Oxidative degradation of poly(ethyl acrylate)

Abstract

AbstractThe oxidative degradation of poly(ethyl acrylate) was investigated by infrared spectrophotometric techniques, and the volatile degradation products were determined by vapor‐phase chromatographic analysis. During the course of degradation, no change in the spectrum of the polymer, indicating the formation of other moieties, was detected. There was only a generally uniform decrease of all the existing absorption bands with the exception of the 5.75–5.85 μ ester‐ketone carbonyl region. This decrease of absorption proceeded appreciably slower than the rate previously reported for the degradation of poly(ethylacrylate). The reported formation of carboxylic acid groups detected in the spectrum of degraded polymer was not substantiated in this study. In contrast to degraded poly(ethyl acrylate), the low molecular weight, volatile polymer formed on oxidation was highly oxidized. In addition, the highly volatile degradation products were identified as carbon dioxide, water, ethyl acetate, and ethyl alcohol. No monomer, ethyl acrylate, could be detected among the volatile products. A methanistic pathway was postulated based on these results. Initially, there is attack of molecular oxygen at the tertiary carbon atoms of the polymer chain to form hydroperoxide groups. Subsequent decomposition of the hydroperoxides results in random chain scission eventually giving low molecular weight polymeric units. Further oxidation of the low polymer units leads to the observed product formation.