EFFECT OF THE SB2O3 CATALYST ON THE SOLID-STATE POSTPOLYCONDENSATION OF POLY(ETHYLENE-TEREPHTHALATE)

The effect of Sb2O3, which is used as the main catalyst in the product ion of poly(ethylene terephthalate) (PET) by melt polymerization, was studied on solid-state postpolycondensation. It was observed that the catalyst works efficiently even in the solid state. The number-average molecular weight of a PET prepolymer with an Sb2O3 content of 2000 pp m was increased from 18,350 to 40,800 after heating at 210 degrees C f or 8 h under vacuum (2-3 Pa), whereas when the catalyst was absent, th e molecular weight of the same prepolymer under the same conditions wa s just increased to 22,500. The activation energies and the frequency factors of the esterification and ester interchange reactions, which t ake place simultaneously during solid-state postpolycondensation, were determined. (C) 1995 John Wiley & Sons, Inc.