Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/8/2003
Publication Date: 3/27/2003
Citation: BIRESAW, G., ADHARYU, A., ERHAN, S.Z. FRICTION PROPERTIES OF VEGETABLE OILS. JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY. 2003. v. 80. p. 697-704. Interpretive Summary: Currently there is an overabundance of vegetable oils that have suppressed prices of oil-bearing crops and the incomes of farmers that grow these crops. One way of overcoming this oversupply is through the development of new uses for vegetable oils. Of particular interest are products currently dominated by petroleum-based oils. Lubricants are one such product that offer a growing new market for vegetable oils. Vegetable oils have several attractive features over petroleum-based oils in lubricant applications. Unlike petroleum-based oils, vegetable oils are renewable, abundantly available, environmentally friendly, and non-toxic. However, widespread application of vegetable oils in lubrication requires overcoming a number of performance hurdles. The work described here deals with the investigation of the friction and adsorption properties of vegetable oils in steel/steel contact. Results from such studies are of great interest to researcher and development personnel engaged in formulating various types of lubricants from vegetable oils.
Technical Abstract: Vegetable oils are renewable and environmentally friendly alternative to petroleum-based oils in lubrication and other important application areas. Vegetable oils comprise a mixture of compounds that fall into two broad chemical categories: triesters (or triglycerides) and monoesters. Most vegetable oils are triesters of glycerol with fatty acids, whose characteristics are dependent on the chemistry and composition of the fatty acid residues. A small percentage of vegetable oils are monoesters of long chain fatty acids and fatty alcohols of varying chemistries. In this work, the free energy of adsorption (deltaGads) of safflower (SA), high oleic safflower (HOSA), jojoba (JO), methyl oleate (MO) and methyl palmitate (MP) on steel were investigated. SA and HOSA are triglycerides of vegetable oils with fatty acid residues of radically different degrees of unsaturation. JO is a monoester vegetable oil. DeltaGads is one of the major factors affecting the boundary friction properties of lubricant ingredients. DeltaGads was found to increase in the order: HOSA = SA < JO < MO = MP. The results are consistent with the degree of functionality and other chemical properties of the oils studied.