The effect of a special additive containing stabilizer and sensitizer groups was studied in thermal and photooxidation of polypropylene. In thermooxidation, the induction period of oxygenz absorption decreased, and its rate increased with the increase of the amount of the additive. In photooxidation, however, the shortest induction period and highest rate of carbonyl formation can be achieved at an optimal additive concentration.The final molecular mass of the samples after irradiation till the spontaneous rupture falls in the range of moldecular mass consumable for the microbes. On the basis of the results, it seems to be possible to stabilize the polymer during processing and storage, and sensitize under solar irradiation with the same additive.Paper presented a t t h e