Special features of low temperature radical polymerization in the high conversion region

Abstract

Non-isothermal conditions of high conversion radical polymerization are analysed within the framework of the quasi-steady-state theory of thermal shock as applied to autocatalytic reactions. In order to describe the gel effect a model is used which takes into account the relation between the chain termination rate constant and the length of the interacting macroradicals. The effect of temperature and monomer conversion on the activation energy is a specific polymerization feature arising from this relation, which is considered as an exothermic reaction with autocatalysis. It is shown that under gel effect conditions the region of permissible heating up for which a quasi-steady-state reaction is possible is considerably widened. A numerical calculation is made of the thermal conditions of the processes and their critical parameters using the polymerization of methyl methacrylate as an example.