COVER SHEET
This is the author version of article published as:
Yu, Zhong-Zhen and Yan, Cheng and Dasari, Aravind and Dai, Shaocong and Mai,
Yiu-Wing and Yang, Mingshu (2004) On Toughness and Stiffness of Poly(butylene
terephthalate) with Epoxide-Containing Elastomer by Reactive Extrusion.
Macromolecular Materials and Engineering 289:pp. 763-770.
Copyright 200 Wiley
Accessed from http://eprints.qut.edu.au
On the Toughness and Stiffness of Polybutylene Terephthalate
with Epoxide-Containing Elastomer by Reactive Extrusion
Zhong-Zhen Yu*, Cheng Yan, A. Dasari, Shaocong Dai, Yiu-Wing Mai
Center for Advanced Materials Technology
School of Aerospace, Mechanical and Mechatronic Engineering (J07)
The University of Sydney
Sydney, NSW 2006, Australia
Mingshu Yang
State Key laboratory of Engineering Plastics
Center for Molecular Science, Institute of Chemistry
The Chinese Academy of Sciences
P. O. Box 2709, Beijing 100080, China
Keywords: blends; fracture; polybutylene terephthalate; reactive extrusion;
toughness
* Corresponding author:
E-mail: [email protected]
Fax: +61-2-9351 3760
Summary
To obtain a balance between toughness and stiffness of polybutylene terephthalate
(PBT), a small amount of tetra-functional epoxy monomer was incorporated into
PBT/ethylene-methyl acrylate-glycidyl methacrylate terpolymer (E-MA-GMA)
blends during reactive extrusion process. The effectiveness of toughening by EMA-GMA and the effect of epoxy monomer were investigated. It was confirmed
that the E-MA-GMA had fine dispersion in PBT matrix. PBT experienced a sharp
jump in toughness with increase in E-MA-GMA content. On the other hand, its
stiffness decreased linearly. The addition of 0.2 phr epoxy monomer further
improved the dispersion of E-MA-GMA particles by increasing the viscosity of
PBT matrix. While the use of the epoxy monomer had an insignificant influence
on impact energy of the blend, however, there was a distinct increase in the
stiffness of the blend. SEM micrographs of impact-fractured surfaces indicated
that extensive matrix shear yielding was the main impact energy dissipation
mechanism in both the blends.
2
1. Introduction
In the recent past, polybutylene terephthalate (PBT) has been extensively used in
automotive and electronic applications. However, high notch sensitivity and
inadequate impact energy of PBT, particularly at low temperatures, restricts their
use. One method, to modify and increase the impact energy of PBT is to blend
with elastomers, such as, maleated styrene-ethylen/butylene-styrene block
coplymer (SEBS-g-MA) or ethylene-propylene binary elastomer,1 maleated
polyethylene-octene
copolymer
(POE-g-MA),2,3
butadiene-co-acrylonitrile
elastomers,4 epoxidized ethylene-propylene-diene monomer ternary elastomer,5
oxazoline
intermediates,6
styrene-acrylonitrile/acrylate
based
core-shell
elastomer,7 isocyanate-containing ethylene-propylene binary elastomer,8 methyl
methacrylate-ethyl acrylate- glycidyl methacrylate terpolymer (MMA-EAGMA),9,10 and ethene-methyl acrylate-glycidyl methacrylate terpolymer (E-MAGMA).11 In spite of immiscible and incompatible nature of PBT with these
elastomers, the ability of the carboxyl and/or hydroxyl end groups of PBT to react
with the elastomer reactive groups proved to be a major advantage in these blends
forming elastomer-co-PBT copolymers in situ during melt extrusion.1-11
In addition to the above-mentioned advantages, these elastomers were also being
used as compatibilizers in PBT/polyolefin blends, which lower the interfacial
tension between PBT matrix and elastomer and suppress the tendency of
coalescence, ultimately improving the dispersion of the elastomer particles in PBT
matrix.12,13 For example, Tsai and Chang12 used ethylene-glycidyl mechacrylate
copolymers (E-GMA) as compatibilizer in PBT/polypropylene blends, while the
effect of MMA-EA-GMA terpolymer on compatibilization of PBT/acrylonitrilebutadiene-styrene (ABS) blends has been studied by Hale et al.9,10,13 In the
PBT/polyolefin blends, the effective compatibilization of E-GMA copolymers
resulted in fine dispersion and improved mechanical properties. This was
3
attributed to in situ formation of PBT-co-E-GMA copolymers due to the reaction
of epoxy groups of E-GMA with carboxyl and/or hydroxyl terminal groups of
PBT. Also, higher GMA content in the E-GMA copolymer produced finer phase
domains, higher viscosity and improved mechanical properties. On the other hand,
although tough PBT/ABS blends were produced in the absence of compatibilizer
(MMA-EA-GMA terpolymer) within limited melt processing situations, however,
Hale et al illustrated that the morphology of these binary blends was unstable,
along with phase coarsening. The presence of 5 wt% MMA-EA-GMA terpolymer
yielded a finer dispersion of ABS domains, improved morphological stability, and
a broadened processing window. Consequently, an increase in low temperature
impact toughness was obtained.
