MISCIBILITY AND TRANSESTERIFICATION IN BISPHENOL-A POLYCARBONATE ETHYLENE TEREPHTHALATE CAPROLACTONE COPOLYESTER BLENDS

The miscibility and microstructure of blends of bisphenol-A polycarbon ate (PC) with ethylene terephthalate (ET)-caprolactone (CL) copolyeste rs (TCL) were studied by differential scanning calorimetry (DSC), infr ared spectroscopy (IR) and phase contrast microscopy (PCM). The DSC re sults showed that PC were immiscible or partially miscible with the co polyesters having ethylene terephthatate contents higher than 60 (wt % ), and miscible with the copolyesters having ET contents lower than 60 (wt %). After annealing at elevated temperature, homogenization will take place in the immiscible or partially miscible blends of PC with h igher ET-content copolyesters. The IR and PCM results revealed that th e homogenization of the blend are caused by the transesterification be tween the PC and copolyesters. (C) 1995 John Wiley and Sons, Inc.