Comparative Analysis of the Influence of Nano- and Microfillers of Oxidized Al on the Frictional-Mechanical Characteristics of UHMWPE

The influence of nano- and microfillers, including nanofibers and powder of Al₂O₃ and aluminum oxyhydrides AlO(OH) on the mechanical and tribological characteristics of ultrahigh-molecular-weight polyethylene (UHMWPE) is studied. It is found that modification of UHMWPE with nanofibers of Al₂O₃ within 0.1-0.5 wt % ensures a considerable increase in its hardness and multifold increase in its wear resistance. Modification with ultradisperse powders of Al₂O₃ (200-500 nm) in the same amounts has an insignificant effect on the polymer characteristics. Filling of UHMWPE with micron-sized particles (3-50 μm) in amounts of 20 wt % results in increased wear resistance of the original polymer, comparable with the wear resistance at low nanofiber content. X-ray diffraction analysis, IR spectroscopy, and electron microscopy are used to show that incorporation of Al₂O₃ nanofibers into UHMWPE results in the formation of a fundamentally different supermolecular structure in comparison with the use of microfillers.