Octadecylamine‐Functionalized Graphene Oxide as a Lubricant Additive Fabricated by Microwave‐Assisted Ball Milling for Castor Oil

Enhancing plant‐derived lubricant additives to reduce friction and improve wear resistance has been a critical focus in advancing sustainable technologies. This study introduces a catalyst‐free method for synthesizing ODA@GO by functionalizing graphene oxide (GO) with octadecylamine (ODA) through microwave‐assisted ball milling. Experimental results demonstrate that ODA@GO, at a concentration of 0.05 wt%, exhibits excellent dispersion stability in castor oil for over 40 days. Tribological tests reveal that, under mixed lubrication conditions, the addition of ODA@GO to castor oil reduces the coefficient of friction by 45.36%, significantly outperforming the 34.05% reduction achieved by GO alone. The lubrication mechanism analysis suggests that ODA@GO enhances the thickness of the fluid lubrication film through simultaneous physical and chemical adsorption on the friction surfaces, thereby forming a robust protective barrier. This leads to significantly improved tribological properties and enhanced lubrication stability, achieving a coefficient of friction as low as 0.05 with the addition of ODA@GO. Furthermore, a consistent decreasing trend in the coefficient of friction is observed. This methodology offers a practical pathway for friction and wear mitigation in plant‐derived lubricants, with observed effects suggesting applicability in industrial environments. The findings may inform ongoing efforts toward sustainable tribology solutions.