Tannic acid-oleylamine modified nano molybdenum disulfide as well as preparation method and application thereof

Abstract

The invention discloses tannic acid-oleylamine modified nano molybdenum disulfide as well as a preparation method and application thereof. The preparation method of the tannic acid-oleylamine modified nano-molybdenum disulfide comprises the following steps: 1) dispersing nano-molybdenum disulfide and tannic acid in a solvent, then adding ferric salt for reaction, and then carrying out product separation to obtain the tannic acid modified nano-molybdenum disulfide; and 2) dispersing the tannic acid modified nano molybdenum disulfide and oleylamine in a solvent for reaction, and then carrying out product separation to obtain the tannic acid-oleylamine modified nano molybdenum disulfide. The tannic acid-oleylamine modified nano molybdenum disulfide disclosed by the invention has the advantages of excellent friction reduction and wear resistance, good dispersity in ester oil, good compatibility with other additives and the like, the preparation raw materials are safe and non-toxic, the preparation method is simple, and the tannic acid-oleylamine modified nano molybdenum disulfide is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] The present invention relates to the technical field of cutting processing, and particularly relates to tannic acid-oleylamine modified nano-molybdenum disulfide, a preparation method thereof, and an application thereof. Background Art

[0002] Ester oils refer to natural oils containing ester groups in their molecular structures. They have excellent biodegradability, high flash points, good lubrication properties, etc., and have become important substitutes for mineral oils in the field of cutting processing. However, when directly used as metal cutting fluids, ester oils have problems such as insufficient anti-wear performance and limited load-carrying capacity, which limit their further expanded application.

[0003] Nano-molybdenum disulfide (MoS₂) is a layered structure material with excellent lubrication and anti-wear properties. Adding it as an additive to ester oils can significantly reduce the friction coefficient of ester oils and the wear rate of cutting equipment, and can improve the lubrication performance of ester oils under harsh conditions such as high loads and high temperatures (the action mechanisms of nano-molybdenum disulfide in ester oils mainly include interlayer slip, surface adsorption, repair action, and synergistic effect), thereby effectively extending the service life of cutting equipment. However, nano-molybdenum disulfide has poor dispersion stability and long-term use performance in ester oils, and has poor compatibility with other additives.

[0004] Currently, the typical modification strategy for nano-molybdenum disulfide is surface modification. Generally, surfactants containing long-chain alkyl groups (such as cetyltrimethylammonium bromide, sodium dodecyl sulfate, etc.) are used to modify the surface of nano-molybdenum disulfide to improve its compatibility with ester oils. However, the improvement of the dispersion stability of nano-molybdenum disulfide by surfactant modification is very limited, usually only maintaining a stable dispersion time of one week. Moreover, due to the competitive relationship between the surfactant and polar ester oils, the anti-wear performance of nano-molybdenum disulfide becomes worse, resulting in an increase in the wear amount of nano-molybdenum disulfide during use, and it cannot fully exert its anti-wear effect, making it difficult to meet the requirements of practical applications.

[0005] Therefore, it is of great significance to develop a modified nano-molybdenum disulfide with excellent friction reduction and anti-wear performance, good dispersion in ester oils, and good compatibility with other additives. Summary of the Invention

[0006] The purpose of the present invention is to provide tannic acid-oleylamine modified nano-molybdenum disulfide, a preparation method thereof, and an application thereof.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A preparation method of tannic acid-oleylamine modified nano-molybdenum disulfide comprises the following steps:

[0009] 1) Disperse molybdenum disulfide nanosheets and tannic acid in a solvent, then add an iron salt for reaction, and then separate the product to obtain tannic acid-modified molybdenum disulfide nanosheets;

[0010] 2) Disperse tannic acid-modified molybdenum disulfide nanosheets and oleylamine in a solvent for reaction, and then separate the product to obtain tannic acid-oleylamine-modified molybdenum disulfide nanosheets.

[0011] Preferably, a method for preparing tannic acid-oleylamine-modified molybdenum disulfide nanosheets comprises the following steps:

[0012] 1) Disperse molybdenum disulfide nanosheets and tannic acid in a solvent, then slowly add an iron salt solution for reaction, centrifuge, and wash the solid to obtain tannic acid-modified molybdenum disulfide nanosheets;

[0013] 2) Disperse tannic acid-modified molybdenum disulfide nanosheets and oleylamine in a solvent for reaction, centrifuge, and wash the solid to obtain tannic acid-oleylamine-modified molybdenum disulfide nanosheets.

