Graphene lubricant additive and preparation method thereof, and graphene lubricant

Abstract

The present application relates to a graphene lubricant additive, a preparation method thereof, and a graphene lubricant. The preparation method of the graphene lubricant additive comprises the following steps: mixing graphite, an oxidant, an oxidation enhancer, and an acid, and then performing an oxidation reaction to obtain iron oxide intercalated graphite oxide; the oxidant comprises potassium ferrate; mixing a magnetized base oil and the iron oxide intercalated graphite oxide and performing an intercalation treatment to obtain a graphene lubricant additive; wherein the magnetized base oil comprises a first base oil, an organic solvent, and a magnetic filler dispersed in the first base oil and the organic solvent, and a magnetic force can be generated between the magnetic filler and the iron oxide. When the graphene lubricant additive prepared by this preparation method is added to the base oil to prepare the lubricant, the friction coefficient and wear spot diameter of the lubricant can be effectively reduced, thereby effectively improving the anti-wear and friction-reducing performance of the lubricant. At the same time, the obtained lubricant is evenly dispersed and has good stability.

Description

Technical Field

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

[0002] Friction and wear are common in industrial production and daily life, resulting in mechanical losses and energy waste. Controlling friction and wear is crucial for energy conservation and consumption reduction.

[0003] Lubricating oil is a liquid or semi-solid lubricant used in various types of automobiles and mechanical equipment to reduce friction and protect machinery and workpieces. It primarily serves the functions of lubrication, auxiliary cooling, rust prevention, cleaning, sealing, and cushioning. In other words, lubricating oil is used between two objects in relative motion to reduce friction and wear caused by contact. Lubricating oil generally consists of two parts: a base oil and additives. Additives are the essence of lubricants, and their anti-wear and friction-reducing properties are primarily provided by additives. Traditional lubricant additives often contain organic pollutants such as sulfur, phosphorus, and chlorine, as well as metal salts. These additives are easily degraded and pollute the environment.

[0004] Graphene, due to its unique two-dimensional structure, ultrahigh elastic modulus (1100 GPa), fracture strength (125 GPa), and thermal conductivity (5000 W / (m·K)), as well as excellent self-lubrication and high-temperature resistance, shows great potential as a lubricant additive. Applying graphene nanotechnology to lubricants can enhance their tribological properties while being environmentally friendly and pollution-free. However, traditional methods for preparing graphene typically involve ultrasonic exfoliation of graphite, which is difficult to fully exfoliate and prone to re-accumulation of graphene flakes. Furthermore, graphene has poor dispersibility in lubricants, resulting in limited improvements in the friction properties of lubricants. Summary of the Invention

[0005] Based on this, the present application provides a graphene lubricant additive and a preparation method thereof, as well as a graphene lubricant that can effectively improve the anti-friction performance of lubricating oil.

[0006] The technical solution of this application to solve the above technical problems is as follows.

[0007] The first aspect of the present application provides a method for preparing a graphene lubricant additive, comprising the following steps:

[0008] Mixing graphite, an oxidant, an oxidation enhancer, and an acid and performing an oxidation reaction to obtain iron oxide intercalated graphite oxide; the oxidant comprises potassium ferrate;

[0009] The magnetized base oil and the iron oxide intercalated graphite oxide are mixed and intercalated to obtain the graphene lubricant additive; wherein the magnetized base oil includes a first base oil, an organic solvent and a magnetic filler dispersed in the first base oil and the organic solvent, and a magnetic force can be generated between the magnetic filler and the iron oxide.

[0010] In some embodiments, in the method for preparing the graphene lubricant additive, the magnetic filler includes ferrosoferric oxide.

[0011] In some embodiments, in the method for preparing the graphene lubricant additive, the organic solvent includes at least one of polyethylene glycol, polyvinyl alcohol, diethylene glycol and triethylene glycol.

[0012] In some embodiments, in the method for preparing the graphene lubricant additive, the mass ratio of the magnetic filler to the organic solvent is 1: (20~45).

[0013] In some embodiments, in the preparation method of the graphene lubricant additive, the organic solvent includes polyethylene glycol, polyvinyl alcohol, diethylene glycol and triethylene glycol, and the mass ratio of the polyethylene glycol, the polyvinyl alcohol, the diethylene glycol and the triethylene glycol is 1: (0.65~1.5): (1.3~3): (1.3~3).

[0014] In some embodiments, in the method for preparing a graphene lubricant additive, the first base oil includes at least one of a poly-α-olefin base oil, an ester base oil, and a silicone oil.

[0015] In some embodiments, in the method for preparing the graphene lubricant additive, the mass ratio of the total mass of the magnetic filler and the organic solvent to the first base oil is (0.01-0.05):1.

