Modified fiber / sheet material composite anticorrosive coating, its preparation and application

Abstract

The application discloses a modified fiber / sheet layer material composite anticorrosive coating and a preparation method and application thereof. The preparation method comprises the following steps: modifying fibers by using a surface modification substance, so as to obtain modified fibers; mixing a two-dimensional sheet layer material, the modified fibers and the surface modification substance to modify and composite, so as to obtain a modified fiber / sheet layer composite material; and mixing the modified fiber / sheet layer composite material with a coating system and applying the coating system to a surface of a base body, so as to obtain the modified fiber / sheet layer material composite anticorrosive coating. The preparation method of the modified fiber / sheet layer material composite anticorrosive coating provided by the application is simple and efficient, can significantly improve the mechanical properties of the coating, especially the anti-erosion corrosion performance, and provides technical support for a composite coating system. Meanwhile, the composite anticorrosive coating has excellent barrier properties, so that the corrosion protection performance of the coating is improved.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion coating technology, specifically relating to a modified fiber / sheet material composite anti-corrosion coating, its preparation method, and its application. Background Technology

[0002] Marine corrosion environment zoning refers to the division of marine corrosion environments into zones based on differences in marine environment, media, and their corrosive effects on metal structures. From top to bottom, it is divided into five zones: the marine atmospheric zone, the splash zone, the tidal zone, the fully submerged zone, and the marine mud zone. Many studies have found that corrosion in the splash zone is more severe than in the atmospheric and underwater zones. This is mainly due to the combined effects of three factors: atmospheric factors (primarily solar radiation and alternating wet and dry periods), seawater factors (primarily temperature changes and chloride ions), and wave current factors (primarily wave impact). The splash zone is located at the surface of the marine environment, with abundant sunshine, large diurnal temperature variations, and frequent wet and dry periods. The ratio of drying to wetting time significantly affects the ion diffusion rate; the longer the drying time, the more pronounced the capillary action, and the greater the chloride ion penetration rate. Furthermore, the splash zone is rich in oxygen and salinity, which accelerates the formation of water films. The evaporation and condensation of these water films lead to surface salt concentration, resulting in pitting corrosion. Metal facilities operating in splash zones are not only affected by the physical and chemical state of the environment, but also subjected to the scouring and additional loads caused by ocean currents and waves, making them prone to corrosion fatigue and stress corrosion, thus accelerating corrosion. Summary of the Invention

[0003] The main objective of this invention is to provide a modified fiber / sheet material composite anti-corrosion coating, its preparation method and application, in order to overcome the shortcomings of the prior art.

[0004] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0005] This invention provides a method for preparing a modified fiber / sheet material composite anti-corrosion coating, comprising:

[0006] Provide two-dimensional sheet materials;

[0007] Fibers are modified by using surface-modifying substances to form at least a surface-active molecular layer on the surface of the fibers, thereby obtaining modified fibers.

[0008] The two-dimensional sheet material, modified fiber, and surface modifier are mixed and modified to obtain a modified fiber / sheet composite material.

[0009] Furthermore, the modified fiber / sheet composite material is mixed with an epoxy resin-based composite coating system and applied to the substrate surface to obtain a modified fiber / sheet composite anti-corrosion coating.

[0010] The present invention also provides a modified fiber / sheet material composite anti-corrosion coating prepared by the aforementioned preparation method.

[0011] This invention also provides the application of the aforementioned modified fiber / sheet material composite anti-corrosion coating in the field of metal material protection for marine engineering equipment serving in extreme marine environments.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] (1) This invention uses surface modification technology to physically and chemically adsorb surface-modifying substances on the fiber surface and grow a molecular layer, which can improve the dispersibility of the fiber and increase the bonding force at the fiber-resin interface; the bonded molecular layer has a complete structure and high surface activity, and the modified fiber significantly enhances the mechanical properties of the composite material.

[0014] (2) Compared with surface oxidation and coating with sizing agents, surface grafting can make the grafted material have better adhesion to the CF (laminated material) surface. Introducing two-dimensional laminar material with functional groups and surface roughness into the CF surface helps the interfacial strength of the composite material.

[0015] (3) The method provided by the present invention can significantly improve the corrosion resistance of the composite coating. At the same time, the method is simple to operate and has significant effects, which can provide technical support for the long-term corrosion resistance of the modified fiber / sheet material composite anti-corrosion coating.

