Lubricating oil and preparation method thereof

Abstract

The present application provides a lubricating oil and a preparation method thereof, wherein the lubricating oil comprises a base lubricating oil and an additive, wherein the additive comprises graphyne and graphene quantum dots dispersed on the surface of the graphyne, wherein the graphene quantum dots and the graphyne are chemically bonded to each other. The additive in the lubricating oil of the present application adopts graphyne and graphene quantum dots, wherein graphyne has abundant carbon covalent bonds and can provide more active sites, and the graphene quantum dots can be dispersed on the graphyne sheets by bonding, thereby effectively avoiding the agglomeration and precipitation of the graphene quantum dots, and improving the stability and lubrication effect of the lubricating oil.

Description

Technical Field

[0001] The present application relates to the technical field of lubricating oils, and in particular to a lubricating oil and a preparation method thereof. Background Art

[0002] Since the base lubricant itself has poor performance in different working environments and weak load-bearing capacity, in order to improve the anti-wear and wear resistance of the base lubricant, it is necessary to add specific lubricant additives to improve the anti-wear and wear resistance of the lubricant. Among them, graphene has great potential in the application field of lubricant additives due to its unique two-dimensional structure, ultra-high elastic modulus (1100 GPa), fracture strength (125GPa) and thermal conductivity (5000 W / (m·K)), as well as excellent self-lubrication and high temperature resistance. Graphene itself has excellent tribological properties and can be functionally modified. Therefore, it has become a new research hotspot for lubricant additives in the development direction of green, environmental protection and high friction reduction.

[0003] However, in the process of using graphene as a lubricant additive, graphene can improve the tribological ability of lubricants to a certain extent. However, due to its own two-dimensional structural characteristics, there is van der Waals force between the layers, which is easy to be adsorbed between the layers and then agglomerated, making it difficult to fully disperse in the lubricant, so that its own excellent physical and chemical properties cannot be fully exerted.

[0004] Therefore, how to provide a lubricating oil with good stability and good wear resistance has become a technical problem that urgently needs to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide a lubricating oil and a preparation method thereof, which have high stability and high wear resistance.

[0006] In a first aspect, the present application provides a lubricating oil, comprising a base lubricating oil and an additive, wherein the additive comprises graphyne and graphene quantum dots dispersed on the surface of the graphyne, wherein the graphene quantum dots are chemically bonded to the graphyne.

[0007] In some embodiments, the mass ratio of the graphene quantum dots to the graphyne is 1:(2-5).

[0008] In some embodiments, the mass of the additive is 0.8% to 1.25% of the mass of the base lubricating oil.

[0009] In some embodiments, the lubricating oil further includes an additive; optionally, the additive includes at least one of a polyol, a co-solvent and a viscosity modifier.

[0010] In some embodiments, the graphyne includes nitrogen-containing graphyne; optionally, the nitrogen atomic percentage content of the nitrogen-containing graphyne is 8% to 20%.

[0011] In some embodiments, the Graphdine sheet diameter is 400nm~800nm.

[0012] In some embodiments, the graphene quantum dots include nitrogen-doped graphene quantum dots.

[0013] In some embodiments, the average particle size D50 of the graphene quantum dots is 5 nm to 50 nm.

[0014] In a second aspect, the present application provides a method for preparing the lubricating oil as described in the first aspect, the preparation method comprising:

[0015] The raw material containing organic acid is subjected to microwave activation treatment, heat treatment and dialysis drying treatment in sequence to obtain the graphene quantum dots;

[0016] The graphene quantum dots, graphyne, a coupling agent and a base lubricating oil are mixed and heated to prepare the lubricating oil.

[0017] In some embodiments, the graphene quantum dots include nitrogen-doped graphene quantum dots, and the method for preparing the nitrogen-doped graphene quantum dots includes:

[0018] An organic acid, an inorganic ammonium salt and an organic amine are mixed to obtain a premix, and the premix is ​​sequentially subjected to microwave activation treatment, heat treatment and dialysis drying treatment to obtain the nitrogen-doped graphene quantum dots.

