▎ 摘　　要

NOVELTY - Preparation of graphene-coated nano copper lubricating oil additive involves adding surface-modified copper nanoparticle dispersion to isocyanate-modified nanographene dispersion at 4-15 drops/min under stirring at 40-60 degrees C and 60 rpm, mixing at 48 rpm and 50 degrees C for 2 hours, transferring the resultant mixed dispersion to a reactor, heating to 120-180 degrees C for 3 hours, performing a self-coupling reaction to obtain a lubricating oil dispersion liquid solution of graphene-coated nano copper, leaving still for 24 hours, discharging the lower turbid liquid, passing the upper liquid through a 300-mesh metal filter and a 1250-mesh fiber cotton, passing the filtrate through a high-vacuum deaerating and dewatering machine at a vacuum of -0.098 MPa and 140 degrees C, and removing low-point component and moisture from the mixture, to obtain brown-red transparent liquid as graphene-coated nano copper lubricating oil additive. USE - Preparation of graphene-coated nano copper lubricating oil additive (claimed). ADVANTAGE - By controlling the amount of copper nanoparticles and nano graphene, the optimal lubrication effect of the additive can be attained. DETAILED DESCRIPTION - Preparation of graphene-coated nano copper lubricating oil additive involves adding surface-modified copper nanoparticle dispersion to isocyanate-modified nanographene dispersion at 4-15 drops/min under stirring at 40-60 degrees C and 60 rpm, mixing at 48 rpm and 50 degrees C for 2 hours, transferring the resultant mixed dispersion to a reactor, heating to 120-180 degrees C for 3 hours, performing a self-coupling reaction to obtain a lubricating oil dispersion liquid solution of graphene-coated nano copper, leaving still for 24 hours, discharging the lower turbid liquid, passing the upper liquid through a 300-mesh metal filter and a 1250-mesh fiber cotton, passing the filtrate through a high-vacuum deaerating and dewatering machine at a vacuum of -0.098 MPa and 140 degrees C, and removing low-point component and moisture from the mixture, to obtain brown-red transparent liquid as graphene-coated nano copper lubricating oil additive. The isocyanate-modified nanographene dispersion is prepared by mixing 500 pts. wt. SN 5W-30 lubricating oil, 12 pts. wt. Tween (RTM: polyethoxylated sorbitan ester), 20 pts. wt. propylene glycol monoethyl ether, 65 pts. wt. T10, 8 pts. wt. diisobutylamide, 8 pts. wt. triethanolamine, and 4 pts. wt. polyethylenetetramine, heating at 80 degrees C in an oil bath, stirring for 30 min, adding 7 pts. wt. isocyanate-modified nanographene, stirring at constant temperature for 60 minutes under nitrogen atmosphere, ultrasonically treating in a three-stage ultrasonic disperser at 500 W and 20 kHz for 2 hours, and cooling to 30 degrees C. The isocyanate-modified nanographene is prepared by dissolving 200 g graphene oxide in dimethylacetamide at ratio of 1 g:250 ml, ultrasonically processing at 200-250 W for 1.5-2 hours, processing in a water bath at 80-85 degrees C, adding 8 g isophorone diisocyanate, performing constant-temperature magnetic stirring, reacting for 4-6 hours, reducing the temperature to 60-65 degrees C, adding 5 g phenylhydrazine, performing constant-temperature magnetic stirring reaction for 4-6 hours, cooling the resultant reaction mixture to room temperature, filtering, washing 2-3 times with dichloromethane, drying in a vacuum oven at 35-40 degrees C to prepare isocyanate-based graphene, dissolving the isocyanate-based graphene in an organic solvent to which an organic amine is added, reacting for 10 hours, centrifuging and vacuum drying. The surface-modified copper nanoparticle dispersion is prepared by mixing surface-modified copper nanoparticles with 500 pts. wt. 250SN III base oil and 120 pts. wt. poly( alpha )olefin-6 base oil, heating to 60 degrees C, adding 80 pts. wt. linoleic acid, 120 pts. wt. succinimide, 100 pts. wt. calcium lauryl petroleum sulfonate, 3 pts. wt. alkyl diphenylamine, 620 pts. wt. antioxidant T20, 10 pts. wt. butylated hydroxytoluene, 13 pts. wt. metal deactivator TH56, 90 pts. wt. calcium stearate and 1 pt. wt. triethanolamine, mixing at 500 rpm for 1 hour, performing high-shear grinding dispersion in a super-high speed colloid mill THX 3000 to obtain a surface-modified copper nanoparticle dispersion having a uniform particle diameter. The surface-modified copper nanoparticles are prepared by mixing 5 wt.% mixed aqueous solution containing 98 g hydrazine hydrate, 60 g KH-550 (RTM: gamma -aminopropyltriethoxysilane) and 5 0g polyvinyl alcohol, and 0.25 mol/L copper sulfate solution containing 32.5 g anhydrous copper sulfate under nitrogen atmosphere, reacting at 50 degrees C, stirring at 120 rpm for 3 hours, cooling to 30 degrees C, stirring for 20 minutes, leaving still at 30 degrees C for 20 hours for layering, collecting the upper layer of brown red liquid, separating the solid powder by centrifugation at 6000 rpm, washing with ethanol, and vacuum drying at 80 degrees C for 10 hours.