Chain‐Reaction Polymerization

Abstract Chain‐reaction polymerization is one of the two processes for converting monomer to polymer; the other is step‐reaction polymerization. Equivalent terms are either chain polymerization or chain‐growth polymerization for the former and step polymerization or step‐growth polymerization for the latter. Chain polymerizations require an initiator, which produces an initiator species with a reactive center. The reactive center may be a free radical, cation, anion, or organometallic complex. Polymerization occurs by the propagation of the reactive center through successive additions of large numbers of monomer molecules in a chain reaction. The utility of chain‐reaction polymerization resides in the wide range of polymer structures that can be obtained through proper choice of monomer and method of initiation, ie, radical, cationic, anionic, and coordination. Further variations in polymer structure are available through copolymerization and stereochemical control.