Research On Tribological Properties Of PMMA Based Composites Filled By UHMWPE

In recent years,injury of human joint has become a common problem affecting the health and quality of life of middle-aged and elderly people,and the artificial joint replacement is the only effective way to cure severe joint damage and necrosis in the late stage.When artificial joints are used in the human body for a long time,the wear debris generated by wear may cause osteolysis that may result in joint failure,which will lead to joint wear more seriously.Therefore,it is one of the most important affairs to focus on finding artificial joint materials with excellent performance in biotribology for the moment.Poly(methyl methacrylate)(PMMA)is used as "bone cement" in the field of biomedicine due to its excellent mechanical properties and biocompatibility,and ultra-high molecular weight polyethylene(UHMWPE)is widely used as a material for the acetabulum of artificial joints because of its good self-lubricating properties and outstanding wear resistance.Combining the advantages of both PMMA and UHMWPE,it is of great practical significance for the development of new artificial joint materials to prepare UHMWPE/PMMA composites and explore its biotribological properties.In this paper,UHMWPE filled PMMA based composites were prepared by the method that self-curing at the room temperature,and the composition and thermodynamic properties of the UHMWPE/PMMA composites were analyzed with the help of Fourier Transform Infrared Spectroscopy,Thermogravimetry and Scanning Electron Microscopy.The ball-on-disk tribometer and conscan confocal optical profilometer were used to study the effects of the filling mass ratio of UHMWPE,heat treatment processes and working conditions on the tribological performances and mechanisms of composites under dry friction conditions,also this paper explored the effects of different kinds of lubricating liquids,soaking time etc under water solution of calf serum on biotribological performance of the UHMWPE/PMMA composites.Under dry friction conditions,filling UHMWPE can significantly reduce the friction coefficients and wear rates of PMMA;when the UHMWPE filling mass ratio is 20wt%,the UHMWPE/PMMA composites show better tribological properties.After heat treatment the friction coefficients and wear rates of UHMWPE/PMMA composites are obviously lower than the unheated composites.On the whole,when the molding temperature 110 ?,the molding pressure 15 MPa and the holding time 15 min,the composites have the best tribological performance.The friction coefficients and wear rates of UHMWPE/PMMA composites both increase with the increasing of load,and the friction coefficients decrease but the wear rates increase as the sliding velocity goes up.Under lubricating liquids,UHMWPE/PMMA composites have the lowest friction coefficients and wear rates in sodium hyaluronate solution.Compared with under the lubrication of deionized water,the friction coefficients of the UHMWPE/PMMA composites under the calf serum solution are higher,and the wear rates are lower.The wear resistance of UHMWPE/PMMA composites drops with the prolonging of immersion time in calf serum solution.Under the calf serum lubrication,the friction coefficients of UHMWPE/PMMA composites display the tendency declining at the begining and rising up in late with the load showing an upward trend,and the wear rates increase all the way;with the increasing of the sliding velocity,the friction coefficients and the wear rates are both gradually decrease.