WO2020052293A1 - Preparation method for perfluorotriethylamine group-based highly thermally conductive and lubricating nanofluid - Google Patents

Preparation method for perfluorotriethylamine group-based highly thermally conductive and lubricating nanofluid Download PDF

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WO2020052293A1
WO2020052293A1 PCT/CN2019/090315 CN2019090315W WO2020052293A1 WO 2020052293 A1 WO2020052293 A1 WO 2020052293A1 CN 2019090315 W CN2019090315 W CN 2019090315W WO 2020052293 A1 WO2020052293 A1 WO 2020052293A1
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graphene
perfluorotriethylamine
nanofluid
reaction
temperature
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French (fr)
Chinese (zh)
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刘金龙
白明洁
李成明
苗建印
何江
魏俊俊
陈良贤
李振宇
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北京科技大学
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/08—Materials not undergoing a change of physical state when used
    • C09K5/10—Liquid materials
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/182—Graphene
    • C01B32/194—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
    • C10M169/04—Mixtures of base-materials and additives
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
    • C10M2201/04—Elements
    • C10M2201/041—Carbon; Graphite; Carbon black
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant compositions
    • C10M2215/02—Amines, e.g. polyalkylene polyamines; Quaternary amines
    • C10M2215/04—Amines, e.g. polyalkylene polyamines; Quaternary amines having amino groups bound to acyclic or cycloaliphatic carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
    • C10N2030/06—Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure

Definitions

  • the invention belongs to the field of preparing a composite liquid working medium for a fluid circuit system for a spacecraft; in particular, it provides a preparation method for preparing a nanofluid based on perfluorotriethylamine, which is characterized by being able to uniformly disperse graphite in a liquid working medium that is super hydrophobic and oleophobic. Ene nanoparticles, so as to achieve efficient heat exchange and friction reduction of liquid working fluid.
  • High-efficiency heat exchange is the eternal theme of the development of fluid circuit technology, and the heat transfer efficiency of the thermal load and heat transfer medium directly affects the scale and performance of the system.
  • the working medium in the mechanical pump-driven fluid circuit heat dissipation technology is required to have a high heat exchange coefficient, which can achieve an effective heat exchange effect for high-power heating components.
  • high-life pumps are the key to pump-driven fluid circuits. Being able to achieve effective lubrication of the pump body will undoubtedly be of great value in extending the life of the pump and increasing its reliability and stability.
  • Perfluorotriethylamine is a commonly used cooling medium in the aerospace field. It is a colorless, odorless, transparent liquid, non-combustible, non-toxic, highly stable to heat and various chemicals and metal materials, good lubrication and abrasion resistance, excellent dielectric and thermal conductivity Characteristics, low pour point, low viscosity, etc., are widely used in aerospace industry, electronics, electric power industry in electrical insulation oil, thermally conductive coolant, dielectric fluid, precision instrument cleaning fluid, etc. A compound consisting of C, N, and F elements and saturated with a fluorine atom. Its boiling point is relatively low, it is more volatile, and its thermal conductivity is relatively low, only 0.1003W / m ⁇ K. In order to improve its thermal conductivity, highly thermally conductive nano-additives are added to the heat transfer working medium to improve its thermal and lubricating properties. It is often referred to as a nanofluid.
  • graphene As an excellent representative of carbon family materials, graphene not only has a high thermal conductivity, but also a low coefficient of friction.
  • the formation of nanofluids will significantly increase the thermal conductivity and reduce the coefficient of friction.
  • Hajjar et al. Used modified Hummers method to prepare graphene oxide and added it to deionized water with different mass fractions (0.05% to 0.25%) to form a uniform and stable graphene oxide / water nanofluid. The thermal conductivity of the nanofluid was measured. The results show that the thermal conductivity of the nanofluid is much higher than that of the base fluid.
  • the graphene nanofluid with a mass fraction of 0.25% at room temperature has an increase in thermal conductivity of 33.9% over deionization, and an increase of 47.5% at 40 ° C. . (International Communications in Heat and Mass Transfer. 57 (2014) 128).
  • Thermal conductivity results show that 0.1% The thermal conductivity of nanofluids has increased by 6.67% to 10.47% (International Journal of Heat and Mass Transfer. 87 (2015) 92).
  • graphene generally has excellent thermal conductivity and lubricating properties, because the complete structure of graphene is a combination of stable six-membered ring benzene-like units, the surface is inert, and the chemical stability is high. The strong ⁇ - ⁇ interaction between them makes its dispersion stability in the heat transfer medium severely affected. Especially for the special heat transfer medium such as perfluorotriethylamine, it is easy to produce aggregate precipitation or agglomeration, which is not sufficient. Graphene exerts high thermal conductivity and lubricating effect in perfluorotriethylamine.
  • an object of the present invention is to provide a method for forming graphene uniformly dispersed in non-polar liquid working fluid perfluorotriethylamine to form a nanofluid, thereby improving the heat transfer performance of the working medium in the fluid circuit driven by the mechanical pump.
  • With antiwear properties Through the surface modification of graphene to form a fluorine terminal, a similar compatibility principle with the working fluid perfluorotriethylamine is used to achieve uniform dispersion of the fluorinated graphene in the heat exchange working fluid perfluorotriethylamine. This can avoid the introduction of dispersant to reduce the thermal conductivity of graphene, and avoid the instability caused by the introduction of larger functional group molecules.
  • a method for preparing perfluorotriethylamine-based highly thermally conductive lubricating nanofluid which is characterized in that nanoscale graphene filler is used, without any additives, and uniform dispersion of perfluorotriethylamine in the base liquid can be achieved only by surface modification. And achieve the improvement of the thermal conductivity of perfluorotriethylamine and the reduction of friction coefficient under typical friction pairs. It includes the following steps:
  • Step 1 Oxidation of graphene to obtain a reactive oxygen terminal.
  • the modified Hummers method is used to prepare graphene oxide, the number of layers of graphene oxide is 1-5, and the sheet diameter is 10nm-1 ⁇ m;
  • the graphene oxide needs to be uniformly dispersed in ultrapure water.
  • the original graphene clusters were broken by ultrasonic vibration, and the polar oxide groups on the graphene surface were used to achieve uniform dispersion in ultrapure water.
  • hydrofluoric acid solution will remain on the graphene surface, and there will be other by-products of uneven size.
  • the reaction solution needs to be filtered and washed, and the pH value of the aqueous solution should be adjusted to neutral to obtain the solid product. After drying, a fluorinated graphene sample is obtained.
  • Step 3 Preparation of perfluorotriethylamine nanofluid based on fluorinated graphene
  • the dried fluorinated graphene needs to be further dispersed in a perfluorotriethylamine solution to form a uniformly dispersed nanofluid.
  • the most direct and intuitive method to evaluate the stability of graphene-perfluorotriethylamine nanofluids is to judge the stability of the dispersion by observing the time without standing for sedimentation. No obvious delamination occurred after standing for 2 weeks, which indicates that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
  • step 1 After the reaction product after the high-temperature reaction described in step 1 is centrifuged and washed, ultrasonic peeling is required, and the peeling is performed for 30-60 minutes. After the ultrasonication is completed, the reaction product is centrifuged at 1000-3000 r ⁇ min -1 for 20-40 minutes.
  • the upper layer liquid after the ultrasonic peeling described in step 1 is the graphene oxide dispersion liquid, which needs to be dried in a vacuum drying box at 60 ° C. for 48 hours, and then used.
  • step 2 firstly, 20-40 mg of graphene oxide is added to ultrapure water, and ultrasonic treatment is performed until a uniform graphene oxide dispersion liquid is obtained.
  • the method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, wherein the graphene fluorination process in step 2 is dispersed, and the dispersion liquid is added to the In a tetrafluoroethylene-lined hydrothermal kettle to 2/3 of the lining volume, add 0.2ml-0.5ml of hydrofluoric acid, tighten the hydrothermal kettle to seal it, and then place it in an oven. The temperature is maintained at a high temperature of 150 ° C-200 ° C for 20-40 hours.
  • step 2 after the graphene described in step 2 is fluorinated by a hydrothermal method, the pH value needs to be adjusted to neutrality, washed, filtered, and dried to obtain a fluorinated graphene sample.
  • the solution concentration is 1mg / ml-3mg / ml
  • the power of ultrasonic oscillation is 100W-300W
  • the time is 5min-10min
  • the ultrasonic temperature does not exceed 35 ° C.
  • the stability of the graphene perfluorotriethylamine nanofluid described in step 4 is evaluated by a room temperature standing method, and it is preferable that no obvious delamination phenomenon occurs after 2 weeks.
  • the stability of nanofluids can also be evaluated by dynamic light scattering methods, Zeta potential methods, and the like.
  • Fluorinated graphene can be prepared not only by hydrothermal method, but also by directly fluorinating graphene or graphene oxide.
  • the main fluorinating agents are F 2 , XeF 2 , and fluorinated plasma (CF 4 and SF 6 ) And fluoropolymer, specific methods include heating reaction, plasma etching, and the like.
  • fluorinated graphene can also be prepared by liquid-phase peeling or mechanical peeling of fluorinated graphite.
  • the surface of the fluorinated graphene used as a perfluorotriethylamine heat transfer medium should have as few hydrogen functional groups as possible to avoid problems caused by irradiation and the like.
  • a method for preparing a perfluorotriethylamine-based highly thermally conductive lubricating nanofluid specifically includes the following steps:
  • Step 1 Oxidation of graphene to obtain a reactive oxygen terminal.
  • Low-speed centrifugal washing removes excess acid and by-products, disperses neutral graphite oxide after washing in water, peels off with ultrasonic vibration for 30-60min, and after centrifugation at 1000-3000r ⁇ min -1 after centrifugation for 20-40min, upper layer
  • the liquid is a graphene oxide dispersion liquid, and dried in a vacuum drying box at 60 ° C. for 48 h, and then used.
