Tribological behavior of fullerene–styrene sulfonic acid copolymer as water-based lubricant additive

A novel fullerene–styrene sulfonic acid copolymer was synthesized. The tribological properties of base stock (2 wt.% triethanolamine aqueous solution) containing the fullerene copolymer were measured using a four-ball tribotester. Experiments indicated that the anti-wear performance and load-carrying capacity of the base stock were raised and its friction coefficient was decreased. Then, the surface of worn scar was investigated by using electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). Finally, its lubrication mechanism was deduced preliminarily.