Preparation and Lubricating Properties of Polystyrene Composite Microspheres

In order to improve the lubrication performance of polystyrene microspheres (PS) as solid lubricant in drilling fluids, elastic graphite–polystyrene composite microspheres (EGR/PS), montmorillonite–elastic graphite–polystyrene composite microspheres (OMMT/EGR/PS), and polytetrafluoroethylene–polystyrene composite microspheres (PTFE/PS) were prepared by suspension polymerization. OMMT/EGR/PS has a rough surface, while the surfaces of the other three composite microspheres are smooth. Among the four kinds of composite microspheres, the largest particle is OMMT/EGR/PS, and the average size is about 400 μm. The smallest particle is PTFE/PS, and the average size is about 49 μm. Compared with pure water, the friction coefficient of PS, EGR/PS, OMMT/EGR/PS and PTFE/PS reduced by 25%, 28%, 48%, and 62%, respectively. The wear tracks of EGR/PS, OMMT/EGR/PS and PTFE/PS are narrower and smoother than those of pure water. When the content of PTFE is 4.0 wt%, the friction coefficient and wear volume of PTFE/PS are 0.213 and 2.45 × 10(−4) mm(3)—74% and 92.4% lower than that of pure water, respectively.