Furthermore, it is also important to note that the increase in impact energy of PBT
in the presence of elastomer was achieved at the expense of stiffness, due to the
low modulus of elastomer. In view of this, Aróstegui and Nazábal14 reported that
the impact energy of PBT/phenoxy (80/20 w/w) blend was improved by POE-gMA elastomers. The presence of phenoxy, which is miscible with PBT, did not
affect the toughening efficiency of the POE-g-MA and the blends exhibited higher
stiffness in comparison to PBT/POE-g-MA blends without phenoxy. In our
previous work, the affect of a bi-functional epoxy monomer on toughness of nylon
6/POE-g-MA blend was studied.15,16 It was shown that the epoxy monomer played
a dual role in the blend. Firstly, the chain extension effect of the epoxy monomer
on nylon 6 improved its melt viscosity. Secondly, the coupling effect of the epoxy
monomer at nylon 6/POE-g-MA interface resulted in mixed copolymers, which
further improved the compatibility of the blend. The combination of which, further
enhanced the dispersion of POE-g-MA, along with the notched impact strength
and stiffness of nylon 6/POE-g-MA blends.15
4
In the present study, a commercial epoxide-containing elastomer (E-MA-GMA)
was used to produce a super-tough PBT with equally higher stiffness. A small
amount of tetra-functional epoxy monomer was incorporated into the PBT/E-MAGMA blends during reactive extrusion to further improve the dispersion of E-MAGMA particles by increasing the viscosity of PBT matrix and improving the
interfacial adhesion between PBT and E-MA-GMA. The effectiveness of
toughening by E-MA-GMA and the affect of the epoxy monomer were
investigated.
2. Experimental procedure
2.1 Materials
Polybutylene terephthalate, a commercial product under the trade name of
Ultradur® B2550, was supplied by BASF Corporation (New Jersey, USA). The
melt flow rate and density of this low-viscosity version PBT were 40 cm3/10 min
(ASTM D1238, 250oC/2.16 kg) and 1.30 g/cm3, respectively. The epoxidecontaining elastomer (E-MA-GMA) was an ethylene-methyl acrylate-glycidyl
methacrylate terpolymer containing 6 wt% glycidyl methacrylate (GMA) and 30
wt% methyl acrylate (MA), purchased from Sumitomo Chemical Co. Ltd (Tokyo,
Japan) marketed under a trade name of IGETABOND 7M. The density and melt
flow index of the elastomer were 0.964 g/cm3 and 9 g/10 min (190oC, 2.16 kg
load), respectively. A liquid tetra-functional epoxy monomer, N,N,N’,N’tetraglycidyl-4,4’-diaminodiphenyl methane (TGDDM), with epoxy equivalent
weight of 110-130 g/eq obtained from Ciba Specialty Chemicals was used to
increase the viscosity of the PBT and improve the interfacial adhesion between
elastomer and PBT matrix.
