Electron spin resonance study of oxidation in X-irradiated poly(ester urethane) containing nitroplasticizer


The effect of oxidation on X-irradiated Estane®5703 containing nitroplasticizer (NP) has been examined by electron spin resonance (ESR) spectroscopy, and the results are compared to similar data previously obtained on pristine Estane®5703. Although both specimens exhibit similar spectra immediately following X-irradiation, their decay upon exposure to air is quite different. The free radical concentration of the pristine specimen continuously decreases with time whereas the NP sample exhibits an initial decrease followed by a significant increase due to the growth of a newly-formed radical. Terminal species of the pristine and NP-Estane®5703 samples are identified as peroxy and nitroxide radicals, respectively. Hyperfine coupling constants and g-values are extracted for the nitroxide radical and a tentative model is proposed to explain the reaction pathway leading to its production. © 2001 Elsevier Science B.V. All rights reserved.

Publication Title

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms