Solid lubricant formulations containing starch‐soybean oil composites

Abstract

Starch-oil composites comprising purified foodgrade corn starch (PFGS) and soybean oil (SBO) were investigated as potential ingredients for water-based solid lubricant formulations. Current solid lubricants are almost exclusively petroleumbased and are used for protecting sheet metal and/or as sheet metal forming lubricants. 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. Steel sheets coated with the PFGS-SBO containing solid lubricant were evaluated for boundary coefficient of friction (COF) and wear properties using ball-on-flat test geometry. The COF was highly dependent on the SBO to PFGS ratio in the 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. Wear evaluation showed no scratches or lubricant transfer on the ball. There were also no wear tracks observed on the flat sheet before or after the solid lubricant was washed off. It was concluded that waterbased solid lubricants formulated with the PFGS-SBO starch-oil composite have acceptable friction and wear properties and should be evaluated further for use in sheet metal forming. SOLID LUBRICANT FORMATIONS WITH STARCH-SOYBEAN OIL COMPOSITES 293 JAOCS, Vol. 79, no. 3 (2002) FIG. 1. Typical run time vs. friction force data of a solid lubricant obtained on a ball-on-flat friction tester.

Renewable feedstocks for lubricant production

“…As a consequence of a large surplus over the demand for starch-bearing crops, which has depressed the price of starch-producing agricultural products and, hence, the income of farmers growing such crops, there has been a considerable effort at developing new starch-based products [387,388]. Non-food applications of starch that lately have been investigated include biodegradable polymers [389], composites [390], elastomers [391] and lubricants [392]. USDA has developed a starch-based product called Fantesk TM that has opened up new applications for starch-based products in food and non-food industries [393,394].…”

Recent Processing Methods for Preparing Starch‐based Bioproducts

“…Non-food applications demonstrating the efficacy of oil delivery in aqueous starch-based media included biodegradable polyurethane foams (Cunningham et al ., 1997 ), lubricants for water-based oil drilling muds (Fanta et al ., 2002a ;Sifferman et al ., 2003 ) and lubricants for metal working (Biresaw, 2004 ;Biresaw and Erhan, 2002 ;Biresaw et al ., 2007 ;Kenar et al ., 2009 ). The jet-cooked starch-oil technology was also used to deliver a soybean oil-based UV absorbing agent to provide UV protection in cosmetic and agricultural applications, and was shown to increase the efficiency of UV absorption (Compton et al ., 2007 ).…”

Friction properties of chemically modified starch

“…After all the oil was added, the mixture was blended at high speed for 5 minutes. Sucrose is necessary to improve the adhesion of the starch fi lm on the sheet metal surface, and was found to have minor effect on the measured coeffi cient of friction (COF) [6].…”

“…As can be seen in Figure 6, plots of [canola] −1 vs θ −1 gave a straight line with a slope of 0.8 ± 0.1, which is in the range predicted by the model. From the slope, K o was obtained and used to calculate ∆G ads using equation (6). Table II is a summary of the ∆G ads of canola oil on the chemically modifi ed starches investigated in this work.…”

“…Because of a large surplus over the demand for starch-bearing crops, there has been an extensive effort at developing new uses for starch [2]. Nonfood applications of starch that are currently being investigated include biodegradable polymers [3], composites [4], elastomers [5] and lubricants [6].…”