Sythesis Of Branched, Comblike And Star-shaped Poly(ε-caprolactone) Copolymers

In this dissertation, using macromonomer and macroinimer strategies, branched poly(ε-caprolactone), branched poly(ε-caprolactone)-block-polystyrene , comblike poly(ethylene glycol) mono-methyl ether-block-poly(ε-caprolactone) amphiphilic copolymer and star-shaped poly(ε-caprolactone)-block-polystyrene block copolymers were prepared by the combination of lipase-catalyzed ring-opening polymerization of ε-caprolactone and living radical polymerization, uch as atom transfer radical polymerization. Their molecular weights, molecular weight distributions and structures were characterized by GPC and ~1HNMR.Branched poly(ε-caprolactone) was synthesized in three reaction steps. In the first step, α-acryloyoxyethyloxy-ω-hydroxyl poly(ε-caprolactone) (APCL-OH) with narrow molecular weight distribution was prepared by lipase-catalyzed ring-opening polymerization of ε-caprolactone with 2-hydroxylethly acrylate as the initiator and Novozyme-435(lipase B from Candida Antarctica fixed by polyacrylate) as the catalyst. In the second step, α-acryloyoxy-ω-2-bromopropionyloxy poly(ε-caprolactone) (APCL-Br) was obtained by esterification of ω-hydroxyl group of APCL-OH with 2-bromopropionyl bromide. In the last step, the branched poly(ε-caprolactone) was obtained from self-condensing atom transfer radical polymerization of APCL-Br whose structure was similar with that of AB* inimer.Branched poly(ε-caprolactone)-block-polystyrene block copolymer was synthesized in the following way. Firstly, hydroxyl-ended polystyrene (Br-PS-OH) with narrow molecular weight distribution was prepared via ATRP of styrene with 2-hydroxylethly bromoisobutylate as the bifunctional initiator and CuBr/bipy complex as the catalyst. Secondly, using Br-PS-OH as the macroinitiator and sequential vinly acrylate as the terminator, macro-inimer α-acryloyoxy poly(ε-caprolactone)-block - (ω-bromo) polystyrene...