Catalyst effect on the transesterification reactions between polycarbonateand polycaprolactone-B-polydimethylsiloxane triblock copolymers

Transesterification reactions between bisphenol-A polycarbonate and polydim ethylsiloxane-polycaprolactone block copolymers were studied in melt at 270 degrees C. Influence of the composition of reaction mixture and the cataly st type on the formation and properties of the products obtained were inves tigated by spectroscopic, chromatographic and thermal methods. Both of the catalysts used, zinc acetate and lanthanum acetylacetonate are very efficie nt transesterification catalysts for the system studied. GPC and DSC result s clearly show the formation of novel polymers displaying combined properti es of the polycarbonate and the silicone-ester copolymer.