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United States Department of Agriculture

Agricultural Research Service

Title: Physical properties study on partially bio-based lubricant blends: Thermally modified soybean oil with popular commercial esters

item Doll, Kenneth - Ken
item Sharma, Brajendra

Submitted to: International Journal of Sustainable Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2011
Publication Date: 2/1/2012
Publication URL:
Citation: Doll, K.M., Sharma, B.K. 2012. Physical properties study on partially bio-based lubricant blends: Thermally modified soybean oil with popular commercial esters. International Journal of Sustainable Engineering. 5(1):33-37.

Interpretive Summary: We have blended modified soybean oil with conventional synthetic lubricant base stocks in order to synthesize a high performance lubricant that is partially bio-based. The use of lubricants is ubiquitous throughout industries, such as transportation and metal manufacturing, and one only has to look at the news to see the growing concern irreparable environmental damage caused by petroleum based products. However, bio-based products are not currently suitable for some applications. Although considerable effort is ongoing in regard to this issue, a blending is also a viable strategy where formulators can take advantage of synthetic materials yet still have a highly bio-based product. This research will benefit those formulators who are working on low cost lubricant formulations where a bio-based product is a clear advantage.

Technical Abstract: An initial evaluation of several oils, including: soybean oil (SBO), high oleic SBO, and thermally modified SBO, compared their acid values and viscosities over 28 days stored at 85 deg C. As expected, the acid values and viscosities increased and the high oleic oil demonstrated a smaller effect. Surprisingly, the thermally modified oil was no better than ordinary SBO showing that a blending strategy may be necessary for the use of this oil in many lubricant applications. Lubricant blends were prepared by mixing thermally modified SBO with a series of compatible ester-based synthetic fluids. These displayed oxidative stabilities, by pressurized differential scanning calorimetry (PDSC), similar to the biobased oil, but the values obtained for viscosity and pour point were as expected from the blend ratio; that is, addition of more ester fluid into the blended lubricant made its properties more like the ester fluid.

Last Modified: 07/26/2017
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