乙烯基二联苯单体的螺旋选择性自由基聚合

发布时间：2018-07-15 12:29

【摘要】：为了深入理解乙烯基二联苯单体自由基聚合过程中的手性传递,进行了手性单体(+)-2-[(S)-异丁氧羰基-5-(4′-己氧基苯基)苯乙烯、非手性单体2-丁氧羰基-5-(4′-己氧基苯基)苯乙烯的均聚反应及它们二者的共聚反应,探讨了聚合温度和溶剂性质对手性单体均聚物旋光活性、手性单体含量对共聚物旋光活性以及聚合反应溶剂的超分子手性对共聚物旋光活性的影响.研究发现,降低聚合温度、采用液晶性反应介质有利于得到旋光度大的聚合物;少量手性单体的引入即可诱导共聚物形成某一方向占优的螺旋构象,比旋光度随手性单体的含量增加呈线性增长;在胆甾相液晶中制备的非手性单体聚合物不具有光学活性.这些结果表明,该类乙烯基二联苯聚合物具有动态螺旋构象,其光学活性主要依赖于主链的立构规整度和侧基不对称原子的手性.
[Abstract]:In order to understand the chiral transport of vinyl diphenyl monomer in the process of free radical polymerization, the chiral monomer () -2- [(S) -isobutyloxycarbonyl-5- (4-hexoxy phenyl) styrene, " The homopolymerization of 2-butyloxycarbonyl -5- (4-hexoxy phenyl) styrene and their copolymerization were studied. The effects of the content of chiral monomers on the optically active properties of the copolymers and the supramolecular chirality of the polymerization solvents on the optically active properties of the copolymers. It was found that decreasing polymerization temperature and using liquid crystal reaction medium were beneficial to the preparation of polymers with high optical rotation, and that a small amount of chiral monomers could induce the copolymers to form a dominant helical conformation in a certain direction. The specific optical rotation increases linearly with the increase of monomer content, and the non-chiral monomers prepared in cholesteric liquid crystal have no optical activity. These results show that this kind of vinyl diphenyl polymers have dynamic helical conformation and their optical activity mainly depends on the degree of alignment of the main chain and the chirality of the asymmetric atoms in the side group.
【作者单位】：北京分子科学国家实验室高分子化学与物理教育部重点实验室北京大学化学与分子工程学院;
【基金】：国家自然科学基金(基金号21674002)资助项目博士后科学基金(基金号8201400159)资助项目
【分类号】：O631.5

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