SOME STUDIES ON SYNTHESIS AND TRIBOLOGICAL PROPERTIES OF BIOLUBRICANT DERIVED FROM CASTOR OIL

Abstract

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. Due to above mentioned reasons and an increased awareness of people about the adverse effects of mineral lubricants on the environment and an ever increasing demand for cleaner and healthier environment has led the government to make very high order strict regulations for mineral lubricants. Due to this, there is an amplified demand for environment friendly lubricants more over in areas where there are chances of interaction between lubricants and water, food or people. Thus, over the past few years vegetable oil lubricants has come out as a potential substitute to the lubricants derived from mineral oils and they are currently being exhaustively researched by scientists Lubricants derived from vegetable oils are extremely eye-catching auxiliary to the lubricants derived from mineral oil as these are completely environment friendly, renewable in nature, not-hazardous and fully naturally degradable. Lubricants derived from vegetable oils are chosen not only because of renewable nature but also because of the fact that they possess great lubricating characteristics like high VI, higher flash-point, lower volatility, great contact lubricating capacity and good solvency with other liquid additives. However, a high degree of multiple C–C unsaturations 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 bio-degradable lubricants simple esterification reaction was carried out between raw castor oil (RCO) and methanol to form castor oil methyl ester (COME).Also raw castor oil (RCO) was chemically modified via epoxidation to vi formulate chemically modified castor oil (CMCO) to increase oxidative stability of castor oil. Apart from this, as part of another formulation castor oil was thermally modified to form thermally modified castor oil (TMCO 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 lubricant SAE 20W40.The castor oil based formulations showed promising properties to justify themselves to be an excellent substitute to conventional SAE 20W40 oil.