Homopolymerization of 4-propionoxybenzoic acid: A kinetic study

A kinetic study of the synthesis of poly(4-oxybenzoate) by melt-step growth polymerization using para-propionoxybenzoic acid is reported. The polycond ensations obey second-order kinetics, irrespective of whether the reaction was catalyzed or uncatalyzed. Breaks are observed in the kinetic plots, sug gesting the presence of different kinetic regimes during the course of the reaction. An elaborate kinetic model that presupposes precipitation of olig omers predicts two-stage kinetics as well as breaks in the rate plots and f its experimental data well throughout the course of the reaction and the pe rformance of two transesterification catalysts are estimated. No isokinetic temperature is displayed for the transesterification reaction. Activation energy values for catalyzed reactions are found to be higher than the uncat alyzed reaction, indicating that entropy factors drive the reaction to comp letion. (C) 1999 John Wiley & Sons, Inc.