues with a lower carbon content, such as whey, wastewater from plant oil
mills, etc. are not suitable for fed-batch fermentations, the most frequent fermentation mode for
bioproduction. This problem can be circumvented by either concentrating the carbon in the feed stream
or retaining the cells during the fermentation in the bioreactor. The latter strategy has the advantage that
it can also be used for substrates containing low concentrations of inhibitors, which would get coconcentrated along the desired carbon source. Furthermore, excretion products during the fermentation
are continuously removed from the bioreactor.
In order to implement this concept, we developed a cell-recycle membrane bioreactor for the highcell-density production of poly(3-hydroxybutyrate) (PHB) and tested it on synthetic medium.
2. Results and Conclusion
Cupriavidus necator DSM 545 was continuously supplied with synthetic medium containing 50 g/L of
glucose. If the continuous supply was not sufficient, an automatic DO and pH-triggered increase in the
pump rates was executed. A constant working volume of 0.5 L inside the bioreactor was maintained by an
external polysulfone microfiltration membrane module. The PHB-production phase was started after
8 hours by supplying nitrogen-free medium. After another 32 hours, 52 g/L dry biomass was accumulated
containing 92 % PHB. The process is characterised by a high average productivity of 1.2 g PHB/Lh.
This fermentation strategy is promising for low carbon concentrations in the feed stream, as often
found in agricultural residues.
79
P11
HAERNVALL, KAROLINA: ENHANCED ENZYMATIC MODIFICATIONS OF POLYESTERS BY
MODULATION OF ENZYME ADSORPTION
1*
1
1
2
1
Karolina Haernvall , Sara Vecchiato , Doris Ribitsch , Enrique Herrero Acero ,
2, 4
1, 3
Helmut Schwab , Georg M. Guebitz
ACIB - Austrian Centre of Industrial Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln, Austria
2
ACIB - Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
3
Institute of Environmental Biotechnology, IFA-Tulln, BOKU - University of Natural Resources and Life Sciences,
Konrad Lorenz Strasse 20, 3430 Tulln, Austria
4
Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
*[email protected]
1. Introduction
The application possibilities for synthetic polymers is increasing and with that the interest of improving
polymers’ properties and of their degradation potential. Degradation of natural polyesters is generally
initiated by a variety of physical, chemical, and biological forces, where an important factor is enzymatic
activity. In theory, enzymes should also be able to functionalize and degrade synthetic polyesters. The
challenge is to speed up enzymatic processes which are rather slow due to the fact that synthetic
polymers are not natural substrates for enzymes. Genetic engineering is a general tool used to tune
substrate specificity and enhance sorption properties of enzymes [1, 2] to facilitate the enzymatic activity.
Surface properties have recently been shown to have a great impact on polymer sorption and therefore
on the enzymatic activity for two closely related enzymes from Thermobifida cellulosilytica [3]. This opens
up for an alternative approach to enhance sorption properties of enzymes by facilitating adsorption onto
insoluble polymers, namely fusion of binding modules to already active enzymes [4, 5]. This study aims to
investigate the effect on hydrolysis by fusion of the substrate binding module from a
polyhydroxyalkanoate depolymerase from Alcaligenes faecalis (Thc_Cut1+PBM) to a cutinase from T.
cellulosilytica (Thc_Cut1). The binding module was chosen due to similarity of the natural polyester
polyhydroxyalkanoate to the synthetic polyester polyethylene terephthalate (PET) in terms of
hydrophobicity.
2. Experimental
The enzymes were cloned, expressed in E. coli and purified as described by Herrero Acero et al. [2].
The enzymes were characterized and degradation capacities of polymers were compared regarding
amount of released soluble degradation products. Esterase activity was measured using paranitrophenylbutyrate (pNPB) as substrate. For measuring enzymatic activity on polymers amorphous PET
films were used. The PET films (0.5x1cm) were incubated in 1.5 ml eppendorf tubes in a shaker at 50°C
and 100 rpm with 25 mM enzyme in 100 mM K2HPO4/KH2PO4 buffer at pH 7. After time intervals, as
indicated below, samples were diluted 1 to 1 with methanol on ice. Analysis of the released products was
performed via HPLC-RP as described by Herrero Acero et al. [2].
3. Results and discussion
The cutinase from T. cellulosilytica (Thc_Cut1) and the cutinase fused with the substrate binding
module from a polyhydroxyalkanoate depolymerase from A. faecalis (Thc_Cut1+PBM) were successfully
cloned and expressed in E. coli. The enzymes were characterized and their degradation capacities were
compared regarding the amount of released soluble hydrolysis products. Thc_Cut1 showed esterase
activity on pNPB, as well as on insoluble amorphous PET films. Thc_Cut1+PBM showed, compared to the
native enzyme, decreased activity on small soluble substrates but increased activity on the PET films
(Figure 1).
80
Thc_Cut1
Thc_Cut1
Thc_Cut1+CBM
Thc_Cut1+CBM
Thc_Cut1+PBM
Thc_Cut1+PBM
Figure 1. Time profile of soluble hydrolysis products of PET by Thc_Cut1 and Thc_Cut1+PBM.
4. Conclusions
The cutinase from T. cellulosilytica (Thc_Cut1) showed esterase activity, which makes it a potential
enzyme for both functionalization and degradation for polyesters. Fusion of the substrate binding module
to Thc_Cut1 showed, as expected, an enhanced hydrolytic activity on insoluble PET. This is a highly
interesting observation since it is one of the first times a binding module enhance the activity of an
already active enzyme. As the binding module has a strong and general adsorption capacity this finding
opens up for a wide range of future application possibilities to enhance enzymatic modifications of
hydrophobic substrates. The possible combination of a binding module fused to an enzyme with an
improved active site by genetic engineering enables unlimited possibilities of improving enzymatic
treatment of polymers in the near future.
Acknowledgements
This work has been supported by the Federal Ministry of Economy, Family and Youth (BMWFJ), the
Federal Ministry of Traffic, Innovation and Technology (bmvit), the Styrian Business Promotion Agency
SFG, the Standortagentur Tirol and ZIT - Technology Agency of the City of Vienna through the COMETFunding Program managed by the Austrian Research Promotion Agency FFG.
References
[1] Guebitz G. M., Cavaco-Paulo A., Trends in Biotechnology, 2008;26(1):32-38.
[2] Herrero Acero E. Ribitsch R, Steinkellner G, Gruber K, Greimel K, Eiteljoerg I, Trotscha E, Wei R,
Zimmermann W, Zinn M, Cavaco-Paulo A, Freddi G, Schwab S, Guebitz G, Macromolecules,
2011;44(12):4632–4640.
[3] Herrero Acero E, Ribitsch D, Dellacher A, Zitzenbacher S, Marold A, Steinkellner G, Gruber K, Schwab
H, Guebitz G.M. Biotechnology and Bioengineering 2013;110(10):2581-2590
[4] Ribitsch D, Orcal Yebra A, Zitzenbacher S, Wu J, Nowitsch S, Steinkellner G, Greimel K, Doliska
A, Oberdorfer G, Gruber CC, Gruber K, Schwab H, Stana-Kleinschek K, Herrero Acero E, Guebitz G.M.
Biomacromolecules, 2013;14(6):1769–1776.
