title: Electron beam radiation effects on UHMWPE: an EPR study.
abstract: Electron paramagnetic resonance (EPR) technique has been employed to detect and characterise a series of different radical species generated in ultra-high molecular weight polyethylene (UHMWPE) via electron beam irradiation. Three different radical species have been found and assigned on the basis of their EPR spectra and of the related computer simulations. A secondary alkyl species, the prevalent one, is present immediately after irradiation, an allyl species appears only 24 h after irradiation when the alkyl species disappears.The third species, clearly visible at high microwave power only, has been observed for the first time and assigned to a tertiary alkyl carbon radical, whose formation is strictly connected with a Y-shape crosslink and a migration of the unpaired electron on a carbon atom localised in an adjacent position.
authors.affiliation: Dipartimento di Chimica IFM and NIS Centre of Excellence, via Giuria 7, 10125 Torino, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Brunella
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Paganini
mesh_terms: D055984:Cathode Ray Tube; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D005609:Free Radicals / Q000737:chemistry*; D008872:Microwaves; D011095:Polyethylenes / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene