Polymerization is a chemical process important in the production of plastics, artificial fibers, synthetic rubber, and paints. In this process, many small molecules called monomers combine to build much larger molecules called polymers. If only one kind of monomer is used, the process is called homopolymerization. If more than one kind of monomer is used, it is called copolymerization. The homopolymerization of the gas vinyl chloride produces polyvinyl chloride, a solid plastic commonly called vinyl. The copolymerization of vinyl chloride with vinylidene chloride forms a plastic used in food wrapping.
Chemists sometimes classify polymerization processes by the chemical reactions that occur. In addition polymerization, entire monomer molecules bond together to form the growing polymer chain. In condensation polymerization, small pieces of the monomers split off, usually as water molecules, as the polymer forms.
See also Monomer ; Petroleum (Refining petroleum) ; Polymer .
