Which of the following would you expect to be elastomers and which thermosetting polymers at room temperature? Justify each choice.
(a) Epoxy having a network structure
(b) Lightly crosslinked poly(styrene-butadiene) random copolymer that has a glass-transition temperature of -50(C
(c) Lightly branched and semicrystalline polytetrafluoroethylene that has a glass-transition temperature of -100(C
(d) Heavily crosslinked poly(ethylene-propylene) random copolymer that has a glass-transition temperature of 0(C
(e) Thermoplastic elastomer that has a glass-transition temperature of 75(C