[0016] In some embodiments, in the preparation method of the graphene lubricant additive, the mass ratio of the iron oxide intercalated graphite oxide to the magnetized base oil is (0.01~0.08):1.

[0017] In some embodiments, in the preparation method of the graphene lubricant additive, a fluid accelerator is used for the intercalation treatment, and the parameters of the intercalation treatment are: treatment temperature of 50°C to 60°C, treatment diameter of 2 cm to 4 cm, flow linear velocity of 30 m / s to 50 m / s, and treatment time of 10 h to 14 h.

[0018] In some embodiments, in the method for preparing the graphene lubricant additive, the preparation of the magnetized base oil comprises the following steps:

[0019] The magnetic filler, the organic solvent and the first base oil are mixed and magnetized to obtain the magnetized base oil. The parameters of the magnetization treatment are: magnetic field intensity of 80 mT to 200 mT, temperature of 30° C. to 60° C., and time of 40 min to 60 min.

[0020] In some embodiments, in the method for preparing the graphene lubricant additive, the oxidation reaction temperature is 10° C. to 20° C., and the time is 1 h to 2 h.

[0021] In some embodiments, in the method for preparing the graphene lubricant additive, the oxidation enhancer includes sodium nitrate.

[0022] In some embodiments, in the method for preparing the graphene lubricant additive, the acid includes concentrated sulfuric acid.

[0023] The second aspect of the present application provides a graphene lubricant additive, which is prepared using the preparation method of the graphene lubricant additive provided by the first aspect.

[0024] A third aspect of the present application provides a graphene lubricant, comprising a second base oil and the graphene lubricant additive provided in the second aspect.

[0025] In some embodiments, in the graphene lubricant, the mass ratio of the graphene lubricant additive to the second base oil is (0.05-0.5):1.

[0026] In some embodiments, in the graphene lubricant, the second base oil includes at least one of a poly-α-olefin base oil, an ester base oil, and a silicone oil.

[0027] Compared with the prior art, the preparation method of the graphene lubricant additive of the present application has the following beneficial effects:

[0028] The preparation method of the above-mentioned graphene lubricant additive comprises treating graphite with potassium ferrate as an oxidant in combination with an acid and an oxidation enhancer, causing expansion between graphite layers and simultaneously intercalating and adsorbing the generated iron oxide product into the oxidized graphite to obtain iron oxide intercalated graphite oxide; further mixing a magnetized base oil comprising a first base oil, an organic solvent, and a magnetic filler dispersed in the first base oil and the organic solvent with the iron oxide intercalated graphite oxide, and performing an intercalation treatment on the iron oxide intercalated graphite oxide using the magnetized base oil as a high-speed fluid. The magnetic force between the magnetic filler in the magnetized base oil and the iron oxide in the iron oxide intercalated graphite oxide is utilized to effectively promote the stripping speed and efficiency of the high-speed fluid on the graphite, and synthesize the graphene lubricant additive in situ, which helps to improve the dispersion effect of graphene in the graphene lubricant additive, thereby facilitating the improvement of the stability of the graphene lubricant additive product.

[0029] Furthermore, when the above-mentioned graphene lubricant additive is added to the base oil to prepare the graphene lubricant, the friction coefficient and wear spot diameter of the graphene lubricant can be effectively reduced, thereby effectively improving the anti-wear and friction-reducing performance of the graphene lubricant. At the same time, the prepared graphene lubricant is evenly dispersed and has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 This is a diagram showing the dispersion of the graphene lubricant obtained in Example 1;

[0032] Figure 2 This is a physical picture of polyalphaolefin base oil;

[0033] Figure 3 This is a diagram showing the dispersion of the graphene lubricant obtained in Example 7;

[0034] Figure 4 This is a diagram showing the dispersion of the graphene lubricant obtained in Comparative Example 1. DETAILED DESCRIPTION

[0035] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are described below. Each example is provided to illustrate, not to limit, the present invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment may be used in another embodiment to produce further embodiments.

[0036] Therefore, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the present invention are disclosed in or are obvious from the following detailed description. Those skilled in the art will appreciate that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the present invention.

[0037] 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 this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0038] The term "comprises", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements limited by the sentence "comprising a ..." do not exclude the presence of other identical elements in the process, method, article or equipment comprising the elements. The indefinite articles "a" and "an" before the elements or components of the present invention have no restriction on the quantity requirements (i.e., the number of occurrences) of the elements or components. Therefore, "a" or "a" should be interpreted as including one or at least one, and elements or components in the singular also include plural forms, unless the quantity obviously refers only to the singular form. The meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] The weights of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally increased or decreased according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the weights mentioned in the description of the embodiments of the present invention may be mass units known in the chemical industry, such as μg, mg, g, and kg.

