Friction Analysis between Uhmwpe, Alumina - Magnesia Ceramic and Pva Hydrogel, Biomaterials for Prosthetic Devices

This paper presents experimental analysis of the phenomenon of friction that occurs between two surfaces, one of polyethylene and other ceramics. Alumina ceramic is being recognized like a good biomaterial for its high strength and toughness. This ceramic, is used to manufacture the femoral head for arthroplasty of the hip joint in association with an ultra-high-molecular-weight polyethylene (uhmwpe) socket. Wear-resistant properties of uhmwpe were screened on two principally wear devices: first made by polyethylene – alumina-magnesia ceramic and the second by polyethylene – alumina-magnesia ceramic covered with polyvinyl alcohol (pva) layer. Sterile physiological saline is chosen as the lubricant fluid media. After hydration the pva layer provide lubricant properties. Depending on the lubricant medium, the friction coefficient (cof) of polyethylene and alumina-magnesia ceramic-pva counterfaces was about 0.38 (24 times low that polyethylene and alumina-magnesia ceramic counterfaces). Polyethylene friction coefficient in contact with alumina-magnesia ceramic was more susceptible in saline solution in which was about 0.46 compared with 0.016 on alumina-magnesia ceramic-pva. On the other hand, fluid environment shows a strong effect on polyethylene wear in contact with ceramic surfaces, increasing friction coefficient by ceramic hydration. The wear particles obtained in dried conditions are aglomerated and well individualized compared with lubricated conditions which are poorly individualized and with fine structure.