[0014] Preferably, in step 1), the mass ratio of the molybdenum disulfide nanosheets to tannic acid is 0.5 - 5:1.

[0015] Preferably, in step 1), the molar ratio of tannic acid to the iron salt is 1:0.5 - 5.

[0016] Preferably, the solvent in step 1) is at least one of water, ethanol, and methanol.

[0017] Preferably, the iron salt in step 1) is at least one of ferric chloride, ferric nitrate, and ferric sulfate.

[0018] Preferably, the reaction time in step 1) is 1 min - 10 min.

[0019] Preferably, in step 2), the mass ratio of the tannic acid-modified molybdenum disulfide nanosheets to oleylamine is 1:2 - 50.

[0020] Preferably, the reaction in step 2) is carried out at a temperature of 30°C - 70°C for a reaction time of 2 h - 12 h.

[0021] Preferably, the solvent in step 2) is at least one of water, ethanol, and methanol.

[0022] A tannic acid-oleylamine-modified molybdenum disulfide nanosheet is prepared by the above preparation method.

[0023] Preferably, the tannic acid-oleylamine-modified molybdenum disulfide nanosheet exhibits a uniform nanosheet structure.

[0024] A cutting fluid contains trimethylolpropane trioleate and the above tannic acid-oleylamine-modified molybdenum disulfide nanosheet.

[0025] Preferably, the mass ratio of the trimethylolpropane oleate to the tannic acid-oleylamine modified nano-molybdenum disulfide is 1:0.001-0.005.

[0026] The beneficial effects of the present invention are as follows: The tannic acid-oleylamine modified nano-molybdenum disulfide of the present invention has excellent anti-friction and anti-wear properties, good dispersibility in ester oils, and good compatibility with other additives. Moreover, its preparation raw materials are safe and non-toxic, and the preparation method is simple, which is suitable for large-scale industrial production and application.

[0027] Specifically:

[0028] 1) The present invention uses a two-step modification method, which not only improves the polarity of nano-molybdenum disulfide but also significantly enhances the dispersibility and anti-friction and anti-wear properties of nano-molybdenum disulfide in ester oils.

[0029] 2) The tannic acid-oleylamine modified nano-molybdenum disulfide of the present invention has good dispersibility in ester oils, which is beneficial to fully exert its anti-friction and anti-wear effects. The cutting fluid prepared by adding it to ester oils has excellent performance and can be stably stored for a long time.

[0030] 3) The preparation raw materials of the tannic acid-oleylamine modified nano-molybdenum disulfide of the present invention are safe and non-toxic, and the preparation method is simple, which is suitable for large-scale industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a mechanism diagram for modifying nano-molybdenum disulfide in the present invention.

[0032] Figure 2 It is an FT-IR diagram of MoS2 and OAm-TA-MoS2 in Example 1.

[0033] Figure 3 It is an SEM diagram of OAm-TA-MoS2 in Example 1.

[0034] Figure 4 It is a test result diagram of the dispersibility of OAm-TA-MoS2 in ester oil in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be further explained and illustrated below with specific examples.

[0036] Example 1:

[0037] A tannic acid-oleylamine modified nano-molybdenum disulfide, and its preparation method is as follows (the modification mechanism is as Figure 1 shown):

[0038] 1) Add 50 mg of nanomolybdenum disulfide (MoS2) and 50 mg of tannic acid to 25 mL of absolute ethanol, stir and ultrasonicate to form a homogeneous nanomolybdenum disulfide - tannic acid dispersion without precipitation. Then dissolve 7.94 mg of ferric chloride hexahydrate in 5 mL of absolute ethanol and slowly add it to the stirring nanomolybdenum disulfide - tannic acid dispersion. After adding, continue stirring for 5 min, then transfer it to a centrifuge and centrifuge at 9000 rpm for 6 min. Take the solid and wash it 3 times with absolute ethanol (the color of the supernatant changes from purple to colorless) to obtain tannic acid - modified nanomolybdenum disulfide (denoted as TA - MoS2).

