(i) Polythene or PVC is example of addition polymer.
(ii) Nylon-66 or Nylon-6 is example of condensation polymer.
(iii) Buna-S or Buna-N is example of copolymer.

(i) Elastomers: The polymers in which polymer chains are held together by the weakest intermolecular forces.These weak forces permit the polymer to be stretched.A few 'cross-links' are introduced in between the chains which held the polymer to retract to its original position after the force is released, as in vulcanised rubber
(ii) Condensation polymers: It involves a series of condensation reaction generally involving two monomers.Each monomer normally contains two functional groups.The condensation reactions result in the loss of small molecules usually water and ammonia, e.g. nylon, terylene, bakelite are condensation polymers.This  process is Known as 'condensation polymerisation'
(iii) Addition polymers: The polymers which are formed by repeated addition of monomers to the polymer chain.The monomers are unsaturated compounds and commonly derivatives of ethene.the addition polymers have same empirical as their monomers, e.g

This process is 'addition polymerisation'.

Polythene, polyvinyl and polystyrene soften on heating and harden on cooling. Such polymers are called thermoplastic polymers. These possess intermolecular forces of attraction whose strength lies between strength of intermolecular forces of elastomers and. fibers. These polymers are linear or slightly.