Evaluation of Tribological Properties of UHMW-PE Composite Coatings Reinforced with Crumb Rubber Particles

Ultra-High molecular weight polyethylene (UHMW-PE) coatings have been gaining ground in various tribological applications because of their ease of deposition, outstanding wear resistance and low coefficient of friction. To further strengthen these properties, different types of micro/nanofillers such as carbon nanotubes, nanoclay, graphene oxide, alumina either individually (composite) or in combination (hybrid composite) are being added. As a result, these developed composite/hybrid composite coatings present with better mechanical and tribological properties including improved wear resistance and low coefficient of friction. In the current study, vastly found new low-cost fillers, namely, crumb rubber (CR) particles, which constitute majority of polymeric waste, are being explored as a reinforcement. UHMW-PE composite coatings reinforced with different loadings (5, 10 and 15 wt%) of CR were deposited on mild steel coupons using the electrostatic spray coating technique. These coatings’ mechanical and tribological properties were assessed using microhardness testing and ball on disk sliding wear tests, respectively. Results showed that, the composite coating reinforced with 10 wt% CR was able to sustain a considerably high load of 15 N, which was higher than the load bearing capacity of other similar UHMWPE coatings in the literature filled with a variety of fillers (12 N). The improvement in the performance of the coating is attributed to the excellent mechanical properties with a 94% increase in hardness, a 86% increase in the elastic modulus leading to higher H/E and H³/E² parameters, coupled with the uniform dispersion of CR particles within the UHMWPE matrix.