Pathak, V., Gupta, D., and Kumar, N., "Studying Synthesis of Thermally and Chemically Modified Plant Oil and their Tribological Evaluation for Use as a Base Stock for Environmentally Friendly Bio-Lubricant," SAE Technical Paper 2014-01-1477, 2014, doi:10.4271/2014-01-1477.
The world today is facing severe oil crisis and environmental pollution, thus there is a great urgency of developing and applying bio based products as a substitute to mineral oil based products. Rapid industrialization and automation in the last decade has increased the demand of mineral oil based lubricant that will get exhausted in the years to come. Also in addition to the above fact, the biodegradability of mineral-oil based lubricants is around 25% maximum. About 50% of all lubricants sold worldwide end up in the Environment. Due to extensive use of mineral oil based lubricants, several environmental issues such as surface water and groundwater contamination, Air pollution, soil contamination, agricultural product and food contamination are emerging very rapidly. This has led the researchers to look for plant oil based bio- lubricant as an alternative to mineral oil based lubricant. Vegetable oils are renewable raw materials that possess certain excellent frictional properties e.g. good lubricity, low volatility, high viscosity index, solvency for lubricant additives, and easy miscibility with other fluids etc. However, a high degree of multiple C-C unsaturation in the fatty acid (FA) chain of vegetable oils causes poor thermal and oxidative stability. This fact confines their use as lubricants to a modest range of temperature. In the current work for formulation of biodegradable lubricants simple esterification reaction was carried out between crude orange peel oil (OPO) and higher alcohols (butanol and octanol) to form orange peel oil butyl ester (OPOBE) and orange peel oil octyl ester (OPOOE).Also orange peel oil (OPO) was chemically modified via epoxidation to formulate chemically modified orange peel oil (CMOPO) to increase oxidative stability of orange peel oil. Also to these formulations bio-additive packages were added to improve some of the properties. Finally all the formulated bio-lubricants were subjected to various tribological tests viz. evaporative loss, viscosity index, iodine value, pour point, oxidation stability and four ball wear test. Results were analyzed and compared with conventional synthetic lubricant SAE 20W40.The plant oil based formulations showed promising properties to justify themselves to be an excellent substitute to conventional SAE 20W40 oil.