[0019] Optionally, the microwave power of the microwave activation treatment is 2 kW to 3 kW, and the treatment time is 15 min to 30 min.

[0020] Optionally, the heat treatment is performed at a temperature of 200° C. to 220° C. and for a time of 6 h to 10 h.

[0021] In some embodiments, the mass proportion of the organic acid in the premix is ​​50% to 77%.

[0022] In some embodiments, the organic acid includes at least one of lactic acid, ascorbic acid, tartaric acid, citric acid, and malic acid.

[0023] In some embodiments, the inorganic ammonium salt accounts for 10% to 23% by mass in the premix.

[0024] In some embodiments, the inorganic ammonium salt includes at least one of ammonium sulfate, ammonium nitrate, ammonium chloride, and ammonium bromide.

[0025] In some embodiments, the mass proportion of the organic amine in the premix is ​​5% to 13%.

[0026] In some embodiments, the organic amines include aliphatic diamines and polyamines.

[0027] In some embodiments, the heating temperature is 60°C to 65°C.

[0028] In some embodiments, the mixing is carried out at a stirring speed of 300 rpm to 500 rpm and for a time of 8 h to 12 h.

[0029] In some embodiments, the coupling agent includes a silane coupling agent.

[0030] In some embodiments, an auxiliary agent is added to the lubricating oil during mixing; optionally, the auxiliary agent includes at least one of a polyol, a cosolvent and a viscosity modifier.

[0031] In some embodiments, the preparation method further comprises: performing jet homogenization treatment on the lubricating oil.

[0032] Optionally, during the homogenization process, the temperature is 60° C. to 65° C., the pressure is 28000 to 32000 psi, the flow rate is 40 m / s to 50 m / s, and the treatment time is 2 h to 4 h.

[0033] Compared with the traditional technology, this application has at least the following beneficial effects:

[0034] The additives in this application use graphyne and graphene quantum dots. Graphene has abundant carbon covalent bonds and can provide more active sites. Graphene quantum dots can be dispersed on the graphyne sheets by bonding, effectively avoiding the aggregation and precipitation of graphene quantum dots, and improving the stability and lubrication effect of the lubricant. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a comparison chart of the dispersion stability test results of Example 1 and Comparative Example 2 of the present application, where a represents Example 1 and b represents Comparative Example 2;

[0036] Figure 2 This is a comparison diagram of the wear spot diameters of Example 1 and Comparative Example 2 of the present application, where a represents Example 1 and b represents Comparative Example 2. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with the embodiments and examples. These embodiments and examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. The purpose of providing these embodiments and examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive. It should also be understood that the present invention can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various changes or modifications without violating the connotation of the present invention, and the equivalent form obtained also falls within the protection scope of the present invention. In addition, in the description below, a large number of specific details are given in order to provide a more comprehensive understanding of the present invention. It should be understood that the present invention can be implemented without one or more of these details.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0039] In the present invention, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel solutions of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0040] In the present invention, the terms "first", "second", etc. in "the first aspect", "the second aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0041] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0042] In the present invention, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0043] All documents mentioned in the present invention are cited as references in this application, just as each document is cited as a reference separately. Unless they conflict with the invention purpose and / or technical solution of the present application, the cited documents involved in the present invention are cited with all contents and all purposes. When the present invention involves cited documents, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the present invention involves cited documents, the examples and preferred embodiments of the cited relevant technical features may also be incorporated into this application as references, but are limited to the ability to implement the present invention. It should be understood that when the content of the citation conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0044] In the conventional technology, the use of graphene as an additive for lubricating oil has problems such as poor dispersion stability; and the use of graphene quantum dots as an additive has poor effect on improving the wear resistance of lubricating oil. However, the present application disperses graphene quantum dots on graphyne sheets to form a multi-element friction enhancing material, which effectively improves the problem of poor dispersion of graphene materials in lubricating oil and improves the comprehensive performance of graphene lubricating oil.

