An Investigation on the Tribology of Bentonite/Silane/NBR Nanocomposites and the Effects of Solid Lubricants

In this work, effects of three silane coupling agents and two solid lubricants (graphite and molybdenum disulfide) on the tribological properties of bentonite/nitrile butadiene rubber (NBR) nanocomposites were investigated. Further inlfluences of the lubricants to the mechanical properties of the nanocomposites were also evaluated and discussed. The hybrid nanocomposites were fabricated with a brief one-step method. Three silane coupling agents, (3-mercaptopropyl) trimethoxysilane (MPTMS), bis[3-(triethoxysilyl)propyl]tetrasulfide (TESPT) and [3-(2-aminoethylamino) propyl] triethoxysilane (AEAPTMS) were employed in our research. They exhibited various effects on the intercalation/exfoliation of bentonite in rubber matrices and the networks formed during vulcanization, and thus further influenced the friction coefficients of the nanocomposites. In the wear test, bentonite/silane/NBR nanocomposites showed better wear resistance compared with the specimens without silanes. It is revealed that the incorporation of solid lubricants further decreased the friction coefficient of the nanocomposites. However, the wear resistance of the materials was not improved. Meanwhile, a synergistic effect between MoS₂ and bentonite on the reinforcement of the mechanical strength of the nanocomposites appeared, which is out of our expectation.