Solved: For each of the following pairs of polymers, do

Chapter 15, Problem 15.19

(choose chapter or problem)

For each of the following pairs of polymers, do the following: (1) State whether it is possible to decide whether one polymer has a higher tensile modulus than the other; (2) if this is possible, note which has the higher tensile modulus and cite the reason(s) for your choice; and (3) if it is not possible to decide, state why. (a) Branched and atactic poly(vinyl chloride) with a weight-average molecular weight of 100,000 g/mol; linear and isotactic poly(vinyl chloride) having a weight-average molecular weight of 75,000 g/mol (b) Random styrene-butadiene copolymer with 5% of possible sites crosslinked; block styrenebutadiene copolymer with 10% of possible sites crosslinked (c) Branched polyethylene with a number-average molecular weight of 100,000 g/mol; atactic polypropylene with a number-average molecular weight of 150,000 g/mol