Solid-State Condensation Polymerization of Aromatic Oligoesters from Bisphenol A and Diphenyl Terephthalate/lsophthalate Mixtures

Abstract

Industrially available aromatic polyesters of bisphenol A polyarylate is conventionally produced by the interfacial condensation polymerization of bisphenol A and the mixture of terephthaloyl/isophthaloyl chlorides. We now report a new synthetic method without using the acid chloride derivatives. The synthesis of oligomeric polyarylate by the melt condensation polymerization of bisphenol A and diphenyl terephthalate/isophthalate (mole ratio of reactants is 1/0.5/0.5), and the crystallization of this oligomeric polyarylate contacting with the proper solvent have been previously repoted. This crystallized oligomeric polyarylate could be polymerized by the solid-state condensation polymerization into a high molecular weight polymer with excellent color. The key point to obtain a high molecular weight polymer was to adjust precisely the mole ratio of the end-groups of -OH and phenyl. The molecular weight of the obtained polymer reached to twice that of the commercial polyarylate and the molecular weight distribution hadthe most probable distribution of Mw/Mn=2. The high molecular weight polyarylate showed an excellent wear property. The melting points of the obtained polymers were over 280°C, and some polymers showed a melting point over 300°C. These values were nearly 40°C higher than the reported value of the maximum melting point of the random copolyarylate composed of bisphenol A, terephthalic and isophthalic acid (mole ratio of bisphenol A/terephthalic/isophthalic acid =1/0.5/0.5).