Photodegradation of polypropylene in the presence of ferric chloride

Abstract

Abstract The effect of ferric chloride (FeCl 3 ) on photodegradation of isotactic polypropylene (PP) was investigated using mainly ESR spectrometry. PP powder, its oxidized samples, and FeCl 3 ‐adsorbing PP samples were irradiated under a nitrogen atmosphere at 77°K with ultraviolet light from a high‐pressure mercury lamp and a superhigh‐pressure mercury lamp modified by various filters. Methyl, polymerci alkyl, and peroxy radicals were observed in the ESR spectra of the irradiated samples, and it was found that FeCl 3 depresses the formation of alkyl radicals and accelerates the formation of peroxy radicals catalyzing the reaction. From infrared study of UV‐irradiated film samples, it was also inferred that FeCl 3 accelerates the photodegradation the hydroperoxide and carbonyl groups.