Reversible addition−fragmentation chain-transfer polymerization

Reversible addition−fragmentation chain transfer or RAFT polymerization is one of several kinds of reversible deactivation radical polymerization. It makes use of a chain transfer agent (CTA) in the form of a thiocarbonylthio compound to afford control over the generated molecular weight and dispersity during a free-radical polymerization. Discovered at the Commonwealth Scientific and Industrial Research Organization (CSIRO) of Australia in 1998, RAFT polymerization is one of several living or controlled radical polymerization techniques, others being atom transfer radical polymerization (ATRP) and nitroxide-mediated polymerization (NMP), etc. RAFT polymerization uses thiocarbonylthio compounds, such as dithioesters, thiocarbamates, and xanthates, to mediate the polymerization via a reversible chain transfer process. As with other controlled radical polymerization techniques, RAFT polymerizations can be performed under conditions that favor low dispersity Đ and a pre-chosen molecular weight. RAFT polymerization can be used to design polymers of complex architectures, such as linear block copolymers, comb-like, star, brush polymers, dendrimers and cross-linked networks.