81
P12
HAERNVALL, KAROLINA: FUNCTIONALIZATION OF POLY(L-LACTIC ACID) FILMS VIA A
TWO-STEP ENZYMATIC PROCESS
1
2
2
2
3, 4
Alessandro Pellis *, Karolina Haernvall , Sara Vecchiato , Enrique Herrero Acero , Rolf Breinbauer ,
5
1,2
Ewald Srebotnik and Georg M. Guebitz
1
BOKU – University of Natural Resources and Life Sciences, Department IFA-Tulln, Institute for Environmental
Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria
2
ACIB – Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria
3
TUGraz – Graz University of Technology, Institute of Organic Chemistry, Stremayrgasse 9, 8010 Graz, Austria
4
ACIB – Austrian Centre of Industrial Biotechnology GmbH, Petersgasse 14, 8010 Graz, Austria
5
Vienna University of Technology, Institute of Chemical Engineering, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
*[email protected]
1. Introduction
Poly(lactic acid) (PLA) is a renewable, biodegradable and biocompatible polyester that represents a
promising sustainable alternative to petrochemical based polymers such as polypropylene. PLA can be
polymerized starting from renewable resources (e.g. corn starch and vegetable oil) using up to 55% less
energy than producing conventional petroleum-based plastics. It is a widely used polyester in food
packaging, automotive parts, textiles and biomedical applications (e.g. sutures, stents, drug delivery
vectors and skin substitutes). Therefore, there is an increasing interest in modifying PLA surfaces in order
to improve properties like hydrophilicity and/or creating reactive anchor groups for further
functionalization. The latter includes for example covalent immobilization of bioactive compounds or
decoration of nanoparticles for targeted drug delivery while retaining the bulk properties. Surface
functionalization of polyesters is usually achieved via wet chemistry, photografting or plasma treatment In
order to avoid the use of harsh chemicals and to reduce the energy consumption different enzymes,
especially lipases, have been investigated to improve the surface hydrophilicity of renewable polyesters
such as PLA. Enzymes do not only work at mild process conditions and are not restricted to planar
surfaces like plasma treatment but can specifically introduce modifications on polymer surface while
leaving the bulk properties unchanged.
Here, a two-step enzymatic process for the grafting of different molecules onto the surface of poly(Llactic acid) (PLLA) films was developed. The aim was to functionalize the surface of PLA films using
hydrolytic enzymes, both for surface “activation” and for the subsequent coupling of a model molecule.
This enzymatic coupling approach is an interesting environmentally friendly way to create PLA based
materials where the surface is functionalized while leaving the bulk properties unchanged.
2. Experimental
In a first step hydroxyl and carboxylic groups are created by controlled cutinase hydrolysis of the outer
polymer chains. These new functional groups serve as grafting points for the coupling of different model
molecules on the surface by using Candida antarctica lipase B (CaLB).
The surface functionalization was proven using 14C-labeled and fluorine-containing molecules. These
model compounds were chosen in order to easily detect and optimize the modification of the polymer
surface by means of 14C-liquid scintillation analysis and X-ray photoelectron spectroscopy (XPS). For a
more comprehensive study of the activated surface, different chemical and enzymatic hydrolysis
pretreatments of the PLA film were assessed.
3. Results and discussion
PLLA films were functionalized with 14C-radio labeled butyric acid or 4,4,4-trifluorobutyric acid using
Candida antarctica lipase B as catalyst in n-heptane at a reaction temperature below the glass transition
temperature (T<Tg) of the biopolymer. The feasibility of the functionalization was investigated via 14Cradiochemical analysis while the surface composition was investigated via XPS analysis. No significant
82
difference in the yield was observed while functionalizing pre-hydrolyzed and non-pre-hydrolyzed
polymer. This is most probably due to a rearrangement of the outer polymer chains in the hydrophobic
reaction environment. It is indeed remarkable how PLLA films maintained their bulk properties despite
the enzymatic functionalization of the surface in contrast to other commonly used surface modification
methods previously reported so far.
4. Conclusion
In conclusion an innovative enzymatic method for the surface functionalization of poly(L-lactic acid)
films is presented. We conclude that is possible to perform a pre-treatment independent lipase-catalyzed
trans-esterification reaction of the poly(L-lactic acid) surface chains of the film.
The results presented here form the basis to further investigate enzymatic functionalization to tune
PLLA properties using more complex substrates like those of biomedical interest.
Acknowledgements
The research leading to these results has received funding from the People Programme (Marie Curie
Actions) of the European Union’s Seventh Framework Programme FP7/2007-2013/ under REA grant
agreement no [289253].
Reference
[1] Williams, C. K. Chem. Soc. Rev. 2007, 36, 1573–1580
[2] Kobayashi, S. Proc. Jpn. Acad. Ser. B Phys. Biol. Sci.2010, 86, 338–365
[3] Matsumura, S. in Enzyme-Catalyzed Synth. Polym. (Kobayashi, S., Ritter, H. & Kaplan, D.) 95–132
(Springer Berlin Heidelberg, 2006). at <http://link.springer.com/chapter/10.1007/12_030>
[4] Cheng, Y., Deng, S., Chen, P. & Ruan, R. Polylactic acid (PLA) synthesis and modifications: a review.
Front. Chem. China 4, 259–264 (2009).
[5] Rasal, R. M., Janorkar, A. V. & Hirt, D. E. Prog. Polym. Sci. 2010, 35, 338–356
83
P13
HUŠ, SEBASTJAN: PLA-BASED BIOCOMPOSITES WITH EXCELENT TRIBOL OGICAL
PROPERTIES
1*
1
2
Sebastjan Huš ,Silvester Bolka , Mitjan Kalin , Irena Pulko
1
1
Polymer Technology College, Ozare 19, 2380, Slovenj Gradec, Slovenia
University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 100 Ljubljana, Slovenia
*[email protected]
2
1. Introduction
Bio-based and bio-degradable polymers and their composites are attracting more and more attention
since their use does not affect the environment to such an extent as the use of conventional plastics. This
is why biopolymers are used for all kind of applications, replacing conventional plastics.[1-6] One of the
interesting field is also the use of biopolymers for construction parts where good resistance to wear is
needed. In this study we present the use of bio-based composite with excellent tribological properties for
sliding elements.
2. Experimental
For the composite preparation the following materials were used: poly(lactic acid) (PLA) Ingeo
Biopolymer 2003D supplied by NatureWorks LCC, elastomer poly(styrene-ethylene-butylene-styrene)
(SEBS) Solplast TH 90A9000 B1, supplied by Uteksol d.o.o., and fillers wood flour and paper pulp, supplied
by a local company as waste material. Fillers were dried in the oven for 4 h at 80°C, grinded into fine
powder and sieved trough 1000 µm sieve. Before extrusion all materials were additionally dried in an
oven for 4 h at 80°C.
Composites were prepared on a twin-screw extruder Collin teach line ZK 25Twith temperature profile:
170, 180, 190, 180 and 175°C (from hopper to die) and screw rotation speed of 35 rpm.
Mechanical properties of the prepared composites were analysed on a testing machine AG-X plus
(Shimadzu) using a stress-strain test ISO 527. Thermal analysis was performed on a TGA 4000
(PerkinElmer) and Mettler-Toledo fast scanning calorimeter Flash DSC 1. Pin-on-disc measurements were
conducted using a CETR UMT-2 tribometer (Bruker), while worn scar morphology of samples from
tribology tests were taken on 3D optical microscope (Bruker).