  • Step 2 The surface of graphene is fluorinated.
  • a 20 mg-40 mg graphene oxide sample was weighed and added to ultrapure water, placed in an ultrasonic vibration cleaner, and subjected to ultrasonic treatment to obtain a uniform graphene oxide dispersion.
  • the reaction kettle is naturally cooled to room temperature.
  • the pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral.
  • the obtained solid product was dried to obtain a fluorinated graphene sample.
  • Step 3 Preparation of perfluorotriethylamine nanofluid based on fluorinated graphene
  • the stability of the dispersion was judged by observing the non-settling time at rest.
  • the premise of hydrothermal method to prepare fluorinated graphene is to first obtain graphene oxide.
  • Graphene oxide is generally obtained by oxidizing graphite with a strong acid.
  • the Hummers method has relatively good timeliness and is relatively safe during preparation. It is currently the most commonly used method.
  • Hydrofluoric acid is used as a fluorinating agent to fluorinate graphene.
  • the fluorine atoms in fluorinated graphene mainly exist in the form of C-F bonds.
  • graphene is fluorinated, and after ultrasonic treatment, it is dispersed in perfluorotriethylamine, which solves the problem that graphene is easy to agglomerate in perfluorotriethylamine.
  • Fluorinated graphene can also be prepared by directly fluorinating graphene or graphene oxide.
  • the main fluorination reagents are F 2 , XeF 2 , fluorinated plasma (CF 4 and SF 6 ), and fluoropolymers. Specific methods include heating reaction and plasma etching.
  • fluorinated graphene can also be prepared by liquid-phase peeling or mechanical peeling of fluorinated graphite.
  • the hydrogen-containing functional group on the surface should be as small as possible, so as to avoid problems caused by irradiation and the like.
  • Fluorinated graphene has good dispersibility in perfluorotriethylamine working fluid, and because no dispersant is needed, the thermal resistance at the heat transfer interface can be reduced, and the thermal conductivity of the nanofluid can be significantly provided.
  • Fluorine atoms are inserted between the layers of graphene sheets, which expands the interlayer distance and reduces the force between layers. At the same time, the strong repulsive force between fluorine atoms is more conducive to sliding between the layers, which can significantly improve the nanometer. Anti-wear lubrication performance of fluid.
  • FIG. 1 is an XPS chart of a fluorinated graphene sample prepared by the method of the present invention.
  • the obtained mixed solution was slowly added to about 100 mL of low-temperature deionized water, and then the above mixed solution was placed in a ⁇ 95 ° C water bath to react for 30 minutes, while maintaining moderate mechanical stirring; after the high-temperature reaction, 60 mL of deionized water was added to stop the reaction, and then 25 mL ( 30 Vol%) of hydrogen peroxide. After reacting for about 15 minutes, 40 mL (10 Vol%) of hydrochloric acid solution is added to dissolve. The low-speed centrifugal washing removes excess acid and by-products. The neutral graphite oxide is dispersed in water after washing, and it is stripped by ultrasonic vibration for 30 minutes.
  • the ultrasonication After the ultrasonication, it is centrifuged at 2000 r ⁇ min -1 for 40 minutes. The upper layer is graphene oxide. The dispersion was dried in a vacuum drying box at 50 ° C. for 50 h to obtain a graphene oxide sample. .
  • a 40 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and sonicated at 200 W for 30 min to obtain a uniform graphene oxide dispersion.
  • Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene liner, to 2/3 of the liner volume, and add 0.25 ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it, and then It was placed in an oven and held at 180 ° C for 30 hours. After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
  • the stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
  • the obtained mixed solution was slowly added to about 100 mL of low-temperature deionized water, and then the above mixed solution was placed in a ⁇ 90 ° C water bath to react for 60 minutes, while maintaining moderate mechanical stirring; after the high-temperature reaction, 60 mL of deionized water was added to stop the reaction, and then 25 mL ( 30 Vol%) of hydrogen peroxide. After about 20 minutes of reaction, 40 mL (10 Vol%) of a hydrochloric acid solution is added to dissolve. The low-speed centrifugal washing removes excess acid and by-products. The neutral graphite oxide is dispersed in water after washing, and it is peeled off by ultrasonic vibration for 60min.
  • the ultrasonication After the ultrasonication, it is centrifuged at 3000r ⁇ min -1 for 30min. The upper layer is graphene oxide. The dispersion was dried in a vacuum drying box at 70 ° C. for 40 h to obtain a graphene oxide sample.
  • a 40 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and sonicated at 200 W for 1 h to obtain a uniform graphene oxide dispersion.
  • the stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
  • a 20 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and subjected to ultrasonic treatment at 200 W for 30 minutes to obtain a uniform graphene oxide dispersion.
  • Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene lining to 2/3 of the lining volume, and add 0.2ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it, and then It was placed in an oven and kept at 150 ° C for 20 hours. After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
  • the stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
  • the obtained mixed solution was slowly added to about 100 mL of low-temperature deionized water, and then the above mixed solution was placed in a water bath at ⁇ 95 ° C for 30 minutes to maintain moderate mechanical stirring during the reaction; after the high-temperature reaction, 60 mL of deionized water was added to stop the reaction, and then 30 mL ( 30 Vol%) of hydrogen peroxide. After reacting for about 30 min, 40 mL (10 Vol%) of hydrochloric acid solution is added to dissolve. The low-speed centrifugal washing removes excess acid and by-products. The neutral graphite oxide is dispersed in water after washing, and it is peeled off by ultrasonic vibration for 60min.
  • the ultrasonication After the ultrasonication, it is centrifuged at 3000r ⁇ min -1 for 30min.
  • the upper layer is graphene oxide.
  • the dispersion was dried in a vacuum drying box at 60 ° C. for 30 h to obtain a graphene oxide sample.
  • a 40 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and subjected to ultrasonic treatment at 300 W for 1 h to obtain a uniform graphene oxide dispersion.
  • Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene liner to 2/3 of the liner volume, and add 0.3ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it. It was placed in an oven and held at 190 ° C for 30 hours. After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
  • the stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.

Abstract

A preparation method for a perfluorotriethylamine group-based highly thermally conductive and lubricating nanofluid, belonging to the field of composite liquid working medium preparation for fluid circuit systems for spacecrafts. The preparation of a fluorinated graphene-perfluorotriethylamine group nanofluid realizes efficient heat exchange and effective lubrication of a fluid circuit system. The present invention successfully prepares multi-layer fluorinated graphene by fluorinating graphene oxide by means of the hydrothermal method and using hydrofluoric acid as a fluorinating reagent, the experimental apparatus being simple, and the preparation process being easy to operate. Furthermore, the fluorine content in the surface of the graphene can be adjusted controllably. The fluorinated graphene has good dispersibility in the perfluorotriethylamine working medium, and as no dispersant is required, the thermal resistance of the heat transfer interface can be reduced and the thermal conductivity of the nanofluid can be significantly improved. Fluorine atoms are inserted between layers of the graphene, increasing spacing between the layers, reducing the force between the layers; moreover, the strong repulsive force between the fluorine atoms facilitates sliding between the layers, significantly improving the abrasion-reduction and lubrication performance of the nanofluids.

Description

一种全氟三乙胺基高导热润滑纳米流体的制备方法Preparation method of perfluorotriethylamine-based highly thermally conductive lubricating nanofluid 技术领域：Technical field:
本发明属于航天器用流体回路***复合液体工质制备领域；特别是提供了一种制备基于全氟三乙胺纳米流体的制备方法，特点是能够在超疏水疏油的液体工质中均匀分散石墨烯纳米颗粒，从而实现液体工质的高效换热与减磨润滑。The invention belongs to the field of preparing a composite liquid working medium for a fluid circuit system for a spacecraft; in particular, it provides a preparation method for preparing a nanofluid based on perfluorotriethylamine, which is characterized by being able to uniformly disperse graphite in a liquid working medium that is super hydrophobic and oleophobic. Ene nanoparticles, so as to achieve efficient heat exchange and friction reduction of liquid working fluid.
背景技术：Background technique:
高效率换热是流体回路技术发展永恒的主题，而热载荷与传热工质的换热效率高低则直接影响***的规模与性能。为实现航天器高效率流体回路散热***研制，要求机械泵驱动流体回路散热技术中的工作介质具有较高的换热系数，能够实现对高功率发热部件进行有效换热效果。与此同时，高寿命的泵也是泵驱流体回路的关键。能够实现泵体的有效润滑，无疑会对延长泵的寿命与增加可靠稳定性具有重要价值。High-efficiency heat exchange is the eternal theme of the development of fluid circuit technology, and the heat transfer efficiency of the thermal load and heat transfer medium directly affects the scale and performance of the system. In order to realize the spacecraft high-efficiency fluid circuit heat dissipation system development, the working medium in the mechanical pump-driven fluid circuit heat dissipation technology is required to have a high heat exchange coefficient, which can achieve an effective heat exchange effect for high-power heating components. At the same time, high-life pumps are the key to pump-driven fluid circuits. Being able to achieve effective lubrication of the pump body will undoubtedly be of great value in extending the life of the pump and increasing its reliability and stability.
全氟三乙胺是航天领域常用的冷却工质。它是一种无色、无嗅、透明液体，具有不燃烧、无毒，对热和各种化学品及金属材料的高度稳定性，良好的润滑及耐磨性，优良的介电性和热传导性，且倾点低，粘度低等特点，被广泛应用于航天工业、电子、电力工业中的电绝缘油、导热冷却剂、介电液、精密仪器清洗液等。其成分由C、N、F元素组成的，且由氟原子饱和的化合物。其沸点偏低，较易挥发，且导热系数相对不高，仅为0.1003W/m·K。为提高其导热系数，将高导热纳米添加剂加入到传热工质中改善其导热性质与润滑性质，通常称其为纳米流体。Perfluorotriethylamine is a commonly used cooling medium in the aerospace field. It is a colorless, odorless, transparent liquid, non-combustible, non-toxic, highly stable to heat and various chemicals and metal materials, good lubrication and abrasion resistance, excellent dielectric and thermal conductivity Characteristics, low pour point, low viscosity, etc., are widely used in aerospace industry, electronics, electric power industry in electrical insulation oil, thermally conductive coolant, dielectric fluid, precision instrument cleaning fluid, etc. A compound consisting of C, N, and F elements and saturated with a fluorine atom. Its boiling point is relatively low, it is more volatile, and its thermal conductivity is relatively low, only 0.1003W / m · K. In order to improve its thermal conductivity, highly thermally conductive nano-additives are added to the heat transfer working medium to improve its thermal and lubricating properties. It is often referred to as a nanofluid.
