Bio-lubricants from vegetable oils: Characterization, modifications, applications and challenges – Review

One of the biggest utilization of oils in the world is in the field of lubricants. Over the past 20 years, bio-based lubricating oils have been proven to be competent with traditional petroleum-based oils. Numerous reasons, including stringent government regulations and policy implications, on fuels and lubricants being derived from petroleum and the fast depletion of oil reserves, have contributed to this trend. The need for bio-lubricants has increased due to the harmful and negative effects caused by using petroleum oils on the ecological and environmental aspects. Due to several intrinsic technical characteristics and their capacity for biodegradation, vegetable oils offer powerful alternatives to petroleum-based oils, to function as lubricant base oils. Physico-chemical modifications of vegetable oils to generate substitutes for mineral oils are one of the most significant expanding industrial research disciplines at the moment. Due to their improved multifunctional capabilities and biodegradability compared to conventional enhancers, sustainable additives have recently gained particular interest. Periodic updating of the swift changes in the field of bio-lubricants is highly essential for all the researchers in this area for investigating the hitherto unexplored aspects of different vegetable oils, as base fluids, and of a spectrum of compatible additives. Accordingly, an overview of the charm of bio-lubricants, including the possible modifications, characterization, applications and challenges has been highlighted in this article. Various types of chemical modification techniques aimed at enhancing the bio-lubricant grade and the protocols for assessing their biodegradability have also been discussed.