Photo-oxidative degradation of poly(epichlorohydrin- co-ethylene oxide) elastomer at 254 nm

The photo-degradation of unstabilised poly(epichlorohydrin- co-ethylene oxide) was evaluated under accelerated ageing conditions by infrared spectrophotometry (FTIR), gel permeation chromatography (GPC) and scanning electron microscopy (SEM). The elastomer photo-degradation leads to the formation and increase of carbonyl containing products, hydroxyl and hydroperoxide groups. FTIR spectra after elastomer photo-degradation and derivatization in an inert atmosphere, indicate that hydroperoxides are the first products of the photo-oxidation and their photolysis produces carbonyl-containing products. These are subsequently photolyzed to produce carboxylic acids, alcohols, esters and others minor products. The study of the average molar mass by GPC shows that it decreases exponentially during the first 2 h of irradiation, with evidence for random chain scission. The SEM study shows that photo-degradation leads to the formation of micro-cracks on the polymer surface.