A conductive nanofluid lubricant and its preparation method and application

Abstract

The present application belongs to the technical field of lubricating materials, and specifically relates to a conductive nanofluid lubricant and its preparation method and application. By selecting electrically conductive nanomaterials that can be charged and non-polar base oils with relatively low electrical conductivity as raw material components of the lubricant, the present application can be coordinated with the electrostatic dispersion treatment process and parameters. By means of the repulsive force between the charged conductive nanoparticles, the conductive nanomaterials dispersed in the lubricant raw material mixed system are driven to depolymerize and be uniformly dispersed in the system with smaller particle sizes. Furthermore, by controlling the type and even the addition ratio of the gel factor added, it can be coordinated with other components to adjust the lubricant raw material mixed system and the finally prepared conductive nanofluid lubricant to a liquid with a certain fluidity. Therefore, it can be coordinated with conductive nanoparticles of a specific charge under the electrostatic dispersion treatment parameters to achieve moderate dispersion and movement of conductive nanoparticles in the lubricant raw material mixed system.

Description

Technical Field

[0001] The present application belongs to the technical field of lubricating materials, and specifically relates to a conductive nanofluid lubricant and a preparation method and application thereof. Background Art

[0002] Conductive nanofluid lubricants offer high thermal conductivity, excellent electrical conductivity, lubricity, and environmental friendliness, holding great potential for application in a wide range of fields. However, due to the high surface energy and interparticle attraction of conductive nanomaterials, they tend to spontaneously aggregate, forming large aggregates over time. This agglomeration causes the nanoparticles to settle in the lubricant, depleting their unique functionalities. Therefore, improving the dispersion and stability of conductive nanomaterials in lubricants is an urgent issue.

[0003] To address this technical issue, currently used methods include physical and chemical dispersion. Physical dispersion uses mechanical force or ultrasound to break up aggregates and disperse nanoparticles. Common physical dispersion methods include ball milling, stirring, and ultrasound. Ball milling is a common physical dispersion method that uses the collision and friction between the high-speed rotating ball mill and the milling balls to break up aggregates and disperse nanoparticles. Stirring dispersion uses the shear force generated by an agitator to break up aggregates and disperse nanoparticles. Ultrasonic dispersion uses the cavitation and mechanical effects of ultrasound in liquids to break up aggregates and disperse nanoparticles. Physical dispersion methods offer advantages such as simplicity and low cost. Chemical dispersion methods use chemical substances such as surfactants or modifiers to modify the surface properties of nanoparticles, weakening or eliminating interparticle interactions, thereby dispersing nanoparticles. Surface modifiers used in chemical dispersion methods include surfactants, polymers, and grafting modifiers. By modifying the nanoparticle surface, they reduce interparticle interactions, increase steric hindrance, and reduce the tendency for nanoparticles to aggregate and settle. The chemical dispersion method has the advantages of good dispersion effect and high dispersion stability.

[0004] Applicants have discovered that while physical dispersion methods can temporarily break up aggregates, their effectiveness is significantly affected by operating conditions and equipment performance, and achieving long-term, stable dispersion is difficult. Chemical dispersion methods can reduce the interaction between nanoparticles through surface modification, but even then, the modified nanoparticles still exist as clusters, especially in complex fluid environments. Therefore, while both physical and chemical methods can be used to disperse conductive nanomaterials, achieving long-term, uniform, and stable dispersion with no or low agglomeration in practical applications remains a technical challenge for current conductive nanofluid lubricants. Summary of the Invention

[0005] To solve the above technical problems, this application mainly provides a method for preparing a conductive nanofluid lubricant, which is specifically achieved through the following technical solutions:

[0006] A method for preparing a conductive nanofluid lubricant comprises: performing electrostatic dispersion treatment on a mixed system of lubricant raw materials to obtain the conductive nanofluid lubricant; the lubricant raw materials comprise, by mass percentage, 0.01-0.2 wt% of a conductive nanomaterial, 97.50-99.93 wt% of a non-polar base oil, 0.01-0.75 wt% of a first gelling factor, and 0.05-2 wt% of a second gelling factor; the first gelling factor comprises one or more of sodium sulfate organic matter and sodium sulfonate organic matter, and the second gelling factor comprises a carboxylic acid organic matter; and the electrostatic dispersion treatment comprises a voltage of -2-8 kV and a time of 5-60 min.

