Photooxidative degradation of polyether-based polymers

The mechanisms of photooxidation of several polyether based polymers were compared in order to give general rules of orientation of the oxidative reactions. These polymers were a poly(ether-ester) and two poly(ether-urethane)s. The behavior of the polyether component as homopolymer was also studied. This study was extended to copolymers of fluorinated olefins and allyl or vinyl ethers, and the non fluorinated homologues. The elucidation of the photooxidation mechanisms was based on the identification of the photoproducts by analysis of both the solid polymeric matrix and the gaz phase formed on irradiation. It was shown that the photochemical sensitivity of the polyether component was responsible for the rapid oxidation of the copolymers. However, in the case of the fluorinated compounds, different behaviors were observed. It was shown that the presence of the fluorine atoms strongly influenced the orientation of the reaction and modified the oxidation kinetics. The reactivity of the methylene groups in alpha-position of the oxygen atom of the ether groups were not found to be equivalent regarding oxidation and the secondary was more oxidizable than the tertiary one.