Stereoblock-like Brush Copolymers Consisting of Poly(l-lactide) and Poly(d-lactide) Side Chains along Poly(norbornene) Backbone: Synthesis

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• 作者：Takuya Isono ; Yohei Kondo ; Shun Ozawa ; Yougen Chen ; Ryosuke Sakai ; Shin-ichiro Sato ; Kenji Tajima ; Toyoji Kakuchi ; Toshifumi Satoh
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：47
• 期：20
• 页码：7118-7128
• 全文大小：600K
• ISSN：1520-5835

文摘

Random and block copolymerizations of poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) macromonomers having an exo-norbornene group at the 伪- or 蠅-chain end (D/L ratio = 1/1, M_n = ca. 5000 g mol^鈥?) were performed via ring-opening metathesis polymerization to produce the brush random and block copolymers consisting of parallel or antiparallel aligned PLLA and PDLA side chains on a poly(norbornene) backbone. The molecular weight and polydispersity index of the brush copolymers were in the range of 40鈥?00鈥?58鈥?00 g mol^鈥? and 1.03鈥?.14, respectively. Despite such high molecular weights, these brush copolymers formed a stereocomplex without homochiral crystallization. The melting temperature (T_m) and crystallinity (X) of the resulting stereocomplex varied depending on the backbone length, relative chain direction, and distribution of the PLLA/PDLA side chains. The parallel brush copolymers showed significantly higher T_m and X values than the antiparallel ones.