[0045] A first aspect of the present application provides a lubricating oil, comprising a base lubricating oil and an additive, wherein the additive comprises graphyne and graphene quantum dots dispersed on the surface of the graphyne, wherein the graphene quantum dots and the graphyne are chemically bonded to each other.

[0046] The additives in this application use graphyne and graphene quantum dots. Graphene has abundant carbon covalent bonds and can provide more active sites. Graphene quantum dots can be dispersed on the graphyne sheets by bonding, effectively avoiding the aggregation and precipitation of graphene quantum dots, and improving the stability and lubrication effect of the lubricant.

[0047] It should be noted that graphene quantum dots refer to graphene with a size less than 100nm, which is close to quasi-zero-dimensional graphene in appearance. Compared with ordinary graphene, they have more obvious quantum confinement effect and stronger edge effect. Their structural characteristics make them easier to disperse in the medium, thereby better exerting the tribological properties of graphene.

[0048] In some embodiments, the graphyne and the graphene quantum dots are connected via covalent bonds.

[0049] In some embodiments, the base lubricant oil includes at least one of a poly-alpha-olefin synthetic base oil, an ester synthetic base oil, and a silicone oil.

[0050] In some embodiments, the mass ratio of the graphene quantum dots to the graphyne is 1:(2-5), for example, 1:2.0, 1:2.3, 1:2.6, 1:2.9, 1:3.2, 1:3.5, 1:3.8, 1:4.1, 1:4.4, 1:4.7 or 1:5.0.

[0051] The present application controls the mass ratio between graphene quantum dots and graphyne, thereby having the advantages of high lubrication, high synthesis efficiency and low cost; if the proportion of graphyne is relatively large, there may be problems such as graphyne sheet accumulation and insufficient attachment of quantum dots; if the proportion of graphyne is relatively small, there may be problems such as the inability of quantum dots to be completely combined with graphyne, which may lead to problems such as poor dispersion and poor lubrication effect.

[0052] In some embodiments, the mass of the additive is 0.8% to 1.25% of the mass of the base lubricant, for example, it can be 0.80%, 0.85%, 0.90%, 0.95%, 1.00%, 1.05%, 1.10%, 1.15%, 1.20% or 1.25%.

[0053] The present application controls the amount of additives added, thereby having the advantages of high lubricity and low cost; if the proportion of additives is relatively large, there may be problems such as enhanced particle accumulation and high cost; if the proportion of additives is relatively small, there may be problems such as uneven mixing and poor lubrication effect.

[0054] In some embodiments, the lubricating oil further includes an additive; optionally, the additive includes at least one of a polyol, a co-solvent and a viscosity modifier.

[0055] The polyol is combined with the silane coupling agent to provide hydroxyl groups for the silane coupling agent to hydrolyze and form a bridge between the quantum dots and the graphene to improve the connection effect. Optionally, the polyol includes ethylene glycol.

[0056] In some embodiments, the graphyne includes nitrogen-containing graphyne; optionally, the nitrogen atomic percentage of the nitrogen-containing graphyne is 8% to 20%, for example, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%. The atomic percentage refers to the percentage of the number of nitrogen atoms in the total number of atoms.

[0057] In some embodiments, the Graphene sheet diameter is 400 nm to 800 nm, for example, it can be 400 nm, 440 nm, 480 nm, 520 nm, 560 nm, 600 nm, 640 nm, 680 nm, 720 nm, 760 nm or 800 nm.

[0058] In some embodiments, the graphene quantum dots include nitrogen-doped graphene quantum dots. Optionally, the nitrogen atomic percentage content in the nitrogen-doped graphene quantum dots is 10% to 30%, for example, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%.