[0039] 2) Add 20 mg of tannic acid - modified nanomolybdenum disulfide and 200 mg of oleylamine to 20 mL of absolute ethanol, ultrasonicate to form a homogeneous tannic acid - modified nanomolybdenum disulfide - oleylamine dispersion without precipitation, then place it in a water bath and stir at 60 °C for 8 h. Then transfer it to a centrifuge and centrifuge at 9000 rpm for 6 min. Take the solid and wash it 3 times with absolute ethanol (the color of the supernatant changes from yellow to colorless) to obtain tannic acid - oleylamine - modified nanomolybdenum disulfide (denoted as OAm - TA - MoS2).

[0040] Performance test:

[0041] 1) The Fourier transform infrared spectroscopy (FT - IR) spectra of the nanomolybdenum disulfide (MoS2) and tannic acid - oleylamine - modified nanomolybdenum disulfide (OAm - TA - MoS2) in this example are as Figure 2 shown.

[0042] It can be seen from Figure 2 that the surface of OAm - TA - MoS2 contains the characteristic functional groups of tannic acid and oleylamine, indicating that nanomolybdenum disulfide has been successfully modified with tannic acid and oleylamine.

[0043] 2) The scanning electron microscopy (SEM) image of the tannic acid - oleylamine - modified nanomolybdenum disulfide (OAm - TA - MoS2) in this example is as Figure 3 shown.

[0044] It can be seen from Figure 3 that OAm - TA - MoS2 presents a uniform nanosheet structure.

[0045] 3) Add 90 mg of the tannic acid - oleylamine - modified nanomolybdenum disulfide (OAm - TA - MoS2) in this example to 30 mL of trimethylolpropane oleate, stir and ultrasonicate to form a homogeneous cutting fluid without precipitation. Then let it stand at room temperature for 30 days, observe the state of the cutting fluid and take pictures. The test results of the dispersion of the obtained tannic acid - oleylamine - modified nanomolybdenum disulfide in ester - based oil are as Figure 4 shown.

[0046] It can be seen from Figure 4 that after storing the cutting fluid containing OAm-TA-MoS2 at room temperature for 30 days, there is no stratification or precipitation, indicating that OAm-TA-MoS2 has good dispersibility in ester oil.

[0047] Example 2:

[0048] A tannic acid-oleylamine modified nano-molybdenum disulfide, except that the amount of tannic acid in step 1) is adjusted from "50 mg" to "100 mg" and the amount of ferric chloride hexahydrate is adjusted from "7.94 mg" to "15.88 mg" during preparation, the rest is exactly the same as in Example 1.

[0049] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid-oleylamine modified nano-molybdenum disulfide in this example does not show stratification or precipitation after storing at room temperature for 30 days, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide has good dispersibility in ester oil.

[0050] Example 3:

[0051] A tannic acid-oleylamine modified nano-molybdenum disulfide, except that the amount of tannic acid in step 1) is adjusted from "50 mg" to "10 mg" and the amount of ferric chloride hexahydrate is adjusted from "7.94 mg" to "0.79 mg" during preparation, the rest is exactly the same as in Example 1.

[0052] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid-oleylamine modified nano-molybdenum disulfide in this example does not show stratification or precipitation after storing at room temperature for 24 days, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide has good dispersibility in ester oil.

[0053] Example 4:

[0054] A tannic acid-oleylamine modified nano-molybdenum disulfide, except that the amount of ferric chloride hexahydrate in step 1) is adjusted from "7.94 mg" to "3.97 mg" and "placed in a water bath and stirred at 60 °C for 8 h" in step 2) is adjusted to "placed in a water bath and stirred at 70 °C for 8 h", the rest is exactly the same as in Example 1.

[0055] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid-oleylamine modified nano-molybdenum disulfide in this example does not show stratification or precipitation after storing at room temperature for 25 days, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide has good dispersibility in ester oil.

[0056] Example 5:

[0057] A tannic acid-oleylamine modified nano-molybdenum disulfide, except that the dosage of ferric chloride hexahydrate in step 1) is adjusted from "7.94 mg" to "39.7 mg" during preparation, the rest is exactly the same as in Example 1.

[0058] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid-oleylamine modified nano-molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 30 days, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide has good dispersibility in ester oil.

