QUANTITATIVE STUDY OF PHOTOCATALYZED OXIDATION OF ETHYLENE-PROPYLENE RUBBER AND ATACTIC POLYPROPYLENE

The effect of photoactive pigments such as ZnO, CdS, and TiO2 on the p hotoorddation ( with and without water vapor) of ethylene - propylene rubber and atactic polypropylene were examined. The effects of surface treatment (passivation) and low granulometry (nanopigments) were also studied for TiO2. A drastic increase of ketone and an inhibition of c arboxylic acid formation for ZnO filled polymers were revealed and qua ntitatively measured by using derivatization reactions. Such a phenome non, as well as a small decrease of average molecular weight, were exp lained by a modification of the ZnO decomposition mechanism of tertiar y hydroperoxides. (C) 1998 John Wiley & Sons, Inc. J AppI Polym Sci 69 : 1681-1689, 1998.