[0059] The present application uses nitrogen-doped graphene quantum dots, so that the surface of the graphene quantum dots has amino groups, which is conducive to the combination of the graphene quantum dots with the active sites on the surface of graphyne. Further, the present application uses nitrogen-doped graphene quantum dots and nitrogen-containing graphyne to ensure the bonding efficiency and stability between the quantum dots and graphyne, thereby ensuring the stability and dispersibility of the additive.

[0060] In some embodiments, the average particle size D50 of the graphene quantum dots is 5 nm to 50 nm, for example, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm.

[0061] The second aspect of the present application provides a method for preparing the lubricating oil according to the first aspect, the preparation method comprising:

[0062] The raw material containing organic acid is subjected to microwave activation treatment, heat treatment and dialysis drying treatment in sequence to obtain the graphene quantum dots;

[0063] The graphene quantum dots, graphyne, a coupling agent and a base lubricating oil are mixed and heated to prepare the lubricating oil.

[0064] The present application realizes the bonding connection between graphene quantum dots and graphyne through a coupling agent, and the graphene quantum dots are adsorbed and distributed on the surface of the graphyne sheet, effectively avoiding the agglomeration and precipitation of the graphene.

[0065] In some embodiments, the graphene quantum dots include nitrogen-doped graphene quantum dots, and the method for preparing the nitrogen-doped graphene quantum dots includes:

[0066] An organic acid, an inorganic ammonium salt and an organic amine are mixed to obtain a premix, and the premix is ​​sequentially subjected to microwave activation treatment, heat treatment and dialysis drying treatment to obtain the nitrogen-doped graphene quantum dots.

[0067] The present application uses organic acid, ammonium salt and organic amine as raw materials, and utilizes microwave and heat treatment to prepare nitrogen-containing graphene quantum dots. Microwave treatment is beneficial to improving the preparation efficiency of quantum dots in heat treatment.

[0068] Optionally, the microwave power in the microwave activation treatment process is 2 kW to 3 kW, for example, it can be 2.0 kW, 2.1 kW, 2.2 kW, 2.3 kW, 2.4 kW, 2.5 kW, 2.6 kW, 2.7 kW, 2.8 kW, 2.9 kW or 3.0 kW.

[0069] Optionally, the treatment time of the microwave activation treatment is 15 min to 30 min, for example, it can be 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min or 30 min.

[0070] Optionally, the heat treatment temperature is 200°C to 220°C, for example, it can be 200°C, 202°C, 204°C, 206°C, 208°C, 210°C, 212°C, 214°C, 216°C, 218°C or 220°C.

[0071] The present application controls the temperature of the heat treatment to achieve controllable quantum dot size and high yield. If the temperature is relatively low, the quantum dot yield may be low; if the temperature is relatively high, the size of the generated quantum dots may be uncontrollable.

[0072] Optionally, the heat treatment time is 6 h to 10 h, for example, it can be 6 h, 7 h, 8 h, 9 h or 10 h.

[0073] In some embodiments, the mass proportion of the organic acid in the premix is ​​50% to 77%.

[0074] In some embodiments, the organic acid comprises at least one of lactic acid, ascorbic acid, tartaric acid, citric acid and malic acid. Preferably, the organic acid comprises lactic acid and ascorbic acid. Further preferably, the mass proportion of the lactic acid in the premix is ​​30% to 60%, and the mass proportion of the ascorbic acid in the premix is ​​18.5% to 34%.

[0075] In some embodiments, the inorganic ammonium salt accounts for 10% to 23% by mass in the premix.

[0076] In some embodiments, the inorganic ammonium salt includes at least one of ammonium sulfate, ammonium nitrate, ammonium chloride, and ammonium bromide.

[0077] In some embodiments, the mass proportion of the organic amine in the premix is ​​5% to 13%.

[0078] In some embodiments, the organic amines include aliphatic diamines and polyamines.

[0079] In some embodiments, the raw materials for preparing the graphene quantum dots include, by weight:

[0080] Lactic acid, 20 to 30 parts; ascorbic acid, 10 to 15 parts; inorganic ammonium, 6 to 9 parts; organic amine, 3 to 5 parts.

