Controlled Synthesis of Polymers Using the Iniferter Technique: Developments in Living Radical Polymerization

Abstract

In this review, we describe the concept of iniferters and the model for living radical polymerization in a homogeneous system, which was proposed in 1982 by one of the authors to enable the controlled synthesis and molecular design of polymers through the radical polymerization process. The iniferters are classified into several types: thermal or photoiniferters; mono-, di-, tetra-, or polyfunctional iniferters; monomeric, polymeric, or gel iniferters; monomer or macromonomer-iniferters, leading to the syntheses of monofunctional, telechelic, and polyfunctional polymers, block and graft copolymers, and branched, star, and cross-linked polymers. Phenylazotriphenylmethane and tetraphenylethane derivatives serve as thermal iniferters, and some organic sulfur compounds act as photoiniferters. Among the iniferters, several compounds containing N,N-diethyldithiocarbamyl groups were found to be excellent for the synthesis of polymers with well-controlled structures. The synthesis of various types of block, star, and graft polymers with a controlled chain structure through living radical polymerization using dithiocarbamate compounds as photoiniferters is described. In the last section, the recent developments in living radical polymerization using nitroxides and transition-metal complexes since 1993 up to 1997 have also been reviewed.