[0059] Example 6:

[0060] A tannic acid-oleylamine modified nano-molybdenum disulfide, except that "continue to stir for 5 min after adding" in step 1) is adjusted to "continue to stir for 1 min after adding" during preparation, the rest is exactly the same as in Example 1.

[0061] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid-oleylamine modified nano-molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 24 days, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide has good dispersibility in ester oil.

[0062] Example 7:

[0063] A tannic acid-oleylamine modified nano-molybdenum disulfide, except that "continue to stir for 5 min after adding" in step 1) is adjusted to "continue to stir for 10 min after adding" during preparation, the rest is exactly the same as in Example 1.

[0064] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid-oleylamine modified nano-molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 27 days, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide has good dispersibility in ester oil.

[0065] Example 8:

[0066] A tannic acid-oleylamine modified nano-molybdenum disulfide, except that the dosage of oleylamine in step 2) is adjusted from "200 mg" to "40 mg" during preparation, the rest is exactly the same as in Example 1.

[0067] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid-oleylamine modified nano-molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 19 days, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide has good dispersibility in ester oil.

[0068] Example 9:

[0069] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that the dosage of oleylamine in step 2) is adjusted from "200 mg" to "1000 mg" during preparation, the rest is exactly the same as in Example 1.

[0070] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 30 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester oil.

[0071] Example 10:

[0072] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that "stirring in a water bath at 60 °C for 8 h" in step 2) is adjusted to "stirring in a water bath at 30 °C for 8 h" during preparation, the rest is exactly the same as in Example 1.

[0073] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 22 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester oil.

[0074] Example 11:

[0075] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that "stirring in a water bath at 60 °C for 8 h" in step 2) is adjusted to "stirring in a water bath at 70 °C for 8 h" during preparation, the rest is exactly the same as in Example 1.

[0076] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 30 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester oil.

[0077] Example 12:

[0078] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that "stirring in a water bath at 60 °C for 8 h" in step 2) is adjusted to "stirring in a water bath at 60 °C for 2 h" during preparation, the rest is exactly the same as in Example 1.

[0079] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 21 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester oil.

[0080] Example 13:

[0081] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that in the preparation, "stirring in a water bath at 60 °C for 8 h" in step 2) is adjusted to "stirring in a water bath at 60 °C for 12 h", the rest is exactly the same as in Example 1.

[0082] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 30 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester - based oils.

[0083] Example 14:

[0084] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that in the preparation, "anhydrous ethanol" in step 1) is replaced with "deionized water" of equal volume (both anhydrous ethanol are replaced), the rest is exactly the same as in Example 1.

[0085] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 20 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester - based oils.

[0086] Example 15:

[0087] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that in the preparation, "anhydrous ethanol" in step 1) is replaced with "anhydrous methanol" of equal volume (both anhydrous ethanol are replaced), the rest is exactly the same as in Example 1.

[0088] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 30 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester - based oils.

[0089] Example 16:

[0090] A tannic acid - oleylamine modified nano - molybdenum disulfide, except that in the preparation, "anhydrous ethanol" in step 2) is replaced with "anhydrous methanol" of equal volume, the rest is exactly the same as in Example 1.

[0091] After testing (the testing method is the same as in Example 1), the cutting fluid containing the tannic acid - oleylamine modified nano - molybdenum disulfide in this example did not show stratification and precipitation after being stored at room temperature for 30 days, indicating that the tannic acid - oleylamine modified nano - molybdenum disulfide has good dispersibility in ester - based oils.

[0092] Comparative Example 1:

[0093] A tannic acid modified nano - molybdenum disulfide, and its preparation method is as follows:

[0094] 50 mg of molybdenum disulfide nanoparticles (MoS2) and 50 mg of tannic acid were added to 25 mL of absolute ethanol, followed by stirring and sonication to form a homogeneous molybdenum disulfide-tannic acid dispersion without precipitation. Then, 7.94 mg of ferric chloride hexahydrate was dissolved in 5 mL of absolute ethanol and slowly added to the stirring molybdenum disulfide-tannic acid dispersion. After addition, stirring was continued for 5 min, and then the mixture was transferred to a centrifuge and centrifuged at 9000 rpm for 6 min. The solid was washed three times with absolute ethanol to obtain tannic acid-modified molybdenum disulfide nanoparticles (denoted as TA-MoS2).

