APPLICATIONS OF ANIONIC-POLYMERIZATION TO MACROMOLECULAR ENGINEERING

The development of ''macromolecular engineering'' owes much to living anionic polymerizations. When carried out under conditions preventing spontaneous transfer and termination reactions, and with efficient ini tiators, these processes are well suited to the synthesis of model mac romolecules of various kinds. Functionalizations at chain end can be a chieved upon induced deactivation; macromonomer synthesis, end-to-end cyclization, and chain extension processes can be achieved; and end-li nking reactions yield model networks. The use of anionic polymerizatio n processes to synthesize well-defined block copolymers exhibiting low heterogeneity in molecular weight and in composition is of major impo rtance because of the various specific applications of such materials. New efficient bi- and multifunctional metal-organic initiators have b een developed. Recently, progress in star polymer synthesis, including core-first methods, has been achieved. Amphiphilic star-block copolym ers have been made, as well as heterostar copolymers, whose cores carr y two different kinds of arms (of different chemical natures) in rough ly equal numbers. All these novel species have attracted wide interest because of their controlled structure and potential applications.