Improving tribological properties and shear stability of base lubricant using Eichhornia crassipes carboxylmethyl cellulose polymer under different conditions

In response to the global environmental issues over inorganic additives in lubrication process in solving friction and wear challenges. There is growing interest in the development of polymer additives, particularly biopolymer, to address the issues given by friction and wear of contact surfaces exposed to boundary and mixed lubrication regimes. The investigation employed a unidirectional ball on disc tribo-tester machine. Using rapeseed lubricant as a base oil sample, this study examined the effect of bio-based Eichhornia crassipes carboxylmethyl cellulose (EC-CMC) polymer to inorganic polyphosphate as well as mixing the two to determine their synergetic and antagonistic effect on reducing friction and wear. The additives were tested for tribological enhancement in terms of friction and wear reduction, and load-carrying effect. Scanning Electron Microscope (SEM) and energy dispersive x-ray (EDX) spectroscopy were used to examine the substrate morphology and elemental distribution of worn surfaces. Introducing 1 wt% EC-CMC, 1 wt% polyphosphate, and 1 wt% EC-CMC + 1 wt% polyphosphate into the base lubricant resulted in improved lubricant performance and reduced friction and wear. However, as compared to base rapeseed oil, the polyphosphate sample provided the best friction (44.8%), while EC-CMC gives better wear reduction (0.3073). The higher the operating capacity, the better the tribological properties of nanoparticles, according to the findings. The best tribofilm creation performance, notably with EC-CMC, is achieved when a load of 100 N is applied, resulted in outstanding tribological performance. When compared to polyphosphate, the strong and efficient nature of EC-CMC results in excellent shear stability.