3. Results and discussion
First mechanical properties of the prepared composites were analysed. As it can be seen from Table 1,
the addition of fillers lowered the tensile strength in all cases (B1, B2, B3) as compared to neat PLA (B0)
and also affected the Young modulus. With the addition of elastomer SEBS, the composites became more
flexible; ε at break increased for 120% in the case of sample M3. It can be also seen that thermal stability
of composites, as compared to sample B0, slightly decreases, which is probably due to the decrease in
molecular weight of PLA during processing.
Table 1.Mechanical properties and thermal stability of prepared samples
Sample
Composition
B0
B1
B2
B3
100% PLA
90% PLA + 10% wood flour
88% PLA + 2% SEBS + 10% wood flour
60% PLA + 30% SEBS + 10% paper pulp
Young
modulus
[GPa]
3,4
2,0
3,4
3,1
Tensile
strength
[MPa]
62,2
27,5
47,8
24,5
Ɛ at break
[%]
Td
[°C]
2,5
2,8
3,5
5,5
380,6
353,6
349,7
348,1
On the other hand we can see (Figure 1) that the addition of SEBS in combination with paper pulp had
good impact on tribological properties since the wear of the sample was not possible to detect with
optical microscope. This could be attributed to increased flexibility and consequently to increased
toughness of B3 compared to neat PLA.
84
85
Figure 1. Description
Flash DSC results showed that the addition of pulp and SEBS (B3) lowered the glass transition of the
composites and consequently the spherulite growth at the same temperature was higher and the
spherulite size was smaller. The increased number of nuclei increased the cold crystallization and also
showed the best results on tribological tests.
4. Conclusions
In this work we investigated the influence of different mixture ratios of PLA, SEBS and waste wood
flour or paper pulp on the mechanical, thermal and tribological properties of the prepared samples in
correlation with Flash DSC results. The addition of fillers lowered the tensile strength and also affected
the Young modulus. The addition of SEBS improved flexibility but also reduced thermal stability of the
samples. Tribological tests showed that waste paper pulp had good interactions with biopolymer PLA
while in combination with elastomer SEBS the composite had excellent tribological properties since no
significant wear was detected.
Acknowledgements
This contribution was made within operation »Creative Core VŠTP«. The operation is partially cofinanced by European Union, European Regional Development Fund. Operation is executed within
framework of operative Programme for Strengthening Regional Development Potentials for Period 2007-
2013, 1st development priority: Competitiveness of the companies and research excellence, priority aim
1.1.: Improvement of the competitive capabilities of companies and research excellence.
Authors wish to thank R. Bobovnik and C. Hiter for their technical support.
References
[1] EPA, United States Environmental Protection Agency 2000.
[2] J.F. Jenck, F. Agterberg, M.J. Droesche, Products and processes for a sustainable chemical industry: a
review of achievements andprospects, Green Chemistry, 2004, 544–56.
[3] D.L. Kaplan, Biopolymers from renewable resources, Heidelberg: Springer, 1998, 421.
[4] R. Auras, B. Harte, S. Selke, An overview of polylactides as packagingmaterials, Macromolecular
Bioscience, 2004, 835–64.
[5] O. Faruk, A.K. Bledzki, H.P. Fink, M. Sain, Biocomposites reinforced with natural fibers: 2000–2010,
Progress in Polymer Science, 2012, 1552-1596
[6] K. Oksman, M. Skrifvars, J.F. Selin, Natural fibers as reinforcement in polylactic acid (PLA) composites,
Composites Science and Technology, 2003, 1317-1324
P14
JOVANOVSKI, VASKO: SYNTHESIS OF NANOCRY STALLINE ZnO DECORATED WITH IONIC
LIQUID MOIETIES AND THEIR ANTIMICROBIAL ACTIVITY
Vasko Jovanovski, Marjeta Čepin and Zorica Crnjak Orel
National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI-1000, Slovenia
[email protected]
1. Summary
The development and optimization of synthesis of nanocrystalline ZnO with strong antimicrobial
properties is presented. This nanocrystalline ZnO exhibiting strong inherent antimicrobial activity was
then further functionalized with covalent modifications via silane anchoring. In order to achieve further
improvement of antimicrobial activity compared to synthesised ZnO its surface was successfully
covalently modified with commercially available aminosilanes and laboratory-prepared ionic liquidsilanes. For this purpose two ionic liquids comprising trimethoxysinale group and imidazolium or
pyridinium moiety, were designed and prepared.
Successful ionic liquid surface immobilization on ZnO and application of this hybrid material was
achieved with a simple moderate temperature process. Different microscopic (SEM, TEM) and
spectroscopic techniques (IR) as well as size (DLS), surface ( -potential) and elemental composition (ICPOES) analysis were employed to prove the effective of surface functionalisation. These characterizations
revealed that surface and antimicrobial properties strongly depend on the surface modification/pendant
functional silane employed.
Predominant number of amino- and ionic liquid decorated nanocrystalline ZnO exhibited significantly
improved antimicrobial activity compared to commercially available silane-containing antimicrobial agent
attached to nanocrystalline ZnO or nanocrystalline ZnO itself. Bacterial growth reduction was assessed by
following optical density of bacterial growth in the time interval of 15 h with different concentrations of
antimicrobial nanomaterials employed. Complete bacterial reduction was achieved for specific aminoand ionic liquid- modifications at 0.125 g L-1, revealing synergistic effect of ZnO and its modifications,
exhibiting up to 100 % improvement compared to unmodified ZnO or commercially available
antimicrobial agent also comprising silane group.
86
References:
[1] M. Čepin, V. Jovanovski, M. Podlogar, Z. Crnjak Orel, J. Mater. Chem. B, 2015, 3, 1059
Figure 1. TEM image of untreated ZnO nanocrystal in the (011) direction showing a lattice distance in
(100) plane. (b) Corresponding fast Fourier transform (FFT) pattern along with (c) simulated diffraction
pattern. (d) TEM image of ZnO covered with amorphous layer of an ionic liquid silane.
87
P15
JÓZÓ, MURIEL: SYNTHESIS OF CARBON AEROGEL PRECURSOR POLYMERS IN DEEP
EUTECTIC SOLVENT MEDIA
Muriel Józó*, Balázs Nagy, Krisztina László
Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics,
Budafoki út 8., Budapest, H-1111 Hungary
*
[email protected]
1. Introduction
Carbon aerogels (CAs) are simultaneously macro- and mesoporous materials, which are most
frequently made from resorcinol-formaldehyde (RF) hydrogels. The sol-gel process makes it possible to
modify the features of the product by varying the reaction conditions such as stoichiometry,
concentration, solvent quality, etc. The tailored pore structure, which offers several advantages over the
other forms of carbons, can be preserved by the careful removal of the solvent [1]. During the conversion
to carbon the pore size distribution in the mesopore range is generally conserved.
Introduction of nitrogen functionalities into the CAs of open structure may enhance the affinity of the
carbon surface towards biologically active molecules of and may increase its biocompatibility [2]. Nitrogen
can be introduced in several ways among one is the use of a N-containing reactive solvent. Ionic liquids as
green, environmentally friendly reaction medium is an expanding field of interest. They can play the role
of solvent, catalyst and/or reactant in synthetic processses. Deep eutectic solvents (DESs) are a special
group of ionic solvents. In this contribution we report the synthesis of dry RF gels in two different DES
media. Both of them are based on choline chloride and the other component is either urea or ethylene
glycol. The porosity and the nitrogen content of the polymer aerogel was followed as a function of the R:F
ratio in the reaction mixture.
