Which of the following would you expect to be elastomers and

Which of the following would you expect to be elastomers and which thermosetting polymers at room temperature? Justify each choice. Note that answer can be \"neither\" it could be a thermoplast Linear and highly crystalline polyethylene phenol-formaldehyde Heavily crosslinked polysoprene having a glass transition temperature of 50 degree C Lightly crosslinked polysoprene having a glass transition temperature of -60 degree C Linear and partially amorphous poly (vinyl chloride)

Solution

Answer

Elastomer is (d) and
Thermosetting polymers are (b), (c) and (d)

Explanation

(a) Linear and highly crystalline polyethylene is a linear polymer.Hence it would neither be a elastomer nor a thermoset.

(b) Phenol-formaldehyde have network structure but doesn\'t have cross linked chain structure. Hence it is thermoset but not an elstomer.

(c) Heavily crosslinked polyisoprene having a glass-transition temperature of 50 deg C will be an thermoset. It will not be elastomer because it is heavily cross linked above room temperature.

(d) Lightly crosslinked polyisoprene having a glass-transition temperature of -60 deg C is lightly cross linked. so it is both elastomer and thermoset.

(e) Linear and partially amorphous poly (vinyl chloride) is neither an elastomer nor a thermoset.