▎ 摘　　要

NOVELTY - An aqueous coolant used for machine tool processing is prepared by: (1) performing surface oxidation of graphene by taking graphene, then adding a strong acid solution, heating and stirring, adding potassium permanganate, continuously stirring, taking out, then washing with deionized water until neutral and drying; (2) sulfonating graphene by putting the graphene obtained after the surface oxidation in step (1) into 100-300 pts. wt. deionized water, adding 5-15 pts. wt. ammonium sulfate to deionized water, ultrasonically dispersing for 20-30 minutes, then heating and evaporating to remove water, finally placing the solid mixture after heating and evaporation in a heating box, using nitrogen as a protective gas to carry out treatment and cooling; and (3) modifying nano-aluminum oxide by taking octadecyldimethylbenzylammonium chloride, putting into deionized water, stirring and dissolving, adding nano-aluminum oxide, then ultrasonically processing, then taking out and drying. USE - The aqueous coolant is useful for machine tool processing. ADVANTAGE - The aqueous coolant has excellent lubrication property by using the lubricity of graphene. The addition of ethylene glycol, butanol polyoxyethylene ether, antirust agent and organosilicon defoamer can also increase the lubricating, cooling, antifouling and antifoaming properties of the coolant. DETAILED DESCRIPTION - An aqueous coolant used for machine tool processing is prepared by: (1) performing surface oxidation of graphene by taking 16-20 pts. wt. graphene, then adding a strong acid solution with mass of 4-6 times than the mass of graphene, heating at 55 degrees C and stirring for 3 minutes, adding 6-9 pts. wt. potassium permanganate, continuously stirring for 50 minutes, taking out, then washing with deionized water until neutral and drying; (2) sulfonating graphene by putting the graphene obtained after the surface oxidation in step (1) into 100-300 pts. wt. deionized water, adding 5-15 pts. wt. ammonium sulfate to deionized water, ultrasonically dispersing for 20-30 minutes, then heating and evaporating to remove water, finally placing the solid mixture after heating and evaporation in a heating box, using nitrogen as a protective gas to carry out treatment at 150-220 degrees C for 1-2 hours, and cooling to room temperature; (3) modifying nano-aluminum oxide by taking 36-44 pts. wt. octadecyldimethylbenzylammonium chloride, putting into 120-150 pts. wt. deionized water, stirring and dissolving, adding 18-24 pts. wt. nano-aluminum oxide, then ultrasonically processing at a frequency of 165-180 kHz for 30-40 minutes, then taking out and drying; (4) preparing a sulfonated graphene/aluminum oxide nanocomposite material by taking 12-14 pts. wt. sulfonated graphene obtained in step (2), putting into 150-220 pts. wt. deionized water, ultrasonically dispersing for 20-30 minutes to obtain a dispersion (A), simultaneously putting 55-60 pts. wt. modified nano-aluminum oxide obtained in step (3) into 300-400 pts. wt. deionized water, ultrasonically dispersing for 40-50 minutes to obtain a slurry (B), then pouring the dispersion (A) into the slurry (B), stirring at 600 rpm for 20 minutes until the upper and lower layers appear, finally filtering and drying; and (5) preparing mixed coolant by taking 14-32 pts. wt. sulfonated graphene/aluminum oxide nanocomposite material prepared in step (4), ultrasonically dispersing in 260-400 pts. wt. deionized water for 20 minutes, adding 26-32 pts. wt. ethylene glycol, 5-8 pts. wt. hexenylbis(stearamide), 4-7 pts. wt. butanol polyoxyethylene ether, 2-4 pts. wt. antirust agent and 1-2 pts. wt. organosilicon defoamer, heating at 45 degrees C and finally stirring at 1200 rpm until the mixture is uniform.