Synthesis and phase behavior of a new 2-vinylbiphenyl-based mesogen-jacketed liquid crystalline polymer with a high glass transition temperature and low threshold molecular weight
Synthesis and phase behavior of a new 2-vinylbiphenyl-based mesogen-jacketed liquid crystalline polymer with a high glass transition temperature and low threshold molecular weight
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DOI：
10.1039/c3py01755a
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发表时间：
2014-07
影响因子：
4.6
通讯作者：
Qi-Kai Zhang;Hai-jian Tian;Chang-Feng Li;Yu-feng Zhu;Yongri Liang;Zhihao Shen;Xinghe Fan
中科院分区：
文献类型：
--
作者：
Qi-Kai Zhang;Hai-jian Tian;Chang-Feng Li;Yu-feng Zhu;Yongri Liang;Zhihao Shen;Xinghe Fan
合成了一种新型的侧链含有联苯核的介晶夹套型液晶聚合物聚（4′-（甲氧基）-2-乙烯基联苯-4-甲基醚）（PMVBP）。PMVBP具有较小的单体分子量（MW）、较高的玻璃化转变温度和较低的形成液晶（LC）的阈值MW。PMVBP通过氮氧自由基介导的活性自由基聚合获得，其特征在于通过凝胶渗透色谱法，差示扫描量热法，偏振光显微镜，和一维和二维广角X-射线衍射（WAXD）实验。聚合物的数均分子量（Mn）范围为0.41 × 104至1.64 × 104 g mol−1。观察到相对高的玻璃化转变温度，其随着MW的增加从173 °C增加到208 °C。在相对高的温度下形成的LC相强烈地依赖于聚合物的Mn。当Mn仅高于0.53 × 104 g mol−1（LC形成的低阈值MW）时，在260 °C以上观察到六方柱状（ΦH）LC相。所有的LC相在冷却期间被保留。
We have synthesized a new mesogen-jacketed liquid crystalline polymer, poly(4′-(methoxy)-2-vinylbiphenyl-4-methyl ether) (PMVBP) containing a biphenyl core in the side-chain. PMVBP has a smaller monomer molecular weight (MW), a higher glass transition temperature and a lower threshold MW for liquid crystalline (LC) formation. PMVBP was obtained via a nitroxide-mediated living radical polymerization and characterized by gel permeation chromatography, differential scanning calorimetry, polarized light microscopy, and one- and two-dimensional wide-angle X-ray diffraction (WAXD) experiments. The number-average MW (Mn) of the polymers ranges from 0.41 × 104 to 1.64 × 104 g mol−1. A relatively high glass transition temperature is observed, which increases from 173 to 208 °C with increasing MW. The LC phase developed at relatively high temperatures is strongly dependent on the Mn of the polymer. A hexagonal columnar (ΦH) LC phase is observed above 260 °C when the Mn is only above 0.53 × 104 g mol−1, a low threshold MW for LC formation. All of the LC phases are retained during cooling.