Recent advances in synthesis of new polymers by living free radical polymerization

T his review covers the current status of living free radical polymerization (LFRP) methods and assesses recent advances made especially in the recently years. Three LFRP methods, nitroxide mediated polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible-addition fragmentation chain transfer (RAFT), are described and the validity of each method is compared on the basis of the range of polymerizable monomers, reaction conditions, and the ease of chain end group transformation. Living radical graft polymerization of monomers such as styrene onto SBR, ABS, PVC and polystyrene formed by NMP and ATRP will be discussed. Also, the synthesis of block, graft, and hyperbranched copolymers by NMP is covered. Studies using ATRP to synthesize block copolymers, bottle brush copolymers, and hydrogels are assessed. Also, the synthesis of star copolymers with alternating hydrophobic and hydrophilic arms is described. For RAFT, the utility of difunctionalized initiators and trithiocarbonates as RAFT agents for ABA block copolymer formation are described.