石墨烯作为碳族材料中的优秀代表，不仅具有高的导热率，还有低的摩擦系数，形成纳米流体后将显著提高热导率，降低摩擦系数。例如Hajjar等利用改性Hummers法制备了氧化石墨烯，并以不同的质量分数(0.05％～0.25％)添加到去离子水中形成了均匀稳定的氧化石墨烯/水纳米流体，纳米流体导热性能测量结果表明，纳米流体热导率大大高于基液的热导率，常温下质量分数为0.25％的石墨烯纳米流体比去离子的导热系数增大了33.9％，40℃时增加值为 47.5％。(International Communications in Heat and Mass Transfer.57(2014)128)。Ijam等使用改性Hummers法制备了氧化石墨烯，并以水/乙二醇做基液(60：40)制备成质量分数为0.01％～0.1％的纳米流体，导热性能结果表明，0.1％的纳米流体热导率提高了6.67％～10.47％(International Journal of Heat and Mass Transfer.87(2015)92)。As an excellent representative of carbon family materials, graphene not only has a high thermal conductivity, but also a low coefficient of friction. The formation of nanofluids will significantly increase the thermal conductivity and reduce the coefficient of friction. For example, Hajjar et al. Used modified Hummers method to prepare graphene oxide and added it to deionized water with different mass fractions (0.05% to 0.25%) to form a uniform and stable graphene oxide / water nanofluid. The thermal conductivity of the nanofluid was measured. The results show that the thermal conductivity of the nanofluid is much higher than that of the base fluid. The graphene nanofluid with a mass fraction of 0.25% at room temperature has an increase in thermal conductivity of 33.9% over deionization, and an increase of 47.5% at 40 ° C. . (International Communications in Heat and Mass Transfer. 57 (2014) 128). Ijam et al. Used modified Hummers method to prepare graphene oxide, and water / ethylene glycol as the base liquid (60:40) to prepare nanofluids with a mass fraction of 0.01% to 0.1%. Thermal conductivity results show that 0.1% The thermal conductivity of nanofluids has increased by 6.67% to 10.47% (International Journal of Heat and Mass Transfer. 87 (2015) 92).
然而尽管石墨烯通常具有优异的导热性质与润滑性质，但由于结构完整的石墨烯是由稳定的类六元环苯单元组合而成表面呈惰性，化学稳定性高，并且石墨烯片与片之间强烈的π-π作用使其在传热工质中的分散稳定性受到严重影响，特别是对于全氟三乙胺这种特殊的传热工质，很容易产生聚集沉淀或团聚，无法充分发挥石墨烯在全氟三乙胺中发挥高导热和润滑效果。However, although graphene generally has excellent thermal conductivity and lubricating properties, because the complete structure of graphene is a combination of stable six-membered ring benzene-like units, the surface is inert, and the chemical stability is high. The strong π-π interaction between them makes its dispersion stability in the heat transfer medium severely affected. Especially for the special heat transfer medium such as perfluorotriethylamine, it is easy to produce aggregate precipitation or agglomeration, which is not sufficient. Graphene exerts high thermal conductivity and lubricating effect in perfluorotriethylamine.
发明内容：Summary of the invention:
为了解决上述问题，本发明的目的在于提供一种石墨烯均匀分散于非极性液态工质全氟三乙胺中形成纳米流体的方法，从而提升机械泵驱动流体回路中工作介质的换热性能与减磨性能。通过石墨烯通过表面修饰形成氟终端，利用与工质全氟三乙胺的相似相溶原理，实现氟化石墨烯在换热工质全氟三乙胺当中的均匀分散。这样既可以避免分散剂的引入降低石墨烯的热导率，又可以避免引入较大的官能团分子带来的不稳定性。In order to solve the above problems, an object of the present invention is to provide a method for forming graphene uniformly dispersed in non-polar liquid working fluid perfluorotriethylamine to form a nanofluid, thereby improving the heat transfer performance of the working medium in the fluid circuit driven by the mechanical pump. With antiwear properties. Through the surface modification of graphene to form a fluorine terminal, a similar compatibility principle with the working fluid perfluorotriethylamine is used to achieve uniform dispersion of the fluorinated graphene in the heat exchange working fluid perfluorotriethylamine. This can avoid the introduction of dispersant to reduce the thermal conductivity of graphene, and avoid the instability caused by the introduction of larger functional group molecules.
一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于采用纳米尺度石墨烯填料，不采用任何添加剂，仅通过表面修饰即可实现在基液全氟三乙胺的均匀分散，并实现全氟三乙胺热导率的提高和在典型摩擦副下摩擦系数的降低。具体包括以下步骤：A method for preparing perfluorotriethylamine-based highly thermally conductive lubricating nanofluid, which is characterized in that nanoscale graphene filler is used, without any additives, and uniform dispersion of perfluorotriethylamine in the base liquid can be achieved only by surface modification. And achieve the improvement of the thermal conductivity of perfluorotriethylamine and the reduction of friction coefficient under typical friction pairs. It includes the following steps:
步骤1：石墨烯的氧化，获得具有反应活性的氧终端。Step 1: Oxidation of graphene to obtain a reactive oxygen terminal.
1.1使用改进Hummers法制备氧化石墨烯，氧化石墨烯的层数为1-5层，片径10nm-1μm；1.1 The modified Hummers method is used to prepare graphene oxide, the number of layers of graphene oxide is 1-5, and the sheet diameter is 10nm-1μm;
1.2经低温、中温与高温反应后，获得表面为氧终端的石墨烯。1.2 After the reaction of low temperature, middle temperature and high temperature, graphene with oxygen termination on the surface is obtained.
步骤2：石墨烯的表面氟化。Step 2: The surface of graphene is fluorinated.
2.1氧化石墨烯与超纯水均匀分散。2.1 Graphene oxide is evenly dispersed with ultrapure water.
为实现氧化石墨烯表面实现均匀氟化，首先需要将氧化石墨烯均匀分散至超纯水中。通过超声振荡打破原本是团簇状的石墨烯团，依靠石墨烯表面极性氧化基团实现在超纯水中的均匀分散。In order to achieve uniform fluorination of the graphene oxide surface, firstly, the graphene oxide needs to be uniformly dispersed in ultrapure water. The original graphene clusters were broken by ultrasonic vibration, and the polar oxide groups on the graphene surface were used to achieve uniform dispersion in ultrapure water.
2.2石墨烯表面氟化修饰2.2 Graphene surface fluorination modification
为使氧化石墨烯表面建立氟终端，通过水热的高温高压环境促使氧终端与氢氟酸溶液反应，实现氧终端向氟终端的可控转变。In order to establish a fluorine terminal on the surface of graphene oxide, the hydrothermal high temperature and high pressure environment is used to promote the reaction between the oxygen terminal and the hydrofluoric acid solution, so as to achieve a controllable transition from the oxygen terminal to the fluorine terminal.
2.3氟化石墨烯的清洗与分离2.3 Cleaning and separation of fluorinated graphene
经水热反应后的石墨烯表面将残留有氢氟酸溶液，还会有尺寸不均一的其他副产物，需要将反应液过滤、洗涤，并进一步调整水溶液pH值至中性，将所得固体产物烘干，即得到氟化石墨烯样品。After hydrothermal reaction, hydrofluoric acid solution will remain on the graphene surface, and there will be other by-products of uneven size. The reaction solution needs to be filtered and washed, and the pH value of the aqueous solution should be adjusted to neutral to obtain the solid product. After drying, a fluorinated graphene sample is obtained.
步骤3：基于氟化石墨烯全氟三乙胺纳米流体的制备Step 3: Preparation of perfluorotriethylamine nanofluid based on fluorinated graphene
干燥后的氟化石墨烯需进一步分散于全氟三乙胺溶液中，形成均匀分散的纳米流体。一方面需要给予氟化石墨烯与全氟三乙胺足够的能量，打破氟化与氧化石墨烯间由于物理与化学间吸附带来的团聚，使其均匀分散到全氟三乙胺中，另一方面需要避免由于过高的能量使得分散开的氟化石墨烯重新团聚。需要严格控制超声震荡的能量与水温。The dried fluorinated graphene needs to be further dispersed in a perfluorotriethylamine solution to form a uniformly dispersed nanofluid. On the one hand, it is necessary to give sufficient energy to fluorinated graphene and perfluorotriethylamine to break up the agglomeration caused by physical and chemical adsorption between fluorinated and graphene oxide, so that it is evenly dispersed in perfluorotriethylamine. On the one hand, it is necessary to avoid re-agglomeration of the dispersed fluorinated graphene due to excessive energy. It is necessary to strictly control the energy and water temperature of the ultrasonic vibration.
