The Role of Wax Origin in Modifying Ultra-High Molecular Weight Polyethylene: Structure and Properties

This study reveals previously unexplored effects of emulsion wax and beeswax on the structural and performance characteristics of ultra-high molecular weight polyethylene (UHMWPE). It was found that composites filled with beeswax UHMWPE-composites exhibit a 50% increase in tensile strength, a 45% increase in relative elongation, a 58% increase in compressive strength, and a 6-fold improvement in wear resistance relative to the origin polymer. In contrast, emulsion wax reduces the coefficient of friction by 57% compared to the initial polymer. The study also evaluated the influence of these waxes on the polymer structure formation during processing. It was demonstrated that the incorporation of both waxes promotes the formation of spherulite-like structures, indicating enhanced mobility of polymer macromolecules during hot pressing due to the plasticizing effect of the waxes and the facilitation of orientation processes. When emulsion wax was added, the formation of elongated fibrils was observed, suggesting polymer plasticization. The addition of wax was found to reduce the extent of tribochemical processes and inhibit tribooxidation of the polymer, which is attributed to the lubrication of adjacent surfaces by the wax in the friction zone. The novelty of this work lies in the application of waxes of varying origin as modifiers for UHMWPE, where beeswax enhances strength, elasticity, and wear resistance, while emulsion wax significantly reduces the coefficient of friction of coefficient.