Comparison between jojoba oil and other vegetable oils as a substitute to petroleum

Jojoba oil and other vegetable oils, such as soybean, sunflower and castor oils, were evaluated to be used as lubricants. Three standard mineral lubricating oils were considered in this study as reference. The essential parameters tested for comparison were the oil viscosity, viscosity index, and viscosity-temperature and shear rate-shear stress relationships. The effect of excessive heating on the vegetable oils' stability was studied and the corresponding parameters were also measured. Jojoba oil was found to be the best among all tested oils, whereas it gave the minimum change in viscosity gradient and hence the highest viscosity index. There was a linear relation between shear rate and shear stress of all oils before and after heat deterioration. Therefore, these oils were considered as Newtonion liquids. However, the oil viscosity, as well as the rate of viscosity variation with temperature, (Deltaeta'/DeltaT ) were affected by heat deterioration being lowered in value, in case of jojoba oil, and higher value, in case of castor oil. Jojoba oil was examined for other important properties for its use as a lubricant, such as refractive index, acid value, peroxide value, saponification value, iodine value, flash, fire and pour points.