[0095] After testing (the testing method is the same as that in Example 1), the cutting fluid containing the tannic acid-modified molybdenum disulfide nanoparticles in this comparative example showed obvious stratification after 30 days of storage at room temperature, indicating poor dispersibility of the tannic acid-modified molybdenum disulfide nanoparticles in ester oil.

[0096] Comparative Example 2:

[0097] A cetyltrimethylammonium bromide-modified molybdenum disulfide nanoparticle, and its preparation method is as follows:

[0098] 50 mg of molybdenum disulfide nanoparticles (MoS2) and 200 mg of cetyltrimethylammonium bromide were added to 25 mL of absolute ethanol, followed by stirring and sonication to form a homogeneous molybdenum disulfide-cetyltrimethylammonium bromide dispersion without precipitation. Then, stirring was continued for 8 h, and then the mixture was transferred to a centrifuge and centrifuged at 9000 rpm for 6 min. The solid was washed three times with absolute ethanol (the supernatant was clear and transparent) to obtain cetyltrimethylammonium bromide-modified molybdenum disulfide nanoparticles (denoted as CTAB-MoS2).

[0099] After testing (the testing method is the same as that in Example 1), the cutting fluid containing the cetyltrimethylammonium bromide-modified molybdenum disulfide nanoparticles in this comparative example showed obvious stratification after 30 days of storage at room temperature, indicating poor dispersibility of the cetyltrimethylammonium bromide-modified molybdenum disulfide nanoparticles in ester oil.

[0100] Comparative Example 3:

[0101] A coconut oil amide propyl betaine-modified molybdenum disulfide nanoparticle, and its preparation method is as follows:

[0102] 50 mg of nano-molybdenum disulfide (MoS2) and 200 mg of cocamidopropyl betaine were added to 25 mL of absolute ethanol, and then stirred and ultrasonicated to prepare a uniform nano-molybdenum disulfide-cocamidopropyl betaine dispersion without precipitation. Then, it was continuously stirred for 8 h, and then transferred to a centrifuge for centrifugation at 9000 rpm for 6 min. The solid was washed 3 times with absolute ethanol (the supernatant was clear and transparent) to obtain cocamidopropyl betaine-modified nano-molybdenum disulfide (denoted as CAB-MoS2).

[0103] After testing (the testing method was the same as that in Example 1), the cutting fluid containing the cocamidopropyl betaine-modified nano-molybdenum disulfide in this comparative example showed obvious stratification after being stored at room temperature for 30 days, indicating that the cocamidopropyl betaine-modified nano-molybdenum disulfide had poor dispersibility in ester oil.

[0104] Friction reduction and anti-wear effect test:

[0105] 1) The tannic acid-oleylamine modified nano-molybdenum disulfide (OAm-TA-MoS2) in Example 1 was added to trimethylolpropane trioleate. The mass ratio of trimethylolpropane trioleate to tannic acid-oleylamine modified nano-molybdenum disulfide was 1:0.001, 1:0.002, 1:0.003, 1:0.004, and 1:0.005. Then, it was stirred and ultrasonicated to prepare a uniform cutting fluid without precipitation. Then, referring to "GB / T 3142-2019 Determination of the load-carrying capacity of lubricants - Four-ball method", the lubrication performance of the cutting fluid was tested using a four-ball tester. The wear scar diameter and friction coefficient of the friction steel balls obtained from the test are shown in the following table (trimethylolpropane trioleate was used as a control):

[0106] Table 1 Test results of friction reduction and anti-wear effects of OAm-TA-MoS2 with different contents

[0107]

[0108] As can be seen from Table 1: After adding the tannic acid-oleylamine modified nano-molybdenum disulfide, the friction coefficient of the cutting fluid decreased significantly, and when the mass ratio of trimethylolpropane trioleate to tannic acid-oleylamine modified nano-molybdenum disulfide was 1:0.002 - 0.004, the wear scar diameter of the friction steel balls also decreased, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide had excellent friction reduction and anti-wear performance.

