PET-HBT嵌段热致性液晶共聚酯的合成

Synthesis of PET-HBT Thermotropic Liquid Crystalline Copolyester

液晶高分子材料具有相当高的强度和模量,被誉为当代超级工程塑料。以对羟基苯甲酸甲酯、1,4-丁二醇为主要原料,经熔融酯交换合成双-对羟基苯甲酸丁二醇酯(BBHB);以四氯乙烷为溶剂,采用溶液缩聚法将过量的BBHB与对苯二甲酰氯(TPC)合成端基为BBHB的齐聚物(PHBT);以对苯二甲酸二甲酯与乙二醇为原料,经熔融酯交换合成对苯二甲酸双β-羟乙酯(BHET),然后采用溶液缩聚法将BHET与少量的TPC合成端基为TPC的齐聚物(PTET);最后以PHBT与PTET为原料,以四氯乙烷为溶剂,采用溶液缩聚法合成目标共聚酯(PET-HBT)。研究了共聚酯的双折射现象及热行为;用偏光显微镜观察了该共聚酯的织态结构并用FTIR表征了共聚酯的微观结构。

Liquid crystalline polymer has the highest strength and modulus. Nowadays it is well known as super engineering plastics. Bis( p -hydroxybenzoic acid butanediolate) (BBHB) was prepared with p-methylhydroxybenzoate, 1,4-bu-tanediol and composite catalyzer by melting transesterification. Then oligomer HBT was synthesised with excessive BBHB and terephthaloyl chloride by solution polycondensation, using tetrachloroethane as solvent. Copolyester PET-HBT was synthesized with ET which was prepared with oligomer HBT, p -hydroxybenzoic acid bis( β-hydroxyethylate) and excessive TPC, using tetrachloroethane as solvent. Double refraction and thermal behavior of the copolyester were also studied. The micro-structures of this block copolymers were characterized by means of FTIR. Photographs of polarizing microscope show that the copolyester is nematic liquid crystalline polymer.