Neoprene is prepared by the free radical polymerization of chloroprene( 2 -chloro- 1 , 3 -butadiene). It is used as an insulator and also used for making conveyor belts and printing roller, etc.

PHBV (Poly 3 -hydroxybutyrate-co- 3 -hydroxyvalerate) is a copolymer of 3 - hydroxybutanoic acid and 3 -hydroxypentanoic acid in which two monomer units are connected by ester linkages. It is used in special packaging, orthopaedic devices and in controlled drug release.

A polymer consisting of two or more chemically different types of monomer units in the chain is called a copolymer. And the process of synthesis of the copolymer is called copolymerization. It may be a chain growth polymerization or a step growth polymerization.