▎ 摘　　要

NOVELTY - Nanoparticle composition comprises (A) at least one graphene nanoparticle, where graphene nanoparticle is a multilayered graphene-based material containing oxygen groups, with a surface area Brunauer, Emmett and Teller of 200-1500 m2/g, and G/D ratio of 0.5-2 in accordance with ISO/TS 80004-13, (B) at least one polymer obtainable by polymerizing a monomer composition comprising (a) 1-30 wt.% at least one functional monomer, (b) 30-70 wt.% at least one alkyl (meth)acrylate monomer, each of the alkyl group of the alkyl (meth)acrylate monomer is linear, cyclic or branched and comprises 1-40C atoms, and (c) 20-60 wt.% at least one polybutadiene-based macromonomer having a number-average molecular weight (Mn) 500-10000 g/mol, (C) at least one 0.02-5 wt.% silane compound (I), and (D) at least one base fluid, the nanoparticle composition is obtainable by milling the nanoparticle composition, preferably via a ball mill process. USE - The composition is useful as a lubricant additive in a lubricating oil composition, preferably in a gear oil composition, a transmission oil composition, a hydraulic oil composition, an engine oil composition, a marine oil composition, an industrial lubricating oil composition or in grease (claimed). ADVANTAGE - The composition exhibits: improved tribological performance, preferably improved anti-friction and anti-wear performance on metal parts; and excellent stability over a long period of time. DETAILED DESCRIPTION - Nanoparticle composition comprises (A) at least one graphene nanoparticle, where graphene nanoparticle is a multilayered graphene-based material containing oxygen groups, with a surface area brunauer, emmett and teller of 200-1500 m2/g, and G/D ratio of 0.5-2 in accordance with ISO/TS 80004-13, (B) at least one polymer obtainable by polymerizing a monomer composition comprising (a) 1-30 wt.% at least one functional monomer comprising (a1) aminoalkyl (meth)acrylates and aminoalkyl (meth)acrylamides, (a2) nitriles of alkyl (meth)acrylic acid and other nitrogen-containing alkyl (meth)acrylates, (a3) (meth)acrylates of ether alcohols, (a4) oxiranyl alkyl (meth)acrylate, (a5) phosphorus-, boron- and/or silicon-containing alkyl (meth)acrylates, (a6) heterocyclic alkyl (meth)acrylates, (a7) vinyl halides, (a8) vinyl esters, (a9) vinyl monomers containing aromatic groups, (a10) heterocyclic vinyl compounds, (a11) vinyl and isoprenyl ethers, and (a12) methacrylic acid and acrylic acid, (b) 30-70 wt.% at least one alkyl (meth)acrylate monomer, each of the alkyl group of the alkyl (meth)acrylate monomer is linear, cyclic or branched and comprises 1-40C atoms, and (c) 20-60 wt.% at least one polybutadiene-based macromonomer having a number-average molecular weight (Mn) 500-10000 g/mol, (C) at least one 0.02-5 wt.% silane compound of formula (Si(R)(M)h(X)3-h) (I), and (D) at least one base fluid, the nanoparticle composition is obtainable by milling the nanoparticle composition, preferably via a ball mill process. h = 0-2, preferably 0; M = a branched or linear 1-4C alkyl residue; R = a branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic 1-30C-based group, or is a branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic 1-30C-based group with a functional group comprising carboxy, carbonyl, hydroperoxycarbonyl, cyan, formyl, oxo, thioxo, hydroxy, amino, imino, hydrazino, epoxy, preferably a linear aliphatic 8C carbonbased group, a linear aliphatic 16C-based group, a linear aliphatic 3-aminopropyl group, or a 3-glycidyloxypropyl group; X = H, Cl or a group OY, preferably methoxy or ethoxy; and Y = H or a 1-8C branched or linear alkyl-, alkenyl-, aryl-, or aralkyl- group, and/or branched or linear 2-8C alkylether-group. INDEPENDENT CLAIMS are also included for: (1) preparing the nanoparticle composition, comprising (i) providing graphene nanoparticle, (ii) providing polymer compound, (iii) providing silane compound, (iv) providing base fluid, (v) combining (i)-(iv) to obtain a mixture, and (vi) milling the mixture of the step (v); and (2) lubricating oil composition comprising the nanoparticle composition and at least one base fluid.