Modeling of Free Radical Polymerization of Styrene by Bifuncational Initiators with Peroxide Groups of Unequal Thermal Stabilities.

Abstract

A detailed kinetic model of the bulk styrene polymerization initiated by diperoxide bifunctional initiators is presented. When chain termination occurs via combination termination mechanism, six distinct polymeric specics are identified in accordance with the nature of polymer end units. It is shown that the unequal thermal decomposition characteristics of the peroxides of the bifunctional initiator system leads to the formation of polymers having considerably higher molecular weight than those obtained by the monofunctional initiator system. It has also been found that molecular weight distribution becomes narrower as the bifunctional initiator system is used. The effect of the bifunctional initiator is more pronounced at high reaction temperatures. The new possibilitics of increasing the monomer conversion and modifying the polymer molecular weight properties effectively through the use of bifunctional initiators are discussed.