Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 12/15/2004
Publication Date: 3/15/2005
Citation: Erhan, S.Z., Sharma, B.K., Adhvaryu, A. 2005. Tribochemical and oxidative properties of soy-lithium grease. American Chemical Society Abstracts. p. 140.
Technical Abstract: A significant amount of lubricating oils and greases can enter the environment producing contamination of both soil and water. Biodegradable and non-toxic products such as vegetable oil based greases, hydraulic oils and gear oils are recommended for use in environmentally sensitive areas where small amounts of leakage are inevitable. Vegetable oil is a potential replacement for mineral oil as a base fluid for making grease. The advantages of using biobased greases are their eco-friendly and non-toxic nature. This paper presents the development and tribochemical evaluation of soy oil-based lithium grease using a variety of fatty acid components to obtain the thickener (metal soap) structure. It has been observed that the physical and chemical properties of grease are largely based on the soap thickener fiber micro-structure. A transmission electron microscope methodology was developed to study the nature and structure of soap dispersoid in a grease matrix. Ball-on-disk geometry was used to study the friction and wear properties, while thin film microoxidation and the rotary bomb oxidation test were used for oxidative properties. It has been observed that the lubricity of greases decrease with more unsaturation in FA chains of soap molecules and decrease in unsaturation in FA chains of soap molecules results in increased volatile loss as a result of oxidative degradation of greases.