步骤4：稳定性评价Step 4: Stability evaluation
最为直接与直观的方法评价石墨烯-全氟三乙胺纳米流体的稳定性方法是通过观察静置无沉降时间来判断分散液的稳定性。静置2周后不发生明显分层现象，则说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。The most direct and intuitive method to evaluate the stability of graphene-perfluorotriethylamine nanofluids is to judge the stability of the dispersion by observing the time without standing for sedimentation. No obvious delamination occurred after standing for 2 weeks, which indicates that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
进一步地，步骤1所述Hummers法制备氧化石墨烯工艺为：低温反应温度控制于0-4℃，加入高锰酸钾后控制温度不超过5-15℃；中温反应温度35-40℃，反应时间20-60min；高温反应80-100℃，反应20-60min。Further, the process for preparing graphene oxide by the Hummers method described in step 1 is: the low temperature reaction temperature is controlled at 0-4 ° C, and the temperature is controlled to not exceed 5-15 ° C after adding potassium permanganate; the intermediate temperature reaction temperature is 35-40 ° C, the reaction Time 20-60min; high temperature reaction 80-100 ° C, reaction 20-60min.
进一步地，步骤1所述的高温反应后的反应产物离心、洗涤后，需进行超声剥离，剥离30-60min，超声结束后在1000-3000r·min -1转速下离心20-40min。 Further, after the reaction product after the high-temperature reaction described in step 1 is centrifuged and washed, ultrasonic peeling is required, and the peeling is performed for 30-60 minutes. After the ultrasonication is completed, the reaction product is centrifuged at 1000-3000 r · min -1 for 20-40 minutes.
进一步地，步骤1所述的超声剥离后的上层液即是氧化石墨烯分散液，需在60℃下于真空干燥箱中干燥48h，备用。Further, the upper layer liquid after the ultrasonic peeling described in step 1 is the graphene oxide dispersion liquid, which needs to be dried in a vacuum drying box at 60 ° C. for 48 hours, and then used.
进一步地，步骤2所述的石墨烯氟化过程，首先需要将20-40mg氧化石墨烯加入超纯水中，超声处理，直到获得均匀的氧化石墨烯分散液。Further, in the graphene fluorination process described in step 2, firstly, 20-40 mg of graphene oxide is added to ultrapure water, and ultrasonic treatment is performed until a uniform graphene oxide dispersion liquid is obtained.
6.根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤2所述的石墨烯氟化过程，经分散后，分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.2ml-0.5ml的氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在150℃-200℃高温下进行保温20-40小时。The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, wherein the graphene fluorination process in step 2 is dispersed, and the dispersion liquid is added to the In a tetrafluoroethylene-lined hydrothermal kettle to 2/3 of the lining volume, add 0.2ml-0.5ml of hydrofluoric acid, tighten the hydrothermal kettle to seal it, and then place it in an oven. The temperature is maintained at a high temperature of 150 ° C-200 ° C for 20-40 hours.
进一步地，步骤2所述的石墨烯经水热法氟化后，需经过调节pH值至中性、洗涤、过滤、烘干，获得氟化石墨烯样品。Further, after the graphene described in step 2 is fluorinated by a hydrothermal method, the pH value needs to be adjusted to neutrality, washed, filtered, and dried to obtain a fluorinated graphene sample.
进一步地，步骤3所述的石墨烯全氟三乙胺纳米流体的制备，溶液浓度1mg/ml-3mg/ml，超声振荡的功率100W-300W，时间5min-10min，超声温度不超过35℃。Further, in the preparation of the graphene perfluorotriethylamine nanofluid described in step 3, the solution concentration is 1mg / ml-3mg / ml, the power of ultrasonic oscillation is 100W-300W, the time is 5min-10min, and the ultrasonic temperature does not exceed 35 ° C.
进一步地，步骤4所述的石墨烯全氟三乙胺纳米流体的稳定性采用室温静置法评价，以2周后不发生明显分层现象为宜。纳米流体的稳定性还可以通过动态光散射法、Zeta电位法等进行评价。Further, the stability of the graphene perfluorotriethylamine nanofluid described in step 4 is evaluated by a room temperature standing method, and it is preferable that no obvious delamination phenomenon occurs after 2 weeks. The stability of nanofluids can also be evaluated by dynamic light scattering methods, Zeta potential methods, and the like.
本发明氟化石墨烯表面F终端的比例直接决定着全氟三乙胺纳米流体的分散性，通过在水热反应中延长反应时间或提高反应温度均有利于氧化石墨烯氟化程度的增加。The ratio of the F terminal on the surface of the fluorinated graphene of the present invention directly determines the dispersibility of the perfluorotriethylamine nanofluid. By extending the reaction time or increasing the reaction temperature in the hydrothermal reaction, the fluorination degree of the graphene oxide is increased.
氟化石墨烯不仅可以通过水热法制备，还可以通过将石墨烯或氧化石墨烯直接氟化来制备，主要的氟化试剂有F 2、XeF 2、氟化等离子体(CF 4和SF 6)以及氟聚合物，具体的方法有加热反应、等离子体刻蚀等。此外，通过液相剥离或机械剥离氟化石墨也可以制备氟化石墨烯。 Fluorinated graphene can be prepared not only by hydrothermal method, but also by directly fluorinating graphene or graphene oxide. The main fluorinating agents are F 2 , XeF 2 , and fluorinated plasma (CF 4 and SF 6 ) And fluoropolymer, specific methods include heating reaction, plasma etching, and the like. In addition, fluorinated graphene can also be prepared by liquid-phase peeling or mechanical peeling of fluorinated graphite.
用于全氟三乙胺传热工质的氟化石墨烯表面含氢官能团要尽可能少，以免由于辐照带来的问题等。The surface of the fluorinated graphene used as a perfluorotriethylamine heat transfer medium should have as few hydrogen functional groups as possible to avoid problems caused by irradiation and the like.
如上所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，具体包括以下步骤：As described above, a method for preparing a perfluorotriethylamine-based highly thermally conductive lubricating nanofluid specifically includes the following steps:
步骤1：石墨烯的氧化，获得具有反应活性的氧终端。Step 1: Oxidation of graphene to obtain a reactive oxygen terminal.
为了实现表面氟化，需要首先将石墨烯表面活化，为进一步氟化做准备。使用改进Hummers制备氧化石墨烯，具体步骤如下：In order to achieve surface fluorination, graphene needs to be activated first to prepare for further fluorination. To prepare graphene oxide using modified Hummers, the specific steps are as follows:
1.1低温反应1.1 Low temperature reaction
量取10-40mL浓硫酸倒入烧杯，烧杯放入冰浴中冷却至0-4℃，称取0.5-2g石墨粉和0.2-1g硝酸钠(石墨烯粉与硝酸钠)放入烧杯，开启超声，0.5-1h 以后缓慢加入1-5g高锰酸钾，关闭超声并开始搅拌，控制温度不超过5-15℃，反应时间共1-3h。Measure 10-40mL of concentrated sulfuric acid into a beaker. Put the beaker into an ice bath and cool to 0-4 ° C. Weigh 0.5-2g of graphite powder and 0.2-1g of sodium nitrate (graphene powder and sodium nitrate) into the beaker and open. Ultrasound, slowly add 1-5g potassium permanganate after 0.5-1h, turn off the ultrasound and start stirring, control the temperature not to exceed 5-15 ° C, and the reaction time is 1-3h.
1.2中温反应1.2 Medium temperature reaction
把烧杯移至水浴锅，开启超声，水浴温度控制在35-40℃反应20-60min。Move the beaker to the water bath, turn on the ultrasound, and control the temperature of the water bath at 35-40 ° C for 20-60 minutes.
1.3高温反应1.3 High temperature reaction
把所得混合液缓慢加入50-200mL的低温去离子水中，接着将以上混合液置于80-100℃水浴中反应20-60min，期间保持适度机械搅拌；高温反应后加入去离子水中止反应，随后加入5-30Vol％的双氧水，待反应10-30min后再加入5-10Vol％的盐酸溶液溶解。低速离心洗涤去除过量的酸及副产物，将洗涤后呈中性的氧化石墨分散于水中，超声振荡剥离30-60min，超声结束后在1000-3000r·min -1转速下离心20-40min，上层液即是氧化石墨烯分散液，60℃下于真空干燥箱中干燥48h，备用。 Slowly add the resulting mixed solution to 50-200mL of low-temperature deionized water, and then place the above mixed solution in a water bath at 80-100 ° C for 20-60min, while maintaining moderate mechanical stirring; add high-temperature reaction to deionized water to stop the reaction, and then Add 5-30 Vol% hydrogen peroxide solution, and wait for 10-30min to add 5-10Vol% hydrochloric acid solution to dissolve. Low-speed centrifugal washing removes excess acid and by-products, disperses neutral graphite oxide after washing in water, peels off with ultrasonic vibration for 30-60min, and after centrifugation at 1000-3000r · min -1 after centrifugation for 20-40min, upper layer The liquid is a graphene oxide dispersion liquid, and dried in a vacuum drying box at 60 ° C. for 48 h, and then used.
步骤2：石墨烯的表面氟化。Step 2: The surface of graphene is fluorinated.
具体包括以下步骤：It includes the following steps:
2.1氧化石墨烯与超纯水均匀分散2.1 Graphene oxide is evenly dispersed with ultrapure water
称取20mg-40mg氧化石墨烯样品加至超纯水中，置于超声震荡清洗器内，进行超声处理，获得均匀的氧化石墨烯分散液。A 20 mg-40 mg graphene oxide sample was weighed and added to ultrapure water, placed in an ultrasonic vibration cleaner, and subjected to ultrasonic treatment to obtain a uniform graphene oxide dispersion.
2.2高温反应2.2 High temperature reaction
将该分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.2ml-0.5ml的氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在150℃-200℃高温下进行保温20-40小时。Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene liner to 2/3 of the liner volume, and add 0.2ml-0.5ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it Then, put it in an oven, and keep it at a high temperature of 150 ° C-200 ° C for 20-40 hours.
