1. No category

PLAST og POLYMERER
DTU og Plastindustrien
april
2012
Anders Daugaard,
Frederikke Bahrt
og Ole Hassager
I tit t ffor Kemiteknik
Institut
K
it k ik
Danmarks Tekniske Universitet
Agenda
• En meningsmåling
• Introduktion
• Råmaterialer
Rå
t i l
• Kemi
• Molekylestrukturer og plasttyper
• Krystallinitet
• Temperatur-egenskaber
• Mekaniske
M k i k egenskaber
k b
Plusord eller minusord?
• Plastik
• Polymerer
• Kompositter
Polymerer er overalt
Examples of polymer products from Denmark:
NKT Flexibles
LEGO
Coloplast
Færch Plast A/S
Novo Nordisk
Vestas Wind Systems
Compositions and Molecular Structures for Some of the
Paraffin Compounds: CnH2n+2
What is a polymer?
since molecules in polymers are normally gigantic = macromolecules
Basic Components
Monomer
HOCH2CH2OH
CH2=CH2
Oligomer
Polymer
-(CH2CH2O)nMacromolecule
-(CH2CH2)n-
How are polymers made?
Example: one way of producing polyethylene (PE)
Poly condensation, example: Polyester
Polymer Composition
repeat unit
Repeat Units of 5 of the Most Common Polymeric Materials
all based on vinyl monomers
PE, PP, PVC & PS
are the most
common polymers termed commodity
plastics
l
((> 90 % of
f
all thermoplastics)
Since all repeat units
in these polymers are
the same (based on
the same monomer)
the resulting polymers are called
homopolymers
From W.D. Callister, Materials Science and Engineering and Introduction, Wiley (2007)
Commodity Plastics
Polymers -Molecular shape
Conformation – Molecular orientation can be
changed by rotation around the bonds
– note: no bond breaking needed
From W.D. Callister, Materials Science and Engineering and Introduction, Wiley (2007)
Molecular Configuration
Tacticity
y – stereoregularity
g
y of chain
Addition of vinyl monomers in head-to-tail polymerization
R
R
R
CH2=CHR --> -CH2-CH-CH2-CH-CH2-CHimportant vinyl monomers
R
R
R
CH2=CR2 --> -CH2-C-CH2-C-CH2-CR
H
R H
R H
R H
R
R
R H
R
isotactic chain segments
polymerization of
monomer CH2=CHR render
stereoregular polymers
with chiral centers:
CH2
H
CH2
R R
CH2
H H
CH2
R R
CH2
H H
R
syndiotactic chain segments
CH2
CH2
CH2
CH2
CH2
a completely random distribution is called atactic or heterotactic
stereoregularity can lead to crystallinity
Isotactic
Atactic
Krystallinitet
ll
From W.D. Callister, Materials Science and Engineering and Introduction, Wiley (2007)
Semi-Krystallinsk
crystalline
region
amorphous
region
Molekylestrukturer
y
From W.D. Callister, Materials Science and Engineering and Introduction, Wiley (2007)
Temperaturafhængighed
thermoset
(Tg)
Tg
Tm
nedbrydning
thermoplast
Transitions-temperaturer og
Anvendelses-temperaturer?
Transitions-temperaturer
• Glasovergang Tg
• Smeltetemperatur Tm
• Krystallisationstemperatur
K
t lli ti
t
t Tx
• Nedbrydningstemperatur
Material
Glass transition
temperature Tg (C)
Crystalline melting
temperature Tm (C).
Polyethylene (LDPE)
-110
115
Polytetrafluoroethylene
-97
327
Polyethylene (HDPE)
-90
90
137
a-Polypropylene
-18
i-Polypropylene
-18
175
Nylon 6,6
57
265
Polyester (PET)
69
265
P l i l hl id (PVC)
Polyvinylchloride
87
212
a-Polystyrene (PS)
100
i-Polystyrene
y y
100
240
Polycarbonate
150
265
Mekaniske egenskaber
• Træk test,
(
)
kraft contra deformation (tavle)
• Elasticitetsmodul
• Flydespænding
• Trækstyrke
From W.D. Callister, Materials Science and Engineering and Introduction, Wiley (2007)
f15_02_pg525
From W.D. Callister, Materials Science and Engineering and Introduction, Wiley (2007)
f15 01 pg525
f15_26_pg568
From W.D. Callister, Materials Science and Engineering and Introduction, Wiley (2007)
BREAK
”Plast kommer fra havet”
Polariseret lys og polymerer
Polariseret lys
og polymerer
Vandbolde
• Polyvinylalkohol (–CH2-CHOH-)
g vand ((H2O))
og
• Boraxopløsning krydsbinder
(danner en gel)
Vandballoner
• ”environmental stress cracking”