[0040] Except as shown in the operating examples or otherwise indicated, all numbers used in the specification and claims to express the amount of ingredients, physicochemical properties, etc. are understood to be adjusted by the term "about" in all cases. For example, therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the appended claims are approximate values, and those skilled in the art will be able to appropriately change these approximate values using the teachings disclosed herein to seek to obtain the desired properties. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0041] One embodiment of the present application provides a method for preparing a graphene lubricant additive, comprising:

[0042] Step S10: mixing graphite, an oxidant, an oxidation enhancer, and an acid, and performing an oxidation reaction to obtain iron oxide intercalated graphite oxide; wherein the oxidant includes potassium ferrate.

[0043] Research by the technical personnel of the present application has found that when graphite is treated with potassium permanganate as an oxidant, potassium permanganate and concentrated sulfuric acid first generate a permanganic anhydride intermediate product at low temperature, and then decompose to produce manganese dioxide and oxygen. Manganese dioxide adheres to the surface and between the layers of graphite sheets. However, manganese dioxide has no magnetism and cannot interact magnetically with the magnetic filler in the intercalant during the subsequent intercalation treatment, resulting in poor intercalation effect, and thus poor exfoliation effect on the graphite, and poor dispersion effect of the obtained graphene in the lubricating oil.

[0044] When graphite is treated with potassium ferrate as an oxidant in combination with acid and an oxidation enhancer, expansion occurs between the graphite layers, and the generated product, iron oxide, is intercalated and adsorbed in the oxidized graphite. The iron oxide in the obtained iron oxide intercalated graphite oxide is magnetic. During the subsequent intercalation treatment, it can produce magnetic effects with the magnetic filler in the intercalation agent, thereby promoting the exfoliation of the graphite, and the obtained graphene has a good dispersion effect in the lubricating oil.

[0045] In some examples, in step S10 , the oxidation enhancer includes at least one of sodium nitrate and potassium nitrate.

[0046] Optionally, in step S10, the oxidation enhancer includes sodium nitrate.

[0047] In some examples, in step S10 , the acid includes concentrated sulfuric acid.

[0048] It can be understood that in some examples, in step S10, graphite, potassium ferrate, sodium nitrate and concentrated sulfuric acid are mixed and then subjected to an oxidation reaction to obtain iron oxide intercalated graphite oxide.

[0049] In some examples, in step S10, the mass ratio of the oxidant, the oxidation enhancer, and the graphite is (2-4):(0.3-1):1.

[0050] It is understood that in step S10, the mass ratio of the oxidant to graphite includes, but is not limited to, 2:1, 2.5:1, 3:1, 3.5:1, and 4:1; the mass ratio of the oxidation enhancer to graphite includes, but is not limited to, 0.3:1, 0.5:1, 0.8:1, and 1:1. In some examples, the mass ratio may be within a range consisting of any two of these values as end points, and the same applies hereinafter.

[0051] Optionally, in step S10, the mass ratio of the oxidant, the oxidation enhancer, and the graphite is (2.5-3.5):(0.3-0.8):1.

[0052] Furthermore, in step S10, the mass ratio of the oxidant, the oxidation enhancer, and the graphite is 3:0.5:1.

[0053] In some examples, in step S10, the volume ratio of the acid to the mass ratio of the graphite is (40-50) mL / g.

[0054] It can be understood that in step S10, the volume ratio of the acid to the mass ratio of graphite includes but is not limited to 40 mL / g, 42 mL / g, 45 mL / g, 46 mL / g, 48 mL / g, and 50 mL / g.

[0055] Optionally, in step S10, the volume ratio of the acid to the mass ratio of the graphite is (42-48) mL / g.

[0056] Furthermore, in step S10, the volume ratio of the acid to the mass ratio of the graphite is 46 mL / g.

[0057] In some examples, in step S10, the oxidation reaction temperature is 10° C. to 20° C., and the time is 1 h to 2 h.

[0058] It is understood that the temperature of the oxidation reaction includes but is not limited to 10°C, 12°C, 15°C, 18°C, and 20°C, and the time is 1 h, 1.2 h, 1.5 h, 1.8 h, and 2 h.

[0059] Furthermore, in step S10, the oxidation reaction temperature is 20° C. and the time is 2 h.

[0060] In some examples, in step S10 , the particle size of the graphite is 30 μm to 50 μm.

[0061] It is understood that the particle size of graphite includes but is not limited to 30 μm, 32 μm, 35 μm, 38 μm, 40 μm, 42 μm, 45 μm, 48 μm, and 50 μm.

[0062] Optionally, the particle size of the graphite is 30 μm to 40 μm.

[0063] In some examples, in step S10 , the carbon content of the graphite is ≥ 99.9%.

[0064] In some examples, in step S10 , the graphite is flake graphite.

[0065] In some examples, after step S10 is completed and before step S30 is performed, the step of performing solid-liquid separation on the reaction liquid obtained after the oxidation reaction, taking the solid phase and washing it is also included.