2.3过滤、洗涤、干燥反应产物2.3 Filtration, washing and drying of reaction products
待反应结束，使反应釜自然冷却至室温。调节pH值，将反应液过滤，滤饼用超纯水多次洗涤，直到其pH值达到中性。将所得固体产物烘干，得到氟化石墨烯样品。After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
步骤3：基于氟化石墨烯全氟三乙胺纳米流体的制备Step 3: Preparation of perfluorotriethylamine nanofluid based on fluorinated graphene
称取经水热法制备的氟化石墨烯10mg-30mg，用称量纸转移到烧杯当中，用移液管量取10ml-全氟三乙胺试剂于烧杯当中，配置浓度为1mg/ml-3mg/ml的氟化石墨烯-全氟三乙胺分散液。随后置于超声震荡清洗器内，100W-300W 功率下超声处理5min-10min，控制超声温度不超过35℃，获得均匀的氟化化石墨烯-全氟三乙胺纳米流体。Weigh 10mg-30mg of fluorinated graphene prepared by the hydrothermal method, transfer it into a beaker with a weighing paper, and measure 10ml-perfluorotriethylamine reagent into the beaker with a pipette, with a concentration of 1mg / ml-3mg / ml of fluorinated graphene-perfluorotriethylamine dispersion. It was then placed in an ultrasonic oscillating cleaner, sonicated at a power of 100W-300W for 5min-10min, and the ultrasonic temperature was controlled to not exceed 35 ° C to obtain a uniform fluorinated graphene-perfluorotriethylamine nanofluid.
步骤4：稳定性评价Step 4: Stability evaluation
通过观察静置无沉降时间来判断分散液的稳定性。The stability of the dispersion was judged by observing the non-settling time at rest.
静置2周后不发生明显分层现象，则说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。No obvious delamination occurred after standing for 2 weeks, which indicates that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
本发明实施过程的关键在于The key to the implementation of the invention is
1、水热法制备氟化石墨烯的前提在于首先获得氧化石墨烯。氧化石墨烯一般由石墨经强酸氧化而得，制备氧化石墨烯的方法通常有三种：Brodie法，Staudenmaier法和Hummers法。其中Hummers法的制备过程时效性相对较好，而且制备过程中也比较安全，是目前最常用的一种。1. The premise of hydrothermal method to prepare fluorinated graphene is to first obtain graphene oxide. Graphene oxide is generally obtained by oxidizing graphite with a strong acid. There are usually three methods for preparing graphene oxide: the Brodie method, the Staudenmaier method, and the Hummers method. Among them, the Hummers method has relatively good timeliness and is relatively safe during preparation. It is currently the most commonly used method.
2、以氢氟酸作为氟化剂氧化石墨烯进行氟化，氟化石墨烯中的氟原子主要以C-F键的形式存在。2. Hydrofluoric acid is used as a fluorinating agent to fluorinate graphene. The fluorine atoms in fluorinated graphene mainly exist in the form of C-F bonds.
3、提高氟化剂/氧化石墨烯的质量比，或在高氟化剂/氧化石墨烯质量比条件下，延长反应时间或提高反应温度均有利于氧化石墨烯氟化程度的增加。3. Increasing the mass ratio of fluorinating agent / graphene oxide, or under the condition of high fluorinating agent / graphene oxide mass ratio, extending the reaction time or increasing the reaction temperature will be beneficial to the increase of the degree of fluorination of graphene oxide.
4、将氧化石墨烯与氢氟酸混合的水热釜加热至150℃-200℃，持续加热30h，以确保氧化石墨烯与氢氟酸充分反应。4. Heat the hydrothermal kettle mixed with graphene oxide and hydrofluoric acid to 150 ° C-200 ° C and continue heating for 30h to ensure that graphene oxide and hydrofluoric acid fully react.
5、将反应液充分洗涤，直至彻底去除氟化石墨烯表面残留的氢氟酸。5. Wash the reaction solution thoroughly until the hydrofluoric acid remaining on the surface of the fluorinated graphene is completely removed.
6、利用相似相溶原理，将石墨烯进行氟化处理，经过超声处理，分散于传热工质全氟三乙胺当中，解决了石墨烯易于全氟三乙胺当中团聚的问题。6. Using similar miscibility principle, graphene is fluorinated, and after ultrasonic treatment, it is dispersed in perfluorotriethylamine, which solves the problem that graphene is easy to agglomerate in perfluorotriethylamine.
7、氟化石墨烯还可以通过将石墨烯或氧化石墨烯直接氟化来制备，主要的氟化试剂有F 2、XeF 2、氟化等离子体(CF 4和SF 6)以及氟聚合物，具体的方法有加热反应、等离子体刻蚀等。此外，通过液相剥离或机械剥离氟化石墨也可以制备氟化石墨烯。 7. Fluorinated graphene can also be prepared by directly fluorinating graphene or graphene oxide. The main fluorination reagents are F 2 , XeF 2 , fluorinated plasma (CF 4 and SF 6 ), and fluoropolymers. Specific methods include heating reaction and plasma etching. In addition, fluorinated graphene can also be prepared by liquid-phase peeling or mechanical peeling of fluorinated graphite.
8、对于用于全氟三乙胺传热工质的氟化石墨烯表面含氢官能团要尽可能少，以免由于辐照带来的问题等。8. For the fluorinated graphene used as the perfluorotriethylamine heat transfer working medium, the hydrogen-containing functional group on the surface should be as small as possible, so as to avoid problems caused by irradiation and the like.
本发明的优点是：The advantages of the invention are:
1、通过水热法，以氢氟酸为氟化试剂对氧化石墨烯进行氟化，成功制备了多层氟化石墨烯，实验设备较为简易，制备过程易于操作。且石墨烯表面的含氟比例可以可控调整。1. Hydrofluoric acid was used to fluorinate graphene oxide using hydrofluoric acid as a fluorinating reagent, and multi-layer fluorinated graphene was successfully prepared. The experimental equipment is relatively simple and the preparation process is easy to operate. And the proportion of fluorine on the graphene surface can be controlled.
2、经过氟化处理的石墨烯在全氟三乙胺工质当中具有良好的分散性，且由于无需使用分散剂，可以减少传热界面热阻，显著提供纳米流体的热导率。2. Fluorinated graphene has good dispersibility in perfluorotriethylamine working fluid, and because no dispersant is needed, the thermal resistance at the heat transfer interface can be reduced, and the thermal conductivity of the nanofluid can be significantly provided.
3、氟原子***到石墨烯片层之间，扩大层间距，降低了层与层之间的作用力，同时氟原子之间强烈的斥力作用更有利于片层之间滑动，可显著提高纳米流体的减磨润滑性能。3. Fluorine atoms are inserted between the layers of graphene sheets, which expands the interlayer distance and reduces the force between layers. At the same time, the strong repulsive force between fluorine atoms is more conducive to sliding between the layers, which can significantly improve the nanometer. Anti-wear lubrication performance of fluid.
附图说明：Brief description of the drawings:
1、图1为本发明方法制得的氟化石墨烯样品的XPS图。1. FIG. 1 is an XPS chart of a fluorinated graphene sample prepared by the method of the present invention.
2、图2为本发明方法制得的氟化石墨烯样品的FTIR图。2. FIG. 2 is an FTIR chart of a fluorinated graphene sample prepared by the method of the present invention.
具体实施方式detailed description
下面结合具体实施例对本发明的技术方案做进一步说明。The technical solution of the present invention is further described below with reference to specific embodiments.
实施例1Example 1
量取23mL浓硫酸倒入烧杯，烧杯放入冰浴中冷却至4℃以下，称取1g石墨粉和0.5g硝酸钠放入烧杯，开启超声，1h以后缓慢加入3g高锰酸钾，关闭超声并开始搅拌，控制温度不超过10℃，反应时间共2h。把烧杯移至水浴锅，开启超声，水浴温度控制在38℃反应0.5h。把所得混合液缓慢加入约100mL的低温去离子水中，接着将以上混合液置于～95℃水浴中反应30min，期间保持适度机械搅拌；高温反应后加入60mL去离子水中止反应，随后加入25mL(30Vol％)的双氧水，待反应约15min后再加入40mL(10Vol％)的盐酸溶液溶解。低速离心洗涤去除过量的酸及副产物，将洗涤后呈中性的氧化石墨分散于水中，超声振荡剥离30min，超声结束后在2000r·min -1转速下离心40min，上层液即是氧化石墨烯分散液，50℃下于真空干燥箱中干燥50h，得到氧化石墨烯样品。。 Measure 23mL of concentrated sulfuric acid into a beaker, place the beaker in an ice bath and cool to below 4 ° C. Weigh 1g of graphite powder and 0.5g of sodium nitrate into the beaker, turn on the ultrasound, slowly add 3g of potassium permanganate after 1h, turn off the ultrasound Stirring was started, the temperature was controlled to not exceed 10 ° C, and the reaction time was 2h. Move the beaker to a water bath and turn on the ultrasound. The temperature of the water bath is controlled at 38 ° C for 0.5h. The obtained mixed solution was slowly added to about 100 mL of low-temperature deionized water, and then the above mixed solution was placed in a ~ 95 ° C water bath to react for 30 minutes, while maintaining moderate mechanical stirring; after the high-temperature reaction, 60 mL of deionized water was added to stop the reaction, and then 25 mL ( 30 Vol%) of hydrogen peroxide. After reacting for about 15 minutes, 40 mL (10 Vol%) of hydrochloric acid solution is added to dissolve. The low-speed centrifugal washing removes excess acid and by-products. The neutral graphite oxide is dispersed in water after washing, and it is stripped by ultrasonic vibration for 30 minutes. After the ultrasonication, it is centrifuged at 2000 r · min -1 for 40 minutes. The upper layer is graphene oxide. The dispersion was dried in a vacuum drying box at 50 ° C. for 50 h to obtain a graphene oxide sample. .
