Submitted to: Tribology Transactions
Publication Type: Book / Chapter
Publication Acceptance Date: 6/20/2007
Publication Date: 6/1/2008
Citation: Sharma, B.K., Doll, K.M., Erhan, S.Z. 2008. Biobased greases: soap structure and composition effects on tribological properties. In: Biresaw, G., Mittal, K.L., editors. Surfactants in Tribology. Boca Raton, FL: CRC Press. p. 309-323.
Technical Abstract: A review containing 58 references on bio-based grease. Bio-based grease use is limited but a successful part of the lubricant market and will likely grow considerably due to economic, environmental and legislative factors. There is not one formulation of grease or grease thickener that will be successful for all applications. The initial choice of lubricating fluid, as well as tailoring the thickener to the application and lubricating oil is critical. The choice of use of an inorganic or soap thickener is especially important in extreme pressure and temperature conditions. If a bio-based soap stock is used, the fatty acid chain length and cation choice are the main factors to consider. Greases can be tested by a variety of methods and should be evaluated for oxidative stability, rheology, low temperature properties, friction and wear properties and hardness. Using these tests, it is possible to formulate acceptable petroleum grease replacements and sometimes even improve lubrication properties. This is one more step toward the renewable economy of the future.