Other Initiating Systems

A purely thermal polymerization is one in which monomer is converted to polymer by thermal energy alone. Self-initiated or spontaneous homo- and co-polymerization has been reported for many monomers and monomer pairs. Homopolymerization generally requires substantial thermal energy whereas copolymerization between certain electron-acceptor and electron-donor monomers can occur at ambient temperature. The occurrence of true thermal polymerization can be difficult to establish since trace impurities in the monomers or reaction vessel often prove to be the actual initiators. In most cases of self-initiated polymerization, the identity of the initiating radicals and the mechanisms by which they are formed remain obscure.