(a) Addition polymers:- A polymers formed by direct addition of repeated monomers without the elimination of by product molecule is called addition polymers. Ex. Polythene, PVC,PTFE, etc
(b) Condensation polymers :- A polymer formed by the condensation of two or more than two monomers with the elimination of simple molecules like water, ammonia, hydrogen sulphide, alcohol, etc. is called condensation polymer. In this each case monomer generally contains two functional groups. Ex. Nylon 66 and Nylon 6, Bakelite, Daecron, etc.