Aniline oligomer modified hexagonal boron nitride nanosheet, wear-resistant and corrosion-resistant organic protective coating and preparation method thereof

Abstract

The application discloses aniline oligomer modified hexagonal boron nitride nanosheet, wear-resistant and corrosion-resistant organic protective coating and a preparation method of the wear-resistant and corrosion-resistant organic protective coating, and belongs to the technical field of material surface protection. The aniline oligomer modified hexagonal boron nitride nanosheet is formed by modifying an aniline oligomer on the surface of a few-layer or single-layer hexagonal boron nitride nanosheet. The application provides a preparation method of the aniline oligomer modified hexagonal boron nitride nanosheet. The hexagonal boron nitride is modified by the aniline oligomer, and the prepared aniline oligomer modified hexagonal boron nitride nanosheet effectively overcomes the defect that the hexagonal boron nitride is difficult to disperse in a solvent, and can be uniformly and stably dispersed in a phenolic aldehyde epoxy coating.

Description

Technical Field

[0001] This invention relates to the field of material surface protection technology, and in particular to an aniline oligomer-modified hexagonal boron nitride nanosheet, a wear-resistant and corrosion-resistant organic protective coating, and a wear-resistant and corrosion-resistant organic protective coating, as well as their preparation methods. Background Technology

[0002] Wear reduces the precision and lifespan of parts, thus accelerating equipment failure; corrosion, on the other hand, damages material structure, leading to serious problems such as pitting, stress corrosion cracking, and even sudden fracture. The combined effect of these two factors easily results in equipment malfunctions and safety hazards, and significantly increases maintenance costs. Therefore, how to reduce the coefficient of friction and wear rate between mechanical parts while improving their surface corrosion resistance has become a research hotspot in recent years.

[0003] Organic coatings play a crucial role in metal protection due to their advantages such as flexible design, convenient application, and controllable cost. As the continuous phase of the coating, the resin is the key component determining its performance. Among commonly used resins, phenolic epoxy resin (FEP) is often used as a binder for high-performance coatings due to its good thermal stability, high mechanical strength, and strong adhesion to the substrate. In addition, solid lubricants, as another important component, can impart a low coefficient of friction to the coating. Polytetrafluoroethylene (PTFE) not only has excellent lubricity but also good chemical inertness and hydrophobic properties, effectively preventing the oxidative degradation of common solid lubricants such as graphite and molybdenum disulfide in humid or corrosive environments, thus it is widely used as a solid lubricant phase. However, single phenolic epoxy / PTFE organic coatings often lack sufficient mechanical load-bearing capacity and wear resistance under high loads or long-term wear conditions, and their barrier properties against corrosive media are weak, making it difficult to achieve long-term effective corrosion protection. Therefore, there is an urgent need to further improve its mechanical load-bearing capacity, wear resistance, and corrosion resistance.

[0004] Introducing functional fillers into coatings is an effective way to improve their wear resistance and corrosion resistance. In recent years, various filler systems have been extensively explored. Among them, hexagonal boron nitride (h-BN), as a novel two-dimensional filler, has a layered structure similar to graphite, thus exhibiting similar lubrication properties. However, unlike the high conductivity of graphite, h-BN is an ultrawide-bandgap insulating material with excellent barrier properties, fundamentally preventing galvanic corrosion, showing broad application prospects in the field of metal corrosion protection. However, h-BN is prone to agglomeration and sedimentation in solvents, severely limiting its dispersion stability and reinforcing effect. Therefore, it is necessary to graft functional groups onto its surface through covalent or non-covalent modification methods to improve its dispersibility in the resin matrix, thereby fully leveraging its synergistic effects of friction reduction, wear resistance, and barrier protection. Summary of the Invention

[0005] To address the technical bottlenecks in existing technologies, such as the tendency of hexagonal boron nitride nanosheets to agglomerate, complex modification processes with limited functionality, and the difficulty in simultaneously achieving both wear resistance and corrosion resistance in coatings, this invention provides aniline oligomer-modified hexagonal boron nitride nanosheets and their preparation method. The aniline oligomer-modified hexagonal boron nitride nanosheets can simultaneously improve the wear resistance and corrosion resistance of the coating.

