Structure-property relationship of thermotropic liquid-crystalline vinyl polymers containing no traditional mesogen
Structure-property relationship of thermotropic liquid-crystalline vinyl polymers containing no traditional mesogen
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不含传统介晶的热致液晶乙烯基聚合物的结构-性能关系
DOI：
10.1016/j.polymer.2008.12.002
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发表时间：
2009-01
期刊：
影响因子：
4.6
通讯作者：
Guan, Yan
中科院分区：
文献类型：
--
作者：
Wan, Xinhua;Shen, Zhihao;Zhou, Qifeng;Chen, Xiaofang;Guan, Yan
通过自由基聚合合成并聚合了一系列非介晶乙烯基单体2,5-双(烷氧基羰基)苯乙烯。系统地改变烷氧基，以研究其尺寸和结构对所得聚合物的热致液晶性质的影响。尽管大分子结构中不存在传统的介晶，但当分子量足够高时，所有聚合物在远高于其玻璃化转变温度的温度下都显示出稳定的六方柱状液晶相，差示扫描量热法、偏光显微镜以及一维和二维广角X射线衍射技术的组合分析证明了这一点。对于烷氧基末端含有五个碳原子的聚合物，随着甲基取代基远离连接苯环，玻璃化转变温度和中间相形成温度降低，中间相d-间距值增加。增加甲基的数量或取代基的大小具有相同的效果。对于具有Y形烷氧基末端的聚合物，侧基越大，玻璃化转变温度和中间相形成温度越低，介晶结构的d间距值越大。
A series of non-mesogenic vinyl monomers, 2,5-bis(alkoxycarbonyl)styrene, were synthesized and polymerized via free radical polymerization. The alkoxy groups were systematically varied to investigate the effects of their size and architecture on the thermotropic liquid-crystalline properties of the resultant polymers. Although no traditional mesogen was present in the macromolecular structure, all the polymers revealed stable hexagonal columnar liquid-crystalline phase at the temperatures well above their glass transitions when the molecular weights were high enough, as evidenced by a combinatory analysis of differential scanning calorimetry, polarized light microscopy, and one- and two-dimensional wide-angle X-ray diffraction techniques. For the polymers containing five carbon atoms in the alkoxy terminals, the temperatures of glass transition and mesophase formation decreased and the d-spacing value of mesophase increased as the methyl substituent moved away from the connecting phenyl ring. Increasing the number of methyl group or the size of the substituent had the same effect. In the case of polymers with Y-shaped alkoxy terminals, the larger the side groups, the lower the glass-transition temperature and mesophase formation temperature and the larger the d-spacing value of mesomorphic structure.
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影响因子：
2.5
作者：
H. Finkelmann;H. Ringsdorf;J. Wendorff
通讯作者：
H. Finkelmann;H. Ringsdorf;J. Wendorff
影响因子：
2.8
作者：
Shinsuke Tsubakihara;A. Nakamura;M. Yasuniwa
通讯作者：
Shinsuke Tsubakihara;A. Nakamura;M. Yasuniwa
影响因子：
5.5
作者：
Hui-lin Tu;X. Wan;Yu-xiang Liu;Xiaofang Chen;D. Zhang;Qifeng Zhou;Zhihao Shen;J. J. Ge-J.;Shi Jin-S
通讯作者：
Hui-lin Tu;X. Wan;Yu-xiang Liu;Xiaofang Chen;D. Zhang;Qifeng Zhou;Zhihao Shen;J. J. Ge-J.;Shi Jin-S
影响因子：
5.5
作者：
Yongfeng Zhao;Xinghe Fan;X. Wan;Xiaofang Chen;Yi;Liangyuan Wang;Xia Dong;Qifeng Zhou
通讯作者：
Yongfeng Zhao;Xinghe Fan;X. Wan;Xiaofang Chen;Yi;Liangyuan Wang;Xia Dong;Qifeng Zhou
影响因子：
2.5
作者：
Jun Ling;Zhi-quan Shen
通讯作者：
Jun Ling;Zhi-quan Shen