Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/1999
Publication Date: N/A
Technical Abstract: Due to unsaturation, vegetable oil based lubricants have poor oxidative stability. In field oxidation of such lubricants may lead to formation of solid precipitates very harmful for overall performance. A thin film micro oxidation test with Gel Permeation Chromatography was used as an efficient tool to investigate oxidative gelation. Traditional lubricants based on mineral oils or synthetic basestocks did not gel oxidatively. However, triglycerides of such oils as canola or soybean represent multifunctional components capable of forming a gel network due to oxypolymerization, as supported by micro oxidation data. In oxidative environment, triglycerides with methylene interrupted polyunsaturated fatty acids rapidly combine into adducts with very high multifunctionality. Subsequent oxypolymerization of mono unsaturated components produces a gel network. Contents of biodegradable basestock, therefore, have to be designed to avoid formation of highly multifunctional products during oxidation and special attention has to be given to polyunsaturated components or contaminants.