Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/7/2002
Publication Date: 3/1/2002
Citation: BIRESAW, G., ERHAN, S.M. SOLID LUBRICANT FORMULATIONS CONTAINING STARCH-SOYBEAN OIL COMPOSITES. JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY. 2002. v. 79. p. 291-296. Interpretive Summary: Development of products that lead to new uses for agricultural commodities is an important area of research. New uses and markets are needed to address the current slump in agricultural commodity prices. One method of obtaining new ag-based products is by replacement of petroleum-based materials with materials from agricultural commodities such as corn and soybeans. Successful replacement will open new value-added markets for agricultural commodities and lessen the United States' dependence on foreign oil. One area of application that is almost completely dominated by petroleum-based materials is in lubrication. Lubricants present a major new market for ag-based products. In the work reported herein, a starch-oil composite was formulated into a solid lubricant for use in sheet metal forming. Lab tests on various formulations of starch-oil solid lubricants showed that these ag-based formulations have the necessary friction and wear characteristics to proceed to the next phase of evaluation. The ag-based formulations also have the additional benefit of being environmentally friendly and non-toxic to users.
Technical Abstract: Starch-oil composites comprising purified food grade corn starch (PFGS) and soybean oil (SBO) were investigated as potential ingredients for water-based solid lubricant formulations. Current solid lubricants are almost exclusively petroleum-based and are used for protecting sheet metal and/or as lubricants in sheet metal forming processes. Starch-oil composites are preferred ingredients for formulating solid lubricants because they are based on renewable and abundantly available raw materials and also have superior environmental and health characteristics. Solid lubricants were prepared by dispersing the PFGS -SBO composites in aq. sucrose solution and applying onto steel sheets with a doctor blade. The boundary friction and wear properties of the solid lubricant film were evaluated using ball-on-flat test geometry. The coefficient of friction (COF) was found to be highly dependent on the SBO to PFGS ratio of the starch-oil composite. In the absence of SBO, the COF was high (~ 0.8) and decreased sharply with increasing SBO content to a minimum value of 0.07. The wear properties of the solid lubricant were evaluated by a visual inspection of the ball and the steel sheet after each friction test. No scratches or lubricant transfer were observed on the ball. There were also no wear tracks observed on the flat sheet before or after the solid lubricant was washed off. It is concluded that water-based solid lubricants formulated with the FGRS-SBO starch-oil composite have acceptable friction and wear properties and should be evaluated further for their use in sheet metal forming.