Submitted to: Industrial Crops and Products
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/1/1999
Publication Date: N/A
Citation: Interpretive Summary: The lubricant market in the U.S. is about $6 billion. More than 90% of all lubricants are based on petroleum. The demand for biodegradable lubricants is expected to grow at about 10% annual rate. Vegetable oil-based lubricants are biodegradable and good for the environment. The basestock typically contributes to more than 80% of lubricant and must meet performance criteria in such aspects as cleanliness, stability and deposit forming tendencies. For vegetable oil-based lubricants, stability and low temperature performance problems are considered the most critical. These problems can only partially be relieved by lubricant additives, thus vegetable oils have to be modified chemically. Vegetable oil based lubricants will benefit U.S. farmers by providing new uses for their commodity, thereby increasing demand, and also benefit lubricant users in general.
Technical Abstract: Compared to the lubricants made of petroleum, vegetable- based lubricants are much more biodegradable but inferior in many other technical characteristics. The basestock typically contributes to more than 80% of lubricant and must meet performance criteria in such aspects as cleanliness, viscometric properties, volatility, oxidative and hydrolytic stability, deposit forming tendencies, solvency, miscibility, or compatibility with system elastomers and other. For vegetable-based lubricants, oxidative stability and low temperature problems are considered the most critical. Thin film oxidation test was used to compare oxidative stabilities. Vegetable oils appear an order of magnitude less stable than mineral oils or synthetic biodegradable basestocks, such as isoalkyl adipates or poly alphaolefins. Low temperature performance of vegetable oils, namely pour points and cold storage, was also problematic. These problems can only partially be relieved by lubricant additives, thus vegetable oils have to be modified chemically to eliminate sites susceptible to oxidation and to disrupt formation of crystals at low temperatures.