[0081] In some embodiments, the heating temperature is 60°C to 65°C, for example, 60°C, 61°C, 62°C, 63°C, 64°C or 65°C.

[0082] In some embodiments, the stirring speed of the mixing is 300 rpm to 500 rpm, for example, it can be 300 rpm, 320 rpm, 340 rpm, 360 rpm, 380 rpm, 400 rpm, 420 rpm, 440 rpm, 460 rpm, 480 rpm or 500 rpm.

[0083] In some embodiments, the mixing time is 8 h to 12 h, for example, 8 h, 9 h, 10 h, 11 h or 12 h.

[0084] In some embodiments, the coupling agent comprises a silane coupling agent. Alternatively, the coupling agent comprises a KH550 silane coupling agent.

[0085] In some embodiments, an auxiliary agent is added to the lubricating oil during mixing; optionally, the auxiliary agent includes at least one of a polyol, a co-solvent and a viscosity modifier.

[0086] In some embodiments, the lubricating oil includes, by weight:

[0087] Graphene quantum dots, 3 to 5 parts; graphyne, 10 to 15 parts; coupling agent, 1 to 1.5 parts; polyol, 2 to 4 parts; flux, 4 to 6 parts; viscosity modifier, 1.5 to 2.5 parts; and base lubricating oil, 1,200 to 1,600 parts.

[0088] Optionally, the flux includes at least one of ethylenediamine, acetamide, nicotinamide and sodium benzoate.

[0089] Optionally, the viscosity modifier includes at least one of polymethacrylate, polymethyl acrylate, sodium tripolyphosphate and sodium hexametaphosphate.

[0090] In some embodiments, the preparation method further comprises: subjecting the lubricating oil to jet homogenization treatment.

[0091] The present application adopts jet homogenization treatment to regulate the graphyne flakes through high pressure and high flow rate so that they can be evenly and stably dispersed in the lubricating oil.

[0092] Optionally, the temperature of the homogenization treatment is 60°C to 65°C, for example, it can be 60°C, 61°C, 62°C, 63°C, 64°C or 65°C.

[0093] Optionally, the pressure during the homogenization process is 28000psi~32000psi, for example, it can be 28000psi, 28500psi, 29000psi, 29500psi, 30000psi, 30500psi, 31000psi, 31500psi or 32000psi.

[0094] Optionally, the flow rate during the homogenization process is 40m / s~50m / s, for example, it can be 40m / s, 41m / s, 42m / s, 43m / s, 44m / s, 45m / s, 46m / s, 47m / s, 48m / s, 49m / s or 50m / s.

[0095] Optionally, the processing time during the homogenization process is 2h~4h, for example, it can be 2.0h, 2.5h, 3.0h, 3.5h or 4.0h.

[0096] Exemplarily, a method for preparing the above lubricating oil is provided, comprising:

[0097] An organic acid, an inorganic ammonium salt and an organic amine are mixed to obtain a premix, wherein the premix comprises 20 to 30 parts of lactic acid, 10 to 15 parts of ascorbic acid, 6 to 9 parts of inorganic ammonium and 3 to 5 parts of organic amine, the premix is ​​subjected to microwave activation treatment at a power of 2 kW to 3 kW for 15 min to 30 min, and then subjected to heat treatment at 200° C. to 220° C. for 6 h to 10 h, and after the heat treatment, is subjected to dialysis drying treatment for 48 h, and is spray-dried to obtain the graphene quantum dots;

[0098] 3 to 5 parts of the above-mentioned graphene quantum dots, 10 to 15 parts of graphyne, 1 to 1.5 parts of a coupling agent, 2 to 4 parts of a polyol, 4 to 6 parts of a flux, and 1.5 to 2.5 parts of a viscosity modifier are mixed uniformly, and 1200 to 1600 parts of a base lubricating oil are added, and stirred at 60 to 65° C. and 300 to 500 rpm for 8 to 12 hours to obtain a mixed oil;

[0099] The mixed oil is homogenized by a microfluidizer at a homogenization temperature of 60-65° C., a processing pressure of 28000psi-32000psi, a flow rate of 40m / s-50m / s, and a homogenization time of 2-4 hours to obtain the lubricating oil.

