Improving tribological efficiency of isopropyl palmitate oil with cellulose nanocrystals: a sustainable approach for high-performance lubricants

Abstract

This article explores the potential of cellulose nanocrystals (CNCs) as a lubricant additive for isopropyl palmitate (IPP) oil to enhance its tribological performance. CNCs, derived from renewable sources, offer a sustainable and environmentally friendly alternative to traditional lubricant additives. A two-step method was used to prepare the nanolubricants, with visual control and dynamic light scattering measurements to assess their temporal stability. The viscous behavior of the nanolubricants, in terms of viscosity and viscosity index, was evaluated at different temperatures. The study assesses the effectiveness of CNC/IPP oil blends as lubricants through tribological tests, including evaluations under pure sliding and rolling–sliding conditions. Studies on worn surfaces were conducted using surface roughness analysis, Raman mapping, and XPS, and the thermal stability was examined to determine their suitability for different operating conditions. CNCs significantly reduce friction by up to 44% and improve wear resistance compared to the neat IPP base oil, presumably due to a self-repairing effect. Furthermore, an improvement of the thermal conductivity of pure IPP base oil has been revealed with increasing CNC concentration. This study enhances the understanding of cellulose nanocrystals as lubricant additives and their potential to transform traditional lubricating oils into high-performance and sustainable solutions.