A substance which has a molecular structure built completely from a large number of similar units bonded together known as polymers. Polymers has high molecular mass. They are also called macromolecules. Some examples of polymers are polythene, bakelite, rubber, etc.

There are three different types based on the structure of the polymers.
(i) Linear polymer: These polymers consist of long and straight chains. Such as polythene, polyvinyl chloride etc.
(ii) Branched chain polymers: These polymers contain linear chains having some branches. Such as low density polythene.
(ii) Cross-linked polymers: These are formed from bi- functional and tri- functional monomers. Such as bakelite, malamin etc.

Hexamethylene diamine and adipic acid.

Caprolactum.