[0006] The present invention further provides a wear-resistant and corrosion-resistant organic protective coating reinforced with hexagonal boron nitride nanosheets modified with the above-mentioned aniline oligomer, as well as a wear-resistant and corrosion-resistant organic protective coating formed by the coating and a method for preparing the coating.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A type of aniline oligomer-modified hexagonal boron nitride nanosheet is formed by modifying the surface of few-layer or single-layer hexagonal boron nitride nanosheets with aniline oligomers.

[0009] The preparation method of the above-mentioned aniline oligomer modified hexagonal boron nitride nanosheets includes the following steps:

[0010] S1: Aniline is added to a sodium dodecyl sulfate solution and dispersed evenly; then ammonium persulfate solution is added, and stirring is continued until the reaction is complete. After centrifugation and drying, aniline oligomer powder is obtained; the concentration of sodium dodecyl sulfate solution in step S1 is 1~3 mg / mL, the concentration of aniline in sodium dodecyl sulfate solution is 1~1.5 mg / mL, and the concentration of ammonium persulfate solution is 40~70 mg / mL;

[0011] S2: Mix aniline oligomer powder with hydrochloric acid solution, then add sodium nitrite solution, mix thoroughly, and let stand to obtain aniline oligomer mixture; the concentration of hydrochloric acid solution in step S2 is 0.5~2 mol / L; the concentration of aniline oligomer powder in hydrochloric acid solution is 50~70 mg / mL; the concentration of sodium nitrite solution is 0.1~0.2 mol / L; the volume ratio of hydrochloric acid solution to sodium nitrite solution is 8:12~20;

[0012] S3: Add hexagonal boron nitride nanosheet dispersion to aniline oligomer mixture, and react under heating and stirring conditions to obtain reaction product; wherein the mass ratio of aniline oligomer powder in mixture to hexagonal boron nitride nanosheets in hexagonal boron nitride nanosheet dispersion is 1~3:1; the heating temperature in step S3 is 60~80 ℃, and the reaction time in step S3 is 3~5 h;

[0013] S4: The reaction product obtained in step S3 is centrifuged and dried to obtain aniline oligomer-modified hexagonal boron nitride nanosheets.

[0014] The reaction time in step S1 is 15-45 min.

[0015] In step S1, the ammonium persulfate solution is added dropwise.

[0016] The sodium nitrite solution in step S2 is added dropwise;

[0017] The settling process in step S2 is carried out in an ice-water bath.

[0018] The preparation steps of the hexagonal boron nitride nanosheet dispersion are as follows:

[0019] S01: Hexagonal boron nitride powder is ultrasonically dispersed in a mixed solution of deionized water and ethanol, then frozen in liquid nitrogen, and then thawed by ultrasonic treatment to obtain a solution containing few-layer or single-layer hexagonal boron nitride nanosheets.

[0020] S02: Centrifuge the solution obtained in step S01 and take the supernatant. The supernatant is the extract of hexagonal boron nitride nanosheets.

[0021] S03: The hexagonal boron nitride nanosheet extract obtained in step S02 is filtered, washed and dried sequentially to obtain few-layer or single-layer hexagonal boron nitride nanosheet powder.

[0022] S04: Disperse the few-layer or single-layer hexagonal boron nitride nanosheet powder obtained in step S03 in deionized water at a concentration of 0.4~0.8 mg / mL, and sonicate for 20~50 min to obtain a hexagonal boron nitride nanosheet dispersion.

[0023] In step S01, the volume ratio of deionized water to ethanol is 9:1~4, and the concentration of the hexagonal boron nitride powder in the mixed solution is 8~12 mg / mL.

[0024] The drying temperature in steps S1, S4 and S03 is 30~60 ℃ and the drying time is 10~15 h.

[0025] The centrifugation speed in steps S1 and S4 is 3000~8000 r / min, and the centrifugation time is 10~30 min.

[0026] A wear-resistant and corrosion-resistant organic protective coating comprises the following raw materials in the indicated mass fractions: 9-15 parts of phenolic epoxy resin, 3-6 parts of curing agent phenolic resin, 5-9 parts of polytetrafluoroethylene, 0.1-0.4 parts of aniline oligomer-modified hexagonal boron nitride nanosheets as described in claim 1, and 70-80 parts of mixed solvent; wherein the volume ratio of ethylene glycol ethyl ether to 2-butanone in the mixed solvent is 1:0.5-1.5.

