9. High performance polymers Flashcards
1
Q
Does the number of carbons in polyamide affect the Tg for nylons?
A
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2
Q
Which type of liquid crystalline behavior is important for the processing of Kevlar?
A
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3
Q
How can you modify the preparation of a polyurethane to improve the mechanical properties? (maintained stoichiometry)
A
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4
Q
What is a mesophase?
A
The ordered regions in liquid crystallines.
5
Q
What is the difference between lyotropic and thermotropic liquid crystals?
A
Lyotropic is formed in solvent, thermotropic is formed in melts.
6
Q
What type of polymer are nylons?
A
Polyamides.
7
Q
What is the odd-even effect on melting temperature for nylons?
A
Even numbered carbon chain will give higher Tg, because it gives more hydrogen bonding.
