Preparation method of graphene modified grease

Abstract

A preparation method of graphene-modified grease relates to the technical field of graphite products. The purpose of the present invention is to solve the problems of inadequate lubrication and poor heat dissipation during the lubrication of large equipment by traditional grease. The present invention uses a mechanical method to prepare graphene and modifies the graphene, which not only ensures the thermal conductivity of graphene but also opens the interlayer spacing of graphene, facilitating its dispersibility in grease (the mass percentage of modified graphene in the graphene-modified grease is 0.1% - 2%). Thereby, the heat dissipation and lubrication performance of the grease are improved. Finally, the friction coefficient of the graphene-modified grease is reduced by 30% compared with the original lithium-based grease. The present invention can obtain a preparation method of graphene-modified grease.

Description

Technical Field

[0001] The present invention relates to the technical field of graphite products, and particularly relates to a preparation method of graphene-modified grease. Background Art

[0002] With the progress and development of technology, lubrication protection faces new challenges, and traditional greases can no longer meet the current lubrication requirements. Graphene has a unique two-dimensional lamellar structure, with strong thermal conductivity and excellent lubrication performance, which can enable good heat dissipation during the operation of equipment. At the same time, it can weaken and repair defects such as scratches and grooves on the worn surface. Graphene can form a protective film in the grease, which can play a "passivation film"-type protection role during the friction process. At the same time, graphene can fill small grooves to reduce the friction coefficient, so as to achieve the purpose of enhancing the performance of the grease.

[0003] However, at present, traditional greases usually have problems such as insufficient lubrication and poor heat dissipation effect during the lubrication process of large equipment, which urgently need to be optimized and solved by technical personnel. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of insufficient lubrication and poor heat dissipation effect existing in the lubrication process of traditional greases for large equipment, and to provide a preparation method of graphene-modified grease.

[0005] A preparation method of graphene-modified grease is carried out according to the following steps:

[0006] Step 1: Using natural graphite as raw material, prepare graphene by mechanical method;

[0007] Step 2: Modify the graphene in Step 1 by chemical method to obtain modified graphene;

[0008] Step 3: Add a dispersant to the modified graphene in Step 2, and disperse it by ultrasonic dispersion technology to obtain a modified graphene dispersion; the mass fraction of the dispersant in the modified graphene dispersion is 5% - 200%;

[0009] Step 4: Add lithium-based grease to the modified graphene dispersion in Step 3, and prepare by mechanical method to obtain graphene-modified grease; the mass fraction of the modified graphene in the graphene-modified grease is 0.1% - 2%.

[0010] Advantages of the present invention:

[0011] The present invention prepares graphene by a mechanical method and modifies the graphene, which not only ensures the thermal conductivity of graphene but also opens the interlayer spacing of graphene, facilitating its dispersibility in the grease (the mass percentage of the modified graphene in the graphene-modified grease is 0.1% to 2%). Thereby, the heat dissipation and lubrication performance of the grease are improved. Finally, the friction coefficient of the graphene-modified grease is reduced by 30% compared with the original lithium-based grease.

[0012] The present invention can obtain a preparation method of a graphene-modified grease. Description of the Drawings

[0013] Figure 1 It is a physical diagram of the graphene-modified grease of the present invention;

[0014] Figure 2 It is a physical diagram of the original grease;

[0015] Figure 3 It is a friction coefficient diagram of the original grease without graphene modification;

[0016] Figure 4 It is a friction coefficient diagram of the graphene-modified grease with a graphene mass fraction of 0.1% in Example 1;

[0017] Figure 5 It is a friction coefficient diagram of the graphene-modified grease with a graphene mass fraction of 1% in Example 2;

[0018] Figure 6 It is a friction coefficient diagram of the graphene-modified grease with a graphene mass fraction of 1.5% in Example 3. Detailed Embodiments

[0019] Detailed Embodiment 1: A preparation method of a graphene-modified grease in this embodiment is carried out according to the following steps:

[0020] Step 1: Using natural graphite as raw material, prepare graphene by a mechanical method;

[0021] Step 2: Modify the graphene in Step 1 by a chemical method to obtain modified graphene;

[0022] Step 3: Add a dispersant to the modified graphene in Step 2 and disperse it by ultrasonic dispersion technology to obtain a modified graphene dispersion; the mass fraction of the dispersant in the modified graphene dispersion is 5% to 200%;

[0023] Step 4: Add lithium-based grease to the modified graphene dispersion in Step 3 and prepare it by a mechanical method to obtain graphene-modified grease; the mass fraction of the modified graphene in the graphene-modified grease is 0.1% to 2%.

