Organic-inorganic core-shell materials as reinforced fillers of UHMWPE to improve its tribological and mechanical properties

Generally, modification of materials by adding multiple types of nano particles could cause dispersion problems, generally limited the performance improvement effect. Herein, we report the modification of UHMWPE materials by organic-inorganic core-shell particles with PTFE as the core and Al(OH)3 as the shell, which prepared by in-situ polymerization of sodium bicarbonate and aluminum sulfate solution. Core-shell particles were filled in UHMWPE matrix and sintered into composite by spark plasma sintering (SPS). The mechanical and tribological properties of the composites were characterized by tensile compression testing machine, universal micro tribometer (UMT-5), three-dimensional white light interferometer and scanning electron microscope (SEM). The results showed that the addition of core-shell structural materials effectively improved the tribological properties (friction coefficient decreased by 40%, wear rate decreased by 30%) and mechanical properties (compression strength increased by 2.4 times) of the composites. It was demonstrated that the inorganic framework provided strength to improve the mechanical properties and wear resistance of materials, and the organic phase was used as a lubricating phase to reduce the friction coefficient of materials. Surface treatment of core-shell particles both improved the binding between particles and matrix and decreased the formation of agglomerations, thus significantly reducing ploughing phenomena's effect produced by abrasive wear of agglomeration