5
2.2 Blend preparation
Prior to blending, PBT was dried at 120oC in vacuum for 6 h. A Werner &
Pfleiderer ZSK-30 twin-screw extruder (L/D = 30, L = 0.88 m) equipped with a
high intensity mixing screw (operating at 240°C with a screw speed of 300 rpm)
was used for the preparation of blends. The extrudates were pelletized at the die
exit, dried and then injection molded into standard dumbbell tensile (50 mm gauge
length, 10 mm width, and 4 mm thickness) and rectangular bars (127 mm length,
12.7 mm width, and 12.7 mm thickness) by an injection molding machine (SZ160/80 NB, China). The temperatures at the barrel and the mould were maintained
at 240°C and 60°C, respectively. The rectangular bars were subsequently cut into
two equal halves along the longitudinal axis for Izod impact testing. A 45° Vnotch (depth 2.54 mm) was machined mid-way on one side of the bar with a slow
speed to avoid plastic deformation.
2.3 Viscosity measurements
Dynamic viscosity measurements were conducted using a Bohlin VOR-HTC
rheometer equipped with parallel plate geometry of 25 mm diameter at 240oC in
nitrogen atmosphere. The gap between the plates was set at 1.0 mm. The
specimens were pre-dried in vacuum oven at 120oC for 6 h. All specimens were
firstly heated to 240oC and held at that temperature until thermal equilibrium was
established between the plate and the melt. The temperature was measured using a
thermocouple mounted in the center of the top plate.
2.4 Mechanical testing and microstructural evolution
Tensile tests were performed on the dumbbell samples using an Instron 5567
testing machine according to ASTM D638. Tensile strength, Young’s modulus
and elongation-at-break were measured at a crosshead speed of 50 mm/min.
Notched Izod impact strength was measured on V-notch bars in a ITR-2000
instrumented impact tester in accordance with ASTM D256. During impact
6
testing, a load cell in the tup recorded the force generated in the deformed sample.
The integral of the load-deflection curve gives the fracture energy absorbed. All
these tests were conducted at ambient temperature (~ 25°C) and the average value
of five repeated tests was taken for each composition. The impact tested fracture
surfaces were observed using a Philips S-505 scanning electron microscope (SEM)
to investigate the fracture mechanisms of the blends. Also, freeze-fractured
experiments were conducted to estimate the particle size of the dispersed E-MAGMA in the PBT matrix. Fracture surfaces were etched with xylene at ambient
temperature for 12 h to remove the dispersed phase and then observed with SEM.
2.5 Quantification of morphology
The morphology of the blends was quantified by image analysis to determine the
efficiency of epoxy monomer on the minor phase (E-MA-GMA) size distribution.
A minimum number of 400 E-MA-GMA particles were considered on each
fractograph to identify the size distribution. The image analysis program used was
Image J (based on NIH software).
3. Results and discussion
3.1 Dispersion of E-MA-GMA
SEM micrographs of the freeze-fractured surfaces of PBT blends with different
weight percentage of E-MA-GMA are presented in Figure 1. The cavities on the
fractographs correspond to the E-MA-GMA particles, which were selectively
removed by etching with xylene solvent before SEM observations for better
understanding of the dispersion of E-MA-GMA particles. In order to ensure that
the results were indeed typical of the specimens, i.e., xylene solvent selectively
etched E-MA-GMA particles and not affected the blend morphology, freezefractured surfaces of blends without etching with xylene were also observed and
confirmed that the blend morphology is unaffected.