[0024] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is as follows: The specific steps of preparing graphene by mechanical method in Step 1 are as follows: An intercalating agent is added to natural graphite, and ultrasonic equipment is used to perform ultrasonic treatment at a temperature of 5 - 20°C for 2 - 16 h, then shearing is performed using a high-speed shearing machine for 2 - 8 h, followed by washing with water and drying to obtain graphene. The mass ratio of the natural graphite to the intercalating agent is 10:(175 - 200).

[0025] Other steps are the same as those in Specific Embodiment 1.

[0026] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 or 2 is that the intercalating agent is absolute ethanol or deionized water.

[0027] Other steps are the same as those in Specific Embodiment 1 or 2.

[0028] Specific Embodiment 4: The difference between this embodiment and any one of Specific Embodiments 1 to 3 is as follows: The specific steps of modifying graphene by chemical method in Step 2 are as follows: A modifier is added to graphene, and ultrasonic technology is used for modification for 1 - 2 h, followed by washing with water and drying to obtain modified graphene. The mass ratio of the graphene to the modifier is 1:(1 - 2).

[0029] Other steps are the same as those in Specific Embodiments 1 to 3.

[0030] Specific Embodiment 5: The difference between this embodiment and any one of Specific Embodiments 1 to 4 is that the modifier is oleic acid, lithium-based base oil or polyvinylpyrrolidone.

[0031] Other steps are the same as those in Specific Embodiments 1 to 4.

[0032] Specific Embodiment 6: The difference between this embodiment and any one of Specific Embodiments 1 to 5 is as follows: The specific steps of preparing a modified graphene dispersion by ultrasonic dispersion technology in Step 3 are as follows: A dispersant is added to the modified graphene, stirred evenly, and then ultrasonic dispersion is performed for 1 - 2 h to obtain a modified graphene dispersion. The mass ratio of the modified graphene to the dispersant is 1:(0.05 - 2).

[0033] Other steps are the same as those in Specific Embodiments 1 to 5.

[0034] Specific Embodiment 7: The difference between this embodiment and any one of Specific Embodiments 1 to 6 is that the dispersant is N-methylpyrrolidone, N,N-dimethylformamide or dimethyl sulfoxide.

[0035] Other steps are the same as those in Specific Embodiments 1 to 6.

[0036] Embodiment 8: The difference between this embodiment and any one of Embodiments 1 to 7 is as follows: The specific steps for preparing graphene-modified grease by mechanical method in Step 4 are as follows: Add lithium grease to the modified graphene dispersion liquid, first grind it in an agate mortar for 3 to 5 minutes, then use a variable-frequency disperser to disperse it for 30 to 60 minutes under the rotational speed condition of 100 to 200 r / min, and finally use a three-roll grinder to grind it for 30 to 60 minutes under the condition of circulating cooling water to obtain graphene-modified grease.

[0037] Other steps are the same as those in Embodiments 1 to 7.

[0038] Embodiment 9: The difference between this embodiment and any one of Embodiments 1 to 8 is that the mass fraction of the dispersant in the modified graphene dispersion liquid is 10%, 100%, or 150%.

[0039] Other steps are the same as those in Embodiments 1 to 8.

[0040] Embodiment 10: The difference between this embodiment and any one of Embodiments 1 to 9 is that the mass fraction of the modified graphene in the graphene-modified grease is 0.1%, 1%, or 1.5%.

[0041] Other steps are the same as those in Embodiments 1 to 9.

[0042] The following examples are used to verify the beneficial effects of the present invention:

[0043] Example 1: A preparation method of graphene-modified grease is carried out according to the following steps:

[0044] Step 1: Add intercalating agent absolute ethanol to natural graphite, use an ultrasonic device to ultrasonically treat it for 6 hours at a temperature of 15°C, then shear it with a high-speed shearer for 3 hours, wash it with water and dry it to obtain graphene. The mass ratio of the natural graphite to the intercalating agent is 10:175;

[0045] Step 2: Add modifier polyvinylpyrrolidone to the graphene, use ultrasonic technology to modify it for 1 hour, wash it with water and dry it to obtain modified graphene. The mass ratio of the graphene to the polyvinylpyrrolidone is 1:1;

[0046] Step 3: Add dispersant N,N-dimethylformamide to the modified graphene, stir it evenly, and then ultrasonically disperse it for 1 hour to obtain a modified graphene dispersion liquid. The mass ratio of the modified graphene to the N,N-dimethylformamide is 1:0.05. The mass fraction of the dispersant in the modified graphene dispersion liquid is 10%;

[0047] Step 4: Add lithium-based grease to the modified graphene dispersion. First, grind it in an agate mortar for 5 minutes, then disperse it with a variable-frequency disperser at a rotation speed of 150 r / min for 30 minutes. Finally, grind it with a three-roll mill under circulating cooling water conditions for 30 minutes to obtain graphene-modified grease. The mass fraction of the modified graphene in the graphene-modified grease is 0.1%.