[0007] Preferably, the conductive nanomaterial includes one or more of carbon-based nanomaterials, metal and metal oxide nanomaterials and conductive polymers; the first gel factor includes one or more of sodium dodecyl sulfate, sodium p-toluenesulfonate and sodium dodecylbenzenesulfonate; the second gel factor includes one or more of oleic acid, linoleic acid, linolenic acid and palmitoleic acid; the non-polar base oil includes one or more of mineral oil and alkane base oil.

[0008] Preferably, the size of the conductive nanomaterial is between 1 and 500 nm.

[0009] Preferably, the conductive nanomaterial further comprises a modifier modified on the conductive nanomaterial, and the modifier is a saturated or monounsaturated alkyl long chain.

[0010] Preferably, the main carbon chain length of the modification differs from the length of a single main carbon chain of the gel factor by less than 6 carbon atoms.

[0011] Preferably, the electrostatic dispersion treatment parameters also include: temperature 20-80°C, ultrasound 200-2000W.

[0012] A conductive nanofluid lubricant is prepared by any of the above-mentioned preparation methods.

[0013] Preferably, the particle size D50 of the conductive nanomaterial in the conductive nanofluid lubricant is 50-5000 nm.

[0014] Preferably, the charge-to-mass ratio of the conductive nanofluid lubricant is 10 -3 ~10 -2 C / kg.

[0015] The conductive nanofluid lubricant prepared by any of the preparation methods described above or the use of the conductive nanofluid lubricant described in any of the above in the lubrication of mechanical equipment.

[0016] Compared with the prior art, this application has the following beneficial effects:

[0017] This application selects electrically conductive nanomaterials that can be charged and non-polar base oils with relatively low electrical conductivity as raw material components of the lubricant, which can be coordinated with the electrostatic dispersion treatment process and parameters. By leveraging the repulsive force between the charged conductive nanoparticles, the conductive nanomaterials dispersed in the lubricant raw material mixture are driven to depolymerize and be uniformly dispersed in the system with smaller particle sizes.

[0018] By controlling the type and even the addition ratio of the gelling factor, the present application can coordinate with other components to adjust the lubricant raw material mixed system and the finally prepared conductive nanofluid lubricant to a liquid with a certain fluidity. Therefore, it can be coordinated with conductive nanoparticles of a specific charge under electrostatic dispersion treatment parameters to achieve moderate dispersion and movement of the conductive nanoparticles in the lubricant raw material mixed system.

[0019] The present application selects a first gelling factor and a second gelling factor, and sets a modifier on the conductive nanomaterial. The modifier can cooperate with the gelling factor. After the static electricity of the conductive nanoparticles dissipates, the conductive nanoparticles can be pulled, thereby ensuring the long-term dispersion stability of low-particle-size conductive nanoparticles in the conductive nanofluid lubricant, and solving the technical problem that the conductive nanoparticles have high surface energy and are prone to agglomeration and sedimentation during long-term storage.

[0020] This application further achieves uniform and stable dispersion of small-sized conductive nanoparticles in conductive nanofluid lubricating liquid through the synergistic dispersion method of electrolytic depolymerization-gel traction. The electrostatic dispersion treatment process is simple and easy to implement. By adjusting the parameters of the electrostatic dispersion treatment within the process parameter conditions of this application, the particle size of the carbon nanoparticles can be adjusted to adapt to different lubrication situations, which has excellent application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to clearly illustrate the embodiments, the drawings are briefly introduced below:

[0022] Figure 1 Schematic diagram of the deagglomeration of electrostatic dispersion in this application;

[0023] Figure 2 This is a diagram showing the particle size distribution of conductive nanoclusters in the nanofluid lubricant before and after electrodepolymerization in performance test 1;

[0024] Figure 3Distribution of conductive nanoclusters in the conductive nanofluid lubricant after centrifugation in performance test 2, from left to right (a) uncharged graphene, (b) charged graphene, (c) uncharged carbon nanotubes, and (d) charged carbon nanotubes.

