The kinetics of oxidation of atactic polystyrene in solution

The oxidation of polystyrene initiated by the photodecomposition of 2,2′-azoisobutyronitrile at λ > 300 nm was studied at 25°C in chlorobenzene solution. The order of the reaction is approximately unity with respect to AIBN concentration and to the light intensity. The effects of concentration and molecular weight on the rate are apparently related to their effects on bulk viscosities of the solutions. The overall kinetics have been interpreted by a general oxidation scheme which incorporates the effect of bulk viscosity on the rate of radical production in the initiation step. Diphenyl alkanes were oxidized under identical conditions and their kinetic parameters are compared with those of the polymer. It would appear that a considerable degree of intramolecular propagation occurs in both systems.