Ester-carbonate interchange reaction in the solid state: synthesis of poly(ester-carbonate)

Abstract

Poly(ethylene terephthalate-co-bisphenol A carbonate) was synthesized by ester-carbonate interchange reaction in the solid state. The polymerization reaction was carried out by heating two chemically distinct oligomers, namely, poly(aryl carbonate) and poly(ethylene terephthalate) in the temperature range of 180-230°C, during which period both chain extension as well as interchange reactions occurred. A copolymer of η_inh = 0.84 dL/g was obtained. With the progress of the interchange reaction the T_g of the copolymer slowly increases and reaches a maximum value of 102°C. The oligomer mixture, which exhibits initially two distinct T_m's, shows a single T_m at the end of the reaction. Formation of copoly(aryl ester-carbonate)s by an ester-carbonate interchange reaction was also found in the solid state at temperatures below 230°C. High molecular weight poly(aryl ester-carbonate)s with a T_g = 163°C and η_inh = 0.52 dL/g were prepared from the corresponding low molecular weight oligomers of poly(aryl ester) and poly(aryl carbonate)s.