Polyethylene Uv Surface Grafting Mpc And Its Performance Study

Ultra-high molecular weight polyethylene (UHMWPE) has been widely used as artificial joint materials. During the long employed period, a great deal of wear debris accumulated and making a series of ill biology reaction, leading to periprosthetic osteolysis and asepsis loosening. So the wear is the primary cause of failure in joint replacement prostheses.In order to meliorate the lubricating ability and biocompatibility, and improve the wear resistance, this study has synthesized a biocompatible monomer, 2-methacryloyloxyethyl phosphorylcholine (MPC), and poly(MPC) was grafted on the surface of polyethylene(PE) pieces by photoinduced polymerization technique. This study also investigates the biocompatibility of PE pieces. The tribological properties of PE pieces, before and after grafted water-soluble polymer, against Al₂O₃ ceramic balls were investigated by sliding friction under distilled water and saline lubrications. The structure of MPC and middle outcomes were characterized by IR. The surface structure of PE pieces before and after grafted with poly(MPC) were measured by ATR-FTIR and XPS. The surface morphologies and the amount of adhesive platelets were observed by SEM. The contact angles between distilled water and PE pieces were measured by goniometer at room temperature. The hemolysis rates of the pure PE and grafted poly(MPC) PE pieces were measured by 722 spectrophotometer.The results shows that, the structure of MPC and middle outcomes are confirmed by IR spectrum; The absorption at 969cm^-1 which corresponds to the phosphate group in ATR-FTIR spectrum and the peaks of P_2p in XPS and the increased concentration of N,O confirmes that the MPC have grafted on the surface. With the prolongation of photopolymerization time, the grafted poly(MPC) amount on the PE surface increases, and the contact angle decreases markedly; Contact angle changes from 64-76°to 15-26°. There is nubby substance on the grafted PE pieces. The hemolysis rate of the grafted PE pieces is lower than that of the blank PE pieces. The amount of platelets adhering to the grafted PE pieces is fewer than that of the pure PE. The results of friction and wear tests shows that the wear resistance of PE improves after grafted with poly(MPC) and the friction coefficient reduces.