Covalent Functionalization of Fluorinated Graphene and Subsequent Application as Water-based Lubricant Additive

Abstract

Although the fluorinated graphene (FG) possesses numerous excellent properties, it can not be really applied in aqueous environments due to its high hydrophobicity. Therefore, how to achieve hydrophilic FG is a challenge. Here, a method of solvent-free urea melt synthesis is developed to prepare the hydrophilic urea-modified FG (UFG). Some characterizations via transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transfer infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermo gravimetric analysis (TGA) demonstrate that the urea molecules can covalently functionalize the FG and the hydrophilic UFG can be prepared. According to the tribological tests run on an optimal-SRV-I reciprocation friction tester, it can be found that the antiwear ability of water can be largely improved by adding the appropriate UFG. When the concentration of UFG aqueous dispersion is 1 mg/mL, the sample of UFG-1 has the best antiwear ability with a 64.4% decrease of wear rate compared with that of the pure water (UFG-0), demonstrating the prepared UFG can be used as a novel and effective water-based lubricant additive.

Application of graphene derivatives and their nanocomposites in tribology and lubrication: a review

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Chemistry of Graphene Derivatives: Synthesis, Applications, and Perspectives

“…A different approach, based on a substitution reaction on fluorographene, was successfully employed for the preparation of alkylamino graphenes by the reaction of alkylamines, and amino graphene formation by the use of sodium amide . Also, the reaction of fluorographene with urea led to the partial introduction of amine functionalities and, as a consequence, to water dispersible fluorographene …”

“…[46] Also, the reaction of fluorographene with urea led to the partial introduction of aminef unctionalities and, as ac onsequence, to water dispersible fluorographene. [47] Graphene azide represents av ery interesting derivative of graphene. The traditional methodo fp reparation is the same as, for example, amino substituted analogues, by treatment of graphene oxide with sodium azide.…”

Research Progress in Application of 2D Materials in Liquid-Phase Lubrication System

“…Thus, 2D materials are selected as high-performance and environmentally friendly lubricants [45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60]. …”