Oxidative stability and antiwear properties of high oleic vegetable oils

Environmental concerns resulted in the utilization of vegetable oils as a possible replacement of mineral oil basestocks. Their low oxidative stability is often a major concern. Data from the Klaus Penn State microreactor test on steel surfaces at 225°C demonstrate that uninhibited high oleic vegetable oils are much poorer in oxidative stability than neat mineral oils. Nevertheless, they show an advantage of low volatility. The possibility to dramatically inhibit deposit formation in high oleic sunflower oil using 1 % wt. of proprietary antioxidant is demonstrated, resulting in oxidative stability comparable to 10W30 SG-grade commercial crankcase lubricant. Addition of ZDDP reduces the effect of the antioxidant but greatly improves antiwear properties of the fluid, as demonstrated by the four-ball wear test. Neat high oleic sunflower oil shows better lubricity than neat mineral oil and its formulation with the antioxidant and ZDDP is superior to commercial crankcase lubricant in antiwear properties.