[0100] The embodiments of the present invention will be described in detail below in conjunction with examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are preferably referred to the guidance provided in the present invention, and can also be based on the experimental manual or normal conditions in this area, can also be based on the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0101] Example 1

[0102] (1) Graphene quantum dots

[0103] Take 20g of lactic acid, 10g of ascorbic acid, 6g of ammonium sulfate, and 3g of octadecylamine, mix them evenly, and treat them at a microwave power of 2kW for 15min. Then, heat treat them at 200℃ for 6 hours. After the treatment, add 50g of deionized water, stir well, dialyze the above solution for 48 hours, and obtain graphene quantum dot powder by spray drying.

[0104] (2) Lubricating oil

[0105] Take 3g of the above-mentioned graphene quantum dots, 10g of graphyne (sheet diameter 400nm, nitrogen content 8at.%), 1g of KH550 silane coupling agent, 2g of ethylene glycol, 4g of ethylenediamine and 1.5g of polymethacrylate, mix them evenly, add 1200g of poly-α-olefin base lubricant, stir at 300rpm for 8h at 60℃ to obtain a mixed oil;

[0106] The mixed oil was homogenized for 2 hours using a microfluidizer at 60° C., a processing pressure of 30,000 psi, and a flow rate of 40 m / s to obtain the lubricating oil.

[0107] Example 2

[0108] (1) Graphene quantum dots

[0109] Take 30g of lactic acid, 15g of ascorbic acid, 9g of ammonium sulfate, and 5g of octadecylamine, mix them evenly, and treat them at a microwave power of 3kW for 30min. Then, heat treat them at 220℃ for 10 hours. After the treatment, add 80g of deionized water, stir well, dialyze the above solution for 48 hours, and spray dry to obtain graphene quantum dot powder.

[0110] (2) Lubricating oil

[0111] Take 5 g of the above-mentioned graphene quantum dots, 15 g of graphyne (sheet diameter 400 nm, nitrogen content 8 at.%), 1.5 g of KH550 silane coupling agent, 4 g of ethylene glycol, 6 g of ethylenediamine and 2.5 g of polymethacrylate, mix them evenly, add 1600 g of poly-α-olefin base lubricant, stir at 500 rpm for 12 h at 65 ° C to obtain a mixed oil;

[0112] The mixed oil was homogenized by using a microfluidizer at 65° C., a processing pressure of 30,000 psi, and a flow rate of 50 m / s for 4 hours to obtain the lubricating oil.

[0113] Example 3

[0114] (1) Graphene quantum dots

[0115] Take 25g of lactic acid, 13g of ascorbic acid, 7g of ammonium sulfate, and 4g of octadecylamine, mix them evenly, and treat them at a microwave power of 2.5kW for 20min. Then, heat treat them at 210℃ for 8 hours. After the treatment, add 80g of deionized water, stir well, dialyze the above solution for 48 hours, and obtain graphene quantum dot powder by spray drying.

[0116] (2) Lubricating oil

[0117] Take 4g of the above-mentioned graphene quantum dots, 2g of graphyne (sheet diameter 400nm, nitrogen content 8at.%), 1.25g of KH550 silane coupling agent, 3g of ethylene glycol, 5g of ethylenediamine and 2g of polymethacrylate, mix them evenly, add 1400g of poly-α-olefin base lubricant, stir at 400rpm for 10h at 62°C to obtain a mixed oil;

[0118] The mixed oil was homogenized for 3 hours using a microfluidizer at 62° C., a processing pressure of 30,000 psi, and a flow rate of 45 m / s to obtain the lubricating oil.

