Aromatic polyesters via transesterification of dimethylterephthalate/isophthalate with bisphenol-A

Abstract

As a part of our work in the area of transesterification chemistry, we have studied the transesterification of dimethyl terephthalate/isophthalate with bisphenol-A for the synthesis of aromatic polyester. The process comprises two steps. The first step comprises preparation of aromatic polyester prepolymer by reacting the dimethyl esters of terephthalic/isophthalic acids and bisphenol-A in the melt phase via catalyzed interchange reaction. The second step involves the postpolycondensation of aromatic polyester prepolymer under reduced pressure, eliminating the by-product and driving the equilibrium of the reversible reaction to the formation of a high molecular weight aromatic polyester. In both steps, methanol is eliminated as a by-product. The method explored is the simplest one, permits the use of commercial materials as the feed stock, and leads to a low boiling by-product that can be recycled.