This study investigated the potential of inedible mustard oil (MO) (Brassica juncea) as a suitable bio-lubricant for enhanced thermal, oxidative stability, and tribological performance. To improve the MO's oxidative stability, it was subjected to a chemical epoxidation reaction, forming epoxidized mustard oil (EMO). The MO and EMO were evaluated for viscosity, functional groups, wettability, oxidative stability, thermal stability, friction, and wear performance. The epoxidation process resulted in nearly doubling the oxidative stability, as well as improving the thermal stability of the MO. Results showed that the EMO exhibited better lubricating properties than the MO, including lower friction and wear. To further improve the lubrication performance of the EMO, solid lubricant additives (SLAs) were incorporated in various concentrations. These SLAs were graphene nanoplatelets (GNP) and hexagonal boron nitride (hBN). The GNP and hBN nano lubricants reduced friction by 31% and 13% compared to the EMO. The same nano lubricants also lowered wear by 73% and 51% relative to the EMO. The underlying mechanisms behind the improvement in the friction and wear performance were discussed. The EMO can be considered as a suitable base stock for renewable and sustainable energy applications.

中文翻译：

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环氧化过程对提高芥子油纳米润滑油的氧化、热稳定性和摩擦学性能的作用

本研究调查了不可食用芥末油 (MO)（芥菜）作为合适的生物润滑剂以增强热稳定性、氧化稳定性和摩擦学性能的潜力。为了提高 MO 的氧化稳定性，对其进行化学环氧化反应，形成环氧化芥子油 (EMO)。对 MO 和 EMO 的粘度、官能团、润湿性、氧化稳定性、热稳定性、摩擦和磨损性能进行了评估。环氧化过程使氧化稳定性几乎翻倍，并提高了 MO 的热稳定性。结果表明，EMO 表现出比 MO 更好的润滑性能，包括更低的摩擦和磨损。为了进一步提高 EMO 的润滑性能，加入了不同浓度的固体润滑剂添加剂 (SLA)。这些 SLA 是石墨烯纳米片 (GNP) 和六方氮化硼 (hBN)。与 EMO 相比，GNP 和 hBN 纳米润滑剂将摩擦减少了 31% 和 13%。相对于 EMO，相同的纳米润滑剂还使磨损降低了 73% 和 51%。讨论了摩擦和磨损性能改善背后的潜在机制。 EMO 可被视为可再生和可持续能源应用的合适基础油。