7
Figure 1a (10 wt% E-MA-GMA) exhibits fine dispersion of E-MA-GMA in PBT
matrix, which was shown previously to be due to the in situ formation of PBT-coE-MA-GMA copolymer at the PBT/E-MA-GMA interface as a result of reaction
between epoxide groups of E-MA-GMA chain and the carboxyl end groups of
PBT.9-11 However, it is interesting to note that the size of dispersed E-MA-GMA
particles increased with increase in percentage of E-MA-GMA (Figure 1b, 20 wt%
and Figure 1c, 30 wt%). This is different to the general trend of a compatibilized
polymer blend, where the average size of dispersed phase was less dependent on
the elastomer content.17,18 According to Martin et al11, during melt blending of
PBT/E-MA-GMA, two simultaneous competitive reactions will occur: (i) the
formation of PBT-co-E-MA-GMA copolymer and (ii) crosslinking of the
dispersed phase through a reaction between epoxide groups and secondary
hydroxyl species present on neighboring E-MA-GMA chains. However, the
observed increase in size of the dispersed phase in the present case may be due to
undesirable crosslinking reaction of E-MA-GMA. At high E-MA-GMA contents,
the crosslinking of E-MA-GMA was expected to be more severe, which makes the
dispersed phase highly viscous and limits the dispersion. It should be also be
pointed out that inspite of the increase in size and size distribution of E-MA-GMA
particles due to the undesirable crosslinking, the average size of E-MA-GMA
particles is still in sub-micron scale even at 30 wt% of E-MA-GMA (please see
below, section 3.2).
In Figure 2, SEM micrographs of freeze-fractured surfaces of PBT/E-MA-GMA
blends with 0.2 phr tetra-functional epoxy monomer are presented. Similar to the
PBT blends without epoxy monomer (Figure 1a), fine dispersion was achieved at
10 wt% E-MA-GMA in the presence of epoxy monomer (Figure 2a). With
subsequent increase in E-MA-GMA content, in a manner similar to PBT blend
without epoxy monomer, there was an increase in size of the dispersed phase
(Figure 2b, 20 wt% and Figure 2c, 30 wt%). However, the presence of the
8
monomer resulted in finer dispersion, especially at higher E-MA-GMA contents.
Previously, tetra-functional epoxy monomer has been successfully used to
compatibilize PBT/nylon 6, PBT/maleated polypropylene (PP-g-MA) and
PET/polyphenylene ether blends.19-21 It was also reported that the monomer
reacted with PBT and PP-g-MA simultaneously to form PBT-co-epoxy-co-PP-gMA copolymers at the interface that were able to anchor along the interface and
served as efficient compatibilizers.20
The positive role of monomer in the dispersion of E-MA-GMA particles can be
better explained by considering its influence on the viscosity of PBT/E-MA-GMA
blend (Figure 3). Figure 3 clearly illustrates that 0.2 phr of epoxy monomer
increased the viscosity of PBT melt, which was attributed to the chain extension
effect of monomer on PBT.19,20 Higher matrix viscosity in turn favored a finer
dispersion of E-MA-GMA elastomer along with an increase in the viscosity of
PBT/E-MA-GMA blend. It is also expected that the interfacial adhesion between
PBT and E-MA-GMA will be enhanced by the coupling reaction of monomer at
the PBT/E-MA-GMA interface, which increases the blend viscosity. It is also
possible that the monomer reacts with E-MA-GMA component and makes the
elastomer more viscous hindering the dispersion of E-MA-GMA. However, in the
present case of improved dispersion by the monomer, this reaction appears to be
less predominant.
3.2 Quantification of morphology
The efficiency of dispersion of E-MA-GMA particles in the PBT matrix and the
effect of epoxy monomer on the minor phase (E-MA-GMA) size distribution were
quantified using the image analysis program. Figure 4a illustrates the E-MA-GMA
particle size distribution in the PBT matrix in the absence of epoxy monomer. It
can be clearly seen that at low weight percentages of E-MA-GMA, the dispersion
is finer and with increase in E-MA-GMA content, the size of dispersed E-MA9
GMA particles increased. The mean particle size of at least 400 E-MA-GMA
particles at different E-MA-GMA weight percentages (10, 20, and 30) is 282, 325,
and 377 nm, respectively. With the addition of epoxy monomer to PBT/E-MAGMA blend, finer dispersion was observed at all weight percentages of E-MAGMA (10, 20, and 30, Figure 4b), in relation to PBT/E-MA-GMA blends without
epoxy monomer (Figure 4a). The mean particle size at different weight
percentages of E-MA-GMA in the presence of epoxy is 119, 322, and 343 nm,
respectively.
