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论文类型：期刊论文

发表时间：2017-08-01

发表刊物：MACROMOLECULAR CHEMISTRY AND PHYSICS

收录刊物：Scopus、SCIE、EI

卷号：218

期号：16

ISSN号：1022-1352

关键字：block copolymer; chain topology; double crystalline; polylactide; star-comb shaped

摘要：A series of highly branched star-comb poly(epsilon-caprolactone)-block-poly(L-lactide) (scPCL-b-PLLA) are successfully achieved using star-shaped hydroxylated polybutadiene as the macroinitiator by a simple "grafting from" strategy. The ration of each segment can be controlled by the feed ratio of comonomers. These star-comb double crystalline copolymers are well-defined and expected to illustrate the influences of the polymer chain topology by comparing with their counterparts in linear-shaped, star-shaped, and linear-comb shape. The crystallization behaviors of PCL-b-PLLA copolymers with different architectures are investigated systematically by means of wide-angle X-ray diffraction, differential scanning calorimetry, and polarized optical microscopy analysis. It is shown that the comb branched architectures promote the crystallization behavior of each constituent significantly. Both crystallinity and melting temperature greatly raise from linear to comb-shaped copolymers. Compared to linear-comb topology, the star-comb shape presents some steric hindrance of the graft points, which decrease the crystallinity of scPCL-b-PLLA. Effects of copolymer composition and chain topology on the crystallization are studied and discussed.