Abstract: Ultra-high molecular weight polyethylene （PE-UHMW）/boron nitride （BN） composites were prepared through high-speed ball milling and hot pressing， and their hardness， mechanical properties and tribological properties were investigated. The results indicated that the addition of BN improved the yield strength of the composites but reduced their tensile fracture stress and elongation at break. When the BN loading was 3 wt%， the increasing effect of BN on the yield strength of the composites was most significant， but there was the least effect on the tensile stress and elongation at break. The addition of BN could reduce the friction coefficient of the PE-UHMW matrix significantly， and the friction coefficient of the composites decreased with an increase in the BN content. The composites obtained the most significant effect of BN on the lubricating performance at a loading of 3 wt%， and their friction coefficient decreased by 60% compared to pure PE-UHMW. The lubrication effect decreased at a BN loading of 7 wt%. The addition of no more than 3 wt% BN can improve the surface hardness of PE-UHMW and therefore increases the wear resistance of the composites effectively. However， the surface hardness of the composites decreased with the addition of 7 wt% BN due to an agglomeration effect. As a result， the wear of the composites increased， but their resistance to wear decreased.

Key words: ultra-high molecular weight polyethylene, boron nitride, hardness, tribological behavior, mechanical property