3.2 Mechanical properties
Figure 5 illustrates the variation of Young’s modulus with E-MA-GMA content
for PBT blends (with and without epoxy monomer). With increase in E-MA-GMA
content, the modulus of all blends decreased. The observed decrease in modulus
with elastomer content was also reported earlier in many rubber/polymer
systems.3,9,14-15,22-23 However, as expected, the addition of 0.2 phr epoxy monomer
increased the Young’s modulus of PBT at all E-MA-GMA contents owing to its
chain extension effect on PBT. Aróstegui and Nazábal14 obtained a similar result
by modifying PBT and 20 wt% phenoxy mixture with maleated elastomers.
In a manner similar to Young’s modulus, yield strength of PBT blends (with and
without epoxy monomer) decreased almost linearly with E-MA-GMA content
(Figure 6). However, the addition of 0.2 phr epoxy monomer exhibited an
insignificant influence on yield strength in relation to PBT blends without epoxy.
Theoretically, a relationship has been proposed between yield strength and
elastomer volume fraction (ϕ) in nylon/elastomer blends at low (0.05 min-1) and
high (600 min-1) deformation rates:24,25
σ blend = σmatrix (1-ϕ2/3 )
(1)
The predicted yield strength using Equation (1) is also presented in Figure 6,
which follows closely with the experimental values.
10
Figure 7 shows the Izod impact strength as a function of E-MA-GMA content for
the PBT blends (with and without epoxy monomer). As expected, greater notch
sensitivity of PBT yielded low notched impact strength (~ 24.8 J/m). The presence
of E-MA-GMA improved the notched impact strength of PBT to a small degree at
lower E-MA-GMA content (10 wt%), and to a much higher degree at higher EMA-GMA content (20 and 30 wt%). A brittle-ductile transition was observed with
increasing E-MA-GMA content. Furthermore, the addition of epoxy monomer did
not have a significant influence on the notched Izod impact strength of PBT/EMA-GMA blends (Figure 7). However, it is worth noting that even though the
impact strength of PBT/E-MA-GMA (70/30) decreased at higher E-MA-GMA
content (30 wt%) in the presence of monomer, the blend was still super-tough
(please see below, section 3.3).
Figures 5 and 7 also illustrate contribution of the epoxy monomer to impact
energy and stiffness of the PBT/E-MA-GMA blends. At a particular Izod impact
strength, for the corresponding E-MA-GMA content, the blend with monomer
exhibited higher modulus in comparison to the blend without monomer. Likewise,
at a given modulus, for the corresponding E-MA-GMA content, the blend with
monomer showed higher Izod impact strength. This is similar to the investigation
of nylon 6/POE-g-MA blend, in which the use of small amount of epoxy monomer
increased notched impact strength and stiffness in relation to those without
monomer.15
3.3 Microstructural evolution
SEM micrographs of the impact-fractured surfaces of PBT/E-MA-GMA (90/10)
blend in the absence of monomer are presented in Figure 8 at different
magnifications. Two kinds of fracture morphology can be seen on the low
magnification SEM micrograph (Figure 8a): a flat area close to the blunt notch
(Region 1), followed by a rough zone of ridges and hackles (Region 2). It is
11
important to note that the crack growth is from top to bottom in Figure 8a. Even
though at low magnification (Figure 8a), the two kinds of fracture morphology are
clearly delineated, however, at high magnifications (Figures 8b and 8c), they look
similar, resembling a brittle fracture mode. Also, no rubber cavitation or voids can
be seen on the fracture surface. The morphology of PBT/E-MA-GMA blends
shown here closely resembles with those of other polymer/rubber blends having
low toughness.26-30
With increase in E-MA-GMA content, a complete change in the fracture
morphology, from brittle (Figure 8) to ductile (Figure 9, 20 wt% and Figure 10, 30
wt%) was observed. At 20 wt% of elastomer, the fracture surfaces exhibited
distinct parabolic-shaped markings (Figure 9a), which closely resemble to that of
cleavage fracture in metals. Each parabolic marking contained a flaw at the locus
at which the secondary fracture seems to have initiated.34 At high magnifications
(Figure 9b), extensive matrix yielding occupied entire fracture surface, which was
believed to be the major impact energy dissipation mechanism. With subsequent
increase in the content of E-MA-GMA, parabolic-shaped markings nearly
disappeared on the fracture surface (Figure 10, 30 wt% of E-MA-GMA).