2. Experimental
RF gels were prepared in the two different DES reaction media (choline chloride:urea, and
choline chloride:ethylene glycol, both 1:2) at 85 °C. Na2CO3 was used as catalyst. The R:F ratio – and thus
the water content - was systematically varied. The hydrogels were dried in ambient conditions. The
chemical composition of the dry polymers was investigated by CHN analysis. The morphology was
characterized by scanning electron microscopy (SEM) and low temperature nitrogen adsorption.
3. Results and discussion
Highly porous, open structure dry polymer gels were obtained in both DES media after cost-effective
ambient drying. The morphology was strongly affected by the type of the solvent and also by the amount
of formaldehyde in the initial sol.
Using the urea based DES resulted in polymer gels of high nitrogen content (up to 22 wt%). The nitrogen
content depended on the R:F ratio.
Acknowledgements
We express our gratitude to Hedvig Medzihradszky-Schweiger for the CHN analysis, to Péter Gordon
(BME-ETT) for the SEM micrographs and to György Bosznai for the gas adsorption measurements.
References
[1] Orsolya Czakkel, Katalin Marthi, Erik Geissler, Krisztina Lászl , Microporous and Mesoporous
Materials, 2005, 86, 124.
[2] Rui-Lin Liu, Wen-Juan Ji, Tian He, Zhi-Qi Zhang, Jing Zhang, Fu-Quan Dang, Carbon, 2014, 76, 84.
88
P16
KÁRPÁTI, ZOLTÁN: INTERFACIAL INTERACTIONS IN POLYLACTIC ACID/LIGNOCELLULOSIC
COMPOSITES
1
1
1
1
1
Zoltán Kárpáti *, Dávid Kun , Gábor Faludi , János Móczó , Béla Pukánszky
1,2
Laboratory of Plastics and Rubber Technology, Budapest University of Technology and Economics,
H-1521 Budapest, P.O.Box 91, Hungary
2
Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences,
H-1525 Budapest, P.O.Box 17, Hungary
*[email protected]
1. Introduction
Polylactic acid (PLA) is one of the most studied biopolymers nowadays. Its production uses natural,
renewable resources; in addition, PLA itself is a stiff, biodegradable polymer. However, it has a number of
drawbacks such as physical ageing, sensitivity to moisture during processing, poor impact resistance and
high costs of production. Therefore researchers have made a lot of effort to modify the properties of PLA
through plasticization [1-3], copolymerization [4, 5], blending [6] or the production of composites [2, 3].
During our research, we reinforced PLA with several lignocellulosic fillers to maintain its biodegradability.
The properties of composites depend significantly on interfacial interactions so the goal of our research
was to investigate the strength of adhesion between the components.
2. Experimental
The PLA used in the experiments was the Ingeo 4032D grade (Mn = 88500 g/mol and Mw/Mn = 1.8)
purchased from NatureWorks recommended for extrusion by the producer. Four types of lignocellulosic
fillers were applied as reinforcement: a corn cob (GM200), a sunflower seed hull (SP20) and two wood
flour fillers (EFC1000 and CW630). Particle characteristics were determined quantitatively by laser light
scattering, but also by image analysis from scanning electron microscope micrographs.
Both poly(lactic acid) and the fibers were dried in a vacuum oven before composite preparation (110
°C for 4 h and 105 °C for 4 h, respectively). The polymer and the filler were homogenized using a
Brabender W 50 EHT internal mixer for 10 min at 180 °C, 50 rpm. Lignocellulosic content changed from 5
to 60 vol%. The homogenized material was compression molded to 1 mm thick plates at 180 °C using a
Fontijne SRA 100 machine. All specimens were kept in a room with controlled temperature and humidity
(23 °C and 50 %) for at least two weeks prior further testing. Mechanical properties were characterized by
the tensile testing of specimens cut from the 1-mm-thick plates using an Instron 5566 apparatus,
accompanied by acoustic emission measurement (AE, Sensophone AED40/4). Micrographs were recorded
on tensile fracture surfaces using a scanning electron microscope (SEM, JEOL JSM 6380 LA) and a
polarized optical microscope (POM, Zeiss Axioskop 20).
100
30
80
20
AE
60
10
40
3500
2500
1500
500
0
0.0
0.5
1.0
Cumulative number of signals
40
Amplitude (dB)
Stress (MPa)
3. Results and discussion
Micromechanical deformation processes often result in acoustic signals so AE testing is an indirect
method to investigate and determine them in a material subjected to loading. Characteristic stress
indicating the initiation of micromechanical deformation processes was determined from the data of
tensile testing and AE measurement (Fig. 1).
20
Deformation (%)
Figure 1. Determination of the characteristic stress (σAE) related to the initiation of micromechanical
deformation process
According to the results the slope of the cumulative number of acoustic signals does not change after
an initial stage, which indicates the fracture of lignocellulosic particles. This observation indicates strong
interfacial adhesion between the components, which was also confirmed by the SEM and POM
micrographs (Fig. 2). In addition, there is a close correlation between the characteristic stress and the
tensile strength, thus the macroscopic failure of the investigated composites is affected by the
89
micromechanical deformation processes occurring around the fillers. The extent of reinforcement was
estimated quantitatively from the composition dependence of tensile properties such as yield stress and
tensile strength [7, 8]. These results show that particles with higher aspect ratio have larger load-bearing
capacity.
Figure 2. Particle fracture in SEM (left) and POM (right) micrographs
4. Conclusions
The results show that the dominating micromechanical deformation process is particle fracture in
PLA/lignocellulosic composites, which indicates strong interfacial adhesion. Furthermore, lignocellulosic
fillers with higher aspect ratio have larger load-bearing capacity.
Acknowledgements
The research was financed by the National Scientific Research Fund of Hungary (OTKA Grant No. K
101124) and the Forbioplast FP7 project of EU (212239).
References
[1] N. Ljungberg, B. Wesslén, Polymer 2003, 44, 7679-7688.
[2] M-A. Paul, M. Alexandre, P. Degée, C. Henrist, A. Rulmont, P. Dubois, Polymer 2003, 44, 443-450.
[3] M. Murariu, A. Da Siva Ferreira, M. Pluta, L. Bonnaud, M. Alexandre, P. Dubois, Eur. Polym. J. 2008,
44, 3842-3852.
[4] A. Södergård, M. Stolt, Prog. Polym. Sci. 2002, 27, 1123-1163.
[5] C-H. Ho, C-H. Wang, C-I Lin, Y-D. Lee, Polymer 2008, 49, 3902-3910.
[6] B. Imre, K. Renner, B. Pukánszky, Express Polym Lett 2014, 8, 2-14.
[7] B. Turcsányi, B. Pukánszky, F. Tüdős, J. Mater. Sci. Lett. 1988, 7, 160-162.
[8] B. Pukánszky, Composites 1990, 21, 255-262.
P17
KUN, DÁVID: POLYMER/LIGNIN BLENDS: STRUCTURE, INTERACTION, PROPERTIES
1
1
1
1
Gábor Szabó , Brúnó Bozsódi , Vivien Romhányi , Dávid Kun *, Béla Pukánszky
1
Laboratory of Plastics and Rubber Technology, Budapest University of Technology,
H-1521 Budapest, P.O.Box 91, Hungary
2
Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences,
H-1519 Budapest, P.O. Box 286, Hungary
*[email protected]
1,2
90
1. Introduction
The interest in using natural materials increased considerably in recent years also in the plastic
industry. Wood and natural fibers are applied extensively as reinforcements in a wide variety of polymers.
