Sustainable Lubrication Solutions: Rheological and Tribological Analysis of ZDDP-Enhanced Castor and Cashew Nut Shell Oil Biogenic Greases

Bio-greases offer a more sustainable alternative to synthetic-based greases, mitigating ecological harm while ensuring effective lubrication in environmentally sensitive applications. This study examines the formulation and performance of bio-greases derived from renewable resources, such as vegetable oils and biogenic thickeners. It underscores their advantages over conventional petroleum-based lubricants, particularly in terms of biodegradability and non-toxicity. A novel blend of Cashew Nut Shell Oil (CNSO), combined with fumed silica as a thickener and ZDDP as an additive, was investigated to enhance wear resistance, biodegradability, and other lubricating properties. This study highlights the significance of thickener consistency in converting liquid base oils into semi-solid greases, which is essential for effective lubrication. Various assessments, including extreme pressure and tribological analyses, demonstrate that the bio-grease samples exhibit non-Newtonian shear-thinning behavior, with performance metrics suggesting potential applications in food processing and agriculture. The results indicate that the addition of additives such as ZDDP can considerably enhance the lubricating properties and decrease the coefficient of friction (COF) in bio-greases.