LAUSR

The kinetics of the radical bulk polymerization of styrene in the presence of rubber particles from recycled tires, commercially called ground tire rubber (GTR), have been studied using isothermal differential scanning calorimetry. Two different radical initiators, namely benzoyl peroxide and 2,2-azobis(2-methylbutyronitrile), were tested in a series of variable-composition experiments under three different polymerization temperatures, in order to selectively address the role of the presence of GTR on the course of the polymerization reaction. The variation of the overall effective kinetic rate constant and activation energy were also determined to quantify the effect of the presence of GTR in the reaction mixture. The results of the study demonstrate that the evolution of the monomer conversion versus time is significantly affected when the GTR content in the polymerization system is above 30 mass/%. The observed phenomena are consistent with previous results and may be primarily attributed to the chemical interactions taking place between the initiator and additives contained in the mixture.