[0066] Furthermore, the solid phase is washed with water to neutrality to obtain a yellow powder, which is iron oxide intercalated graphite oxide.

[0067] Step S20: Mixing the magnetized base oil and the iron oxide intercalated graphite oxide obtained in step S10 and performing an intercalation treatment to obtain a graphene lubricant additive; wherein the magnetized base oil includes a first base oil and a magnetic filler and an organic solvent dispersed in the first base oil, and a magnetic force can be generated between the magnetic filler and the iron oxide.

[0068] The preparation method of the above-mentioned graphene lubricant additive comprises treating graphite with potassium ferrate as an oxidant in combination with an acid and an oxidation enhancer, causing expansion between graphite layers and simultaneously intercalating and adsorbing the generated iron oxide product into the oxidized graphite to obtain iron oxide intercalated graphite oxide; further mixing a magnetized base oil comprising a first base oil, an organic solvent, and a magnetic filler dispersed in the first base oil and the organic solvent with the iron oxide intercalated graphite oxide, and performing an intercalation treatment on the iron oxide intercalated graphite oxide using the magnetized base oil as a high-speed fluid. The magnetic force between the magnetic filler in the magnetized base oil and the iron oxide in the iron oxide intercalated graphite oxide is utilized to effectively promote the stripping speed and efficiency of the high-speed fluid on the graphite, and synthesize the graphene lubricant additive in situ, which helps to improve the dispersion effect of graphene in the graphene lubricant additive, thereby facilitating the improvement of the stability of the graphene lubricant additive product.

[0069] Furthermore, when the above-mentioned graphene lubricant additive is added to the base oil to prepare the graphene lubricant, the friction coefficient and wear spot diameter of the graphene lubricant can be effectively reduced, thereby effectively improving the anti-wear and friction-reducing performance of the graphene lubricant. At the same time, the prepared graphene lubricant is evenly dispersed and has good stability.

[0070] The preparation method of the graphene lubricant additive combines the exfoliation of graphite and the dispersion of graphene into one, which simplifies the process flow and is environmentally friendly.

[0071] It can be understood that in step S20, the iron oxide intercalated graphite oxide is intercalated with the magnetized base oil as a high-speed fluid.

[0072] In some examples, in step S20, the mass ratio of iron oxide intercalated graphite oxide to magnetized base oil is (0.01-0.08):1.

[0073] It can be understood that in step S20, the mass ratio of iron oxide intercalated graphite oxide to magnetized base oil includes but is not limited to 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, and 0.08:1.

[0074] Optionally, the mass ratio of iron oxide intercalated graphite oxide to magnetized base oil is (0.01-0.05):1.

[0075] Furthermore, the mass ratio of iron oxide intercalated graphite oxide to magnetized base oil is (0.03~0.05):1.

[0076] In some of these examples, in step S20, a fluid accelerator is used for intercalation treatment, and the parameters of the intercalation treatment are: treatment temperature of 50°C to 60°C, treatment aperture of 2 cm to 4 cm, flow linear velocity of 30 m / s to 50 m / s, and treatment time of 10 h to 14 h.

[0077] It can be understood that the processing temperature includes but is not limited to 50°C, 52°C, 55°C, 58°C, and 60°C; the processing diameter includes but is not limited to 2 cm, 3 cm, and 4 cm; the flow line speed includes but is not limited to 30 m / s, 35 m / s, 40 m / s, 45 m / s, and 50 m / s; and the processing time includes but is not limited to 10 h, 11 h, 12 h, 13 h, and 14 h.

[0078] It can be understood that in some examples, after the intercalation treatment step in step S20 is completed, the step of removing impurities from the mixed solution obtained after the intercalation treatment is also included.

[0079] It can be understood that impurity removal is the removal of iron oxide, magnetic filler, organic solvent and the like, which are products of potassium ferrate.

[0080] In some examples, in step S20, impurities are removed by standing or centrifuging.

[0081] It is understood that the density of iron oxide, magnetic fillers and organic solvents is higher than that of base oil. Impurities such as iron oxide, magnetic fillers and organic solvents can be removed from the lubricating oil by standing or centrifuging.

[0082] It can be further understood that the graphene is uniformly dispersed in the graphene lubricant additive.

[0083] Furthermore, the centrifugal speed is 600 rpm~800 rpm, and the time is 5 min~20 min.

[0084] Optionally, the centrifugation speed is 800 rpm and the time is 10 min.

[0085] In some examples, in step S20 , the magnetic filler includes ferrosoferric oxide.

[0086] In some examples, in step S20, the average particle size of the magnetic filler is 2 nm to 10 nm.

[0087] Furthermore, the average particle size of the magnetic filler is 5 nm.

