Magnetic resonance studies on cross-links produced in irradiated n-Eicosane as a model compound of polyethylene

Abstract

Normal (n)-eicosane was taken as a model compound for polyethylene. ESR combined with the spin-trap method was applied to study the radiation effect of α and neutron beams on the eicosane. Three kinds of radicals, two cross-linked radicals and one precursor radical for cross-linking, were identified by ESR. A difference was found in the molecular mobility between the effects of the α and neutron irradiations. Three kinds of cross-linked eicosane molecules (dimers) were found by ¹³C-NMR and FI-mass spectroscopy; one is a saturated dimer, the others are two kinds of nonsaturated dimers; one with one double bond, the other with two double bonds. It was concluded from ¹³C-NMR that a majority of the cross-linked eicosane was of the H-type, in which a cross-link is formed in the central part of the molecules.