[0027] The preparation method of the above-mentioned wear-resistant and corrosion-resistant organic protective coating includes the following steps:

[0028] Phenolic epoxy resin is dissolved in a mixed solvent by ultrasonication, and then curing agent phenolic resin, polytetrafluoroethylene and aniline oligomer modified hexagonal boron nitride nanosheets as described in claim 1 are added in sequence. The mixture is then homogenized by a high-speed dispersion homogenizer to obtain a wear-resistant and corrosion-resistant organic protective coating.

[0029] A method for preparing a wear-resistant and corrosion-resistant organic protective coating involves spraying the aforementioned wear-resistant and corrosion-resistant organic protective coating onto a substrate and curing it to obtain the wear-resistant and corrosion-resistant organic protective coating.

[0030] The beneficial effects of this invention are as follows:

[0031] (1) The present invention provides a method for preparing aniline oligomer modified hexagonal boron nitride nanosheets. By modifying hexagonal boron nitride with aniline oligomers, the prepared aniline oligomer modified hexagonal boron nitride nanosheets effectively overcome the defect that hexagonal boron nitride is difficult to disperse in solvents and can be uniformly and stably dispersed in phenolic epoxy coatings.

[0032] (2) The aniline oligomer modified hexagonal boron nitride nanosheets of the present invention have a synergistic effect with the lubricant polytetrafluoroethylene (PTFE), which significantly improves the wear resistance and corrosion resistance of the phenolic epoxy resin coating. Attached Figure Description

[0033] Figure 1 The electrochemical impedance spectroscopy spectra of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3 were measured in 3.5 wt.% NaCl solution. Figure 1 (a) in the figure is the Nyquist curve. Figure 1 (b) in the diagram is the Bode impedance diagram.

[0034] Figure 2 The results show the tribological properties of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3; wherein, Figure 2 In Figure (a), the friction coefficient of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3 varies with the sliding distance. Figure 2 (b) shows the test results of the wear rate of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0036] In the following embodiments, unless otherwise stated, the experimental methods used are conventional methods in the art, and the experimental materials used are all available through conventional commercial channels.

[0037] A type of aniline oligomer-modified hexagonal boron nitride nanosheet is formed by modifying the surface of few-layer or single-layer hexagonal boron nitride nanosheets with aniline oligomers.

[0038] The preparation method of the above-mentioned aniline oligomer modified hexagonal boron nitride nanosheets includes the following steps:

[0039] S1: Aniline is added to a sodium dodecyl sulfate solution and dispersed evenly; then ammonium persulfate solution is added, and stirring is continued until the reaction is complete. After centrifugation and drying, aniline oligomer powder is obtained; the concentration of sodium dodecyl sulfate solution in step S1 is 1~3 mg / mL, the concentration of aniline in sodium dodecyl sulfate solution is 1~1.5 mg / mL, and the concentration of ammonium persulfate solution is 40~70 mg / mL;

[0040] S2: Mix aniline oligomer powder with hydrochloric acid solution, then add sodium nitrite solution, mix thoroughly, and let stand to obtain aniline oligomer mixture; the concentration of hydrochloric acid solution in step S2 is 0.5~2 mol / L; the concentration of aniline oligomer powder in hydrochloric acid solution is 50~70 mg / mL; the concentration of sodium nitrite solution is 0.1~0.2 mol / L; the volume ratio of hydrochloric acid solution to sodium nitrite solution is 8:12~20;

[0041] S3: Add hexagonal boron nitride nanosheet dispersion to aniline oligomer mixture, and react under heating and stirring conditions to obtain reaction product; wherein the mass ratio of aniline oligomer powder in mixture to hexagonal boron nitride nanosheets in hexagonal boron nitride nanosheet dispersion is 1~3:1; the heating temperature in step S3 is 60~80 ℃, and the reaction time in step S3 is 3~5 h;

[0042] S4: The reaction product obtained in step S3 is centrifuged and dried to obtain aniline oligomer-modified hexagonal boron nitride nanosheets.

[0043] The reaction time in step S1 is 15-45 min.

[0044] In step S1, the ammonium persulfate solution is added dropwise; in step S2, the sodium nitrite solution is added dropwise; and in step S2, the settling is carried out in an ice-water bath.