[0016] (4) The method provided by the present invention has excellent step characteristics and can be combined with sheet materials of different sizes, thus achieving the blocking effect of corrosive ions, thereby greatly improving the protective effect of the modified fiber / sheet material composite anti-corrosion coating on the metal substrate. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a surface morphology diagram of the original MAX phase material in Embodiment 1 of the present invention;

[0019] Figure 2 This is a surface morphology diagram of the modified fiber / two-dimensional sheet material in Example 1 of the present invention;

[0020] Figure 3 The modified carbon fiber / two-dimensional sheet Ti3C2T in Example 1 of this inventionx Surface morphology of the composite coating after erosion;

[0021] Figure 4 This is a post-erosion surface morphology diagram of the modified fiber / sheet material composite anti-corrosion coating in Example 2 of the present invention;

[0022] Figure 5 This is a post-erosion surface morphology diagram of the modified fiber / sheet material composite anti-corrosion coating in Example 3 of the present invention;

[0023] Figure 6 This is a surface morphology diagram of the composite coating after erosion in Comparative Example 1 of the present invention;

[0024] Figure 7 This is a surface morphology diagram of the composite coating in Comparative Example 2 of the present invention after erosion.

[0025] Figure 8 This is a surface morphology diagram of the composite coating in Comparative Example 3 of the present invention after erosion.

[0026] Figure 9 This is a surface morphology diagram of the composite coating after erosion in Comparative Example 4 of the present invention. Detailed Implementation

[0027] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] Specifically, as one aspect of the technical solution of this invention, the method for preparing a modified fiber / sheet material composite anti-corrosion coating includes:

[0029] Provide two-dimensional sheet materials;

[0030] Fibers are modified by using surface-modifying substances to form at least a surface-active molecular layer on the surface of the fibers, thereby obtaining modified fibers.

[0031] The two-dimensional sheet material, modified fiber, and surface modifier are mixed and modified to obtain a modified fiber / sheet composite material.

[0032] Furthermore, the modified fiber / sheet composite material is mixed with an epoxy resin-based composite coating system and applied to the substrate surface to obtain a modified fiber / sheet composite anti-corrosion coating.

[0033] In some preferred embodiments, the two-dimensional sheet material in the modified fiber / sheet composite material significantly increases the surface roughness of the fiber, greatly improving the load-bearing capacity and service life of the composite anti-corrosion coating.

[0034] In some preferred embodiments, the two-dimensional sheet material includes MoS2, GO, and Ti3C2T. x Any one or more combinations thereof, and not limited to this.

[0035] Furthermore, the sheet diameter of the two-dimensional sheet material is 0.5-2 μm.

[0036] Furthermore, the two-dimensional sheet material has a single layer or fewer layers, wherein fewer than 5 layers are used.

[0037] Furthermore, the two-dimensional sheet material is Ti3C2T. x The specific preparation method includes: etching the MAX phase material with HF solution at a mass ratio of HF to MAX of 1:5-10 at 80-150℃ for more than 24 hours to obtain multilayer MXene; immersing 500 mg of multilayer MXene material in 100 mL of tetrabutylammonium hydroxide, 800-1000 mg / L ascorbic acid, and 800-1000 mL of deionized water, stirring uniformly at room temperature (25-30℃) for more than 24 hours, ultrasonicating for 40 min, and washing repeatedly with distilled water until the supernatant is transparent or until its pH value is 6-7, and then intercalating to obtain few-layer Ti3C2T. x Two-dimensional sheet materials.

[0038] In some preferred embodiments, the surface-modifying material includes any one or more combinations of ester compounds, long-chain polymers, and inorganic acid compounds, but is not limited thereto.

[0039] Furthermore, the ester compounds include, but are not limited to, polyurethanes.

[0040] Furthermore, the long-chain polymer includes, but is not limited to, polydopamine.

[0041] Furthermore, the inorganic acid compounds include, but are not limited to, nitric acid.

[0042] In some preferred embodiments, the surface-modifying material includes, but is not limited to, any one or more combinations of dopamine, perfluoroacrylate, stearic acid, perfluorooctyl thiol, and nitric acid.

[0043] For example, carbon fiber is immersed in sulfuric acid solution for 4-6 hours to modify the surface of carbon fiber with carboxyl groups, thereby increasing the surface roughness of the carbon fiber. The acid-treated carbon fiber is then immersed in Tris-HCl solution containing dopamine to further improve the hydrophobicity of the modified carbon fiber, reduce the surface energy of the modified carbon fiber, and prevent the corrosion resistance of the modified fiber composite coating.

[0044] In some preferred embodiments, the fibers include organic fibers and / or inorganic fibers.

[0045] In some preferred embodiments, the fiber has a diameter of 6–110 μm and a length of 90–110 μm.

[0046] In some preferred embodiments, the surface-modifying material is grown and bonded to the surface of the fiber by physical and / or chemical adsorption, so that the active groups are uniformly coated on the fiber surface to form the surface-active molecular layer.

