Synthesis and Characterisation of Biobased Grease Derived from Chemically Modified Waste Cooking Oil

Abstract As the global population rises, the dependency on edible oils also rises. The used oil possesses environmental concerns due to improper waste oil disposal. This study emphasises the feasibility of repurposing waste cooking oil (WCO) for eco-friendly lubricating grease production, emphasising enhanced stability and performance through chemical modifications. Chemical modifications, primarily transesterification, enhance the oxidative stability and chemical properties of WCO. Gas chromatography and mass spectroscopy analyse the fatty acid profile, and the hot oil oxidation test (HOOT) assesses the oxidative characteristics of WCO. The formulated grease using WCO undergoes tribological testing and penetration value testing. Results indicate post-transesterification improvements in chemical and oxidative stability, with lowered acid and peroxide values. Modified waste cooking oil (MWCO) exhibits enhanced thermal stability with higher flash and fire points. Viscosity results suggest the potential of MWCO as a lubricant with superior oxidative stability. Tribological properties reveal an improved characteristic value for MWCO, establishing its potential as an eco-friendly grease. Cone penetration tests categorise the formulated grease as NLGI grade 2, indicating a softer consistency with potential advantages for specific applications. The findings offer insights into the sustainable development of the lubricant industry, presenting MWCO as a promising alternative to conventional lubricants.