[0088] In some examples, in step S20 , the organic solvent includes at least one of polyethylene glycol, polyvinyl alcohol, diethylene glycol, and triethylene glycol.

[0089] It is understood that the organic solvents may be one, two, three or four.

[0090] Optionally, the organic solvent includes polyethylene glycol, polyvinyl alcohol, diethylene glycol and triethylene glycol.

[0091] In some examples, in step S20, the mass ratio of the magnetic filler to the organic solvent is 1: (20-45).

[0092] It will be appreciated that the mass ratio of the magnetic filler to the organic solvent includes, but is not limited to, 1:20, 1:22, 1:25, 1:28, 1:30, 1:32, 1:35, 1:38, 1:40, 1:42, and 1:45.

[0093] In some examples, in step S20, the organic solvent includes polyethylene glycol, polyvinyl alcohol, diethylene glycol and triethylene glycol, and the mass ratio of polyethylene glycol, polyvinyl alcohol, diethylene glycol and triethylene glycol is 1: (0.65~1.5): (1.3~3): (1.3~3).

[0094] It can be understood that when the mass fraction of polyethylene glycol is 1, the mass fraction of polyvinyl alcohol includes but is not limited to 0.65, 0.7, 0.8, 1, 1.1, 1.2, 1.4, and 1.5; the mass fraction of diethylene glycol includes but is not limited to 1.3, 1.5, 1.8, 2, 2.2, 2.5, 2.8, and 3; and the mass fraction of triethylene glycol includes but is not limited to 1.3, 1.5, 1.8, 2, 2.2, 2.5, 2.8, and 3.

[0095] In some examples, in step S20, the mass ratio of the total mass of the magnetic filler and the organic solvent to the first base oil is (0.01-0.05):1.

[0096] It can be understood that in step S20, the mass ratio of the total mass of the magnetic filler and the organic solvent to the first base oil includes but is not limited to 0.01:1, 0.02:1, 0.03:1, 0.04:1, and 0.05:1.

[0097] Optionally, the mass ratio of the total mass of the magnetic filler and the organic solvent to the first base oil is (0.02-0.03):1.

[0098] It can be understood that the effect is better if the type of the first base oil is consistent with the type of the base oil in the lubricating oil to be treated.

[0099] In some examples, in step S20 , the first base oil includes at least one of a poly-α-olefin base oil, an ester base oil, and a silicone oil.

[0100] In some examples, in step S20, the preparation of the magnetized base oil includes the following steps:

[0101] The magnetic filler, the organic solvent and the first base oil are mixed and magnetized to obtain a magnetized base oil. The parameters of the magnetization treatment are: magnetic field intensity of 80 mT to 200 mT, temperature of 30°C to 60°C, and time of 40 min to 60 min.

[0102] It can be understood that after the magnetic filler, the organic solvent and the first base oil are mixed and magnetized, the magnetic filler and the organic solvent are respectively combined with the first base oil. Under the action of the magnetic field, the energy generated by the Lorentz force can distort and destroy the hydrogen bonds in the organic solvent and the base oil, thereby changing their molecular structure and enhancing the binding ability, so that the magnetic filler is better dispersed in the first base oil and the organic solvent, which facilitates the subsequent intercalation treatment.

[0103] The technicians of the present application have found that if the magnetic filler and the organic solvent are not first dispersed in the first base oil, but the magnetic filler, the organic solvent, the first base oil and the iron oxide intercalated graphite oxide obtained in step S10 are mixed and then the intercalation treatment is directly performed, or if the magnetic filler, the organic solvent, the first base oil and the iron oxide intercalated graphite oxide obtained in step S10 are mixed and then magnetized, the iron oxide intercalated graphite oxide and the ferroferric oxide in the magnetic filler will agglomerate and precipitate due to the action of the magnetic force, which will not only affect the dispersion, but also affect the stripping effect in the next step.

[0104] In some of the examples, in the step of preparing the magnetized base oil, the magnetic filler and the organic solvent are uniformly mixed, and then the first base oil is added for magnetization treatment.

[0105] Furthermore, after the magnetic filler and the organic solvent are mixed, ultrasonic dispersion is used to uniformly disperse them, and then the first base oil is added to perform magnetization treatment.

[0106] Furthermore, after uniformly mixing 20-30 parts of nano-ferroferric oxide, 100-150 parts of polyethylene glycol, 100-150 parts of polyvinyl alcohol, 200-300 parts of diethylene glycol and 200-300 parts of triethylene glycol, by mass, the first base oil is added for magnetization treatment at a mass ratio of the total mass of the magnetic filler and the organic solvent to the first base oil of (0.01-0.05):1.

