From classical to living/controlled statistical free-radical copolymerization

Solvent effects on monomer reactivity ratio values along with the determination of radical reactivity ratios, their possible origins as well as their importance in conventional free-radical copolymerization is described first. Predictions from data obtained at low conversion of cumulative composition and stereochemical distribution in copolymer chain along with glass transition temperature and the lumped overall copolymerization parameter (k(p)) over bar/<(k(t)(1/2))over bar> at high conversion are described. Transfer reactions in free-radical copolymerization using classical chain transfer agent as well as the new catalytic chain transfer agent and the effect on the copolymer structure and properties are also studied. Finally the new living/controlled free-radical polymerization process and the preparation of well-controlled statistical copolymers are described to stand out the subtle mechanisms differences between living/controlled and conventional free-radical copolymerization. (C) 2002 Elsevier Science Ltd. All rights reserved.