Kinetics of polymer degradation involving the splitting off of small molecules: Part 9—thermal dehydrobromination of polyvinyl bromide

Abstract

High conversion kinetic runs of the thermal dehydrobromination of polyvinyl bromide have been treated using the theory developed previously. The results suggest that the dehydrobromination occurs most probably via the mechanism of gradual zip growth where the initiation step of the zip reaction is not autocatalytic. Good agreement between experimental and theoretical kinetic curves has been achieved for this mechanism. The activation energy and pre-exponential factor for random elimination of HBr are E a = 153 kJ mol −1 and log( A/ s −1) = 13·7. The ratio of the rate constants of zip propagation and random elimination decreases with increasing temperature.