Continuous distribution kinetics for degradation of polystyrene in sub- and supercritical toluene

When the degradation of polystyrene is carried out above 300 °C, the process of degradation is very complex with concurrent random scission and chain-end scission including depolymerization, intramolecular transfer and followed β-scission which produce volatile products. A quick-depolymerization assumption was proposed to simplify the reaction mechanism of this process. Based on this assumption, continuous distribution kinetics was used to describe the model of polystyrene degradation at the mechanistic level. Toluene was used as solvent to study the sub- and supercritical degradation of polystyrene at 310–370 °C and high yields of volatile products were obtained. The experimental data supported the assumption and determined rate coefficients of random scission and chain-end scission. The activation energies of random scission and chain-end scission, determined from the temperature dependence of the rate coefficients, were 43.2 and 42.7 kcal/mol, respectively.