Which of the following polymers does not soften on heating and harden on cooling?
Polythene, Polyvinyls and Polystyrene are Thermoplastic polymers.
Urea-formaldehyde resin is a thermosetting polymer.
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