Radical addition–fragmentation chemistry in polymer synthesis

TLDR

This review outlines the evolution of addition–fragmentation chain transfer agents and ring‑opening monomers, emphasizing recent innovations and the RAFT process’s ability to impart living characteristics to radical polymerizations, enabling precise control over molecular weight, distribution, composition, and architecture. The review focuses on RAFT reagents—dithioesters, trithiocarbonates, dithiocarbamates, and xanthates—that enable reversible addition–fragmentation chain transfer, compatible with most radical monomers and robust across diverse reaction conditions. RAFT chemistry offers a versatile route to functional polymers, including cyclopolymers, gradient copolymers, block copolymers, and star polymers.

Abstract

This review traces the development of addition–fragmentation chain transfer agents and related ring-opening monomers highlighting recent innovation in these areas. The major part of this review deals with reagents that give reversible addition–fragmentation chain transfer (RAFT). These reagents include dithioesters, trithiocarbonates, dithiocarbamates and xanthates. The RAFT process is a versatile method for conferring living characteristics on radical polymerizations providing unprecedented control over molecular weight, molecular weight distribution, composition and architecture. It is suitable for most monomers polymerizable by radical polymerization and is robust under a wide range of reaction conditions. It provides a route to functional polymers, cyclopolymers, gradient copolymers, block polymers and star polymers.