[0045] In one embodiment, the preparation steps of the hexagonal boron nitride nanosheet dispersion are as follows:

[0046] S01: Hexagonal boron nitride powder is ultrasonically dispersed in a mixed solution of deionized water and ethanol, then frozen in liquid nitrogen, and then thawed by ultrasonic treatment to obtain a solution containing few-layer or single-layer hexagonal boron nitride nanosheets.

[0047] S02: Centrifuge the solution obtained in step S01 and take the supernatant. The supernatant is the extract of hexagonal boron nitride nanosheets.

[0048] S03: The hexagonal boron nitride nanosheet extract obtained in step S02 is filtered, washed and dried sequentially to obtain few-layer or single-layer hexagonal boron nitride nanosheet powder.

[0049] S04: Disperse the few-layer or single-layer hexagonal boron nitride nanosheet powder obtained in step S03 in deionized water at a concentration of 0.4~0.8 mg / mL, and sonicate for 20~50 min to obtain a hexagonal boron nitride nanosheet dispersion.

[0050] In step S01, the volume ratio of deionized water to ethanol is 9:1~4, and the concentration of the hexagonal boron nitride powder in the mixed solution is 8~12 mg / mL.

[0051] The drying temperature in steps S1, S4 and S03 is 30~60 ℃ and the drying time is 10~15 h.

[0052] The centrifugation speed in steps S1 and S4 is 3000~8000 r / min, and the centrifugation time is 10~30 min.

[0053] A wear-resistant and corrosion-resistant organic protective coating comprises the following raw materials in the indicated mass fractions: 9-15 parts of phenolic epoxy resin, 3-6 parts of curing agent phenolic resin, 5-9 parts of polytetrafluoroethylene, 0.1-0.4 parts of aniline oligomer-modified hexagonal boron nitride nanosheets as described in claim 1, and 70-80 parts of mixed solvent; wherein the volume ratio of ethylene glycol ethyl ether to 2-butanone in the mixed solvent is 1:0.5-1.5.

[0054] The preparation method of the above-mentioned wear-resistant and corrosion-resistant organic protective coating includes the following steps:

[0055] Phenolic epoxy resin is dissolved in a mixed solvent by ultrasonication, and then curing agent phenolic resin, polytetrafluoroethylene and aniline oligomer modified hexagonal boron nitride nanosheets as described in claim 1 are added in sequence. The mixture is then homogenized by a high-speed dispersion homogenizer to obtain a wear-resistant and corrosion-resistant organic protective coating.

[0056] A method for preparing a wear-resistant and corrosion-resistant organic protective coating involves spraying the aforementioned wear-resistant and corrosion-resistant organic protective coating onto a substrate, followed by curing to obtain the wear-resistant and corrosion-resistant organic protective coating. The coating thickness obtained from each spraying is 20-30 μm (preferably 25-30 μm), and the number of sprayings is 20-50 times (preferably 30 times). The curing procedure is as follows: curing at 70-90 ℃ for 2 h, followed by heating to 170-200 ℃ for 2.5 h, preferably curing at 80 ℃ for 2 h, followed by heating to 180 ℃ for 2.5 h.

[0057] Example 1

[0058] Part 1: Preparation of hexagonal boron nitride nanosheet dispersion.

[0059] S01: Hexagonal boron nitride powder was ultrasonically dispersed at a concentration of 10 mg / mL in a mixed solution of deionized water and ethanol at a volume ratio of 9:1, and then rapidly placed in liquid nitrogen for freezing. After ultrasonic treatment to thaw, a solution containing few-layer or single-layer hexagonal boron nitride nanosheets was obtained.

[0060] S02: Centrifuge the solution containing few-layer or single-layer hexagonal boron nitride nanosheets at 1000 r / min for 5 min, and take the supernatant to obtain the hexagonal boron nitride nanosheet extract.

[0061] S03: The hexagonal boron nitride nanosheet extract was sequentially filtered, washed, and dried (drying temperature was 40 ℃, drying time was 10 h) to obtain few-layer or single-layer hexagonal boron nitride nanosheet powder.

