REACTIVE BLENDING OF POLY(ETHYLENE-TEREPHTHALATE) AND BISPHENOL-A POLYCARBONATE - EFFECT OF VARIOUS CATALYSTS AND MIXING TIME ON THE EXTENTOF EXCHANGE-REACTIONS

The catalytic activity towards exchange reactions in poly(ethylene ter ephthalate) (PET)-bisphenol-A polycarbonate (PC) reactive blending was compared for various lanthanide compounds (based on europium, cerium, samarium, terbium and erbium), and for titanium- and calcium/antimony -based catalysts. The effect of reaction time on the extent of reactio n was studied by selective solubility tests coupled with H-1 n.m.r. an d a selective degradation procedure for PC sequences was carried out t o achieve information on the PET block length change. Each of the abov e methods can be used to get information on the reaction extent; howev er, a better understanding of the reaction mechanism is achieved by us ing more than just a single method. Titanium showed a higher catalytic activity; however, lanthanide catalysts, especially those based on sa marium, europium and cerium, allowed the block length in the PC/PET bl ock copolymers formed by exchange reactions during melt mixing to be c ontrolled more easily, and at the same time they did not promote the s ide-reactions that occurred in the presence of titanium- or calcium/an timony-based catalysts. Copyright (C) 1996 Elsevier Science Ltd.