Sulfur‐Free Radical RAFT Polymerization of Methacrylates in Homogeneous Solution: Design of <i>exo</i>‐Olefin Chain‐Transfer Agents (R−CH<sub>2</sub>C(=CH<sub>2</sub>)Z)
Maki Amano, Mineto Uchiyama, Kotaro Satoh, Masami Kamigaito
Abstract
Abstract In this work, the development of exo ‐olefin compounds (R−CH 2 C(=CH 2 )Z) as chain‐transfer agents for the sulfur‐free reversible addition‐fragmentation chain transfer (RAFT) radical polymerization of methacrylates in homogeneous solution is described. A series of exo ‐olefin compounds with a methyl methacrylate (MMA) dimer structure as the R group and a substituted α‐methylstyrene unit as the −CH 2 C(=CH 2 )Z (Z: Ph−Y) group were synthesized and used for the radical polymerization of MMA in toluene and PhC(CF 3 ) 2 OH. These compounds underwent transfer of the CH 2 C(=CH 2 )Z group via addition‐fragmentation of the propagating methacryloyl radical. More electron‐donating (Y) substituents, such as methoxy and dimethylamino groups, produced polymers with narrower molecular weight distributions. A continuous monomer addition method further improved molecular weight control and enabled the synthesis of colorless, sulfur‐free, multiblock copolymers of methacrylates in homogeneous solutions.