Polystyrene thermodegradation IV. Kinetics of radical formation in the presence of solid catalysts

The catalytic degradation of polystyrene, carried out in sealed tubes with solid catalysts having different acidic properties (i.e. silica-magnesia, silica-titania, mordenite and two silica-aluminas), was studied. Reaction temperatures in the range 360-420°C for reaction times up to 30 min were investigated. The reaction was followed by ESR analysis through a direct quantitative determination of radicals. The kinetic parameters of the initiation step of the multi-step process of polystyrene degradation were obtained, through a computer optimization routine applied to the experimental data. The results are compared with those obtained for the pure thermal reaction.