Oxidation and low temperature stability of vegetable oil-based lubricants

Vegetable oils are promising candidates as base fluid for eco-friendly lubricants because of their excellent lubricity, biodegradability, viscosity-temperature characteristics and low volatility. Their use, however, is restricted due to low thermo-oxidative stability and poor cold flow behavior. This paper presents a systematic approach to improve the oxidation behavior and low temperature fluidity of vegetable oil derivatives. Among the various possible avenues available, the combination of chemical additives, diluent (polyalphaolefin), and high-oleic vegetable oils offer the best option for achieving the ultimate goal. Vegetable oil-based lubricants formulated using the above approach exhibit superior oxidative stability, and improved low temperature properties such as pour points compared to commercially available industrial oils such as bio-based hydraulic fluids. The above vegetable oil-based formulations compare at par with petroleum-based lubricants for use in high-temperature applications and often outperform the competition in some of its properties. (C) 2006 Elsevier B.V. All rights reserved.