Lignin is produced as a byproduct in the paper and bioethanol industry, thus using it in value added
applications would be beneficial. However, lignin is a very polar material with a large number of
functional groups, thus its molecules interact with each other very strongly. Furthermore, the polymer
cannot be melted, fused or dissolved in most solvents and it is not miscible with commodity polymers.
Although several attempts have been made to blend lignin with various polymers, the properties of the
blends deteriorated in most cases especially in polyolefins. The goal of our work was to prepare polymer
blends with various thermoplastics and study their interfacial interactions, structure and properties.
2. Experimental
Polymer/lignin blends were prepared in a wide composition range (0-70 vol%). The applied polymers
were polypropylene, PP (H 649 FH, TVK); poly(lactic acid), PLA (Ingeo 4032, NatureWorks); polystyrene, PS
(Styron 686E, Americas Styrenics); glycol modified poly(ethylene terephthalate), PETG (Ecozen SE, SK
Chemicals); polycarbonate, PC (Makrolon 2658, Bayer Material Science); ethylene-methacrylic acid
copolymer partially neutralized with zinc-hydroxide, ION (Surlyn 1706, DuPont). The Bretax C
lignosulfonate (LS) was supplied by Burgo Cartiere SpA (Italy).
Homogenization was carried out in a Haake 2515 internal mixer for 10 min at 190 °C, 50 rpm. The
homogenized material was compression molded into 1 mm thick plates using a Fontijne SRA 100 machine
at 190 °C. Tensile testing (Instron 5566) was used on specimens cut from the plates to determine the
mechanical properties of the blends. Scanning electron microscopy (SEM) was also applied to study their
morphology.
3. Results and discussion
According to the results, mechanical properties depend on composition, but also on structure and
interfacial interactions between the polymer and the lignosulfonate. Interactions can be estimated
quantitatively from the composition dependence of tensile properties by using simple semi-empirical
formulae [1-3]. The model applied assumes that both particle size and reinforcement depends on
interfacial interactions and predicts a linear correlation between a parameter derived from tensile
strength (C*σLS) and the reciprocal value of the square of particle size (1/d2). The correlation is presented
in Fig. 1 for the polymers studied and it indicates that the strongest interfacial interactions develop in the
ION/LS blends, while the weakest in the PP/LS blends.
7000
6000
ION
C*LS (MPa)
5000
4000
PETG
3000
2000
1000
PLA
PC
PS
PP
0
0.0
0.2
0.4
0.6
0.8
1.0
-2
1.2
Particle size (m ), 1/d
1.4
1.6
2
Figure 1. Correlation between interfacial interactions and the particle size of lignin in polymer/lignin
blends
91
4. Conclusions
A close correlation was found between the strength of interfacial interactions and the particle size of
lignosulfonate, showing that the stronger the adhesion is, the smaller the dispersed particles are. The
strength of interfacial adhesion is affected by the type of the polymer matric since lignin forms different
interactions in the various blends. The strongest adhesion can be observed in the ION/LS blend, while the
weakest in the PP/LS blends.
Acknowledgements
The research was financed by the National Scientific Research Fund of Hungary (OTKA Grant No. K
101124) and the Forbioplast FP7 project of EU (212239). The authors would like to thank Burgo Cartiere
SpA for supplying the lignin sample.
References
[1] B. Turcsányi, B. Pukánszky, F. Tüdős, J. Mater. Sci. Lett. 1988, 7(2), 160-162.
[2] B. Pukánszky, Composites 1990, 21(3), 255-262.
[3] E. Fekete E, B. Pukánszky B, Z. Peredy Z., Angew. Makromol. Chem. 1992, 199(1), 87-101.
P18
OLEWNIK-KRUSZKOWSKA, EWA: THE INFLUENCE OF OZONE ON DEGRADATION PROCESS
OF PLA – MMT COMPOSITES
Ewa Olewnik-Kruszkowska*, Jacek Nowaczyk
Nicolaus Copernicus University, Faculty of Chemistry, Gagarin 7 Street, 87-100 Torun, Poland
*[email protected]
1. Introduction
Poly(L-lactide) (PLA) is a linear thermoplastic polyester produced from renewable resources. It is a very
promising material used in a number of fields. In aim to improve their mechanical properties or decrease
its permeability to gases the different types of nanofillers are introduced into polymer matrix. The
nanofillers can also influence the degradation process of PLA.
The photodegradation and the hydrolytic degradation of polylactide-based composites was previously
discussed but there is no publication devoted to degradation of polymer composites induced by ozone.
Degradation occurring in the presence of ozone is another important mechanism worth focusing on.
Ozone is an allotrope of oxygen in which the molecule is composed of three oxygen atoms. This gaseous
substance is known as one of the most powerful oxidizing agent [1]. Degradation process initiated by
ozone results in a formation of a macro-radical which reacts with oxygen, forms a peroxide or hydroxides
prone to decomposition when exposed to radiation. Compounds comprising non-saturated C=C groups
are a commonly applied group of modifying agents. They react with oxygen, in the presence of catalysts –
metal salts, to form peroxides and decompose into radicals reacting with the polymer matrix [2].
The main aim of this paper is to determine the impact the ozone as well as an additive such as
montmorillonite have got on the degradation of polylactide. Structural changes in the polymer caused by
ozone were determined by means of FTIR spectroscopy FTIR. The thermal properties, during degradation,
were studied by means of differential scanning calorimetry (DSC). Obtained results indicate that the
addition of the filler delays ozone induced degradation.
92
2. Experimental
Materials:
Polylactide (PLA), typ 2002D (NatureWorks®, USA), with melt flow rate (MFR) of 5-7g/10min (2,16kg;
463 K), Montmorillonit K-10 as nanofiller (Acros Organics, Belgium).
Conditions of ozonization:
Samples in the shape of films consisting of neat polylactide, filled MMT polylactide at the 1, 3 and 5%
weight ratio were subjected to ozone induced degradation. The samples were studied in the presence of
ozone, under atmospheric pressure, at room temperature and prevented from access to light. The
influence of nanoadditive on the ozone induced degradation was studied with an increased quantity of
ozone compared to tropospheric conditions.
Technique of characterization:
- The FTIR spectra were obtained using a Nicolet iS10 spectrometer.
- Differential scanning calorimetry (DSC) was performed on a Polymer Laboratories, Epson, UK
differential scanning calorimeter under nitrogen screening. Thermal behaviour of PLA and PLA/clay
nanocomposites was examined in a temperature range of 25-220 oC with a heating rate of 10 oC min-1
according to PN-EN ISO 11357:2002. The degree of crystallinity (Xm) was evaluated by applying the
following equation (1), also used by other authors [3, 4]:
Xm=
Hm
H0 x XPLA
x
100%
(1)
where Hm is the measured heat of fusion of sample, Ho is the heat of fusion of a 100% crystalline
polylactide and Ho=109 mJ mg-1 [5], XPLA is the mass fraction of polylactide.
3. Results and discussion
The effect of the amount of clay on the degradation of polylactide/clay nanocomposite films occuring
in the presence of ozone was studied. Figure 1 depicts FTIR spectra of selected materials (polylactide (L)
and polylactide filled with 5wt% of montmorillonite (LS5)) before degradation and after 4 months of
presence in ozone atmosphere.
