Analysis of lubrication properties of zinc-dialkyl-dithio-phosphate (ZDDP) additive on Karanja oil (Pongamia pinnatta) as a green lubricant

Environmental pollution is a major concern when petroleum based lubricants are used in industries [1]. The effluents produced and their subsequent disposal cause severe environmental hazards especially in the hydraulic, mining, agriculture and petrochemical industries. The mineral based oils cannot be used in food industry because of their toxic nature [2]. Vegetable oils with high oleic acid content are the preferred substitute for mineral oils in industries. Vegetable oils are preferred to synthetic fluids because they are renewable, economic and eco-friendly [3]. Furthermore, vegetable oil lubricants are biodegradable and non-toxic unlike conventional mineral based oils. They have low volatility due to high molecular weight of the triacylglycerol molecule and have a narrow range of viscosity changes with temperature i.e. they have high value of viscosity