Question

Which of the following are characteristics of thermosetting polymers?

(a) Heavily branched cross linked polymers

(b) Linear slightly branched long chain molecules

(c) Become infusible on moulding so cannot be resused

(d) Soften on heating and harden on cooling, can be reused

Answer 1

Answers: (a) and (c).

Thermosetting polymers are heavily branched cross-linked polymers. They cannot be reused because they cannot melt on heating and cannot be remolded.

Thermosetting polymer

(i) These are a cross-linked or heavily branched molecule.

(ii) These on heating undergo extensive cross-linking in molds and become infusible

(iii) These cannot be reused.

(iv) Examples: Bakelite.