Effect of Copper Stearate on the Thermal Oxidation of Polypropylene in Solution

Abstract

Thermal oxidation of atactic polypropylene (APP) was carried out in trichlorobenzene and the effects of copper stearate and octanoic acid as a model compound of oxidation products were examined mainly by oxygen uptake method. The copper-catalyzed thermal oxidation of APP was enhanced with increasing concentration of the copper, but at the higher concentration of the copper (more than ca. 7.9×10^-4M) the polymer oxidation was retarded. Addition of a very small amount of octanoic acid (10^-16-10^-2 M) retarded the copper-catalyzed oxidation of APP, but at the higher concentration (more than ca. 10^-1 M), it showed acceleration. By the addition of propionic acid or fresh APP into a reaction system where oxygen uptake leveled off, the oxidation APP started again. The results suggested that a very small amount of the initial oxidation products remarkably affect the catalytic activity of the copper in the copper-catalyzed thermal oxidation of APP in solution.