[0119] Example 4

[0120] Lubricating oil was prepared according to the method of Example 1, except that ascorbic acid was replaced by tartaric acid, ammonium sulfate was replaced by ammonium chloride, and octadecylamine was replaced by dodecylamine.

[0121] Example 5

[0122] Lubricating oil was prepared according to the method of Example 1, except that ethylenediamine was replaced by acetamide and polymethacrylic acid was replaced by polymethyl acrylate.

[0123] Example 6

[0124] The lubricating oil was prepared according to the method of Example 1, except that during the homogenization process, the temperature was 65° C., the flow rate was 50 m / s, and the treatment time was 4 h.

[0125] Example 7

[0126] Lubricating oil was prepared according to the method of Example 1, except that the added amount of graphene quantum dots was 1 g.

[0127] Example 8

[0128] Lubricating oil was prepared according to the method of Example 1, except that the amount of graphene quantum dots added was 7 g.

[0129] Example 9

[0130] The lubricating oil was prepared according to the method of Example 1, except that the added amount of the graphene quantum dots was 4.5 g and the added amount of the graphyne was 15 g.

[0131] Example 10

[0132] The lubricating oil was prepared according to the method of Example 1, except that the heat treatment temperature was 180° C. during the preparation of graphene quantum dots.

[0133] Embodiment 11

[0134] The lubricating oil was prepared according to the method of Example 1, except that the heat treatment temperature was 240° C. during the preparation of graphene quantum dots.

[0135] Example 12

[0136] The lubricating oil was prepared according to the method of Example 1, except that the homogenization process was replaced by mechanical stirring.

[0137] Comparative Example 1

[0138] The lubricating oil was prepared according to the method of Example 1, except that graphyne was replaced by graphene with the same nitrogen doping amount.

[0139] Comparative Example 2

[0140] The lubricating oil was prepared according to the method of Example 1, except that the microwave treatment was not performed during the preparation of the graphene quantum dots, and the heat treatment was performed directly.

[0141] Comparative Example 3

[0142] Lubricating oil was prepared according to the method of Example 1, except that graphene quantum dots were not added.

[0143] Comparative Example 4

[0144] The lubricating oil was prepared according to the method of Example 1, except that no graphyne was added.

[0145] The lubricating oils prepared in the above examples and comparative examples were subjected to performance tests, and the testing methods included:

[0146] Four-ball friction test: Tested in accordance with SH / T 0189-2017.

[0147] Dispersion stability test: The sample was placed horizontally at room temperature (25°C) for 90 days to observe the dispersion. The dispersion stability test results of Example 1 and Comparative Example 2 are as follows: Figure 1 As shown, Figure 1 a represents Example 1, b represents Comparative Example 2; the comparison diagram of wear spot diameters of Example 1 and Comparative Example 2 is shown in Figure 2 As shown, Figure 2 Wherein a represents Example 1, and b represents Comparative Example 2.

[0148] The test results are shown in Table 1.

[0149] Table 1

[0150]

[0151] From the above table we can see that:

[0152] In this application, additives are used in graphyne and graphene quantum dots. Graphene quantum dots are prepared by microwave and heat treatment. Microwave pretreatment is beneficial to improve the efficiency of quantum dot preparation in heat treatment. Moreover, compared with graphene, graphyne has more abundant carbon covalent bonds on the surface, which can provide more active sites. It also has a wider interplanar spacing and excellent chemical stability. Graphene quantum dots can be dispersed on the lamellae of graphyne by covalent bonds, effectively avoiding the agglomeration and precipitation of graphene quantum dots, and improving the stability and lubrication effect of lubricating oil. In addition, this application uses jet homogenization to homogenize the lubricating oil, and uses high pressure and high flow rate to regulate the graphyne lamellae so that it can be evenly and stably dispersed in the lubricating oil.