称取40mg氧化石墨烯样品加至20ml超纯水中，置于超声震荡清洗器内，200W功率下，超声处理30min，获得均匀的氧化石墨烯分散液。将该分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.25ml的 氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在180℃高温下,保温30h。待反应结束，使反应釜自然冷却至室温。调节pH值，将反应液过滤，滤饼用超纯水多次洗涤，直到其pH值达到中性。将所得固体产物烘干，得到氟化石墨烯样品。A 40 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and sonicated at 200 W for 30 min to obtain a uniform graphene oxide dispersion. Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene liner, to 2/3 of the liner volume, and add 0.25 ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it, and then It was placed in an oven and held at 180 ° C for 30 hours. After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
称取经水热法制备的氟化石墨烯10mg，用称量纸转移到烧杯当中，用移液管量取10ml全氟三乙胺试剂于烧杯当中，配置浓度为1mg/ml的氟化石墨烯-全氟三乙胺分散液。随后置于超声震荡清洗器内，100W功率下超声处理10min，获得均匀的氟化化石墨烯-全氟三乙胺纳米流体。Weigh 10mg of fluorinated graphene prepared by hydrothermal method, transfer it into a beaker with a weighing paper, measure 10ml of perfluorotriethylamine reagent into a beaker with a pipette, and arrange the fluorinated graphene with a concentration of 1mg / ml -Perfluorotriethylamine dispersion. It was then placed in an ultrasonic oscillating cleaner and sonicated at 100 W for 10 min to obtain a uniform fluorinated graphene-perfluorotriethylamine nanofluid.
通过观察静置无沉降时间来判断分散液的稳定性。静置2周后分散液不发生明显分层现象，说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。The stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
实施例2Example 2
量取23mL浓硫酸倒入烧杯，烧杯放入冰浴中冷却至4℃以下，称取1g石墨粉和0.5g硝酸钠放入烧杯，开启超声，1h以后缓慢加入3g高锰酸钾，关闭超声并开始搅拌，控制温度不超过10℃，反应时间共2h。把烧杯移至水浴锅，开启超声，水浴温度控制在35℃反应0.5h。把所得混合液缓慢加入约100mL的低温去离子水中，接着将以上混合液置于～90℃水浴中反应60min，期间保持适度机械搅拌；高温反应后加入60mL去离子水中止反应，随后加入25mL(30Vol％)的双氧水，待反应约20min后再加入40mL(10Vol％)的盐酸溶液溶解。低速离心洗涤去除过量的酸及副产物，将洗涤后呈中性的氧化石墨分散于水中，超声振荡剥离60min，超声结束后在3000r·min -1转速下离心30min，上层液即是氧化石墨烯分散液，70℃下于真空干燥箱中干燥40h，得到氧化石墨烯样品。 Measure 23mL of concentrated sulfuric acid into a beaker, place the beaker in an ice bath and cool to below 4 ° C. Weigh 1g of graphite powder and 0.5g of sodium nitrate into the beaker, turn on the ultrasound, slowly add 3g of potassium permanganate after 1h, turn off the ultrasound Stirring was started, the temperature was controlled to not exceed 10 ° C, and the reaction time was 2h. Move the beaker to a water bath and turn on the ultrasound. The temperature of the water bath is controlled at 35 ° C for 0.5h. The obtained mixed solution was slowly added to about 100 mL of low-temperature deionized water, and then the above mixed solution was placed in a ~ 90 ° C water bath to react for 60 minutes, while maintaining moderate mechanical stirring; after the high-temperature reaction, 60 mL of deionized water was added to stop the reaction, and then 25 mL ( 30 Vol%) of hydrogen peroxide. After about 20 minutes of reaction, 40 mL (10 Vol%) of a hydrochloric acid solution is added to dissolve. The low-speed centrifugal washing removes excess acid and by-products. The neutral graphite oxide is dispersed in water after washing, and it is peeled off by ultrasonic vibration for 60min. After the ultrasonication, it is centrifuged at 3000r · min -1 for 30min. The upper layer is graphene oxide. The dispersion was dried in a vacuum drying box at 70 ° C. for 40 h to obtain a graphene oxide sample.
称取40mg氧化石墨烯样品加至20ml超纯水中，置于超声震荡清洗器内，200W功率下，超声处理1h，获得均匀的氧化石墨烯分散液。将该分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.5ml的氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在200℃高温下，保温30h。待反应结束，使反应釜自然冷却至室温。调节pH值，将反应液过滤，滤饼用超纯水多次洗涤，直到其pH值达到中性。将所得固体产物烘干，得到氟化石墨烯样品。A 40 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and sonicated at 200 W for 1 h to obtain a uniform graphene oxide dispersion. Add the dispersion to a hydrothermal kettle with a polytetrafluoroethylene liner, to 2/3 of the liner volume, and add 0.5ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it, and then It was placed in an oven and held at 200 ° C for 30 hours. After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
称取经水热法制备的氟化石墨烯10mg，用称量纸转移到烧杯当中，用移液管量取10ml全氟三乙胺试剂于烧杯当中，配置浓度为1mg/ml的氟化石墨烯-全氟三乙胺分散液。随后置于超声震荡清洗器内，100W功率下超声处理10min，获得均匀的氟化化石墨烯-全氟三乙胺纳米流体。Weigh 10mg of fluorinated graphene prepared by hydrothermal method, transfer it into a beaker with a weighing paper, measure 10ml of perfluorotriethylamine reagent into a beaker with a pipette, and arrange the fluorinated graphene with a concentration of 1mg / ml -Perfluorotriethylamine dispersion. It was then placed in an ultrasonic oscillating cleaner and sonicated at 100 W for 10 min to obtain a uniform fluorinated graphene-perfluorotriethylamine nanofluid.
通过观察静置无沉降时间来判断分散液的稳定性。静置2周后分散液不发生明显分层现象，说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。The stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
实施例3Example 3
量取12mL浓硫酸倒入烧杯，烧杯放入冰浴中冷却至4℃以下，称取0.5g石墨粉和0.5g硝酸钠放入烧杯，开启超声，1h以后缓慢加入1.5g高锰酸钾，关闭超声并开始搅拌，控制温度不超过10℃，反应时间共2h。把烧杯移至水浴锅，开启超声，水浴温度控制在35℃反应0.5h。把所得混合液缓慢加入约50mL的低温去离子水中，接着将以上混合液置于95℃水浴中反应30min，期间保持适度机械搅拌；高温反应后加入30mL去离子水中止反应，随后加入12mL(30Vol％)的双氧水，待反应约15min后再加入10mL(10Vol％)的盐酸溶液溶解。低速离心洗涤去除过量的酸及副产物，将洗涤后呈中性的氧化石墨分散于水中，超声振荡剥离30min，超声结束后在1000r·min -1转速下离心30min，上层液即是氧化石墨烯分散液，60℃下于真空干燥箱中干燥30h，得到氧化石墨烯样品。 Measure 12mL of concentrated sulfuric acid into a beaker, place the beaker in an ice bath and cool to below 4 ° C, weigh 0.5g of graphite powder and 0.5g of sodium nitrate into the beaker, turn on the ultrasound, and slowly add 1.5g of potassium permanganate after 1h. Turn off the ultrasound and start stirring. Control the temperature not to exceed 10 ° C. The reaction time is 2h. Move the beaker to a water bath and turn on the ultrasound. The temperature of the water bath is controlled at 35 ° C for 0.5h. Add the obtained mixed solution slowly to about 50mL of low-temperature deionized water, and then place the above mixed solution in a 95 ° C water bath for 30min, with moderate mechanical stirring during the reaction; after high-temperature reaction, add 30mL of deionized water to stop the reaction, and then add 12mL (30Vol %) Of hydrogen peroxide. After about 15 minutes of reaction, 10 mL (10 Vol%) of a hydrochloric acid solution is added to dissolve. The low-speed centrifugal washing removes excess acid and by-products. The neutral graphite oxide is dispersed in water after washing, and it is peeled off by ultrasonic vibration for 30min. After the ultrasonication, it is centrifuged at 1000r · min -1 for 30min. The upper layer is graphene oxide. The dispersion was dried in a vacuum drying box at 60 ° C. for 30 h to obtain a graphene oxide sample.
称取20mg氧化石墨烯样品加至20ml超纯水中，置于超声震荡清洗器内，200W功率下，进行超声处理30min，获得均匀的氧化石墨烯分散液。将该分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.2ml的氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在150℃高温下，保温20h。待反应结束，使反应釜自然冷却至室温。调节pH值，将反应液过滤，滤饼用超纯水多次洗涤，直到其pH值达到中性。将所得固体产物烘干，得到氟化石墨烯样品。A 20 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and subjected to ultrasonic treatment at 200 W for 30 minutes to obtain a uniform graphene oxide dispersion. Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene lining to 2/3 of the lining volume, and add 0.2ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it, and then It was placed in an oven and kept at 150 ° C for 20 hours. After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
称取经水热法制备的氟化石墨烯10mg，用称量纸转移到烧杯当中，用移液管量取10ml全氟三乙胺试剂于烧杯当中，配置浓度为1mg/ml的氟化石墨烯-全氟三乙胺分散液。随后置于超声震荡清洗器内，240W功率下超声处理10min，获得均匀的氟化化石墨烯-全氟三乙胺纳米流体。Weigh 10mg of fluorinated graphene prepared by hydrothermal method, transfer it into a beaker with a weighing paper, measure 10ml of perfluorotriethylamine reagent into a beaker with a pipette, and arrange the fluorinated graphene with a concentration of 1mg / ml -Perfluorotriethylamine dispersion. It was then placed in an ultrasonic oscillating cleaner and sonicated at 240 W for 10 min to obtain a uniform fluorinated graphene-perfluorotriethylamine nanofluid.