However, the entire fracture surface exhibited extensive matrix yielding (Figure
10b). Additionally, it is worth noting that visibly, stress whitening behaviour,
typical of polymers with high impact energy,17,26-33 was more intense and
appealing on the fracture surfaces of PBT blends with increase in E-MA-GMA
content.
Furthermore, the fracture surfaces of PBT/E-MA-GMA blends containing 0.2 phr
epoxy monomer were similar to the blends without monomer (Figures 8-10) at
identical elastomer content. The major difference observed on the fractographs of
the two blends (with and without monomer) was the rubber cavitation. It is
surprising to note that PBT/E-MA-GMA blend with 0.2 phr epoxy monomer
12
exhibited fine cavitation in some localized regions close to the notch. An
illustration of this is presented in Figure 11 for PBT blend with 10 wt% E-MAGMA. Also, with increase in E-MA-GMA content (20 wt% and 30 wt%), blend
with epoxy exhibited distinctive parabolic-shaped markings. However, parabolic
markings were not distinctive in PBT blend without epoxy monomer at 30 wt% EMA-GMA (Figure 10). The presence of the parabolic markings in the PBT/E-MAGMA/epoxy (70/30/0.2) blend may be responsible for its lower impact strength
than the PBT/E-MA-GMA (70/30) blend which exhibited seldom secondary crack
markings and had higher impact strength.
4. Conclusions
Super-toughened polybutylene terephthalate blends with equally higher stiffness
were prepared by incorporating a small amount of tetra-functional epoxy monomer
during reactive extrusion process. The E-MA-GMA elastomer exhibited fine
dispersion in PBT matrix. The impact strength of PBT increased with E-MAGMA content, however, at the expense of its stiffness. SEM micrographs of
impact-fractured surfaces of PBT/E-MA-GMA blends indicated that extensive
matrix shear yielding was the main impact energy dissipation mechanism.
The addition of 0.2 phr of the epoxy monomer further improved dispersion quality
of the E-MA-GMA particles by increasing viscosity of PBT matrix. The epoxy
monomer had an insignificant influence on toughening efficiency of E-MA-GMA
but clearly increased the modulus and strength of PBT/E-MA-GMA blends.
13
Acknowledgements
The authors like to thank the Australian Research Council (ARC) for continued
financial support during the course of this project. Y.-W. Mai acknowledges the
award of an inaugural Federation Fellowship by the ARC, tenable at the
University of Sydney. Cheng Yan acknowledges the receipt of an ARC Australian
Research Fellowship, tenable at the CAMT. The Microscopy and Microanalysis
Unit at the University of Sydney has kindly provided access to its facilities.
14
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16
Captions to Figures
Figure 1. SEM micrographs of freeze-fractured surfaces of PBT/E-MA-GMA
blends without epoxy monomer at (a) 10 wt%, (b) 20 wt%, and (c) 30 wt% of EMA-GMA.
Figure 2. SEM micrographs of freeze-fractured surfaces of PBT/E-MA-GMA
blends with 0.2 phr epoxy monomer at (a) 10 wt%, (b) 20 wt%, and (c) 30 wt% of
E-MA-GMA.
Figure 3. Dynamic viscosity as a function of frequency at 240oC for PBT and its
blends.
