Thermotropic behavior of syndiotactic polymethylenes with alkyloxycarbonyl side chains
Thermotropic behavior of syndiotactic polymethylenes with alkyloxycarbonyl side chains
复制标题
DOI：
10.1016/j.polymer.2012.12.072
复制
发表时间：
2013-02
期刊：
影响因子：
4.6
通讯作者：
M. Tokita;K. Shikinaka;T. Hoshino;Kyohei Fujii;J. Mikami;Noboru Koshimizu;Koichi Sakajiri;Sungmin Kang;J. Watanabe;K. Shigehara
中科院分区：
文献类型：
--
作者：
M. Tokita;K. Shikinaka;T. Hoshino;Kyohei Fujii;J. Mikami;Noboru Koshimizu;Koichi Sakajiri;Sungmin Kang;J. Watanabe;K. Shigehara
采用铑配合物催化的立体选择性聚合方法，合成了一系列含烷氧基羰基侧链的间规聚亚甲基，每个主链碳原子上的烷基碳数分别为2、6、12和18。差示扫描量热仪(DSC)和X射线衍射仪表明，所有聚合物都形成了热致液晶相。具有乙氧基羰基侧链的聚亚甲基形成向列相，而具有己氧基、十二氧基和十八烷氧基侧链的聚亚甲基形成六方柱状相。这些聚合物形成液晶相的倾向是由于聚合物主链中的棒状螺旋构象，估计每两圈(7/2)有7个单位，沿螺旋轴的单位高度为1.054Å。
A series of syndiotactic polymethylenes having an alkyloxycarbonyl side chain, with the alkyl carbon numbers 2, 6, 12, and 18 at every main-chain carbon atom, was synthesized by rhodium complex-catalyzed stereo-selective polymerization. Differential scanning calorimetry (DSC) and X-ray diffraction revealed that all polymers formed thermotropic liquid crystalline phases. The polymethylene having an ethoxycarbonyl side chain formed a nematic phase whereas those having hexyloxy-, dodecyloxy-, and octadecyloxy-carbonyl side chains formed hexagonal columnar phases. The tendency of these polymers to form liquid crystalline phases is due to the rod-like helical conformation in the polymer backbone, which is estimated to be seven units per two turns (7/2) with a unit height of 1.054Å along the helix axis.