Polystyrene thermodegradation. 3.Effect of acidic catalysts on radical formation and volatile product distribution

The catalytic degradation of polystyrene, carried out in sealed tubes with different acidic catalysts (i.e., silica, zeolites, and silica-aluminas), was studied. Two reaction temperatures, 350 and 400°C, for reaction times up to 120 min were investigated. The reaction was followed both by electron spin resonance and gas chromatography-mass spectrometric analysis. The different distributions of volatile products (C6-C24) obtained in the various cases are discussed, arranging the products into groups. An initiation mechanism, involving the formation of radical cations, is proposed for the degradation of polystyrene on strongly acidic catalysts.