[0048] Example 2: The difference between this example and Example 1 is that: in Step 3, the mass fraction of the dispersant in the modified graphene dispersion is 100%, and in Step 4, the mass percentage of the modified graphene in the graphene-modified grease is 1%. The remaining test conditions are the same as those in Example 1.

[0049] Example 3: The difference between this example and Example 1 is that: in Step 3, the mass fraction of the dispersant in the modified graphene dispersion is 150%, and in Step 4, the mass percentage of the modified graphene in the graphene-modified grease is 1.5%. The remaining test conditions are the same as those in Example 1.

[0050] Figure 3 is the friction coefficient diagram of the original grease without graphene modification, Figure 4 is the friction coefficient diagram of the graphene-modified grease with a mass fraction of 0.1% of graphene in Example 1, Figure 5 is the friction coefficient diagram of the graphene-modified grease with a mass fraction of 1% of graphene in Example 2, Figure 6 is the friction coefficient diagram of the graphene-modified grease with a mass fraction of 1.5% of graphene in Example 3.

[0051] From Figures 3 - 6 the data in it, it can be seen that the average friction coefficient of the grease with a mass fraction of 0% of graphene is 0.0907, the average friction coefficient of the grease with a mass fraction of 0.1% of graphene is 0.0799, the average friction coefficient of the grease with a mass fraction of 1% of graphene is 0.0737, and the average friction coefficient of the grease with a mass fraction of 1.5% of graphene is 0.0824. It can be seen that the friction performance of the grease modified by graphene has been improved, and when the addition amount of graphene is 1%, the lubrication performance of the modified grease is the best.

Claims

1. A preparation method of graphene-modified grease, characterized in that The preparation method is carried out according to the following steps: Step 1: Using natural graphite as raw material, graphene is prepared by mechanical method. The specific steps for preparing graphene by mechanical method in Step 1 are as follows: An intercalating agent is added to natural graphite, and ultrasonic equipment is used to ultrasonicate for 2 - 16 h under the temperature condition of 5 - 20 °C, then sheared by a high-speed shearing machine for 2 - 8 h, washed with water and dried to obtain graphene. The mass ratio of the natural graphite to the intercalating agent is 10:(175 - 200); the intercalating agent is anhydrous ethanol or deionized water. Step 2: The graphene in Step 1 is modified by chemical method to obtain modified graphene. The specific steps for modifying graphene by chemical method in Step 2 are as follows: A modifier is added to graphene, and modified by ultrasonic technology for 1 - 2 h, washed with water and dried to obtain modified graphene. The mass ratio of the graphene to the modifier is 1:(1 - 2), and the modifier is oleic acid. Step 3: A dispersant is added to the modified graphene in Step 2, and ultrasonic dispersion technology is used for dispersion to obtain a modified graphene dispersion; the mass fraction of the dispersant in the modified graphene dispersion is 10%. The specific steps for preparing the modified graphene dispersion by ultrasonic dispersion technology in Step 3 are as follows: A dispersant is added to the modified graphene, stirred evenly, and then ultrasonically dispersed for 1 - 2 h to obtain a modified graphene dispersion. The mass ratio of the modified graphene to the dispersant is 1:(0.05 - 2), and the dispersant is N-methylpyrrolidone, N,N-dimethylformamide or dimethyl sulfoxide. Step 4: Lithium-based grease is added to the modified graphene dispersion in Step 3, and prepared by mechanical method to obtain graphene-modified grease; the mass fraction of the modified graphene in the graphene-modified grease is 0.1%, 1% or 1.5%.

2. The preparation method of a graphene-modified grease according to claim 1, characterized in that The specific steps for preparing graphene-modified grease by mechanical method in Step 4 are as follows: Lithium-based grease is added to the modified graphene dispersion, first ground in an agate mortar for 3 - 5 min, then dispersed by a variable-frequency disperser at a rotation speed of 100 - 200 r / min for 30 - 60 min, and finally ground by a three-roll mill under circulating cooling water conditions for 30 - 60 min to obtain graphene-modified grease.

Images