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

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 degrees C, during which period both chain extension as well as interchange reactions occurred. A copolymer of eta(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 degrees 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 degrees C. High molecular weight poly(aryl ester-carbonate)s with a T-g = 163 degrees C and eta(inh) = 0.52 dL/g were prepared from the corresponding low molecular weight oligomers of poly(aryl ester)s and poly(aryl carbonate)s.