[0109] 2) The tannic acid-oleylamine modified nano-molybdenum disulfide (OAm-TA-MoS2) in Example 1, the cetyltrimethylammonium bromide modified nano-molybdenum disulfide (CTAB-MoS2) in Comparative Example 2, and the cocamidopropyl betaine modified nano-molybdenum disulfide (CAB-MoS2) in Comparative Example 3 were respectively added as anti-friction and anti-wear agents to trimethylolpropane oleate. The mass ratio of trimethylolpropane oleate to the anti-friction and anti-wear agent was 1:0.003. Then, stirring and ultrasonic treatment were carried out to prepare a cutting fluid that was uniform and had no precipitation. Then, referring to "GB / T 3142-2019 Determination of the load-carrying capacity of lubricants - Four-ball method", the lubrication performance of the cutting fluid was tested using a four-ball tester. The wear scar diameter of the friction steel ball, the friction coefficient, the maximum non-seizure load P B and the welding load P D are shown in the following table (trimethylolpropane oleate was used as the blank base oil):

[0110] Table 2 Test results of the anti-friction and anti-wear effects of OAm-TA-MoS2, CTAB-MoS2, and CAB-MoS2

[0111] Types of friction reducing and antiwear agents Wear scar diameter (mm) Coefficient of friction <![CDATA[P B (N)]]> <![CDATA[P D (N)]]> Blank base oil 0.457 0.089 392 1570 <![CDATA[OAm-TA-MoS2]]> 0.443 0.069 785 1962 <![CDATA[CTAB-MoS2]]> 0.458 0.080 696 1962 <![CDATA[CAB-MoS2]]> 0.543 0.078 637 1570

[0112] As can be seen from Table 2: The maximum non-seizure load P B of the blank base oil was 392 N, and the welding load P D was 1570 N. For the cutting fluid added with OAm-TA-MoS2, the maximum non-seizure load P B was 785 N, and the welding load P D was 1962 N. P B and P D increased by 100% and 25% respectively. At the same time, compared with the cutting fluid added with CTAB-MoS2 and the cutting fluid added with CAB-MoS2, the wear scar diameter of the friction steel ball and the friction coefficient of the cutting fluid added with OAm-TA-MoS2 were significantly reduced, indicating that the tannic acid-oleylamine modified nano-molybdenum disulfide of the present invention has excellent anti-friction and anti-wear performance.

[0113] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of tannic acid-oleylamine modified nano molybdenum disulfide, characterized in that, It includes the following steps: 1) Disperse molybdenum disulfide nanosheets and tannic acid in a solvent, then add an iron salt to react, and then separate the product to obtain tannic acid-modified molybdenum disulfide nanosheets; 2) Disperse the tannic acid-modified molybdenum disulfide nanosheets and oleylamine in a solvent to react, and then separate the product to obtain tannic acid-oleylamine-modified molybdenum disulfide nanosheets.

2. The preparation method according to claim 1, wherein: In step 1), the mass ratio of the molybdenum disulfide nanosheets to tannic acid is 0.5-5:1; in step 1), the molar ratio of tannic acid to the iron salt is 1:0.5-5.

3. The preparation method according to claim 1 or 2, characterized in that: The iron salt in step 1) is at least one of ferric chloride, ferric nitrate, and ferric sulfate.

4. The preparation method according to claim 1 or 2, characterized in that: The reaction time in step 1) is 1 min to 10 min.

5. The preparation method according to claim 1, characterized in that: In step 2), the mass ratio of the tannic acid-modified molybdenum disulfide nanosheets to oleylamine is 1:2-50.

6. The preparation method according to claim 1 or 5, characterized in that: The reaction in step 2) is carried out at a temperature of 30°C to 70°C, and the reaction time is 2 h to 12 h.

7. The preparation method according to any one of claims 1, 2 and 5, characterized in that: The solvent in step 1) is at least one of water, ethanol, and methanol; the solvent in step 2) is at least one of water, ethanol, and methanol.

8. A tannic acid-oleylamine modified nano-molybdenum disulfide, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 7.

9. A cutting fluid, characterized in that, It contains trimethylolpropane trioleate and the tannic acid-oleylamine-modified molybdenum disulfide nanosheets according to claim 8.

10. The cutting fluid according to claim 9, wherein: The mass ratio of the trimethylolpropane trioleate to the tannic acid-oleylamine-modified molybdenum disulfide nanosheets is 1:0.001-0.005.

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