[0062] S04: Disperse few-layer or single-layer hexagonal boron nitride nanosheet powder in deionized water at a concentration of 0.5 mg / mL, and sonicate for 20-50 min to obtain a hexagonal boron nitride nanosheet dispersion.

[0063] Part 2: Preparation of aniline oligomer mixture.

[0064] S1: Aniline was added to a 2 mg / mL sodium dodecyl sulfate aqueous solution and dispersed evenly by mechanical stirring. Then, a 50 mg / mL ammonium persulfate aqueous solution was added dropwise, and the reaction was continued with stirring for 30 min. The reaction product was repeatedly centrifuged (5000 r / min, 15 min) and vacuum dried (40 ℃, 10 h) to obtain aniline oligomer powder.

[0065] S2: Disperse aniline oligomer powder at a concentration of 62.5 mg / mL in 1 mol / L hydrochloric acid solution, add 0.14 mol / L sodium nitrite aqueous solution (volume ratio of hydrochloric acid solution to sodium nitrite solution is 8:15), and let stand in an ice-water bath for 45 min to obtain aniline oligomer mixture.

[0066] Part 3: Preparation of aniline oligomer-modified hexagonal boron nitride nanosheets.

[0067] The aniline oligomer mixture from the second part was mixed with the hexagonal boron nitride nanosheet dispersion from the first part, wherein the mass ratio of hexagonal boron nitride nanosheet powder to aniline oligomer was 1:2. After mixing, the mixture was reacted for 4 h under heating and stirring in a water bath at 70 ℃. Then, after repeated centrifugation (5000 r / min, 15 min) and vacuum drying (40 ℃, 10 h), aniline oligomer-modified hexagonal boron nitride nanosheet powder was obtained.

[0068] Part Four: Preparation of Abrasion-Resistant and Corrosion-Resistant Organic Protective Coatings.

[0069] Weigh 9.9 g of phenolic epoxy resin and add it to a mixed solution of ethylene glycol ethyl ether and 2-butanone (the solvent is partially added), and dissolve it by sonication. Then, add 5.94 g of polytetrafluoroethylene, 3.96 g of phenolic resin, and 0.2 g of aniline oligomer-modified hexagonal boron nitride nanosheets sequentially. Add the mixed solvent until the total mass of the coating is 100 g. Mix thoroughly using a high-speed dispersion homogenizer to obtain a wear-resistant and corrosion-resistant organic protective coating. The mixed solvent is a mixture of ethylene glycol ethyl ether and 2-butanone, with a volume ratio of ethylene glycol ethyl ether to 2-butanone of 1:0.5~1.5.

[0070] Part 5: Preparation of wear-resistant and corrosion-resistant organic protective coatings.

[0071] The wear-resistant and corrosion-resistant organic protective coating prepared in Part IV is applied to the surface of the treated substrate, cured at 80 ℃ for 2 h, and then heated to 180 ℃ for 2.5 h to obtain the wear-resistant and corrosion-resistant organic protective coating.

[0072] Example 2

[0073] Unlike Example 1, the wear-resistant and corrosion-resistant organic protective coating is composed of the following raw material components by weight: 9.9 g phenolic epoxy resin, 4.95 g polytetrafluoroethylene, 4.95 g phenolic resin and 0.2 g aniline oligomer modified hexagonal boron nitride nanosheets, with a solvent of 80 g.

[0074] Example 3

[0075] Unlike Example 1, the wear-resistant and corrosion-resistant organic protective coating is composed of the following raw material components by weight: 14.85g phenolic epoxy resin, 8.91g polytetrafluoroethylene, 5.94g phenolic resin and 0.3g aniline oligomer modified hexagonal boron nitride nanosheets, with a solvent of 70g.

[0076] Comparative Example 1

[0077] Unlike Example 1, the wear-resistant and corrosion-resistant organic protective coating consists of the following raw material components by weight: 10 g phenolic epoxy resin, 6 g polytetrafluoroethylene, 4 g phenolic resin, and 80 g solvent.

[0078] Comparative Example 2

[0079] Unlike Example 1, the wear-resistant and corrosion-resistant organic protective coating is composed of the following raw material components by weight: 9.9 g phenolic epoxy resin, 5.94 g polytetrafluoroethylene, 3.96 g phenolic resin and 0.2 g virgin hexagonal boron nitride nanosheets, with a solvent of 80 g.

