Publications

17O NMR investigation of oxidative degradation in polymers under γ-irradiation

Alam, Todd M.; Celina, Mathias C.; Assink, Roger A.; Clough, Roger L.; Gillen, Kenneth T.

The γ-irradiated-oxidation of pentacontane (C50H102) and the polymer polyisoprene was investigated as a function of oxidation level using 17O nuclear magnetic resonance (NMR) spectroscopy. It is demonstrated that by using 17O labeled O2 gas during the γ-irradiation process, details about the oxidative degradation mechanisms can be directly obtained from the analysis of the 17O NMR spectra. Production of carboxylic acids is the primary oxygen-containing functionality during the oxidation of pentacontane, while ethers and alcohols are the dominant oxidation product observed for polyisoprene. The formation of ester species during the oxidation process is very minor for both materials, with water also being produced in significant amounts during the radiolytic oxidation of polyisoprene. The ability to focus on the oxidative component of the degradation process using 17O NMR spectroscopy demonstrates the selectivity of this technique over more conventional approaches. © 2001 Elsevier Science Ltd.