[0025] Figure 4 Distribution of conductive nanoclusters in the conductive nanofluid lubricant without modifications after centrifugation in performance test 3, from left to right (a) uncharged graphene, (b) charged graphene.

[0026] Figure 5 Particle size distribution of nanoclusters in graphene oxide nanofluid lubricant at different voltages in performance test 4. DETAILED DESCRIPTION

[0027] The present application will be further described below in the form of specific embodiments. Those skilled in the art will be able to implement the present application based on these descriptions. In addition, the embodiments of the present application involved in the following description are generally only embodiments of a portion of the present application, rather than all embodiments. Therefore, based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative efforts should fall within the scope of protection of the present application.

[0028] Example 1

[0029] This embodiment discloses a conductive nanofluid lubricant. The preparation method of the conductive nanofluid lubricant is as follows:

[0030] (S.1) Adding 0.05 g of oleic acid-modified graphene oxide (GO / OA), 0.05 g of sodium lauryl sulfate, and 0.25 g of oleic acid to 99.65 g of white oil, respectively, and stirring uniformly to obtain a lubricating fluid raw material mixture; wherein the graphene oxide has a nanometer size of 1 to 50 nm;

[0031] (S.2) The obtained lubricating liquid raw material mixed system is placed in an electrolytic cell for electrostatic dispersion treatment. The electrostatic dispersion treatment parameters are a DC voltage of -6kV, a temperature of 60°C, an ultrasound of 1000W, and a time of 10 minutes. After standing at room temperature, a well-dispersed conductive nanofluid lubricant is obtained.

[0032] Example 2

[0033] This embodiment discloses a conductive nanofluid lubricant. The preparation method of the conductive nanofluid lubricant is as follows:

[0034] (S.1) Adding 0.05 g of dodecanethiol-modified hydroxy carbon nanotubes, 0.1 g of oleic acid, and 0.5 g of sodium lauryl sulfate to 99.35 g of PEG400, and stirring uniformly, to obtain a lubricating fluid raw material mixture; wherein the carbon nanotubes have a nanometer size of 1 to 50 nm;

[0035] (S.2) The obtained lubricating liquid raw material mixed system is placed in an electrolytic cell for electrostatic dispersion treatment. The electrostatic dispersion treatment parameters are DC voltage -4kV, temperature 40℃, ultrasound 2000W and time 15min. After standing at room temperature, a well-dispersed conductive nanofluid lubricant is obtained.

[0036] Example 3

[0037] This embodiment discloses a conductive nanofluid lubricant. The preparation method of the conductive nanofluid lubricant is as follows:

[0038] (S.1) 0.05 g of graphene oxide, 1.5 g of an organic amine, and 0.5 g of toluene diisocyanate were added to 97.95 g of white oil, and the mixture was stirred to obtain a lubricating fluid raw material mixture. The graphene oxide had a nanometer size of 1 to 50 nm.

[0039] (S.2) The obtained lubricating liquid raw material mixed system is placed in an electrolytic cell for electrostatic dispersion treatment. The electrostatic dispersion treatment parameters are DC voltage -6kV, temperature 40°C, ultrasound 2000W and time 15min. After standing at room temperature, a well-dispersed conductive nanofluid lubricant is obtained.

[0040] Example 4

[0041] This embodiment discloses a conductive nanofluid lubricant. The preparation method of the conductive nanofluid lubricant is as follows:

[0042] (S.1) Adding 0.01 g of dodecanethiol-modified hydroxy carbon nanotubes, 0.05 g of oleic acid, and 0.01 g of sodium lauryl sulfate to 99.93 g of PEG400, and stirring uniformly, to obtain a lubricating fluid raw material mixture; wherein the carbon nanotubes have a nanometer size of 1 to 50 nm;

[0043] (S.2) The obtained lubricating liquid raw material mixed system is placed in an electrolytic cell for electrostatic dispersion treatment. The electrostatic dispersion treatment parameters are DC voltage -4kV, temperature 40℃, ultrasound 2000W and time 15min. After standing at room temperature, a well-dispersed conductive nanofluid lubricant is obtained.

