welcome to 3 - mit opencourseware...crystalline polyethylene: orthorhombic partially crystallized...
TRANSCRIPT
Welcome to 3.091Lecture 28
November 18, 2009
Polymers: Structure & Composition
Makeup test December 2 during class
3.091 Test #3“celebration part 3”Monday, November 23, 2009
Polythene Pam
(Lennon/McCartney)
Lyrics removed due to copyright restrictions. "Polythene Pam." The Beatles. Abbey Road (1969).
Crystalline polyethylene: orthorhombic
Partiallycrystallizedpolyethylene
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Source: Hayden, H. W., W. G. Moffatt, and J. Wulff.The Structure and Properties of Materials; Vol. III,Mechanical Behavior. John Wiley and Sons, Inc.,1965.© John Wiley and Sons. All rights reserved. Thiscontent is excluded from our Creative Commonslicense. For more information, seehttp://ocw.mit.edu/fairuse.
Diff
ract
ed in
tens
ity
Angle of diffraction (o)12 15 20 25 30
12 30
Crystalline
Amorphous
Partially Crystalline
Polyethelene
(a)
(b)
(c)
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(Alternating copolymer)
CH2 CH2 CH2 CH2 CH2CH CH CH CHCH
CH2 CH2 CH2 CH2 CH2CH CH CH ...
...
CH
CH2 CH2 CH2 CH2 CH2CH CH CH CHCH
Cl
CH
Atactic Polypropylene
Syndiotactic Polystyrene
Isotactic Poly(vinyl chloride)
...
...
...
...
CH3 CH3 CH3
CH3CH3
Cl ClClCl
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CH2 CH2 CH2 CH2 CH2CH CH CH CHCH
CH2 CH2 CH2 CH2 CH2CH CH CH ...
...
CH
CH2 CH2 CH2 CH2 CH2CH CH CH CHCH
Cl
CH
Atactic Polypropylene
Syndiotactic Polystyrene
Isotactic Poly(vinyl chloride)
...
...
...
...
CH3 CH3 CH3
CH3CH3
Cl ClClCl
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Staggered
Eclipsed
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C17H36: 2 different conformations, both straight chain
HH
HHHH
HHHH
HH
HH
HH
H
HH
HH
H
H H
HH
HH
H HHH
HHHH
HH
HH H
H H H H HH
HH H H
H
HH
H H H H H
HH
HH
H HH
HH
HHHH
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2-methyl 1,3-butadiene CH3 ∣
CH2=CCH=CH2
Polyisoprene: S enables crosslinking
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3.091SC Introduction to Solid State ChemistryFall 2009
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