[0107] It can be understood that, by mass, nano ferrosoferric oxide includes but is not limited to 20 parts, 22 parts, 25 parts, 28 parts, and 30 parts; polyethylene glycol includes but is not limited to 100 parts, 110 parts, 120 parts, 125 parts, 130 parts, 140 parts, and 150 parts; polyvinyl alcohol includes but is not limited to 100 parts, 110 parts, 120 parts, 125 parts, 130 parts, 140 parts, and 150 parts; diethylene glycol includes but is not limited to 200 parts, 210 parts, 220 parts, 240 parts, 250 parts, 260 parts, 280 parts, and 300 parts; triethylene glycol includes but is not limited to 200 parts, 210 parts, 220 parts, 240 parts, 250 parts, 260 parts, 280 parts, and 300 parts.

[0108] It can be understood that in step S20, the magnetic field intensity of the magnetization treatment includes but is not limited to 80 mT, 100 mT, 120 mT, 150 mT, 180 mT, and 200 mT, the temperature includes but is not limited to 30°C, 40°C, 50°C, and 60°C, and the time includes but is not limited to 40 min, 45 min, 50 min, 55 min, and 60 min.

[0109] Optionally, the magnetic field intensity of the magnetization treatment is 80 mT to 100 mT, the temperature is 30° C. to 40° C., and the time is 40 min to 50 min.

[0110] In some examples, in step S20 , the magnetic field material used for the magnetic field treatment includes a neodymium iron boron permanent magnet.

[0111] In some examples, in step S20 , the surface tension of the magnetized base oil is 0.02 N / m to 0.04 N / m.

[0112] One embodiment of the present application provides a graphene lubricant additive, which is prepared using the above-mentioned method for preparing the graphene lubricant additive.

[0113] One embodiment of the present application provides a use of the graphene lubricant additive in preparing a lubricant. Another embodiment of the present application provides a graphene lubricant, comprising a second base oil and the graphene lubricant additive.

[0114] When the above-mentioned graphene lubricant additive is added to the base oil to prepare the lubricant, the friction coefficient and wear spot diameter of the lubricant can be effectively reduced, thereby effectively improving the anti-wear and friction-reducing performance of the lubricant. At the same time, the prepared lubricant is evenly dispersed and has good stability.

[0115] In some of the examples, in the graphene lubricant, the mass ratio of the graphene lubricant additive to the second base oil is (0.05-0.5):1.

[0116] It can be understood that the mass ratio of the graphene lubricant additive to the second base oil includes but is not limited to 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.3:1, 0.4:1, and 0.5:1.

[0117] Optionally, the mass ratio of the graphene lubricant additive to the second base oil is (0.05-0.2):1.

[0118] It can be understood that the effect is better if the types of the first base oil and the second base oil in step S20 of the above-mentioned method for preparing the graphene lubricant additive are consistent.

[0119] In some examples, in the graphene lubricant, the second base oil includes at least one of a poly-α-olefin base oil, an ester base oil, and a silicone oil.

[0120] It can be understood that the above-mentioned graphene lubricant can be used in various types of automobiles, mechanical equipment and other fields.

[0121] The present application will be described in further detail below in conjunction with specific implementation methods, but the implementation methods of the present application are not limited thereto.

[0122] Example 1

[0123] (1) Mix 100 g of flake graphite (carbon content ≥ 99.9%, average particle size 30 μm), 2300 mL of concentrated H2SO4, 50 g of sodium nitrate, and 300 g of potassium ferrate. Stir and react at <20°C for 2 h. Filter the reaction solution and wash the solid phase with deionized water to obtain a yellow powder, which is iron oxide intercalated graphite oxide.

[0124] (2) 100 g of polyethylene glycol, 100 g of polyvinyl alcohol, 200 g of diethylene glycol, 200 g of triethylene glycol and 20 g of nano-ferroferric oxide were mixed and stirred for 2 h under ultrasonic-assisted conditions. The mixture was then mixed with 31,000 g of polyalphaolefin base oil (the mass ratio of the total mass of the magnetic filler and the organic solvent to the first base oil was 0.02:1). The mixture was placed in a magnetic field between multiple NdFeB permanent magnets with a magnetic field strength of 80 mT and magnetized at 30°C for 40 min to obtain a magnetized base oil with a surface tension of 0.02 N / m.

[0125] (3) According to the mass ratio of iron oxide intercalated graphite oxide to magnetized base oil of 0.03:1, the iron oxide intercalated graphite oxide obtained in step (1) is added to the magnetized base oil obtained in step (2), and a fluid accelerator is used to perform fluid high-speed differential interlayer motion treatment (i.e., intercalation treatment) at a treatment temperature of 60°C, a treatment aperture of 2 cm, a flow linear velocity of 30 m / s, and a treatment time of 10 h. The mixture is then centrifuged, and the upper layer of uniform dispersion is taken to obtain a graphene lubricant additive;

[0126] (4) The graphene lubricant additive obtained in step (3) is added to the poly-α-olefin base oil (the second base oil) at a mass ratio of the graphene lubricant additive to the second base oil of 0.05:1 to obtain a graphene lubricant.