[0080] Comparative Example 3

[0081] Unlike Example 1, the wear-resistant and corrosion-resistant organic protective coating is composed of the following raw material components by weight: 9.9 g phenolic epoxy resin, 5.94 g polytetrafluoroethylene, 3.96 g phenolic resin and 0.2 g exfoliated hexagonal boron nitride nanosheets, with a solvent of 80 g.

[0082] The exfoliated hexagonal boron nitride nanosheets in Comparative Example 3 were prepared by steps S01 to S03 in the first part.

[0083] I. Electrochemical Performance Testing

[0084] To evaluate the corrosion resistance improvement effect of the organic coating obtained in this invention, electrochemical impedance spectroscopy (EIS) tests were performed on the protective coatings prepared in Example 1 and Comparative Examples 1 to 3. A classic three-electrode system was used: a saturated AgCl electrode as the reference electrode, a platinum sheet as the counter electrode, and the protective coating as the working electrode. The electrolyte was a 3.5 wt.% NaCl aqueous solution, and the area of ​​the coating sample exposed in the electrolyte was 0.2 cm². 2 Before testing, ensure the open-circuit potential has reached a stable state; the test frequency range is 10. -2 -10 5 Hz.

[0085] Figure 1 The electrochemical impedance spectroscopy spectra of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3 were measured in 3.5 wt.% NaCl solution. Figure 1 (a) in the figure is the Nyquist curve. Figure 1(b) in the diagram is the Bode impedance diagram. The diameter of the Nyquist curve reflects the corrosion resistance of the coating; generally, the larger the diameter of the capacitive arc, the better the corrosion resistance of the coating. The low-frequency impedance modulus value (|Z|) in the Bode impedance diagram is also shown. 0.01Hz This can semi-quantitatively reflect the barrier properties of the coating, |Z| 0.01Hz The larger the diameter, the better the coating's barrier properties against corrosive media.

[0086] like Figure 1 As shown in (a), the FEP / PTFE / Modified h-BN coating prepared in Example 1 has the largest capacitive arc diameter, followed by the FEP / PTFE / Exfoliated h-BN coating of Comparative Example 3 and the FEP / PTFE / Unexfoliated h-BN coating of Comparative Example 2. The FEP / PTFE coating of Comparative Example 1 has the smallest capacitive arc diameter.

[0087] Figure 1 The low-frequency impedance modulus value (|Z|) shown in (b) is as follows. 0.01Hz The same trend is observed in the coating of Example 1: |Z| 0.01Hz The value is the largest, followed by Comparative Example 3, then Comparative Example 2, and the smallest is Comparative Example 1. The specific values ​​are 1.89 × 10⁻⁶. 12 Ω·cm 2 5.05×10 11 Ω·cm 2 2.81×10 11 Ω·cm 2 and 1.01×10 11 Ω·cm 2 The results show that the FEP / PTFE / Modified h-BN coating of Example 1 has superior barrier properties and better corrosion protection for the substrate.

[0088] II. Tribological property testing

[0089] To evaluate the friction-reducing and wear-resistant properties of the organic coating obtained in this invention, friction and wear tests were conducted on the protective coatings prepared in Example 1 and Comparative Examples 1 to 3. The tests were performed using TRB. 3 The friction and wear testing machine operates in reciprocating mode, with a load of 10 N, an amplitude of 5 mm, a total sliding distance of 300 m, a sliding speed of 10 cm / s, and a 6 mm diameter GCr15 steel ball as its counterpart.

[0090] Figure 2 The results are the tribological properties of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3.

