Effect of bovine serum albumin on the lubricant properties of rice bran oil: a biomimetic approach

The carcinogenic effects and poor biodegradability of petroleum-based oils have pressurized the industry to develop eco-friendly lubricants. Nowadays vegetable oils are used as a potential base stock for industrial lubricants because of their excellent lubricating properties. Among the vegetable oils, rice bran oil is considered for this work due to its excellent frictional properties but the wear scar diameter generated was not comparable with that of industrial lubricants. These problems can be effectively solved by using suitable additives. Most of the commercially used additives are toxic and non-degradable. This research work focused to experimentally investigate the effect of bovine serum albumin (BSA) as a bio-molecular additive on the lubricant properties of rice bran oil (RBO). The lubrication mechanism of oil with bio-molecular protein additives is through the formation of an oil-protein layer between the surfaces, in which hydrophobic aggregates of the proteins adhere to the bounding surfaces and forms a secondary layer to improve the frictional and wear characteristics. The tribological, Physico-chemical, oxidation stability, and thermal properties of the modified rice bran oil were evaluated and compared with that of the base oil. The performance evaluation of the green cutting fluid formulated using modified RBO was also conducted and compared with that of the commercially available cutting fluid. The results obtained have indicated that the formulated oil-protein combination can be a potential base stock for bio-lubricants and bio-cutting fluids.