Tribological properties of synthetic base oil containing polyhedral oligomeric silsesquioxane grafted graphene oxide

Abstract

The dispersion of graphene-based materials in lubricating oil is a prerequisite for improving its friction and wear performance. In this study, polyhedral oligomeric silsesquioxane (POSS) grafted graphene oxide (GO) was synthesized with an aim to improve the dispersibility of graphene in synthetic base oil. The composition and morphology of POSS-GO conjugates were characterized by FTIR, XPS, Raman spectroscopy, TEM and SPM.The tribological behavior of base oil with various concentrations of POSS-GO were examined using a UMT-3 friction and wear tester, and the worn surfaces were analyzed using Raman spectroscopy. It was found that concentrations of POSS-GO additives in the base oil is an important aspect for decreasing the friction and wear of the lubricated solid contacts. At lower and higher concentrations of POSS-GO, the lubricating effect is not effective or even worse. In contrast, at optimized concentration of POSS-GO, graphene sheets could form a boundary tribofilm between the contact, resulting in reduction of the friction coefficient and wear.

A review of recent advances in tribology

“…For instance, a robust macroscale superlubricity state (μ = 0.0037), by taking advantage of the synergy effect of graphene oxide (GO) nanoflakes and ethanediol between the surfaces of Si 3 N 4 and SiO 2 was reported [131]. Chemically-modified GO in hydrophobic ionic liquids [132], 4-n-pentyl-4'-cyanobiphyl liquid crystal (5CB) added with graphene [128], graphene sheets anchored with molybdenum disulfide (MoS 2 ) nanoflowers [133], ILs with graphene [134,135], chemicallybonded phosphorus-graphene hybrid [136], alkyl phosphate modified graphene oxide [137], and polyhedral oligomeric silsesquioxane (POSS) grafted graphene oxide [138], were synthesized and used as liquid lubricants or additives. The research on transition metal disulfides (TMDs) liquid additives, especially MoS 2 , mainly focused on the preparation of functional MoS 2 nanosheets [118,139], MoS 2 nanotubes [140,141], hollow fullerene-like MoS 2 [142], Fe 3 O 4 @MoS 2 core-shell nanocomposites [143], and MoS 2 /montmorillonite nanocomposites [144], etc.…”

PCL/Gelatin/Graphene Oxide Electrospun Nanofibers: Effect of Surface Functionalization on In Vitro and Antibacterial Response

“…The surface morphology and properties of GO were studied using TEM, AFM, FTIR, and Raman spectroscopy. The TEM ( Figure 1 a) revealed thin, wrinkled, highly transparent, and multi-layer sheets of GO [ 93 , 94 , 95 ]. The average size of the GO sheets obtained was 133 ± 82 nm.…”

Correlation between Lubricating Oil Characteristic Parameters and Friction Characteristics

“…The friction and wear performance of lubricants containing graphene materials have also been studied using the UMT friction and wear tester. The results show that graphene flakes can form boundary friction films between contacting pairs, thus reducing COF and wear [8][9][10].…”