Don't despair of standard dull textbooks. Just close the book once in a while and think what they just said in your own terms as a revelation of the spirit and wonder of nature. The books give you facts, but your imagination can supply life.

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Don't despair of standard dull textbooks. Just
close the book once in a while and think what
they just said in your own terms as a revelation
of the spirit and wonder of nature. The books
give you facts, but your imagination can supply
life. ? Feynman
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Tensile strength
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Glass transition temperature (Tg)
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Glass transition temperature (Tg)
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Glass transition temperature (Tg)
Chemical structure
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Glass transition temperature (Tg)
Chain stiffness
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Glass transition temperature (Tg)
Chain stiffness
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Glass transition temperature (Tg)
Bulky side groups
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Viscous flow
Occurs only by shear
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Viscous flow
Most polymer melts are shear-thinning
(pseudoplastic) - i.e., become thinner at high
shear rates
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Viscous flow
Viscosity increases with MW Plot is for zero
shear rate values
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Creep of cellulose acetate
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Relaxation in PMMA
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Creep recovery
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Some specific polymers
Very rigid and strong, Tg 60-80 C siding,
pipe, conduit, usw.
Presence of Cl gives rise to solubility in
various organic solvents - allows "solvent
welding"
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Some specific polymers
Presence of Cl gives rise to solubility in
various organic solvents Rigid PVC difficult to
form by some techniques (e.g., calendaring)so
add solvent as "plasticizer"
PVC sheet then roll-formed onto fabric backing
and - voilá - "vinyl"!
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Some specific polymers
Rigid PVC difficult to form by some techniques
(e.g., calendaring)so add solvent as
"plasticizer"
PVC sheet then roll-formed onto fabric backing
and - voilá - "vinyl"!
Problem solvent slowly evaporates, exp. when
(auto) vinyl seats fascia heated by sun Soln
Armorall! Periodically put solvent back into
polymer
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Assignment Review today's classnotes a.
tensile strength b. Tg c. viscous flow d.
yielding, relaxation, crazing e. creep,
relaxation, recovery f. PVC g. plasticizers