文献类型：期刊文献

英文题名：R-RAFT approach for the polymerization of N-isopropylacrylamide with a star poly(Ε-caprolactone) core

作者：Bian, Qingqing[1]; Xiao, Yan[1]; Lang, Meidong[1]

机构：[1] Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China

年份：2012

卷号：50

期号：3

起止页码：571

外文期刊名：Journal of Polymer Science, Part A: Polymer Chemistry

收录：EI(收录号：20115214645948)

语种：英文

外文关键词：Living polymerization - Molecular weight distribution - Block copolymers - Biomedical engineering - Free radical polymerization - Kinetics - Ring opening polymerization - Free radicals - Acrylic monomers

摘要：Reversible addition-fragmentation chain transfer (RAFT) polymerization is a more robust and versatile approach than other living free radical polymerization methods, providing a reactive thiocarbonylthio end group. A series of well-defined star diblock [poly(Ε-caprolactone)-b-poly(N- isopropylacrylamide)]4 (SPCLNIP) copolymers were synthesized by R-RAFT polymerization of N-isopropylacrylamide (NIPAAm) using [PCL-DDAT] 4 (SPCL-DDAT) as a star macro-RAFT agent (DDAT: S-1-dodecyl-S′- (α, α′-dimethyl-α″-acetic acid) trithiocarbonate). The R-RAFT polymerization showed a controlled/"living" character, proceeding with pseudo-first-order kinetics. All these star polymers with different molecular weights exhibited narrow molecular weight distributions of less than 1.2. The effect of polymerization temperature and molecular weight of the star macro-RAFT agent on the polymerization kinetics of NIPAAm monomers was also addressed. Hardly any radical-radical coupling by-products were detected, while linear side products were kept to a minimum by careful control over polymerization conditions. The trithiocarbonate groups were transferred to polymer chain ends by R-RAFT polymerization, providing potential possibility of further modification by thiocarbonylthio chemistry. ? 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 A series of well-defined star diblock [poly(Ε-caprolactone)-b-poly(N-isopropylacrylamide)] 4 (SPCLNIP) copolymers were synthesized by combination of ring-opening polymerization and reversible addition-fragmentation chain transfer (RAFT) polymerization. The controlled/living character of R-RAFT was maintained by careful control over polymerization conditions. The reactive trithiocarbonate groups were transferred to polymer chain ends by R-RAFT. Further modification of the end groups was expected to render the star block copolymer functionalized and bioactive as potential biomedical materials. Copyright ? 2011 Wiley Periodicals, Inc.