Design and Synthesis of a Series of Novel Mesogen-Jacketed Liquid Crystal Polymers
Design and Synthesis of a Series of Novel Mesogen-Jacketed Liquid Crystal Polymers
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发表时间：
2000
影响因子：
3.1
通讯作者：
T. Hui
中科院分区：
文献类型：
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作者：
T. Hui
以对三联苯为介晶基元，两端被烷氧基取代的2，5-二（4′-烷氧基苯基）苯乙烯（Mn）为介晶基元，进行了自由基聚合反应。由于不存在极性连接基团，如-COO-或-CONH-，如在以前报道的MJLCP中使用的，Mn被认为是容易通过自由基聚合和离子聚合。Mn的化学结构经1HNMR、质谱和元素分析确证。用DSC和POM表征了它们的相转变和液晶性。M1、M2、M3和M4均为单晶型的双晶型中间相，而M5由于熔融转变温度降低而呈现出双晶型的双晶型中间相。所有单体都容易聚合成中等高分子量的聚合物。当温度高于Tg时，聚[2，5-二（4′-烷氧基苯基）苯乙烯]呈现出非常稳定的中间相。形成的双折射直到热分解开始才消失。与其他MJLCP相比，本文报道的聚合物具有更高的热稳定性。[WT5HZ]
This paper describes the synthesis and free radical polymerization of 2,5 bis(4′ alkyloxyphenyl)styrene(M n ) for mesogen jacketed liquid crystal polymers(MJLCPs), where p terphenyl subsituted by alkoxy groups at both ends was used as mesogenic unit. Because of the absence of the polar linkage groups, such as —COO— or —CONH— as employed in the previous reported MJLCPs, M n is believed to be polymerized easily by both free radical polymerization and ionic polymerization. The chemical structure of M n was proved by 1H NMR, mass spectrometry and elementary analysis. Their phase transition and liquid crystallinity were characterized by DSC and POM. Although M 1, M 2, M 3 and M 4 exhibited monotropic nematic mesophase, M 5 displayed enantiotropic nematic mesophase presumably because of its decreased melting transition temperature. All monomers were easily polymerized to moderately high molecular weight polymers. At elevated temperature above T g, poly[2,5 bis(4′ alkoxyphenyl)styrene] showed a very stable mesophase. The formed birefrigence did not disappear until thermal decomposition started. Compared to other MJLCPs, the polymers reported here have much higher thermal stability. [WT5HZ]