[0091] Figure 2In Figure (a), the friction coefficient of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3 varies with the sliding distance. Figure 2 As shown in (a), the friction coefficient of the FEP / PTFE coating in Comparative Example 1 is generally high. Its friction coefficient initially increases significantly, then stabilizes, and finally increases slowly. This phenomenon is mainly attributed to the fact that under prolonged friction, the aggregated PTFE regions are prone to microcracks, leading to a deterioration of the interfacial friction state and thus increasing the friction coefficient. The friction coefficients of the FEP / PTFE / Unexfoliated h-BN coating in Comparative Example 2 and the FEP / PTFE / Exfoliated h-BN coating in Comparative Example 3 are similar in the initial stage; after a short break-in period, the friction coefficient of the coating in Comparative Example 2 increases sharply, while the friction coefficient of the coating in Comparative Example 3 decreases sharply. These results indicate that the introduction of exfoliated hexagonal boron nitride can accelerate the formation and optimization of the shear layer on the friction surface, thereby significantly reducing the friction coefficient; while the unexfoliated hexagonal boron nitride, due to its agglomeration effect, leads to a deterioration of the friction interface, which in turn increases the friction coefficient. In contrast, the FEP / PTFE / Modified h-BN coating of Example 1 exhibited the lowest coefficient of friction and a more stable friction process, with the coefficient of friction remaining approximately 0.08. This is because the aniline oligomer-modified hexagonal boron nitride nanosheets have excellent dispersibility in the coating, fully leveraging their synergistic lubricating effect with PTFE. Simultaneously, their two-dimensional layered structure allows microcracks generated during friction to deflect and terminate at the layer interface, thereby significantly reducing the coefficient of friction and improving the coating's friction-reducing performance.

[0092] Figure 2 (b) shows the test results of the wear rate of the protective coatings prepared in Example 1 and Comparative Examples 1 to 3. Figure 2 As shown in (b), the FEP / PTFE coating in Comparative Example 1 exhibited the highest wear rate, at 2.66 × 10⁻⁶. -6 mm 3 ·N -1 ·m -1 This is mainly because the PTFE component is relatively soft and prone to shear deformation and flaking during reciprocating friction, resulting in significant material loss. The difference in wear rate between Comparative Example 2 and Comparative Example 3 primarily depends on the thickness of the hexagonal boron nitride: the thinner, exfoliated hexagonal boron nitride (Comparative Example 3) exhibits excellent dispersion and tight interfacial bonding, effectively reducing the wear rate (0.68 × 10⁻⁶) by bearing the load and inhibiting crack propagation. -6 mm 3 ·N -1 ·m -1 However, the thicker, unpeeled hexagonal boron nitride (Comparative Example 2) tends to agglomerate, leading to stress concentration and interface deterioration, resulting in a significantly increased wear rate (1.55 × 10⁻⁶). -6mm 3 ·N -1 ·m -1 In contrast, the FEP / PTFE / Modified h-BN coating of Example 1 exhibited the lowest wear rate, at 0.15 × 10⁻⁶. -6 mm 3 ·N -1 ·m -1 The improvement mechanism can be summarized in two points: First, the aniline oligomer-modified hexagonal boron nitride nanosheets are uniformly dispersed in the coating and have good compatibility with the substrate interface, which can effectively bear the contact load and improve the mechanical strength and deformation resistance of the coating. Second, the uniformly dispersed aniline oligomer-modified hexagonal boron nitride nanosheets work synergistically with PTFE to continuously form a stable and dense transfer film at the friction interface, effectively isolating the mating material from the coating surface, thereby significantly reducing the wear rate.

[0093] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention. The above embodiments are provided only for the purpose of describing the present invention and are not intended to limit the present invention. Parts not described in detail in this specification are well-known in the art and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be covered within the scope of the present invention.

Claims

1. An aniline oligomer-modified hexagonal boron nitride nanosheet, characterized in that, The aniline oligomer-modified hexagonal boron nitride nanosheets are formed by modifying the surface of few-layer or single-layer hexagonal boron nitride nanosheets with aniline oligomers.

2. The method for preparing aniline oligomer-modified hexagonal boron nitride nanosheets according to claim 1, characterized in that, Includes the following steps: S1: Aniline is added to a sodium dodecyl sulfate solution and dispersed evenly; then ammonium persulfate solution is added, and stirring is continued until the reaction is complete. After centrifugation and drying, aniline oligomer powder is obtained; the concentration of sodium dodecyl sulfate solution in step S1 is 1~3 mg / mL, the concentration of aniline in sodium dodecyl sulfate solution is 1~1.5 mg / mL, and the concentration of ammonium persulfate solution is 40~70 mg / mL; S2: Mix aniline oligomer powder with hydrochloric acid solution, then add sodium nitrite solution, mix thoroughly, and let stand to obtain aniline oligomer mixture; the concentration of hydrochloric acid solution in step S2 is 0.5~2 mol / L; the concentration of aniline oligomer powder in hydrochloric acid solution is 50~70 mg / mL; the concentration of sodium nitrite solution is 0.1~0.2 mol / L; the volume ratio of hydrochloric acid solution to sodium nitrite solution is 8:12~20; S3: Add hexagonal boron nitride nanosheet dispersion to aniline oligomer mixture, and react under heating and stirring conditions to obtain reaction product; wherein the mass ratio of aniline oligomer powder in mixture to hexagonal boron nitride nanosheets in hexagonal boron nitride nanosheet dispersion is 1~3:1; the heating temperature in step S3 is 60~80 ℃, and the reaction time in step S3 is 3~5 h; S4: The reaction product obtained in step S3 is centrifuged and dried to obtain aniline oligomer-modified hexagonal boron nitride nanosheets.

