The effect of spin-trapping agent on electron spin resonance spectra of spin labelled polyethylene

Abstract

The spectra of chain-end spin labels on the surface of polyethylene powder were measured for two different spin trapping agents, nitrosobenzene (NB) and N-tert-butyl-α-phenylnitrone (PBN). The influence of the spin-trapping agent on the line shape of the electron spin resonance (ESR) spectra, the extreme separation, and the rotational correlation time was investigated. As the temperature was raised, the ESR spectra of spin-trapped radicals become narrow, and finally at a temperature near the melting point of the polymer, the triplets approached isotropic spectra. In the case of PBN trapped radicals, there was a sub-splitting which started to appear at about 204 K. In contrast to this, no sub-splitting could be observed clearly with NB trapped radicals. Assuming a two-phase model (a more mobile phase and a less mobile phase) for the host polymer, we simulated the ESR spectra and compared them with the experimental results. © 1981 The Society of Polymer Science, Japan.