Tribological Characterization of UHMWPE Composites Reinforced with MoS2 and Graphite: A Comparative Study

Abstract

This study presents a comprehensive analysis of the microstructural, physical and tribological properties of Ultra-High Molecular Weight Polyethylene (UHMWPE) composites reinforced with micro MoS2 and nano Graphite. Microstructural evaluations through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX) reveal intriguing insights into the morphology and elemental composition of the reinforcement materials. SEM images unveil the nanoscale hexagonal lattice structure of nano graphite, affirming its suitability for composite applications. EDAX spectra confirm the purity of both nano graphite and micro MoS2, reinforcing their efficacy as reinforcement agents.Density assessments illustrate an increase in composite density with rising reinforcement percentages for both materials, attributed to their inherently higher densities. This increase in density is complemented by reduced porosity, signifying improved packing efficiency within the composite.Wear evaluations under various load and speed conditions elucidate the tribological behaviour of the composites. UHMWPE composites with micro MoS2 exhibit reduced wear rates, frictional forces, and coefficient of friction (COF) compared to neat UHMWPE, emphasizing the effective lubricating properties of MoS2. Conversely, UHMWPE composites with nano graphite outperform micro MoS2 counterparts across all parameters, showcasing superior wear resistance and friction reduction. This is attributed to nano graphite's lamellar structure, which facilitates enhanced lubrication and reduced friction.