通过观察静置无沉降时间来判断分散液的稳定性。静置2周后分散液不发生明显分层现象，说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。The stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
实施例4Example 4
量取23mL浓硫酸倒入烧杯，烧杯放入冰浴中冷却至4℃以下，称取1g石墨粉和0.5g硝酸钠放入烧杯，开启超声，1h以后缓慢加入3g高锰酸钾，关闭超声并开始搅拌，控制温度不超过15℃，反应时间共3h。把烧杯移至水浴锅，开启超声，水浴温度控制在40℃反应1h。把所得混合液缓慢加入约100mL的低温去离子水中，接着将以上混合液置于～95℃水浴中反应30min，期间保持适度机械搅拌；高温反应后加入60mL去离子水中止反应，随后加入30mL(30Vol％)的双氧水，待反应约30min后再加入40mL(10Vol％)的盐酸溶液溶解。低速离心洗涤去除过量的酸及副产物，将洗涤后呈中性的氧化石墨分散于水中，超声振荡剥离60min，超声结束后在3000r·min -1转速下离心30min，上层液即是氧化石墨烯分散液，60℃下于真空干燥箱中干燥30h，得到氧化石墨烯样品。 Measure 23mL of concentrated sulfuric acid into a beaker, place the beaker in an ice bath and cool to below 4 ° C. Weigh 1g of graphite powder and 0.5g of sodium nitrate into the beaker, turn on the ultrasound, slowly add 3g of potassium permanganate after 1h, turn off the ultrasound Stirring was started, the temperature was controlled to not exceed 15 ° C, and the reaction time was 3h. Move the beaker to a water bath and turn on the ultrasound. The temperature of the water bath is controlled at 40 ° C for 1 hour. The obtained mixed solution was slowly added to about 100 mL of low-temperature deionized water, and then the above mixed solution was placed in a water bath at ~ 95 ° C for 30 minutes to maintain moderate mechanical stirring during the reaction; after the high-temperature reaction, 60 mL of deionized water was added to stop the reaction, and then 30 mL ( 30 Vol%) of hydrogen peroxide. After reacting for about 30 min, 40 mL (10 Vol%) of hydrochloric acid solution is added to dissolve. The low-speed centrifugal washing removes excess acid and by-products. The neutral graphite oxide is dispersed in water after washing, and it is peeled off by ultrasonic vibration for 60min. After the ultrasonication, it is centrifuged at 3000r · min -1 for 30min. The upper layer is graphene oxide. The dispersion was dried in a vacuum drying box at 60 ° C. for 30 h to obtain a graphene oxide sample.
称取40mg氧化石墨烯样品加至20ml超纯水中，置于超声震荡清洗器内，300W功率下，进行超声处理1h，获得均匀的氧化石墨烯分散液。将该分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.3ml的氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在190℃高温下，保温30h。待反应结束，使反应釜自然冷却至室温。调节pH值，将反应液过滤，滤饼用超纯水多次洗涤，直到其pH值达到中性。将所得固体产物烘干，得到氟化石墨烯样品。A 40 mg sample of graphene oxide was weighed and added to 20 ml of ultrapure water, placed in an ultrasonic vibration cleaner, and subjected to ultrasonic treatment at 300 W for 1 h to obtain a uniform graphene oxide dispersion. Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene liner to 2/3 of the liner volume, and add 0.3ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it. It was placed in an oven and held at 190 ° C for 30 hours. After the reaction is completed, the reaction kettle is naturally cooled to room temperature. The pH was adjusted, the reaction solution was filtered, and the filter cake was washed with ultrapure water multiple times until its pH reached neutral. The obtained solid product was dried to obtain a fluorinated graphene sample.
称取经水热法制备的氟化石墨烯10mg，用称量纸转移到烧杯当中，用移液管量取10ml全氟三乙胺试剂于烧杯当中，配置浓度为1mg/ml的氟化石墨烯-全氟三乙胺分散液。随后置于超声震荡清洗器内，100W功率下超声处理10min，获得均匀的氟化化石墨烯-全氟三乙胺纳米流体。Weigh 10mg of fluorinated graphene prepared by hydrothermal method, transfer it into a beaker with a weighing paper, measure 10ml of perfluorotriethylamine reagent into a beaker with a pipette, and arrange the fluorinated graphene with a concentration of 1mg / ml -Perfluorotriethylamine dispersion. It was then placed in an ultrasonic oscillating cleaner and sonicated at 100 W for 10 min to obtain a uniform fluorinated graphene-perfluorotriethylamine nanofluid.
通过观察静置无沉降时间来判断分散液的稳定性。静置2周后分散液不发生明显分层现象，说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。The stability of the dispersion was judged by observing the non-settling time at rest. After standing for 2 weeks, no obvious delamination occurred in the dispersion, indicating that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.

Claims (10)

  1. 一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于采用纳米尺度石墨烯填料，不采用任何添加剂，仅通过表面修饰即可实现在基液全氟三乙胺的均匀分散，并实现全氟三乙胺热导率的提高和在典型摩擦副下摩擦系数的降低，包括以下步骤：A method for preparing perfluorotriethylamine-based highly thermally conductive lubricating nanofluid, which is characterized in that nanoscale graphene filler is used, without any additives, and uniform dispersion of perfluorotriethylamine in the base liquid can be achieved only by surface modification. And achieve the improvement of the thermal conductivity of perfluorotriethylamine and the reduction of friction coefficient under typical friction pairs, including the following steps:
    步骤1：石墨烯的氧化，获得具有反应活性的氧终端：Step 1: Oxidation of graphene to obtain reactive oxygen termination:
    1.1使用改进Hummers法制备氧化石墨烯，氧化石墨烯的层数为1-5层，片径10nm-1μm；1.1 The modified Hummers method is used to prepare graphene oxide, the number of layers of graphene oxide is 1-5, and the sheet diameter is 10nm-1μm;
    1.2经低温、中温与高温反应后，获得表面为氧终端的石墨烯；1.2 After reacting at low, middle and high temperatures, graphene with oxygen termination on the surface is obtained;
    步骤2：石墨烯的表面氟化：Step 2: Surface fluorination of graphene:
    2.1氧化石墨烯与超纯水均匀分散，2.1 Graphene oxide is evenly dispersed with ultrapure water,
    为实现氧化石墨烯表面实现均匀氟化，首先需要将氧化石墨烯均匀分散至超纯水中；通过超声振荡打破原本是团簇状的石墨烯团，依靠石墨烯表面极性氧化基团实现在超纯水中的均匀分散；In order to achieve uniform fluorination on the graphene oxide surface, the graphene oxide needs to be evenly dispersed in ultrapure water; the clustered graphene groups are broken by ultrasonic oscillation, and the polar oxide groups on the graphene surface are used to achieve Evenly dispersed in ultrapure water;
    2.2石墨烯表面氟化修饰，2.2 Graphene surface fluorination modification,
    为使氧化石墨烯表面建立氟终端，通过水热的高温高压环境促使氧终端与氢氟酸溶液反应，实现氧终端向氟终端的可控转变；In order to establish a fluorine terminal on the surface of graphene oxide, the hydrothermal high temperature and high pressure environment is used to promote the reaction between the oxygen terminal and the hydrofluoric acid solution to achieve a controllable transition from the oxygen terminal to the fluorine terminal;
    2.3氟化石墨烯的清洗与分离：2.3 Cleaning and separation of fluorinated graphene:
    经水热反应后的石墨烯表面将残留有氢氟酸溶液，还会有尺寸不均一的其他副产物，需要将反应液过滤、洗涤，并进一步调整水溶液pH值至中性，将所得固体产物烘干，即得到氟化石墨烯样品；After hydrothermal reaction, hydrofluoric acid solution will remain on the graphene surface, and there will be other by-products of uneven size. The reaction solution needs to be filtered and washed, and the pH value of the aqueous solution should be adjusted to neutral to obtain the solid product. Drying to obtain fluorinated graphene samples;
    步骤3：基于氟化石墨烯全氟三乙胺纳米流体的制备：Step 3: Preparation of perfluorotriethylamine nanofluid based on fluorinated graphene:
    干燥后的氟化石墨烯需进一步分散于全氟三乙胺溶液中，形成均匀分散的纳米流体；一方面需要给予氟化石墨烯与全氟三乙胺足够的能量，打破氟化与氧化石墨烯间由于物理与化学间吸附带来的团聚，使其均匀分散到全氟三乙胺中，另一方面需要避免由于过高的能量使得分散开的氟化石墨烯重新团聚；需要严格控制超声震荡的能量与水温；The dried fluorinated graphene needs to be further dispersed in the perfluorotriethylamine solution to form a uniformly dispersed nanofluid. On the one hand, it is necessary to give sufficient energy to the fluorinated graphene and perfluorotriethylamine to break the fluorinated and graphite oxide. Due to agglomeration caused by physical and chemical adsorption between olefins, they are evenly dispersed in perfluorotriethylamine. On the other hand, it is necessary to avoid re-agglomeration of dispersed fluorinated graphene due to excessive energy; strict control of ultrasound is required. Shock energy and water temperature;
    步骤4：稳定性评价：Step 4: Stability evaluation:
    最为直接与直观的方法评价石墨烯-全氟三乙胺纳米流体的稳定性方法是通过观察静置无沉降时间来判断分散液的稳定性，静置2周后不发生明显分层现象，则说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。The most direct and intuitive method to evaluate the stability of graphene-perfluorotriethylamine nanofluids is to determine the stability of the dispersion by observing the time without sedimentation. After 2 weeks of standing, no obvious delamination occurs. This shows that the fluorinated graphene-perfluorotriethylamine nanofluid has good stability.
  2. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤1所述Hummers法制备氧化石墨烯工艺为：低温反应温度控制于0-4℃，加入高锰酸钾后控制温度不超过5-15℃；中温反应温度35-40℃，反应时间20-60min；高温反应80-100℃，反应20-60min。The method for preparing a perfluorotriethylamine-based highly thermally conductive lubricating nanofluid according to claim 1, characterized in that the process of preparing graphene oxide by the Hummers method in step 1 is: the low-temperature reaction temperature is controlled at 0-4 ° C, and After potassium permanganate, the control temperature does not exceed 5-15 ° C; the reaction temperature at medium temperature is 35-40 ° C, the reaction time is 20-60min; the reaction at high temperature is 80-100 ° C, the reaction is 20-60min.
