聚1,4-苯二氧乙酸-1,8-二氧代辛撐基二苯酚酯的结构和液晶行为的研究

用界面聚合方法制备了芳香族聚酯——聚1,4-苯二氧乙酸-1,8-二氧代辛撐基二苯酚酯?镁埘ナ怯珊交返母招粤唇诹友羌谆嵝约涓舳?利用元素分析、红外光谱分析、热台偏光显微镜观察、照相、差示扫描量热法(DSC)、X-射线衍射及小角激光光散射等技术,对该聚合物的结构和性能进行了研究。结果表明,该聚合物为热致液晶,能够呈现近晶相和向列相织构。它的热行为受其热史影响很大。DSC冷却曲线上液晶转变峰大于结晶峰,可认为是由于急冷而使分子链不及排成三维有序晶态所致。聚合物的清亮点转变呈现平衡转变的特征,清亮点转变熵似可用来表征系统介晶态的有序度。

A study on the structure and liquid crystalline behavior of aromatic polyester from 1,4-dichloroacetate hydroquinone and 4,4'-dihydroxy-1,8-diphenoxyhexane

A new aromatic polyester in which the methylene flexible spacers are connected with the rigid unit containing benzene rings was prepared by interfacial polycondensation: The polymer was characterized by the elemental analysis, IR spectroscopy, hot-stage polarized light microscopy, DSC, x-ray diffraction and small angle laser scattering techniques. The structure and properties of polyester obtained was investigated. The results showed that the polymer is a thermotropic liquid crystal and appeared of nematic and smectic texture. Thermal history of polymer had a significant effect on its thermal behavior. According to the results of differential scanning calorimetry of the polymer, liquid crystal transition peak was larger than crystallization peak in cooling run, which was suggested to arise from the supercooling. Furthermore, the thermal analysis of polyester revealed that clearing transition presented the characteristic of equilibrium process, so the entropy of this transition might offer some indication of the order present in the system.