[0153] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0154] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A lubricating oil, It is characterized in that The lubricating oil is composed of the following components by mass: 3 to 5 parts of graphene quantum dots; 10 to 15 parts of graphyne, 1 to 1.5 parts of coupling agent, 2 to 4 parts of polyol, 4 to 6 parts of cosolvent, 1.5 to 2.5 parts of viscosity modifier and 1200 to 1600 parts of base lubricating oil, wherein the graphene quantum dots are dispersed on the surface of the graphyne, and the graphene quantum dots are chemically bonded to the graphyne, wherein The mass ratio of the graphene quantum dots to the graphyne is 1:(2-5), the graphyne is nitrogen-containing graphyne, and the percentage of nitrogen atoms in the nitrogen-containing graphyne to the total number of atoms is 8%-20%; and The graphene quantum dots are nitrogen-doped graphene quantum dots, and the preparation method of the nitrogen-doped graphene quantum dots comprises: An organic acid, an inorganic ammonium salt and an organic amine are mixed to obtain a premix, and the premix is ​​sequentially subjected to microwave activation treatment, heat treatment and dialysis drying treatment to obtain the nitrogen-doped graphene quantum dots, wherein The microwave power of the microwave activation treatment is 2kW~3kW, the treatment time is 15min~30min, the temperature of the heat treatment is 200℃~220℃, and the time is 6h~10h; and wherein The lubricating oil needs to be subjected to jet homogenization treatment.

2. The lubricating oil according to claim 1, It is characterized in that The Graphdiyne satisfies the following conditions: The sheet diameter of the Graphene is 400nm~800nm.

3. The lubricating oil according to claim 1 or 2, It is characterized in that The graphene quantum dots meet the following conditions: The average particle size D50 of the graphene quantum dots is 5nm~50nm.

4. A method for preparing the lubricating oil according to any one of claims 1 to 3, It is characterized in that The preparation method comprises: An organic acid, an inorganic ammonium salt and an organic amine are mixed to obtain a premix, and the premix is ​​sequentially subjected to microwave activation treatment, heat treatment and dialysis drying treatment to obtain nitrogen-doped graphene quantum dots; The nitrogen-doped graphene quantum dots, graphyne, coupling agent, polyol, cosolvent, viscosity modifier and base lubricating oil are mixed and heated to prepare the lubricating oil.

5. The preparation method according to claim 4, It is characterized in that The microwave power of the microwave activation treatment is 2 kW to 3 kW, and the treatment time is 15 min to 30 min.

6. The preparation method according to claim 5, It is characterized in that The method for preparing nitrogen-doped graphene quantum dots satisfies at least one of the following conditions: (1) The mass proportion of the organic acid in the premix is ​​50% to 77%; (2) the organic acid comprises at least one of lactic acid, ascorbic acid, tartaric acid, citric acid and malic acid; (3) The mass proportion of the inorganic ammonium salt in the premix is ​​10% to 23%; (4) the inorganic ammonium salt comprises at least one of ammonium sulfate, ammonium nitrate, ammonium chloride and ammonium bromide; (5) The mass proportion of the organic amine in the premix is ​​5% to 13%; (6) The organic amine includes a polyamine; wherein The sum of the mass percentages of the components in the premix is ​​100%.

7. The preparation method according to claim 6, It is characterized in that The polyamines include fatty diamines.

8. The preparation method according to claim 4, It is characterized in that The preparation method satisfies at least one of the following conditions: (1) The heating temperature in the mixing and heating is 60° C. to 65° C.; (2) The stirring speed of the mixing and heating is 300 rpm to 500 rpm, and the time is 8 h to 12 h.

9. The preparation method according to claim 4, It is characterized in that The preparation method further comprises: performing jet homogenization treatment on the lubricating oil; The homogenization treatment has a temperature of 60° C. to 65° C., a pressure of 28,000 to 32,000 psi, a flow rate of 40 m / s to 50 m / s, and a treatment time of 2 h to 4 h.

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