[0044] Example 5

[0045] This embodiment discloses a conductive nanofluid lubricant. The preparation method of the conductive nanofluid lubricant is as follows:

[0046] (S.1) Adding 0.2 g of dodecanethiol-modified hydroxy carbon nanotubes, 1.55 g of oleic acid, and 0.75 g of sodium lauryl sulfate to 97.5 g of PEG400, and stirring uniformly, to obtain a lubricating fluid raw material mixture; wherein the carbon nanotubes have a nanometer size of 1 to 50 nm;

[0047] (S.2) The obtained lubricating liquid raw material mixed system is placed in an electrolytic cell for electrostatic dispersion treatment. The electrostatic dispersion treatment parameters are DC voltage -8kV, temperature 20℃, ultrasound 2000W and time 5min. After standing at room temperature, a well-dispersed conductive nanofluid lubricant is obtained.

[0048] Example 6

[0049] This embodiment discloses a conductive nanofluid lubricant. The preparation method of the conductive nanofluid lubricant is as follows:

[0050] (S.1) Adding 0.01 g of dodecanethiol-modified hydroxy carbon nanotubes, 2 g of oleic acid, and 0.01 g of sodium lauryl sulfate to 97.98 g of PEG400, and stirring uniformly, to obtain a lubricating fluid raw material mixture; wherein the carbon nanotubes have a nanometer size of 1 to 50 nm;

[0051] (S.2) The obtained lubricating liquid raw material mixed system is placed in an electrolytic cell for electrostatic dispersion treatment. The electrostatic dispersion treatment parameters are DC voltage -2kV, temperature 80℃, ultrasound 200W and time 60min. After standing at room temperature, a well-dispersed conductive nanofluid lubricant is obtained.

[0052] Comparative Example 1

[0053] The difference between this comparative example and Example 1 is that the preparation steps of the conductive nanofluid lubricating liquid do not include step (S.2).

[0054] Comparative Example 2

[0055] The difference between this comparative example and Example 2 is that the preparation steps of the conductive nanofluid lubricating liquid do not include step (S.2).

[0056] Comparative Example 3

[0057] The difference between this comparative example and Example 3 is that the preparation steps of the conductive nanofluid lubricating liquid do not include step (S.2).

[0058] Performance Test 1

[0059] This performance test measures the particle size distribution of nanoclusters in the conductive nanofluid lubricant obtained in Examples 1 and 2 and Comparative Examples 1 and 2, using Zeta potential and particle size analysis. Figure 2 , by observing Figure 2 It can be found that in Examples 1 and 2, the particle size of the conductive nanoclusters can be significantly reduced by electrostatically dispersing the lubricating liquid raw material mixed system. This means that the present application can cooperate with the electrostatic dispersion treatment process and parameters by selecting and designing the lubricating liquid raw materials. The charged conductive nanomaterial can be deagglomerated and dispersed in the lubricating liquid raw material mixed system with certain flow properties under the action of the electric field force and the coulomb within the agglomerate. Therefore, the conductive nanoparticles in the lubricating liquid raw material mixed system are smaller.

[0060] Performance Test 2

[0061] In this performance test, the conductive nanofluid lubricant obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was centrifuged at 2000 r / min for 5 minutes, and then the dispersion of the conductive nanofluid lubricant was checked. Figure 3 By observing Figure 3 It can be found that after high-speed centrifugation, the conductive nanomaterials in Comparative Examples 1 and 2 have aggregated in large quantities and formed a sediment at the lower end of the test tube, while there are only slight aggregates in the conductive nanofluid lubricant obtained in Examples 1 and 2. It can be seen that the present application selects the first gel factor and the second gel factor, and sets a modifier on the conductive nanomaterial. The modifier can cooperate with the first gel factor. After the static electricity of the conductive nanoparticles dissipates, the low-particle-size conductive nanoparticles can be strongly pulled, thereby ensuring the long-term dispersion stability of the low-particle-size conductive nanoparticles in the conductive nanofluid lubricant, effectively overcoming the problem of easy aggregation and precipitation due to the high surface energy of the conductive nanoparticles, and improving the stability of the nanomaterial under long-term storage conditions.

