Synthesis and characterization of novel optically active polyesters with high thermal stability

Abstract

A new optically active diacid (DA) was prepared by nucleophilic substitution reaction of R-(À)-mandelic acid with terephthaloyl chloride in the presence of potassium hydroxide. This DA named terephthalic acid bis(carboxyphenylmethyl) ester was used as a monomer for the preparation of related optically active polyesters. Polycondensation of DA with different aromatic diols, including hydroquinone, 1,5-dihydroxy naphthalene, 1,4-dihydroxy anthraquinone, 1,8-dihydroxy anthraquinone, 2,4-dihydroxy benzophenone, and bisphenol A, in the presence of 4-toluenesulfonyl chloride using high temperature solution method led to preparation of different polyesters. The prepared monomer and all the polymers were characterized by conventional methods. Thermal and physical properties of the polyesters, including thermal stability, thermal behavior, solution viscosity, and solubility behavior, in addition to optical activity were studied. The optically active polyesters showed high thermal stability, whereas the presence of bulky groups improved their solubility.