三元无规芳-脂族聚酯酰胺的热致液晶行为

Thermotropic Liquid Crystalline Behaviour of Ternary Unregular Aromatic-Aliphatic Polyesteramides

采用低温溶液缩聚的方法合成了以对苯二甲酰氯，二甲基联苯胺和己二醇为单体的芳－脂族液晶聚酯酰胺。用ＤＳＣ，Ｘ光衍射分析和偏光显微镜等手段研究了该系列聚酯酰胺的热致液晶行为，确认了二甲基联苯胺单体用量在２０％（ｍｏ１）的情况下，所得聚酯酰胺仍为向列型液晶聚合物。由于聚酯酰胺分子间聚酰胺链段之间的氢键作用，随着二甲基联苯胺用量增加至６０ｍｏｌ．％时，所得的聚酯酰胺己无液晶相转变温度，其液晶区间即从熔融温度直至分解温度。

The aromatic-aliphatic polyesteramides were synthesized by low tempcrature solution copolycondensation of monomers, p-terephthalyl chloride(TPC),dimethylbenzidine(DMBD) and hexylene glycol(HG) in the N-methylpyrrolidone (NMP) -anhydrous lithium chloride(LiCl) solvent system. DSC, polarizing optical microscope(POM) and X-ray diffraction analysis were used to investigate the thermotropic liquid crystalline properties.With the increasing of the DMBD used in copolymerization,the melting temperature(T m) and the liquid crystalline phase transition temperaturee(T i) of PEAs obtained increased rapidly and the T i of PEAs which were prepared by using up to 60 mol.% DMBD could not be obsearved. It was confirmed that all PEAs obtained were thermotropic nematic liquid crystalline polymers.