Evaluating the effects of very long chain and hydroxy fatty acid content on tribological performance and thermal oxidation behavior of plant-based lubricants

Here, we assess several potential plant-based lubricants to reveal their functional characteristics in comparison to the traditionally used synthetic lubricant polyalphaolefin 4 and 10 oils. Our results indicate that jojoba and castor oils demonstrate the best oxidation resistance at elevated temperatures. The low erucic acid (LE) oils demonstrated a decrease in the lubrication efficiency already at 150 °C. This performance was inferior to that of canola oil which also has low erucic acid content, possibly due to the LE pennycress oil having relatively higher polyunsaturated fatty acid content. These results provide a comprehensive overview of plant-based oil candidates, including some with very long chain fatty acids and/or hydroxylated fatty acids, and suggest new concepts for lubrication efficiency improvement.