Surface modification of molybdenum disulfide (MoS₂) fine powder

This work reports a novel method to chemically modify the surface of molybdenum disulfide (MoS₂) powder that is used as the antigalling filler in the lubricants for thread-tubing in oil pipelines. The modification by way of coupling agents effectively reduces friction and improves the antiwear and antigalling properties. The effects of three coupling agents, including KH-570, polyvinylpyrrolidone and hexadecyl cetyltrimethylammonium bromide, on particle resistance to sedimentation, powder activation index and lipophilicity are compared in detail. KH-570 on the powder improves the lipophilicity and the dispersion stability of MoS₂. The modified MoS₂ exhibits a much improved activation index, more than twice the original MoS₂ powder. The amount of DOP absorbed by modified MoS₂ powder decreases significantly. The turbidity is much higher in the modified MoS₂ powders, this is in good accordance with the findings from other tests – that is, the lipophilicity has improved. The lipophilicity of the modified MoS₂ increases then decreases with the increased concentration of KH-570. Overall, KH-570 outperforms the rest and is further explored for optimisation and coupling mechanism.