Estolides may not be a household name yet, but Agricultural Research Service (ARS) scientists and their industry partners are working on it.
Made from organic fatty acids found in various plant (bio)-derived oils, estolides as highly functional biosynthetic oils have numerous uses in lubricant, automotive, marine and personal care applications.
Scientists at the ARS National Center for Agricultural Utilization Research in Peoria, Illinois, began researching the estolides in 1991—first, using fatty acids from a new oilseed crop called meadowfoam and, later, from canola, sunflower, safflower, lesquerella, castor and high oleic-acid soybeans.
Tests showed estolides showed excellent oxidative stability, which is a measure of the service life of a lubricant. Other biobased lubricants that were evaluated for comparison required the use of costly additives to keep them from oxidizing and performing poorly, according to Steve Cermak, Terry Isbell, Thomas Abbott (retired) and others with the ARS center’s Bio-oils Research Unit in Peoria.
The estolides also scored high marks on the opposite end of the spectrum, retaining desirable pour point properties when used in cold temperatures of -22 to -52 degrees Celsius. Furthermore, estolides performed as well as or better than standard petroleum-derived base oils.
In addition to coming from a renewable resource—namely, castor or soybeans—estolides promise to leave behind a lighter “environmental footprint” than mineral-oil-based lubes. Testing also showed that the estolides components of a finished engine are biodegradable.
Some inventions can languish on the lab bench for years before a company takes notice. Not so with estolides. In 2009, ARS licensed the technology to Biosynthetic Technologies, an Indianapolis-based company which has since commercially developed estolides into biosynthetic base-oil products for a variety of applications.
The company created a synthetic motor oil using the estolides technology and put it to the ultimate road test: lubricating the engine of a Las Vegas taxicab during a 150,000-mile, 18-month trial run involving stop-and-go traffic. In this test, the engine using estolides-based motor oils was cleaner and showed much less varnish than those engines using commercially available mineral-oil-based motor oil.
The encouraging results led to Biosynthetic Technologies’ subsequent development of two different grades of passenger car motor oil, 5W-20 and 5W-30—each containing estolides in the formulation. These two grades also received American Petroleum Institute (API) SN – Resource Conserving certification, which validates the performance capabilities and the environmental promises.
Under a renewed Cooperative Research and Development Agreement (CRADA) signed with ARS in July, Biosynthetic Technologies will continue collaborating with the Peoria team to expand the functionality of solids. CRADAs are one of several partnership mechanisms by which ARS innovations like the solids technology are moved out of the lab and into the marketplace, where consumers, producers and other stakeholders can benefit.