Wpływ modyfikacji radiacyjnej elektronami na deformację plastyczną, właściwości mechaniczne oraz zużycie polietylenu GUR 1050, stosowanego na panewki endoprotez

Abstract

The resistance of polyethylene to wear and permanent deformation influences the durability of polymer-metal kinematic systems. The recently introduced polyethylene, GUR 1050, of a molecular weight of 9.2 * 106 g/mole is intended especially for medical implants. This justifies the need for evaluating the resistance of this material to wear and deformation and for determining if its functional properties can be improved by radiation modification. Samples of the initial (base) polymer were electron-irradiated with applying an irradiation multiplication factor I = 1–6 and a dose of 26 kGy. An analysis of changes in the deformation value under the influence of operational loads has shown an increase in the polyethylene resistance to permanent deformation as a result of the irradiation applied. The improvement of mechanical properties has been confirmed in micro-indentation tests. An increase in the hardness and Young's modulus was identified. This effect has been preserved despite an opposite trend that causes a growing level of plastic deformation of the polymer under the influence of load. Tribological tests have shown a significant increase (by ca. 4 times) in the resistance to abrasive wear of the polyethylene modified through irradiation. The significant wear reduction prognosticates a longer life of the friction couple, which will prolong the durability of acetabular cups in the human organism. The test results presented in the paper prove the effectiveness of modification through irradiation that enhances the tested functional properties proportionally to the applied dose of electron irradiation.