[0127] Example 2

[0128] The method is basically the same as Example 1, except that in step (1) of Example 2, the average particle size of the flake graphite used is 50 μm.

[0129] Example 3

[0130] The method is basically the same as Example 1, except that the step (2) of Example 3 is as follows:

[0131] 150 g of polyethylene glycol, 150 g of polyvinyl alcohol, 300 g of diethylene glycol, 300 g of triethylene glycol, and 30 g of nano-ferrosoferric oxide were mixed and stirred under ultrasonic-assisted conditions for 2 h. The mixture was then mixed with 31,000 g of polyalphaolefin base oil (the mass ratio of the total mass of the magnetic filler and organic solvent to the first base oil was 0.03:1). The mixture was then placed in a magnetic field between multiple neodymium iron boron permanent magnets with a magnetic field strength of 80 mT and magnetized at 30°C for 40 min to obtain a magnetized base oil with a surface tension of 0.02 N / m.

[0132] Example 4

[0133] The process is basically the same as Example 1, except that in step (2) of Example 4, the parameters of the magnetization treatment are: magnetic field intensity of 200 mT, temperature of 60°C, and time of 60 min.

[0134] Example 5

[0135] The method is basically the same as Example 1, except that in step (3) of Example 5, the parameters of the intercalation treatment are: treatment diameter 4 cm, flow linear velocity 50 m / s, and treatment time 14 h.

[0136] Example 6

[0137] The method is basically the same as Example 1, except that in step (4) of Example 6, the mass ratio of the graphene lubricant additive to the second base oil is 0.2:1.

[0138] Example 7

[0139] The method is basically the same as Example 1, except that in step (4) of Example 7, the mass ratio of the graphene lubricant additive to the second base oil is 0.5:1.

[0140] Example 8

[0141] The method is basically the same as Example 1, except that in step (3) of Example 8, the mass ratio of iron oxide intercalated graphite oxide to magnetized base oil is 0.08:1.

[0142] Comparative Example 1

[0143] The method is basically the same as Example 1, except that step (1) is omitted and in step (3), flake graphite is directly added to the magnetized base oil obtained in step (2) for intercalation treatment.

[0144] Comparative Example 2

[0145] The method is basically the same as Example 1, except that in step (2), polyethylene glycol, polyvinyl alcohol, diethylene glycol, triethylene glycol and nano-ferroferric oxide are not added, and the poly-α-olefin base oil is directly magnetized.

[0146] Comparative Example 3

[0147] The process is basically the same as Example 1, except that no magnetization treatment is performed in step (2) of Comparative Example 3, as follows:

[0148] 100 g of polyethylene glycol, 100 g of polyvinyl alcohol, 200 g of diethylene glycol, 200 g of triethylene glycol and 20 g of nano-ferrosoferric oxide were mixed, stirred for 2 h under ultrasonic-assisted conditions, and then mixed with 31,000 g of poly-α-olefin base oil. The iron oxide intercalated graphite oxide obtained in step (1) was further added and subjected to fluid high-speed differential interlayer motion treatment.

[0149] Comparative Example 4

[0150] The method is basically the same as Example 1, except that, in step (3) of Comparative Example 4, no intercalation treatment is performed, and the iron oxide intercalated graphite oxide obtained in step (1) is added to the magnetized base oil obtained in step (2), and stirred evenly to obtain the graphene lubricant additive.

[0151] Comparative Example 5

[0152] The method is basically the same as Example 1, except that, in Comparative Example 5, the potassium ferrate in step (1) of Example 1 is replaced by potassium permanganate of equal mass.

[0153] Comparative Example 6

[0154] (1) Mix 100 g of flake graphite (carbon content ≥ 99.9%, average particle size 30 μm), 2300 mL of concentrated H2SO4, 50 g of sodium nitrate, and 300 g of potassium ferrate. Stir and react at <20°C for 2 h. Filter the reaction solution and wash the solid phase with deionized water to obtain a yellow powder, which is iron oxide intercalated graphite oxide.

[0155] (2) 100 g of polyethylene glycol, 100 g of polyvinyl alcohol, 200 g of diethylene glycol, 200 g of triethylene glycol and 20 g of nano-ferroferric oxide were mixed, stirred for 2 h under ultrasonic-assisted conditions, and then mixed with 31,000 g of polyalphaolefin base oil and the iron oxide intercalated graphite oxide obtained in step (1), placed in a magnetic field region between multiple neodymium iron boron permanent magnets with a magnetic field strength of 80 mT, and magnetized at 30°C for 40 min. A fluid accelerator was used to perform a high-speed differential interlayer motion treatment (i.e., intercalation treatment) of the fluid at a treatment temperature of 60°C, a treatment aperture of 2 cm, a flow linear velocity of 30 m / s, a treatment time of 10 h, and centrifugation to remove impurities to obtain a graphene lubricant additive;

[0156] (3) The graphene lubricant additive obtained in step (2) is added to the poly-α-olefin base oil (the second base oil) at a mass ratio of the graphene lubricant additive to the second base oil of 0.05:1 to obtain a graphene lubricant.

