The decomposition of benzoyl peroxide in polystyrene. II

Abstract

AbstractPolystyrene films containing benzoyl peroxide were heated in air at 73 and 90°C. and the products of decomposition were investigated. The products are benzoic acid, phenyl benzoate, polystyrene benzoate, and carbon dioxide. The same products, in very similar quantities, are formed at both 73 and 90°C., suggesting that diffusion of radicals out of the polymer cage is not an important occurrence either above or below the apparent second‐order transition temperature of polystyrene. The change in the temperature dependence of peroxide decomposition rate above 80°C. seems to be associated with a greater ease of reaction of benzoyloxy radicals with the walls of the polymer cage above the glass temperature. Considerably more ester formation and less carbon dioxide evolution are observed in this decomposition than when benzoyl peroxide is decomposed in benzene or toluene. Attack by benzoyloxy radical occurs on both the ring and backbone of polystyrene, the backbone attack seeming to take place predominantly on the secondary carbon atoms of the backbone.