COPPER CARBOXYLATE FORMATION IN THE THERMAL OXIDATIVE-DEGRADATION OF ATACTIC POLYPROPYLENE ON COPPER-OXIDE FILMS

The thermal oxidation of atactic polypropylene on CuO//0//. //6//7 surfaces in air was studied using IR reflection-absorption spectroscopy. Degradative losses of primary, secondary, and tertiary alkyl hydrogens were observed. At 60 and 73 degree C, carboxylic acids are the primary degradation products, while at 85 and 100 degree C, copper carboxylate formation predominates and CuO//0//. //6//7 is decomposed. The distinct change in the oxidative mechanisms between 73 and 85 degree C apparently is related to an irreversible thermal transition in the atactic polypropylene films, which may favor carboxylate production by increasing the permeability of the films to oxygen and water vapor.