3. The method for preparing aniline oligomer-modified hexagonal boron nitride nanosheets according to claim 2, characterized in that, The reaction time in step S1 is 15~45 min.

4. The method for preparing aniline oligomer-modified hexagonal boron nitride nanosheets according to claim 2, characterized in that, The ammonium persulfate solution in step S1 was added dropwise; the sodium nitrite solution in step S2 was added dropwise; and the settling in step S2 was carried out in an ice-water bath.

5. The method for preparing aniline oligomer-modified hexagonal boron nitride nanosheets according to claim 2, characterized in that, The preparation steps of the hexagonal boron nitride nanosheet dispersion are as follows: S01: Hexagonal boron nitride powder is ultrasonically dispersed in a mixed solution of deionized water and ethanol, then frozen in liquid nitrogen, and then thawed by ultrasonic treatment to obtain a solution containing few-layer or single-layer hexagonal boron nitride nanosheets. S02: Centrifuge the solution obtained in step S01 and take the supernatant. The supernatant is the extract of hexagonal boron nitride nanosheets. S03: The hexagonal boron nitride nanosheet extract obtained in step S02 is filtered, washed and dried sequentially to obtain few-layer or single-layer hexagonal boron nitride nanosheet powder. S04: Disperse the few-layer or single-layer hexagonal boron nitride nanosheet powder obtained in step S03 in deionized water at a concentration of 0.4~0.8 mg / mL, and sonicate for 20~50 min to obtain a hexagonal boron nitride nanosheet dispersion.

6. The method for preparing aniline oligomer-modified hexagonal boron nitride nanosheets according to claim 5, characterized in that, In step S01, the volume ratio of deionized water to ethanol is 9:1~4, and the concentration of the hexagonal boron nitride powder in the mixed solution is 8~12 mg / mL.

7. The method for preparing aniline oligomer-modified hexagonal boron nitride nanosheets according to claim 6, characterized in that, The drying temperature in steps S1, S4 and S03 is 30~60 ℃ and the drying time is 10~15 h; The centrifugation speed in steps S1 and S4 is 3000~8000 r / min, and the centrifugation time is 10~30 min.

8. A wear-resistant and corrosion-resistant organic protective coating, characterized in that, The raw materials comprise the following mass fractions: 9-15 parts of phenolic epoxy resin, 3-6 parts of curing agent phenolic resin, 5-9 parts of polytetrafluoroethylene, 0.1-0.4 parts of aniline oligomer-modified hexagonal boron nitride nanosheets as described in claim 1, and 70-80 parts of mixed solvent; wherein the volume ratio of ethylene glycol ethyl ether to 2-butanone in the mixed solvent is 1:0.5-1.

5.

9. The method for preparing the wear-resistant and corrosion-resistant organic protective coating according to claim 8, characterized in that, Includes the following steps: Phenolic epoxy resin is dissolved in a mixed solvent by ultrasonication, and then curing agent phenolic resin, polytetrafluoroethylene and aniline oligomer modified hexagonal boron nitride nanosheets as described in claim 1 are added in sequence. The mixture is then homogenized by a high-speed dispersion homogenizer to obtain a wear-resistant and corrosion-resistant organic protective coating.

10. A method for preparing a wear-resistant and corrosion-resistant organic protective coating, characterized in that, The wear-resistant and corrosion-resistant organic protective coating of claim 8 is sprayed onto the substrate and cured to obtain a wear-resistant and corrosion-resistant organic protective coating.

Images