Determination of Kinetic Parameters of Ethyl Methacrylate Polymerization Initiated by the Redox Pair SO2-tert-Butyl Hydroperoxide

Abstract

In the bulk polymerization of ethyl methacrylate with the redox initiator pair sulfur dioxide-tert-butyl hydroperoxide (SO₂-TBHP), the kinetic parameters were determined by the dead-end polymerization technique using the dilatometric method. Polymerization was conducted with various initiator pair compositions in the temperature interval of 12–35°C. An activation energy of 14.1 kJ/mol for [SO₂]/[TBHP] = 0.44 was determined for this temperature range. The values of k ² _p/k _t obtained in this study were in the interval 1.34 × 10^?4 to 1.11 × 10^?3 L/mol·s. The f/k _d ratios for the redox pair at different temperatures and for different initiator ratios were also calculated. The f/k _d ratios of the initiator pair changed between 15.1 and 187.6 seconds. The wide variations in these kinetic parameters were explained on the basis of competitive reactions between the redox pair and their reaction products.