Plastics

Plastics are cross linked polymers and are very tough. Lac is a natural plastic, chemical plastic can be of two types :

(i) Thermoplastic Plastics : These are the polymers which can be easily softened repeatedly when heated and hardened when cooled with little change in their properties.

Examples : Polyethylene, Polyatyrene, Teflon etc.

Plastic Sheet

(ii) Thermosetting Plastics : These are the polymers which undergo permanent change on heating. On heating they undergo extensive cross linking in moulds and become hard and infusible therefore, they can not be reused.

Examples : Bakelite, Glyptal, Terrylene etc.

Bakelite Handle