The most significant changes in figure 1 are observed in range from 3657cm-1to 3503cm-1. The bands
at this range belong to vibrations of OH groups. During ozone treatment the band at 3657 cm-1 is reduced
while the band at 3509 cm-1 is increased which indicates that the number of end-hydroxylic groups
increases. Another important band was registered at the frequency of approximately 1675 cm-1. It
indicates elongating vibrations of new C=O group formed in the PLA during ozonelysis process [6].
Comparing the changes occurring in the spectra of PLA (L) and sample LS5 we can conclude that more
intensive changes are observed in case of composites material.
93
Figure 1. FTIR spectra of PLA (L) and LS5 composite before and after 4 month ozone treatment
In Table 1 the results obtained from DSC analysis are shown. The values of ΔHc PLA indicate that the
presence of investigated materials under ozone causes an increase in the amorphous phase. There are
therefore reasons to believe that ozone diffuses in the polymer materials and disorders the structure of
PLA. Such assumption is justified also because in the DSC curve of the presented materials during the
degradation process two melting temperatures can be observed. This phenomenon indicates that
polymer matrix consists of two fractions of different molecular mass.
Table 1.
Sample
L
LS1
LS3
LS5
L-4m
LS1-4m
LS3-4m
LS5-4m
PLA
Tg [˚C]
61.7
61.9
63.1
63.1
54.5
57.0
57.2
57.3
PLA
Tc [˚C]
126.0
126.7
126.1
129.6
106.1
107.9
108.8
108.3
PLA
ΔHc
15.9
10.1
11.3
14.6
38.5
37.0
36.9
33.4
[J/g]
PLA
Tm [˚C]
155.8
156.8
155.5
155.7
151.9/144.2
151.2/142.3
152.0/144.0
152.0/143.5
PLA
ΔHm [J/g]
17.3
13.6
13.8
16.9
40.8
39.7
38.5
37.4
PLA
Xc [%]
15.9
12.6
13.1
16.3
37.4
36.8
36.4
36.1
4. Conclusions
- The FT-IR spectra registered before and after degradation process indicated that ozone influences the
decomposition of polymer matrix.
- It has been established that the incorporation of montmorillonite does not change the mechanism of
the degradation process.
- The results showed that the presence of montmorillonite in the polylactide matrix can reduce the
ozone diffusion into polymer matrix and in this way delay degradation process.
Acknowledgements
This research project has been supported by National Centre of Science, Contract No. DEC2011/03/D/ST8/04126
94
References
[1]
[2]
[3]
[4]
[5]
[6]
W. Czerwiński, J. Nowaczyk, K. Kania, Polym. Degrad. Stab. 2003, 80, 93.
B. Singh, N. Sharma, Polym. Degrad. Stab. 2008, 93, 561.
W.S. Chow, S.K. Lok, J Therm. Anal. Calorim. 2009, 95, 627.
Y. Li, C. Chen, J. Li, X.S. Sun, Polymer 2011, 52, 2367.
S. Sosnowski, Polymer 2001, 42, 637.
L. Zaidi, M. Kaci, S. Bruzaud, A. Bourmaud, Y. Grohens, Polym. Degrad. Stab. 2010, 95, 1751.
P19
PUTIĆ, SLAVIŠA: DETERMINATION OF ACID VALUE AND MICROMECHANICAL ANALYSIS
OF MODIFIED NANOCELLULOSE
1
2
1
Nenad Đorđević , Aleksandar Marinković , Marina Stamenović , Slaviša Putić
2
1
College of Vocational Studies Belgrade Polytechnic, Belgrade, Serbia
Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
2
1. Summary
Nanocellulose, including nanocrystalline cellulose, cellulose nanofibril and bacterial cellulose
nanofibers are building blocks for creating new biopolymers. The process for isolating the nano-crystalline
cellulose from cellulose fibers is based on acid hydrolysis. In this paper, the process of obtaining
nanocellulose using sulfuric acid mass fraction of 64% with the ratio of acid to cellulose of 8.75 to 17.5 ml
/ g. Hydrolysis occurred at a temperature of 45 ° C, for a time period of 25-45 min. The resulting
nanocellulose been modified with maleic anhydride. The paper presents the results of the determination
of the acid number and micromechanical analysis of samples modified nanocellulose recorded on SEM.
Nanocellulose is applied to a metal carrier and than recorded. Results of the determination of the acid
number indicated that the modified code nanocellulose anhydride had the acid number increased
compared to an unmodified nanocellulose which is a consequence of the free carboxyl group.
KEYWORDS: nanocellulose, acid hydrolysis, maleic acid, SEM, an acid number
P20
STAMENOVIĆ, MARINA: LIFE CYCLE OF BIODEGRADABLE POLYMERS AND THEIR IMPACT
ON THE ENVIRONMENT
1
1
1
Marina Stamenović , Dominik Brkić , Nenad Đorđević , Slaviša Putić
2
1
College of Vocational Studies Belgrade Polytechnic, Belgrade, Serbia
Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
2
1. Summary
Regardless of the good properties of plastic materials, which have greater application, they become a
key problem in the disposal after use. Worldwide, there are research efforts to develop biodegradable
polymers as an option in waste management.In the market there as plastic packaging, we have as an offer
disposable biodegradable PE-LD and PE-HD products. Life Cycle Assessment (Life cycle assessment, LCA) is
95
a very useful method that allows quantification and assessment of the environmental attributes of a
product, process or activity from its inception to the end of life. LCA methodology is of great importance
for polymer materials, because it provides guidelines for disposal of materials and to properly predict the
behavior of materials and design rules for future life cycle of materials. In this paper highlight is the
importance of biodegradable polymers as well as estimation of useful life, or the study of liability of
products made of these materials to the environment.
KEYWORDS: polymers, biodegradable materials, LCA methods, environment
P21
SZABÓ, GÁBOR: IONOMER/LIGNOSULFONATE BLENDS: INTERACTION, STRUCTURE,
PROPERTIES
1
1
1
1
1
Gábor Szabó *, Brúnó Bozsódi , Balázs Podolyák , Dávid Kun , Béla Pukánszky
1,2
Laboratory of Plastics and Rubber Technology, Budapest University of Technology and Economics,
H-1521 Budapest, P.O.Box 91, Hungary
2
Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences,
H-1519 Budapest, P.O. Box 286, Hungary
*[email protected]
1. Introduction
Recently the demand for the utilization of natural, renewable materials in the polymer industry
increases continuously, because of the considerably improved environmental awareness of the society
and the fear from the depletion of petrochemical based plastics. Lignin may be a solution for this
problem, since it is the second most abundantly available natural polymer on Earth, thus it represents an
enormous resource of renewable raw material. In the paper and bioethanol industry lignin is a by-product
where it is mainly used as fuel to produce energy resulting in significant carbon-dioxide emission. The
application of lignin in polymer blends could yield product with increased value.
In the paper industry sulfonated lignin, i.e. lignosulfonate is produced in the sulfite process. The
complex chemical structure and large number of functional groups of lignosulfonates result in the
formation of various interactions among lignin molecules, but also with other substances. Ionic bonds,
hydrogen bridges and  electron interactions can all develop in lignin. In our research we wanted to
investigate the possible effect of ionic bonds on interactions, so we used ionomers as matrices. Ionomers
are mainly copolymers of ethylene and acrylic or methacrylic acid, which are partially neutralized with
metal cations, such as sodium and zinc.
