Effect of antimony catalyst on solid-state polycondensation of poly(ethylene terephthalate)

The effect of antimony trioxide (Sb2O3) catalyst on the solid-state polycondensation (SSP) of poly(ethylene terephthalate) (PET) has been rigorously studied. It has been deter-mined that the rate constant increases, while the activation energy decreases, linearly with increasing catalyst concentration within the range of 0-100 ppm Sb. The SSP rate reaches its maximum value at about 150 ppm Sb. The activation energies are 30.7 and 23.3 kcal/mol respectively for the uncatalyzed and fully catalyzed SSP. The frequency factor decreases with increasing catalyst concentration due to the decreased mobility of catalyzed end groups. A mechanism of Sb catalysis has been proposed to explain these observations. (C) 2002 Elsevier Science Ltd. All rights reserved.