Effect of structure on the thermal decomposition of polymers

Abstract

During recent years a considerable nurnber of t heoretical and experimental stud ies have been published on t he kinetics and mechanism of t he t hermal decomposition of pol- ymers. The treatment of depo.lymerization as a free-radical chain reaction involving the four basic steps of initiation, propagation, t ransfer, and termination seems adequate for a fairly complete understanding of the p rocess in a large number of cases. Rate data now available a re discussed from t his point of view. It is shown t hat most of t he characteristics of t he thermal decomposition rate curves a re a result of their basic struct ure and not of trace impuities. The magnitude of the rates and act.ivation energies are, however, sensi- t ive to trace stru ctures or impurit ies. It is shown t hat in termolecula r transfer will account for the rate behavior in a large number of polymers. In a relatively few other cases intrmolecular transfer is indicated to bc of more importance