Thermoplastic Polymers : These are the linear (or) slightly branched long chain molecules capable of softening on heating and hardening on cooling .E.g. : Polystyrene, Polythene.
Thermo setting polymers : These polymers are cross linked (or) heavily branched molecules which on heating undergo extensive cross linking in moulds and again become infusible. E.g : Bakelite , urea-formaldehyd , resin etc..........
