Multifunctional ATRP Initiators: Synthesis of Four-Arm Star Homopolymers of Methyl Methacrylate and Graft Copolymers of Polystyrene and Poly(t-butyl methacrylate)

摘要

Tetrakis bromomethyl benzene was used as a tetrafunctional initiator in the synthesis offour-armed star polymers of methyl methacrylate via atom transfer radical polymerization (ATRP) with a CuBr/2,2 bipyridine catalytic system and benzene as a solvent. Relatively low polydispersities were achieved, and the experimental molecular weights were in agreement with the theoretical ones. A combination of 2,2,6,6-tetramethyl piperidine-N-oxyl-mediated free-radical polymerization and ATRP was used to synthesize various graft copolymers withpolyst~ene backbones and poly(t-butyl methacrylate) grafts. In this case, the backbone was produced with a 2,2,6,6-tetramethyl piperidine-N-oxyl-mediated stable free-radical polymerization pro- cess from the copolymerization of st~ene and p-(chloromethyl) st~ene. This polychlo- romethylated polymer was used as an ATRP multifunctional initiator for t-butyl methacrylate polymerization, giving the desired graft copolymers.