A Review on the Science and Technology of Natural and Synthetic Biolubricants

Abstract

Bio-based lubricants have gained prominence over conventional petroleum-based oils, progressively over the last two decades as biolubricants. This trend is observed in almost every industry that has been dependent on lubricants and oils irrespective of their applications. Factors that initiated and fueled this trend vary from stringent government regulations over petroleum-based oils to the high passed depletion of oil reserves. But the most concerning factor that has fast-tracked the need for biolubricants is the toxic and harmful effect of used petroleum oils has on the environment and ecological factors. It is estimated that nearly 50% of all lubricants produced are introduced to the environment which has spurred the interest in biolubricants. This review discusses various types of eco-friendly bio-lubrications that will become a sustainable and economical alternative to the conventional petroleum-based lubricants by being sourced from renewable resources. Biolubricants are seen to be feasible and versatile lubricants with higher lubricity, lower volatility, higher shear stability, higher viscosity index, higher load-carrying capacity, and superior detergency and dispersancy when compared to petroleum-based lubricants. The review also investigates in detail the poor thermal-oxidative stability, biological deterioration, their poor solidification at low temperatures, and hydrolytic instability as well as mechanical and chemical enhancements that seek to rectify these issues. Furthermore, economical and legislative landscape of biolubricants is discussed.