STUDY OF THE RADICAL SPECIES INDUCED BY ELECTRON-BEAM IRRADIATION IN VACUUM ON BIOMEDICAL UHMWPE

Ultra high molecular weight polyethylene (UHMWPE) is a component of mobile prostheses. The irradiation performed to sterilize and cross-link the polymer limits its life because of the free radicals originated during this process. In this work, a UHMWPE was electron-beam irradiated under high vacuum and annealed. Mechanical tests were performed on the UHMWPE samples before and after the annealing treatment. The results were compared with a study of radical species type and amount and the crystalline degree changes. Experimental results show that the annealing treatment prevents degrading reactions, favors intermolecular and/or intramolecular chemical rearrangements, and improves wear resistance without compromising the typical elasto-plastic mechanical behavior.