[0062] Performance Test 3

[0063] In this performance test, the conductive nanofluid lubricant obtained in Example 3 and Comparative Example 3 was centrifuged at 2000 r / min for 5 minutes, and then the dispersion of the conductive nanofluid lubricant was checked to obtain the dispersion. Figure 4 By observing Figure 4 It can be found that when no modifier is provided on the conductive nanomaterial, the conductive nanofluid lubricant prepared by electrostatic dispersion treatment can achieve relatively stable dispersion.

[0064] Performance Test 4

[0065] This performance test is based on Example 1, and the DC voltage is adjusted to 0, -1kv, -2kv, -4kv, -6kv, -8kv and -10kv respectively, and the particle size of the nanoclusters in the conductive nanofluid lubricant is tested. Figure 5 .observe Figure 5 It can be found that after applying electrostatic dispersion treatment to the specific gel system in Example 1, the particle size is greatly reduced. When the voltage is set to -6kv, the particle size reaches the lowest. Furthermore, when the voltage is set to -10kv, the particle size increases instead. After analysis, the applicant believes that excessively high charge density may lead to increased Brownian motion of the particles, promote particle collisions to form larger agglomerates, and ultimately lead to an increase in the average particle size.

Claims

1. A method for preparing a conductive nanofluid lubricant, characterized in that: include: Performing electrostatic dispersion treatment on the lubricating liquid raw material mixed system to obtain a conductive nanofluid lubricating liquid; Calculated in mass percentage, the lubricating fluid raw materials include 0.01~0.2wt% conductive nanomaterials, 97.50~99.93wt% non-polar base oil, 0.01~0.75wt% first gelling factor and 0.05~2wt% second gelling factor; the first gelling factor includes one or more of sodium sulfate organic matter and sodium sulfonate organic matter, and the second gelling factor includes carboxylic acid organic matter; the conditions of the electrostatic dispersion treatment are voltage of -2~-8kV and time of 5~60min; the conductive nanomaterials include one or more of carbon-based nanomaterials, metal and metal oxide nanomaterials and conductive polymers.

2. The method for preparing a conductive nanofluid lubricant according to claim 1, characterized in that: The first gelling factor includes one or more of sodium lauryl sulfate, sodium p-toluenesulfonate, and sodium dodecylbenzenesulfonate; the second gelling factor includes one or more of oleic acid, linoleic acid, linolenic acid, and palmitoleic acid; and the non-polar base oil includes one or more of mineral oil and alkane base oil.

3. The method for preparing a conductive nanofluid lubricant according to claim 2, characterized in that: The size of the conductive nanomaterial is between 1 and 500 nm.

4. The method for preparing a conductive nanofluid lubricant according to claim 1, characterized in that: The conductive nanomaterial further includes a modifier modified on the conductive nanomaterial, and the modifier is a saturated or monounsaturated alkyl long chain.

5. The method for preparing a conductive nanofluid lubricant according to claim 4, characterized in that: The main carbon chain length of the modifier differs from the single main carbon chain length of the first gel factor by less than 6 carbon atoms.

6. The method for preparing a conductive nanofluid lubricant according to claim 1, characterized in that: The electrostatic dispersion treatment parameters also include: temperature 20-80° C., ultrasound 200-2000W.

7. The method for preparing a conductive nanofluid lubricant according to claim 1, characterized in that: The non-polar base oil is white oil, the conductive nanomaterial is oleic acid-modified graphene oxide; the first gelling factor is sodium lauryl sulfate, and the second gelling factor is oleic acid; the conditions of the electrostatic dispersion treatment are voltage -6kV, temperature 60°C, ultrasound 1000W and time 10min.

8. A conductive nanofluid lubricant, characterized in that: The preparation method is described in any one of claims 1 to 6.

9. Use of the conductive nanofluid lubricant according to claim 8 in lubrication of mechanical equipment.

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