INFLUENCE OF DIHYDROQUERCETIN ON FRICTION OF SUPER-HIGH-MOLECULAR POLYETHYLENE BY STEEL AND ALLOY Ti6Al

Abstract

The main reasons reducing the lifetime and failure of implants are tribo-oxidative processes. Stabilizing additives are used to inhibit tribo-oxidative activity and increase the lifetime of the implant. The most common stabilizer is α-tocopherol. The biocompatible stabilizer of a number of flavonoids, dihydroquercetin, was selected as the thermo- and tribo-oxidative stabilizer of UHMWPE. Dihydroquercetin (DHQ) stabilizes peroxide radicals formed as a result of the tribological process (friction of UHMWPE) by detaching a hydrogen atom from OH groups with the formation of a non-reactive phenoxyl radical. A comparative analysis of the samples, stabilized with DHQ and α-tocopherol, was carried out. The samples studied were prepared by direct compression molding at a temperature of 190ºС. The comparative study of thermo- and tribo-oxidative stability of UHMWPE samples modified with DHQ and α-tocopherol evidences that the thermo-oxidative stability induced with DHQ is higher that of α-tocopherol. In the first case the thermal-oxidative stability of the composition is maintained up to a temperature of 230 °C. Evolution of friction compositions at temperatures higher than that of the human body was investigated. Such tests were conducted using a gradual increase in friction velocity. During the tests, an increase in weight of initial UHMWPE and the composition with α-tocopherol induced by tribo-oxidative processes was observed. The introduction of dihydroquercetin, a highly effective biostabilizer of thermal oxidation, leads to the conservation of the original weight of the samples. When selecting a counterbody for the developed composition with DHQ, a study was conducted of friction on steel 3X13 and Ti6Al alloy used in medicine and in endoprostheses of artificial joints. It was found that the best results are obtained in the case of using a steel counterbody.