[0157] The graphene lubricants prepared in each example and comparative example were tested for coefficient of friction according to ASTM D5183-95 and for wear spot diameter according to SH / T 0204-92, Determination of Anti-Wear Properties of Grease (Four-Ball Tester Method). The dispersion of the graphene lubricants was observed after standing at 25°C for 90 days. The results are shown in Table 1.

[0158] Table 1

[0159]

[0160] After standing for 90 days, the dispersion of the graphene lubricant obtained in Example 1 is as follows: Figure 1 As shown, polyalphaolefin base oils such as Figure 2 As shown, the dispersion of the graphene lubricant obtained in Example 7 is as follows Figure 3 As shown, the dispersion of the graphene lubricant obtained in Comparative Example 1 is as follows Figure 4 shown.

[0161] From Table 1 and Figures 1 to 4 It can be seen that compared with the comparative example and the poly-α-olefin base oil, the friction coefficient and the wear spot diameter of the graphene lubricant prepared in the embodiment are significantly reduced, indicating that the anti-wear and friction-reducing performance of the lubricant is improved. At the same time, the graphene lubricant is evenly dispersed and has good stability.

[0162] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0163] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing a graphene lubricant additive, characterized in that: The following steps are involved: Mixing graphite, an oxidant, an oxidation enhancer, and an acid and performing an oxidation reaction to obtain iron oxide intercalated graphite oxide; the oxidant comprises potassium ferrate; The magnetized base oil and the iron oxide intercalated graphite oxide are mixed and intercalated using a fluid accelerator to obtain the graphene lubricant additive; wherein the magnetized base oil comprises a first base oil, an organic solvent, and a magnetic filler dispersed in the first base oil and the organic solvent, and a magnetic force can be generated between the magnetic filler and the iron oxide, wherein The organic solvent comprises at least one of polyethylene glycol, polyvinyl alcohol, diethylene glycol and triethylene glycol; The oxidation enhancer comprises at least one of sodium nitrate and potassium nitrate; and The acid includes concentrated sulfuric acid.

2. The preparation method according to claim 1, wherein The preparation method satisfies at least one of the following characteristics (1) to (4): (1) The magnetic filler includes ferrosoferric oxide; (2) The mass ratio of the magnetic filler to the organic solvent is 1:(20-45); (3) The organic solvent includes polyethylene glycol, polyvinyl alcohol, diethylene glycol and triethylene glycol, and the mass ratio of the polyethylene glycol, the polyvinyl alcohol, the diethylene glycol and the triethylene glycol is 1:(0.65-1.5):(1.3-3):(1.3-3); (4) The first base oil includes at least one of a poly-α-olefin base oil, an ester base oil, and a silicone oil.

3. The preparation method according to claim 1, wherein The mass ratio of the total mass of the magnetic filler and the organic solvent to the first base oil is (0.01-0.05):

1.

4. The preparation method according to claim 1, wherein The mass ratio of the iron oxide intercalated graphite oxide to the magnetized base oil is (0.01-0.08):

1.

5. The preparation method according to any one of claims 1 to 4, wherein The parameters of the intercalation treatment are: treatment temperature of 50° C. to 60° C., treatment aperture of 2 cm to 4 cm, flow linear velocity of 30 m / s to 50 m / s, and treatment time of 10 h to 14 h.

6. The preparation method according to any one of claims 1 to 4, wherein The preparation of the magnetized base oil comprises the following steps: The magnetic filler, the organic solvent and the first base oil are mixed and magnetized to obtain the magnetized base oil. The parameters of the magnetization treatment are: magnetic field intensity of 80 mT to 200 mT, temperature of 30° C. to 60° C., and time of 40 min to 60 min.

7. The preparation method according to any one of claims 1 to 4, wherein The temperature of the oxidation reaction is 10°C to 20°C, and the time is 1 h to 2 h.

8. A graphene lubricant additive, characterized in that: The preparation method according to any one of claims 1 to 7 is used to prepare the compound.

9. A graphene lubricant, characterized in that: comprising a second base oil and the graphene lubricant additive according to claim 8; wherein The second base oil includes at least one of a poly-α-olefin base oil, an ester base oil and a silicone oil.

10. The graphene lubricant according to claim 9, characterized in that The mass ratio of the graphene lubricating oil additive to the second base oil is (0.05~0.5):1.

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