具有热致/溶致液晶性能主链液晶聚合物的合成

Preparation and Properties of a Series of Thermotropic/Lytropic Main Chain Liquid Crystalline Polymers

介晶单体 4,4′ 二羟基 α,α′ 二甲基苄连氮与不同摩尔比的对苯二甲酰氯和癸二酰氯采用界面聚合的方法共聚而得系列聚合物P1～P7·通过傅立叶转换红外光谱 (FT IR)、差示扫描量热仪 (DSC)、偏光显微镜 (POM)、广角X射线衍射分析 (WAXD)等手段对聚合物的结构、热致及溶致液晶性能、热性能进行了表征·单体DDBA与聚合物P1～P6 均为向列型热致液晶 ,呈现清晰的丝状织构 ,但聚合物的热致液晶性能随刚性链段对苯二甲酰含量的增加而逐渐减弱 ;所有聚合物均具有溶致液晶性能 ,其织构从柳叶状逐渐变为砂粒状 ;聚合物均具有较高的热稳定性 ,热分解温度在 3 2 0℃以上 ,且热稳定性随刚性链段对苯二甲酰含量的增大而升高·

A series of main chain polymers P 1～P 7 were synthesized by an interfacial condensation reaction of 4,4′ dihydroxy α,α′ dimethylbenzalazine, a mesogenic monomers, and a mixture of terephaloyl and sebacoyl dichloride. The structure of polymers was characterized by means of IR. DSC, POM and WAXD were used to measure their thermal properties and thermotropic and lytropic liquid crystalline properties. Monomer DDBA and polymers P 1～P 6 are nematic mesophase and exhibits clear thread like textures. The thermotropic mesogenic propertly of polymers is weakened with increasing the concentration of the rigid chain segment. Polymers P 1～P 7 are lytropic liquid crystalline polymers and the textures of polymers in solution changes from multicolor willowy leaf shaped texture to gravel shaped texture for the increase of the rigidity of the polymer chain. The polymers P 1～P 7 are thermal stable up to about 320?℃ and the thermal stability is enhanced from P 1 to P 7.