The word polymer comes from poly- (many) and -mer (part). Polymers are generally high molecular mass substances that have repeating units of smaller molecules. They may be a natural or synthetic macromolecule. The single molecular units of which a large chains are made is known as ‘monomer’. These monomers generally have high molecular mass. (10³-10⁷u). Some examples of polymers are polythene, Bakelite, rubber, Buna-N and many more.