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In this paper, graphene oxide (GO) was prepared by modified Hammer's method using graphite, which was then modified with silane coupling agent (MGO). With two-roll mill mixing method, GO was used as filler and composites like nitrile-butadiene rubber (NBR)/GO(MGO) composites and nitrile-butadiene rubber (NBR)/ 2,2'-methylenebis(6-tert-butyl-4-methyl-phenol) (AO-2246)/ GO(MGO) composites were prepared. Fourier Transform Infrared Spectrometer (FT-IR), Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) were used to observe and study the molecular structure and morphology of GO, MGO and the composites. Dynamic Mechanical Analyzer (DMA) was used to study the damping properties of the composites. The composites reinforced by GO and MGO exhibited better damping and mechanical property. The damping property of NBR/GO composites weakens but the damping property of NBR/AO-2246/GO composites enhances with increase graphene oxide (GO). The damping property of the composites is enhanced by the addition of MGO. The main reason of the excellent properties of the graphene derivatives is its structural characteristics and the associated hydrogen bonds in the structure. [ABSTRACT FROM AUTHOR]

Achieving good dispersion stability of graphene oxide (GO) nanosheets in lubricants remains a challenge due to its inherent nature. Here, the isopropyl triisostearyl titanate modified graphene oxide (T-GO) was prepared for improving its dispersion stability in hydraulic oil via a simple method, and for further enhancing the tribological behaviors. The chemical and structural features of T-GO illustrate that the titanate coupling agent (T) was successfully grafted on the plane or interlayer of GO via the interaction between T and hydroxy. The high dispersibility of T-GO in hydraulic oil was demonstrated by the sedimentation experiment and UV–vis absorption spectra (good stability and no sedimentation after 30 days). The 0.08 wt% T-GO hybrid hydraulic oil displayed excellent extreme pressure performance (load carrying capacity raises at least 400 N), friction reduction (friction cofficient reduces by nearly 50%) and wear resistance (wear volume decreases by about 20%). The surface/interface analysis on the worn surfaces testified the formation of graphene-based tribo-film on the contact interfaces. Hence, the excellent lubrication function of T-GO hybrid hydraulic oil was attributed to not only high dispersion stability of T-GO, but also the formation of graphene-like tribo-film, thereby reducing the friction and protecting the tribo-interfaces against wear. Image 1 • Achieving high dispersion stability of functional graphene oxide (T-GO) in hydraulic oil by grafting the titanate coupling agent (T). • T-GO hybrid nanofluids with excellent extreme pressure performance and friction reduction as well as wear resistance. • Excellent lubrication function of T-GO hybrid nanofluids depends good dispersibility and graphene-like tribo-film. [ABSTRACT FROM AUTHOR]