LAUSR

Abstract The yearly emissions of synthetic oil to the watercourses alarmingly affect the living organisms in the water bodies, lands and affects the entire earth as a harmful pollutant. Oils from the vegetables/seeds are nowadays preferred as base lubricating oil over synthetic oils because of their less toxicity, biodegradability and renewability. Among the agricultural seed oils, sesame oil is one of the major oil produced around the globe and in this work, it is selected because of its variety of advantages reported in various literature and its similar physical properties as that of base polyolester oil. Seven blends were made using sesame oil and polyolester oil and their thermal, rheological, physiochemical, oxidative, corrosive, tribological, foaming, contact angle and ecological properties are studied and compared with that of base oil. The fatty acid profile of oils is found out using GCMS technique. The thermal properties, viscosity and viscosity index, are found to be increasing with the increase in the proportion of sesame oil in the blend. The foaming tendency of all blended lubricants is found to be less than the polyolester oil. The CoF and WSR of the 15POE+25SESO blend are the least when compared to other blends and the base polyolester oil, whereas the contact angle/wettability is found higher for 20POE+20SESO blend. Up to 100μg per ml of water of 15POE+25SESO blend is found to be least toxic to the microorganisms and all the blends were biodegradable as the proportion of sesame oil in the blend increased. Hence as a lubricant, 15POE+25SESO blend is the best alternative for conventional POE oil in terms of thermal, rheological, oxidative, nature-friendly, foaming, wettability and tribological properties in a refrigerant compressor.