Monomers are simple molecules, which combine with each other to form polymers. Each polymer has a repeating structural unit. Polymers formed the same type of monomers are called homopolymers and if two or more different repeating units (monomers) make up the polymer, it is known as a copolymer. Both homopolymers and copolymers may be formed either by addition or condensation reactions. Alkenes and diense polymerize by addition (chain growth) mechanism involving carbocations, carbanions or free radical intermediates. Diense (Chloroprene, isoprene, etc) polymerize by 1,4-addition mechanism to give cis- or trans- polymers. Natural rubber is, however, cis- polyisoprene. Natural rubber is quite soft and flexible but these properties can be improved by a process called vulcanization. In contrast, bifunctional monomer molecules undergo condensation or step-growth polymerization. Polymers which can be heated and reshaped as many times as desired are called thermoplastics (polythene, polystyrene, PVC teflon, etc.) while those which can be heated only once to give a particular shape are called thermosetting polymers (Bakelite, Melmac, etc).
Vinyl chloride is the repeating unit in:

Options

A. polystyrene
B. Neoprene
C. PVC
D. polyethene

Answer

C