2. Background
Interfacial interactions can be estimated quantitatively from the composition dependence of tensile
properties [1, 2]. One of the applied formulae describes the composition dependence of yield stress:
 y   y0 
1
 exp B 
1  2.5
(1)
where σy and σy0 are the yield stress of the blend and the matrix polymer, φ is the volume fraction of
lignin in the blend and B is a constant which is proportional to the load carried by lignosulfonate [3]:
 C   yd
B  n
  y0





(2)
96
where σyd is the yield stress of lignosulfonate and C is related to stress transfer, i.e. to interaction.
3. Experimental
Ionomer/lignin blends were prepared from Bretax SRO2 and Bretax CRO2 lignosulfonates (Burgo
Cartiere SpA, Italy) and several types of ionomers (Surlyn 1601, Surlyn 1706, Surlyn 9020; DuPont, France).
Blends were homogenized in a Brabender W 50 EHT internal mixer for 10 min at 190 °C and 42 rpm. The
homogenized material was compression molded into 1 mm thick plates at 190 °C using a Fontijne SRA 100
machine. Mechanical properties were characterized by the tensile testing (Instron 5566) of specimens cut
from the plates. Scanning electron microscopy, SEM (JEOL JSM 6380 LA) was applied to investigate the
morphology of the blends. The structure and composition of the ionomers were investigated by Fouriertransform infrared spectroscopy (Bruker Tensor 27) and inductive coupled plasma-optical emission
spectroscopy (Labtest Plasmalab ICP). The thermal properties of the blends were determined by dynamic
mechanical analysis, DMA (PerkinElmer Diamond DMA) and differential scanning calorimetry, DSC
(PerkinElmer DSC 7).
4. Results and discussion
Lignosulfonates form stiff droplets in the ionomer matrix thus the stiffness of the blends increases
upon the addition of lignosulfonates, while their elongation decreases at the same time with increasing
lignin amount. Strength varies in a wide range, but depends mainly on the type of ionomer used.
According to SEM micrographs, the originally very large particles (72-82 m) of lignin break down to very
small droplets (0.35-0.85 m) during mixing indicating strong interactions between the two components.
The type of lignin does not seem to influence properties, so we assume that only the type of the ionomer
plays a role in the determination of structure and properties in the studied blends.
According to our results there is no correlation between the ion content and stress transfer (C* σyd)
indicating that besides ionic bonds other interactions also influence interfacial adhesion. On the other
hand, the extent of stress transfer is related to the total concentration of the functional groups in the
ionomers which can form a salt or hydrogen bridge (Fig. 1).
DMA results show that the characteristic relaxation temperature of the peak assigned to ionic clusters
shifts towards higher values, while other peaks remain unchanged, which proves that ionic bonds are
indeed formed in our samples. The formation of ionic clusters was confirmed also by DSC measurements.
2500
ZnMER2/CaLS
2000
ZnMER2/NaLS
C*yd
1500
ZnMER1/NaLS
1000
NaMER/CaLS
ZnMER1/CaLS
500
0
0.0
NaMER/NaLS
0.5
1.0
1.5
2.0
2.5
3
cCOOH + cIon+ cEster (mmol/cm )
Figure 1. Correlation between parameter C and the total concentration of functional
groups in the ionomers which can form ionic or hydrogen bonds
97
5. Conclusions
The results show that lignin particles are very small in the studied ionomer/lignosulfonate blends,
which indicates good compatibility between the components. Mainly the ionomer matrix affects the
properties of the investigated blends and the strength of interfacial interactions is affected by both ionic
bonds and hydrogen bridges.
Acknowledgements
The research was financed by the National Scientific Research Fund of Hungary (OTKA Grant No. K
101124) and the Forbioplast FP7 project of EU (212239). The authors would like to thank Burgo Cartiere
SpA for donating the lignosulfonate sample.
References
[1] B. Turcsányi, B. Pukánszky, F. Tüdős, J. Mater. Sci. Lett. 1988, 7(2), 160-162.
[2] B. Pukánszky, Composites 1990, 21(3), 255-262.
[3] E. Fekete E, B. Pukánszky B, Z. Peredy Z., Angew. Makromol. Chem. 1992, 199(1), 87-101.
P22
VECCHIATO, SARA: BIOPOLYMER BASED DIAGNOSTICS FOR DETECTION OF WOUND
INFECTION
2
2
2
2
1
2
Andrea Heinzle , Sara Vecchiato , Karolina Haernvall , Eva Sigl , Gregor Tegl *, Doris Schiffer , Konstantin P.
2
1,2
Schneider , Georg M. Guebitz
1
Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Vienna, Konrad Lorenz
Strasse20, 3430 Tulln, Austria
2
Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
*[email protected]
1. Introduction
Infection of wounds constitutes a major problem. Especially medical facilities struggle with the
consequences of postoperative wound infections. Current methods for its detection are based on simple
wound status evaluation, PCR or cultivation that makes a timely evaluation of the wound’s contamination
level hardly possible. Therefore, novel diagnostic tools were developed based on enzyme responsive
materials in order to enable a fast and simple detection of wound infection. Thereby elevated activities of
lysozyme in infected wounds are detected and visualized by the release of dyes. A matrix composed of
alginate and agarose, respectively, was chosen to incorporate the labelled enzyme substrate.
2. Experimental
Wound fluid was collected from diverse wounds, 50% of them were described to be clinically infected.
Analyses were conducted with wound fluid cleansed from cells and tissue material.
Enzyme activities were determined by either using commercial kits or already published procedures.
Zymography was performed by Polyacrylamide gel electrophoresis using a Mini Protean Cell (Bio-Rad) at
60V for 2h.
M. lysodeiktikus cells were used as substrate for lysozyme that was previously labeled with Remazol
brilliant blue. Agarose/peptidoglycan layers were prepared by suspending heated agarose in phosphate
buffer and M. lysodeiktikus cell (stained or unstained) in varying concentrations. Alginate/peptidoglycan
98
beads were formed by adding an alginate-peptidoglycan solution to an agitated calcium chloride solution
via a peristaltic pump.
Enzyme hydrolysis studies were performed with commercial lysozyme from chicken white egg
(AppliChem) at 37°C and 350 rpm. The polymers were dried before applying them in enzyme assays.
Reaction products of the lysozyme hydrolysis were investigated by LC-MS using an Agilent Ion Trap SL
(Palo Alto) equipped with electrospray ionization (voltage set to 3500 V).
3. Results and discussion
Lysozyme activities of the obtained wound fluids were determined according to Shugar (1952) and
obtained results indicate elevated activities in infected wounds. The obtained results were further
confirmed by applying zymography.
Diagnostic tool prototypes were prepared in order to develop a solid detection system. An
agarose/peptidoglycan (unstained) blend layer system in microtiter plates was successful comprising
0.45% (w/w) PG, higher PG content yielded in inhomogeneous PG distribution. A layer thickness of 2 mm
seemed to be optimal for visual inspection of transparency.
A monolayer of agarose/peptidoglycan (stained) achieved best results using 8% (w/w) stained PG. LCMS analysis of the supernatant indicated the disaccharide (GlcNAc-MurNAc) to be the major reaction
product of enzyme hydrolysis.
To avoid spectrophotometric analysis of a supernatant, a double layer of agarose/peptidoglycan was
prepared. Thereby the unstained upper layer was hydrolysed, which led to appearance of the stained
lower layer. This system enables a visual judgment of the degree of hydrolysis.
