Extreme pressure and anti-wear properties of polycarboxylate superplasticizer modified 3D porous graphene/SiO2 as water-based lubricant additives

Abstract

Lubricants can effectively solve the large amount of energy loss and environmental pollution caused by frictional wear. Graphene-based materials water-based lubricants have attracted attention due to their excellent various properties. But their application is still hindered by many obstacles. In this paper, a novel polycarboxylate superplasticizer modified 3D porous graphene/SiO2 (PG/SiO2) nanomaterial was prepared as water-based lubrication additives. The base fluid with good cooling properties was obtained by adding Kunlun full synthetic grinding/cutting fluid to deionized water and diluting it to 5% by weight. It is found that PG/SiO2 had a good synergistic effect, which could effectively improve the extreme pressure performance (PB/PD), with the maximum improvement rates of 39.7% and 86.3%, respectively. Meanwhile, significantly enhance the friction reduction (35%) and anti-wear (72.2%) properties of the base fluid. The enhancement mechanism was revealed by experimental and characterization analysis. Due to the excellent mechanical properties of graphene itself and synergistic effects including the rolling bearing effect of PG/SiO2 and the buffering effect of SiO2 in its intercalation, the PG/SiO2 nanomaterials can significantly improve the extreme pressure performance of the base fluid. Further, theoretical calculations revealed the enhancement effects of the long chains of the polycarboxylate superplasticizer on the dispersibility and surface adsorption of graphene, and the modified graphene on the diffusive movement of water molecules.