| Concern over the availability and rising cost of petroleum-based products has generated considerable interest in finding alternative resources. In the case of industrial lubricants, vegetable oils are a promising alternative to petroleum-based products because they are renewable, naturally occurring, and biodegradable. Although vegetable oils are naturally abundant, little is understood about the effect of molecular structure on the physical properties of the oil. Vegetable oils are essentially mixtures of triglycerides. To formulate vegetable oils with optimal lubrication characteristics, however, the influence of the individual triglyceride molecules on the overall oil properties must be considered. Computer simulations can directly relate molecular composition to physical properties and offer a valuable tool for improving our knowledge of this important class of materials.; Atomistic molecular dynamics simulations were used to determine viscosities and densities that agree with experimentally observed values for both vegetable oils and pure triglycerides. The effect of molecular structure on physical properties was explored for triglycerides that are difficult to isolate in vegetable oils and that are chemically modified. The low-temperature properties of vegetable oils such as the pour point, which presents a major limitation to the use of vegetable oils as lubricants, have also been characterized using both molecular modeling methods and experimental rheological techniques. The modification of the thermophysical properties of vegetable oils through the blending of pure oils with additives, including small molecule organics and inorganic nanoparticles, was explored. The ultimate goal of this work into use the knowledge gained from molecular-level modeling and experimental characterization to engineer a vegetable oil-based lubricant with properties that rival traditional petroleum-based products. |
