Aging and degradation of polyolefins. IV. Thermal and photodecompositions of model peroxides

There appear to be no unusual effects of phase change or near-ultraviolet radiation on the reactions of alkoxy radical models for atactic polypropylene. The oxidation of purified atactic polypropylene by singlet oxygen is not an important process at 50°. Photochemical and thermal cleavages of tert-amyloxy radicals, a model for polypropylene oxy radicals, give nearly the same ratio of k_a/k_d at 50°C. Photochemical cleavage of the model compound 1,1-dinonylethyl hydroperoxide (10-methyl-10-nonadecyl hydropenoxide) gives exclusive cleavage of a nonyl group both in solution and in polypropylene film at 50°C.