Synthesis And Characterization Of Bisphenol-a And Its Derivative Thermotropic Thermotropic Liquid Crystal Polyarylester

Polyarylesters is a kind of thermotropic liquid crystal polymers, developed in the1970s with the liquid crystal polyamide. Its macromolecule chain consists of a rigid aromatic ring and ester bond. Macromolecule chain contains inflexible aromatic ring and ester bond mainly. Polyarylesters display excellent tensile strength and modulus, heat-resistance, and small linear expansion coefficient, more outstanding processability than lytropic liquid crystal polymers or heterocyclic polymer. Thus, the study of thermotropic liquid crystal Polyarylesters is one of the hot topics in the study of polymer materials in recent years. To absolute-inflexible polyarylesters, the liquid crystal phase transition temperature is very high, even more than its decomposition temperature. The structure modification should be made by molecular desighing. The vast majority of research work is in the development of lytropic liquid crystal polymers. However, much work has not been focused on investigating the thermotropic liquid crystal polymers. It is necessary to research the melt polymerization synthesis process of polyarylesters. This topic research by bisphenol A and its derivatives polyarylesters from the point of molecular design and synthesis of monomer for copolymerization. the relationship between structure and properties were studied by infrared spectrum (IR), thermo-gravimetric analysis (TGA) and differential thermal scanning (DSC), polarizing microscope (POM) and some other characterization methods.This thesis is based on the tetra copolymer of synthetic 1,1-Bis(4-hydroxyphenyl)-1-phenylethane (BPAP),2-hydroxy-6-naphthoic acid(HNA), p-hydroxybenzoic acid (HBA) and terephthalic acid (TPA). Comparing with the2,2-di (4-hydroxyphenyl) propane(BPA)/HNA/HBA/TPA and2,2-bis(4-hydroxyphenyl)-1,1,1,3,3-hexafluoro propane (BPAF)/HNA/HBA/TPA polyarylester, the molecular modification effects on polyartlester was further researched. And a ternary copolymer was synthesized by using synthesized bis(4-carboxyl phenyl)dimethylsilane and2,7-dihydroxynaphthalene and p-hydroxy benzoic acid, has been tested.BPAP(BPA,BPAF)/HBA/HNA/TPA quaternary copolymer was prepared. And a ternary copolymer was synthesized by using synthesized bis(4-carboxylphenyl)dimethylsilane and2,7-dihydroxynaphthalene and p-hydroxybenzoic acid(HBA). Then thestructure were studied by infrared spectroscopy, the result fit the expected requirement well. The glass transition point and melt point were measured by DSC, respectively, from98to128℃and from217. Both of the polyarylesters were showed flow characteristics to237℃. Also the birefringence was observed by POM and the melt flow index was showed by Melt Flow Index.