Figure 4. Illustration of the E-MA-GMA particle size distribution in PBT matrix
at different weight percentages of E-MA-GMA: (a) in the absence of epoxy
monomer and (b) in the presence of epoxy monomer.
Figure 5. Young’s modulus as a function of E-MA-GMA content for PBT/E-MAGMA blends with and without 0.2 phr epoxy monomer.
Figure 6. Yield strength as a function of E-MA-GMA content for PBT/E-MAGMA blends with and without 0.2 phr epoxy monomer. The dashed line represents
the theoretical yield strength values of PBT blends obtained using Equation (1).
Figure 7. Plot of notched Izod impact strength as a function of E-MA-GMA
content for PBT/E-MA-GMA blends with and without 0.2 phr epoxy monomer.
Figure 8. SEM micrographs of the impact-fractured surface of PBT/E-MA-GMA
(90/10) blend at (a) low magnification delineating the two fracture morphologies
17
in Region 1 and Region 2, (b) high magnification of Region 1, and (c) magnified
view of Region 2. Crack growth is from the top to bottom.
Figure 9. SEM micrographs of the impact-fractured surface of PBT/E-MA-GMA
(80/20) blend at (a) low magnification showing the distinct parabolic markings
and (b) high magnification showing the matrix yielding. Crack growth is from the
top to bottom.
Figure 10. SEM micrographs of the impact-fractured surface of PBT/E-MA-GMA
(70/30) blend at (a) low magnification and (b) high magnification showing the
extensive matrix yielding. Crack growth is from the top to middle.
Figure 11. SEM micrograph of the impact-fractured surface of PBT/E-MAGMA/Epoxy (90/10/0.2) blend, showing small amount of rubber cavitation in a
localized region.
18
a.
10 % E-MA-GMA
b.
20 % E-MA-GMA
c.
30 % E-MA-GMA
19
Figure 1
a.
10 % E-MA-GMA
b.
20 % E-MA-GMA
c.
30 % E-MA-GMA
20
Figure 2
5
10
PBT/E-MA-GMA/Epoxy (70/30/0.2)
PBT/E-MA-GMA (70/30)
E-MA-GMA
PBT/Epoxy (100/0.2)
PBT
4
Viscosity (Pa*s)
10
3
10
2
10
1
10
-1
10
0
1
10
10
2
10
3
10
Frequency (rad/s)
Figure 3
21
250
a.
PBT/E-MA-GMA Blends Without Epoxy Monomer
200
10% E-MA-GMA
20% E-MA-GMA
Number of Particles
30% E-MA-GMA
150
100
50
0
0-100
100-200 200-300 300-400 400-500 500-600 600-700 700-800 800-900
>900
Particle Size, nm
250
b.
PBT/E-MA-GMA Blends With Epoxy Monomer
10% E-MA-GMA
20% E-MA-GMA
200
Number of Particles
30% E-MA-GMA
150
100
50
0
0-100
100-200 200-300 300-400 400-500 500-600 600-700 700-800 800-900
>900
Particle Size, nm
Figure 4
22
1.2
PBT/E-MA-GMA
PBT/E-MA-GMA/Epoxy (0.2 phr)
Young's Modulus (GPa)
1
0.8
0.6
0.4
0.2
0
5
10
15
20
25
E-MA-GMA Content (wt %)
30
Figure 5
23
35
60
Theoretical line
PBT/E-MA-GMA
Yield Strength (MPa)
PBT/E-MA-GMA/Epoxy (0.2 phr)
40
20
0
5
10
15
20
25
30
35
E-MA-GMA Content (wt%)
Figure 6
24
2000
PBT/E-MA-GMA
Notched Izod Impact Strength (J/m)
PBT/E-MA-GMA/Epoxy (0.2 phr)
1600
1200
800
400
0
0
5
10
15
20
25
30
E-MA-GMA content (wt %)
Figure 7
25
35
a.
Region 1
Region 2
b.
c.
Region 1
Region 2
Figure 8
26
a.
b.
Figure 9
27
a.
b.
Figure 10
28
Figure 11
29