Question

For acrylonitrile-butadiene copolymer, can you determine which configuration will have the higher tensile strength?

A. Random acrylonitrile-butadiene copolymer with 10% of possible sites crosslinked.

B. Block acrylonitrile-butadiene copolymers with 5% of possible sites crosslinked.

C. Not possible to determine from information given.

Answer 1

Answer: Option-A

I) The random acrylonitrile-butadiene copolymer will be likely to have to have a lower degree of crystallinity compared to the alternating acrylonitrile-butadiene copolymer since random copolymers do not usually crystallize.

II) The higher the degree of crystallinity, the higher is the tensile modulus of the polymer. Hence, on this basis, it appears that the alternating material would have a higher modulus.

III) However, the random copolymer has a higher degree of crosslinking (10% versus 5% for the block copolymer).

IV) An increase in crosslinking leads to an increase in the tensile modulus. On this basis, it appears that the random copolymer would have the higher tensile modulus.

Hence the answer

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