99
Figure. 1 Visual detection approach: double layers were incubated with different lsysozyme activites
(U/mL) and with 3 infected (i.) and 3 noninfected (n.i.) wound fluid samples
The usability of beads of alginate/peptidoglycan (stained) was investigated too. Due to the higher
surface area of the prepared beads, an elevated dye release was observed. In this case as well 8% (w/w)
stained PG gave the best results.
4. Conclusions
Since elevated lysozyme activities were detected in infected wound fluids, different detection devices
for lysozyme detection were prepared. The sensitivity of detection was enhanced by staining the enzyme
substrate with remazol brilliant blue. To overcome the analysis of liquid phase, visual evaluation of wound
infection was enabled by the design of a double layer system. This kind of diagnostic tools make it
possible to timely detect wound infection by investigation of the respective wound fluid.
Acknowledgement
Financial support from the European FP7-program, the FFG, the SFG, and the Province of Styria is
gratefully acknowledged.
References
[1] Hasmann, A. et al. (2011) Novel peptidoglycan-based diagnostic devices for detection of wound
infection. Diagn. Micr. Infec. Dis. 71, 12–23
[2] Schneider, K.P. et al. (2011) Bioresponsive systems based on polygalacturonate containing hydrogels.
Enzyme Microb. Technol. 48, 312–318
P23
VECCHIATO, SARA: MODIFICATION OF LIGNOSULFONATES BY LACCASE
1*
2
2
1
1
Andreas Ortner , Sara Vecchiato , Karolina Haernvall , Oskar Haske-Cornelius , Gibson S. Nyanhongo ,
1,2
Georg M. Guebitz
1
University of Natural Resources and Life Sciences Vienna, Institute of Environmental Biotechnology,
Konrad-Lorenz Str. 20, A-3430 Tulln, Austria
2
ACIB (Austrian Center of Industrial Biotechnology) GmbH, Konrad-Lorenz Str. 20, A-3430 Tulln, Austria
*[email protected]
1. Introduction
Lignosulfonates are byproducts of the wood pulping process, especially the kraft process. The
delignification with sulfides involves acidic cleavage of ether bonds of the lignin resulting in polydisperse
products with molecular weights between 1000–140,000 da [1].
In order to increase its modifications to improve reactivity and dispersion properties using oxidative
enzymes e.g. laccases are gaining both industrial and scientific interests. Laccases (benzenediol: oxygen
oxidoreductases, EC.1.10.3.2) are multicopper containing enzymes that catalyze the oxidation of various
aromatic compounds (producing reactive species), especially phenolic compounds, concomitantly
reducing molecular oxygen to water [3]. The generated reactive species enhance the reactivity of
molecules/polymers and provide ideal sites for cross-linking leading to polymerization reactions
and consequent formation of new materials or materials with new properties. Further, the discovery of
laccase mediators, (molecules which when oxidized by laccases form highly reactive oxidizing species),
which have the ability to oxidize substrates which would rather be difficult to oxidise with the enzyme
alone, have expanded applications of these enzymes in modifying “inert” polymers.
In this study we investigate the possibility of modifying lignosulfonates in the presence of different
mediators.
100
2. Experimental
Lignosulfonates with 30% dry substance were kindly provided by Sappi, Austria. Laccases from
Myceliopthera thermophila were supplied by Novozyme, Denmark. The chemicals were purchased either
from Merck or Sigma-Aldrich.
Laccase activity was determined spectrophotometrically by monitoring the oxidation of 2,2’-azinobis(3-ethylbenzothiazoline)-6-sulphonate (ABTS) (ε436 = 29,300 M-1cm-1) as substrate at 436 nm in 100 mM
potassium phosphate buffer at pH 7 and 37 °C. The change in absorbance was recorded in time scan
mode for 2 min.
The modification of lignosulfonates by laccase was done in 2ml Eppendorf tubes. Samples were
incubated at 25 °C while shaking at 350 rpm. The modification was monitored during the incubation
period by withdrawing samples at regular intervals and immediately measuring fluorescence intensity. For
the fluorescence intensity measurement, a lignosulfonate sample of 100 μl was added to a solution of 2methoxyethanol and water (2:1 v/v) and then thoroughly mixed.
Fluorescence intensity was monitored using a TECAN Infinite M200 plate reader instrument (Tecan
Austria GmbH, Grödig, Austria) at Ex 355 nm / Em 400 nm [4].
3. Results and Discussion
Myceliopthera thermophila laccase alone was able to oxidize the lignosulfonates to different extents
under different pH conditions. The fluorescence intensity steadily decreased during incubation time. The
highest decrease in fluorescence intensity (corresponding to 31 %) was achieved at pH 7 during 5000 min
of incubation. Previous studies using laccases from different sources also demonstrated this decrease in
fluorescence intensity [2,5].
Since extensive oxidation of the lignosulfonates occurred at pH 7, subsequent reactions with different
mediators were also performed under these conditions. However, in all lignosulfonates incubated with
mediators, a remarkable 70 % decrease in fluorescence intensity was observed. This shows that the
mediators enhance the modification of lignosulfonates which also reduce the needed incubation of time.
In order to gain more insight into the modification of lignosulfonates, different concentrations of
diluted lignosulfonates were further incubated with the best performing mediator (acetosyringone) and
the oxidation monitored. Increasing dilution of increases the oxidation rate. All lignosulfonate samples
diluted above 1:50 were completely oxidized in less than an hour. This information is important for
defining incubation conditions and estimating the extent of the modification.
4. Conclusions
This study shows the ability of laccase to modify lignosulfonates. The obtained polymers could be
potentially developed for application as adhesives, coating material or for molding other materials. This
study demonstrates the ability of laccase to play a major role in activating and polymerizing
lignosuflonates.
Acknowledgements
The authors would like to thank the Austrian K-Project funding for Future Lignin and Pulp Processing
Research (FLIPPR) project.
References
[1] Lebo S, Gargulak J and McNally T (2001) Lignin. Kirk-Othmer Encyclopedia of Chemical Technology.
John Wiley and Sons Inc.
[2] Nugroho Prasetyo E, Kudanga T, Rencoret J, Gutiérrez A, del Río JC, Santos JI, Nieto L, JiménezBarbero J, Martínez AT, Li J, Gellerstedt G, Lepfire S, Silva C, Kim SY, Cavaco-Paulo A, Seljebakken
Klausen B, Frode Lutnaes B, Nyanhongo GS, Guebitz GM (2010) Polymerisation of lignosulfonates by
the laccase-HBT (1-hydroxybenzotriazole) system improves dispersibility. Biores. Technol. 101: 50545062
101
[3] Nyanhongo GS, Nugroho Prasetyo E, Herrero Acero E, Guebitz GM (2012) Advances in the application
of oxidative enzymes in biopolymer chemistry and biomaterial research In: Felber F. et al. eds.
“Functional Materials from Renewable Sources”, ACS symposium series, American Chemical Society
Washington DC, 2012, pp 329-349
[4] Thomson, C.I., Lowe, R.M., Ragauskas, A.J., 2005. Excitation energy transfer in cellulosics: indications
of inter-fibre fluorescence resonance energy transfer. In: 13th International Symposium on Wood,
Forestry, and Pulping Chemistry, Auckland.
[5] Nugroho Prasetyo E, Kudanga T, Fischer R, Eichinger R, Nyanhongo GS, Guebitz GM (2012) Enzymatic
synthesis of lignin-siloxane hybrid functional polymers. Biotech. J. 7: 284–292
102