  3. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤1所述的高温反应后的反应产物离心、洗涤后，需进行超声剥离，剥离30-60min，超声结束后在1000-3000r·min -1转速下离心20-40min。 The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, characterized in that the reaction product after the high-temperature reaction described in step 1 is centrifuged and washed, and then ultrasonic peeling is required to peel off 30- After 60 minutes, the centrifugation was performed at a speed of 1000-3000 r · min -1 for 20-40 minutes after the end of ultrasound.
  4. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤1所述的超声剥离后的上层液即是氧化石墨烯分散液，需在60℃下于真空干燥箱中干燥48h，备用。The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, characterized in that the upper layer liquid after the ultrasonic peeling in step 1 is a graphene oxide dispersion liquid, which needs to be at 60 ° C Dry in a vacuum drying oven for 48h and set aside.
  5. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤2所述的石墨烯氟化过程，首先需要将20-40mg氧化石墨烯加入超纯水中，超声处理，直到获得均匀的氧化石墨烯分散液。The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, wherein the graphene fluorination process in step 2 first requires 20-40 mg of graphene oxide to be added to ultrapure water Sonicate until a uniform graphene oxide dispersion is obtained.
  6. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤2所述的石墨烯氟化过程，经分散后，分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.2ml-0.5ml的氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在150℃-200℃高温下进行保温20-40小时。The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, wherein the graphene fluorination process in step 2 is dispersed, and the dispersion is added to a polytetrafluorofluoride In an ethylene-lined hydrothermal kettle, go to 2/3 of the lining volume, and add 0.2ml-0.5ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it, then place it in an oven at 150 ℃ -200 ℃ for 20-40 hours.
  7. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤2所述的石墨烯经水热法氟化后，需经过调节pH值至中性、洗涤、过滤、烘干，获得氟化石墨烯样品。The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, characterized in that after the graphene in step 2 is fluorinated by a hydrothermal method, it needs to be adjusted to a neutral pH, Wash, filter, and dry to obtain fluorinated graphene samples.
  8. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤3所述的石墨烯全氟三乙胺纳米流体的制备，溶液浓度1mg/ml-3mg/ml，超声振荡的功率100W-300W，时间5min-10min，超声温度不超过35℃。The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, characterized in that the preparation of the graphene perfluorotriethylamine nanofluid in step 3 has a solution concentration of 1mg / ml-3mg / ml, the power of ultrasonic oscillation is 100W-300W, the time is 5min-10min, and the ultrasonic temperature does not exceed 35 ° C.
  9. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于步骤4所述的石墨烯全氟三乙胺纳米流体的稳定性采用室温静置法评价，以2周后不发生明显分层现象为宜；纳米流体的稳定性还可以通过动态光散射法、Zeta电位法进行评价。The method for preparing a perfluorotriethylamine-based highly thermally lubricating nanofluid according to claim 1, wherein the stability of the graphene perfluorotriethylamine nanofluid in step 4 is evaluated by a room temperature standing method, It is advisable that no obvious stratification occurs after 2 weeks; the stability of the nanofluid can also be evaluated by dynamic light scattering method and Zeta potential method.
  10. 根据权利要求1所述一种全氟三乙胺基高导热润滑纳米流体的制备方法，其特征在于具体包括以下制备步骤：The method for preparing a perfluorotriethylamine-based highly thermally conductive lubricating nanofluid according to claim 1, characterized in that it specifically comprises the following preparation steps:
    步骤1：石墨烯的氧化，获得具有反应活性的氧终端：Step 1: Oxidation of graphene to obtain reactive oxygen termination:
    为了实现表面氟化，需要首先将石墨烯表面活化，为进一步氟化做准备。使用改进Hummers制备氧化石墨烯，具体步骤如下：In order to achieve surface fluorination, graphene needs to be activated first to prepare for further fluorination. To prepare graphene oxide using modified Hummers, the specific steps are as follows:
    1.1低温反应1.1 Low temperature reaction
    量取10-40mL浓硫酸倒入烧杯，烧杯放入冰浴中冷却至0-4℃，称取0.5-2g石墨粉和0.2-1g硝酸钠或石墨烯粉与硝酸钠放入烧杯，开启超声，0.5-1h以后缓慢加入1-5g高锰酸钾，关闭超声并开始搅拌，控制温度不超过5-15℃，反应时间共1-3h；Measure 10-40mL concentrated sulfuric acid into a beaker, put the beaker in an ice bath and cool to 0-4 ° C, weigh 0.5-2g graphite powder and 0.2-1g sodium nitrate or graphene powder and sodium nitrate into the beaker, turn on the ultrasound After 0.5-1h, slowly add 1-5g potassium permanganate, turn off the ultrasound and start stirring, control the temperature not to exceed 5-15 ℃, and the reaction time is 1-3h;
    1.2中温反应1.2 Medium temperature reaction
    把烧杯移至水浴锅，开启超声，水浴温度控制在35-40℃反应20-60min；Move the beaker to the water bath, turn on the ultrasound, and control the temperature of the water bath at 35-40 ℃ to react for 20-60min;
    1.3高温反应1.3 High temperature reaction
    把所得混合液缓慢加入50-200mL的低温去离子水中，接着将以上混合液置于80-100℃水浴中反应20-60min，期间保持适度机械搅拌；高温反应后加入去离子水中止反应，随后加入5-30Vol％的双氧水，待反应10-30min后再加入5-10Vol％的盐酸溶液溶解；低速离心洗涤去除过量的酸及副产物，将洗涤后呈中性的氧化石墨分散于水中，超声振荡剥离30-60min，超声结束后在1000-3000r·min -1转速下离心20-40min，上层液即是氧化石墨烯分散液，60℃下于真空干燥箱中干燥48h，备用； Slowly add the resulting mixed solution to 50-200mL of low-temperature deionized water, and then place the above mixed solution in a water bath at 80-100 ° C for 20-60min, while maintaining moderate mechanical stirring; add high-temperature reaction to deionized water to stop the reaction, and then Add 5-30Vol% hydrogen peroxide solution, and wait for 10-30min to add 5-10Vol% hydrochloric acid solution to dissolve. After low speed centrifugal washing to remove excess acid and by-products, disperse the neutral graphite oxide after washing in water and sonicate. After shaking and peeling for 30-60min, centrifugation at 1000-3000r · min -1 for 20-40min after the end of the ultrasound, the upper layer is the graphene oxide dispersion, dried in a vacuum drying box at 60 ° C for 48h, and set aside;
    步骤2：石墨烯的表面氟化：Step 2: Surface fluorination of graphene:
    具体包括以下步骤：It includes the following steps:
    2.1氧化石墨烯与超纯水均匀分散2.1 Graphene oxide is evenly dispersed with ultrapure water
    称取20mg-40mg氧化石墨烯样品加至超纯水中，置于超声震荡清洗器内，进行超声处理，获得均匀的氧化石墨烯分散液；Weigh a 20mg-40mg graphene oxide sample into ultrapure water, place it in an ultrasonic vibration cleaner, and perform ultrasonic treatment to obtain a uniform graphene oxide dispersion;
    2.2高温反应2.2 High temperature reaction
    将该分散液加入到带有聚四氟乙烯内衬的水热釜内，至内衬容积的2/3处，并加入0.2ml-0.5ml的氢氟酸，将水热釜拧紧使其密闭，然后将其置于烘箱内，在150℃-200℃高温下进行保温20-40小时；Add this dispersion to a hydrothermal kettle with a polytetrafluoroethylene liner to 2/3 of the liner volume, and add 0.2ml-0.5ml of hydrofluoric acid. Tighten the hydrothermal kettle to seal it , And then put it in an oven and heat-preserved at a high temperature of 150 ° C-200 ° C for 20-40 hours;
    2.3过滤、洗涤、干燥反应产物2.3 Filtration, washing and drying of reaction products
    待反应结束，使反应釜自然冷却至室温，调节pH值，将反应液过滤，滤饼用超纯水多次洗涤，直到其pH值达到中性，将所得固体产物烘干，得到氟化石墨烯样品；After the reaction is completed, the reaction kettle is naturally cooled to room temperature, the pH value is adjusted, the reaction solution is filtered, and the filter cake is washed with ultrapure water multiple times until the pH value reaches neutrality. The obtained solid product is dried to obtain fluorinated graphite Olefin sample
    步骤3：基于氟化石墨烯全氟三乙胺纳米流体的制备：Step 3: Preparation of perfluorotriethylamine nanofluid based on fluorinated graphene:
    称取经水热法制备的氟化石墨烯10mg-30mg，用称量纸转移到烧杯当中，用移液管量取10ml-全氟三乙胺试剂于烧杯当中，配置浓度为1mg/ml-3mg/ml的氟化石墨烯-全氟三乙胺分散液；随后置于超声震荡清洗器内，100W-300W功率下超声处理5min-10min，控制超声温度不超过35℃，获得均匀的氟化化石墨烯-全氟三乙胺纳米流体；Weigh 10mg-30mg of fluorinated graphene prepared by the hydrothermal method, transfer it into a beaker with a weighing paper, and measure 10ml-perfluorotriethylamine reagent into the beaker with a pipette, with a concentration of 1mg / ml-3mg / ml of fluorinated graphene-perfluorotriethylamine dispersion; then placed in an ultrasonic vibration cleaner and sonicated at a power of 100W-300W for 5min-10min, controlling the ultrasonic temperature to not exceed 35 ° C to obtain uniform fluorination Graphene-perfluorotriethylamine nanofluid;
    步骤4：稳定性评价Step 4: Stability evaluation
    通过观察静置无沉降时间来判断分散液的稳定性，静置2周后不发生明显分层现象，则说明氟化石墨烯-全氟三乙胺纳米流体稳定性良好。The stability of the dispersion was judged by observing the non-settling time after standing, and no obvious delamination occurred after standing for 2 weeks, indicating that the stability of the fluorinated graphene-perfluorotriethylamine nanofluid was good.
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