2. Nature and formation of reaction sites

A polycondensate can be obtained from different reactions and monomers, in contrast to chain polymerizations, which usually involve only one type of reaction and monomer for a given polymer. Thus polyester ~ R-COO-R ′-OOC ~ can be formed from the following reaction systems:

The actual site, responsible for the actual construction of the chain, is very often created in situ. One example is the synthesis of poly (1,4-diisopropylbenzene), prepared by heating 1,4-isopropylbenzene with a free-radical generator (R ^• ) such as a peroxide or an azo derivative. The radicals (R ^• ...