RAFT Agents Effective in Controlled Radical Polymerization

RAFT agents, or chain transfer agents (CTA), are essential mediators for reversible addition-fragmentation chain transfer (RAFT) polymerization reactions, a type of controlled radical polymerization. To achieve these transformations, compounds bearing thiocarbonylthio groups have been shown to be ideal. They are able to easily release radicals which mediate the reversible chain transfer reactions by virtue of the thiocarbonylthio group. It is important to select a proper RAFT agent based on its reactivity towards monomers; trithiocarbonates such as compound 1 and compound 2 are appropriate for polymerization of acrylates and acrylamides, etc. , while N-alkyl-N-aryldithiocarbamates like compound 3 are suitable for that of vinyl esters and vinyl amides.^1,2) In recent years, RAFT polymerization has been applied to various research fields, including biomaterials due to its compatibility with a wide range of monomers and solvents, in addition to being a metal-free process. These advantages of RAFT polymerization have lent to increased usage of these RAFT agents.