The influence of fatty acids on tribological and thermal properties of natural oils as sustainable biolubricants

Experiments were conducted using bio-based liquid lubricants, such as avocado, canola (rapeseed), corn, olive, peanut, safflower, sesame, and vegetable (soybean) oils to study their friction and wear properties. A thermogravimetric analysis and variable-temperature viscosity analysis were conducted to study the thermal response of the lubricants in a high temperature environment. It was found that avocado oil showed the best friction and wear performance when compared to other natural oils. It was determined that the viscosity at room temperature, thermal decomposition, and thermal-oxidative stability of the natural oils was heavily influenced by the variability of the fatty acid composition within the natural oils. These factors influenced the tribological performance of the natural oils and are discussed in this paper.