Evaluation of physicochemical, thermal and tribological properties of sesame oil (Sesamum indicum L.): a potential agricultural crop base stock for eco-friendly industrial lubricants

In the past few decades, researchers are striving for the development of safe alternatives to mineral oils which are getting scarce and hazardous to the environment. Oils extracted from agricultural crops are one among the solutions. In the current work, the potentiality of sesame oil (SESO) is tested to use it as an eco-friendly base stock for lubricants. SESO is one of the major agricultural crop oils produced all over the globe. In the current work, the physicochemical, rheological, thermal, oxidative, and tribological properties of SESO are studied and compared with coconut oil (CO), sunflower oil (SUO) and a commercially available mineral oil, SAE 20W40. The fatty acid profiles of vegetable oils are evaluated using Gas Chromatography-Mass Spectrometry (GC-MS) technique. Tribological properties of the oils are assessed using a four-ball tester. Sesame oil is seen to possess excellent thermal and tribological properties. Its viscosity index is high whereas its viscosity range and oxidative stability need to be improved. SESO shows the better coefficient of friction (COF) and its wear scar diameter (WSD) is less compared to other vegetable oils. On further improvement, by adding suitable additives this crop oil base stock can be developed into a competing environmental friendly lubricant.