[0047] In some preferred embodiments, the surface-modifying material undergoes physical adsorption and / or chemical adsorption reactions at least on the outer surface, cross-section, cross-section, and defects of the fiber.

[0048] In some preferred embodiments, the thickness of the surface-active molecular layer is greater than 10 nm.

[0049] In some preferred embodiments, the preparation method specifically includes: first oxidizing the fiber, and then modifying the obtained fiber with a surface-modifying substance at 25-30°C for 24-30 hours to obtain modified fiber.

[0050] Furthermore, the mass ratio of the fiber to the surface-modifying material is 1.0–1.2:0.4–0.8.

[0051] In some preferred embodiments, the preparation method specifically includes: mixing the two-dimensional sheet material, modified fiber and surface modifier at 25-30°C for 24-30 hours to obtain modified fiber / sheet composite material.

[0052] Furthermore, the mass ratio of the two-dimensional sheet material, modified fiber, and surface modifier is 0.4–0.5: 1.0–1.2: 0.4–0.8.

[0053] In some preferred embodiments, the preparation method specifically includes: mixing the modified fiber / sheet composite material with an epoxy resin-based composite coating system and applying it to the surface of a substrate, and then curing it at 100-120°C for 1-4 hours to obtain a modified fiber / sheet composite anti-corrosion coating.

[0054] Furthermore, the epoxy resin-based composite coating system includes component A and component B; wherein component A includes epoxy resin, and component B includes an amino-based curing agent and an organosilicon defoamer. Specifically, the epoxy resin is an oil-based E44 epoxy resin.

[0055] Furthermore, the mass ratio of component A to component B is 10:5 to 7.

[0056] Furthermore, the defoamer is present at a mass ratio of 0.1 wt% of the composite coating.

[0057] Furthermore, the mass ratio of component A to component B is 10:6.

[0058] Furthermore, the mass ratio of curing agent to defoamer in component B is 0.6–1.0:0.001%.

[0059] Furthermore, the curing agent includes amino-based curing agents or polyamide curing agents.

[0060] Furthermore, the defoamer includes silicone-based defoamers or polyether-based defoamers.

[0061] Furthermore, the mass ratio of the modified fiber / lamellae composite material to the epoxy resin-based composite coating system is 0.5 to 5:100.

[0062] Furthermore, the substrate includes steel pipe piles and / or submarine pipelines.

[0063] The method of this invention can significantly improve the mechanical properties and corrosion protection performance of composite anti-corrosion coatings. The addition of modified fibers enhances the mechanical properties of the coating system, particularly its resistance to erosion corrosion, while the addition of two-dimensional sheet materials improves its corrosion protection performance. Another aspect of this invention provides a modified fiber / sheet material composite anti-corrosion coating prepared by the aforementioned method.

[0064] Furthermore, the thickness of the modified fiber / sheet material composite anti-corrosion coating is 160–230 μm.

[0065] The modified fiber / sheet composite anti-corrosion coating of this invention was characterized for its resistance to erosion corrosion after 600s of erosion under conditions of 10wt% SiC content and erosion rate of 4.71m / s.

[0066] The method for preparing the modified fiber / sheet composite anti-corrosion coating provided by this invention is simple and efficient, and can significantly improve the mechanical properties of the coating, especially its resistance to erosion corrosion, providing technical support for composite coating systems. At the same time, the composite anti-corrosion coating of this invention has excellent barrier properties, thereby improving the corrosion protection performance of the coating.

[0067] Another aspect of the present invention provides the application of the aforementioned modified fiber / sheet material composite anti-corrosion coating in the field of metal material protection for marine engineering equipment serving in extreme marine environments.

[0068] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0069] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0070] Example 1

[0071] S1. The carbon fiber is immersed in a concentrated nitric acid solution for surface oxidation, stirred at 80°C for 5 hours, then diluted with a large amount of deionized water, filtered and dried to obtain the oxidized carbon fiber.

[0072] S2. Oxidized carbon fiber and polydopamine are mixed and reacted at 30°C for 30 hours to obtain polydopamine-modified carbon fiber, wherein the thickness of the surface active molecular layer is 50 nm and the mass ratio of oxidized carbon fiber to polydopamine is 1.2:0.8.

[0073] S3. Preparation of few-layer two-dimensional sheet material Ti3C2T x The MAX phase material (Ti3AlC2) was etched using HF solution at a mass ratio of 1:6 to MAX at 80°C for at least 24 hours to obtain multilayered MXene material. 500 mg of the multilayered MXene material was then immersed in 100 mL of tetrabutylammonium hydroxide, 900 mg / L ascorbic acid, and 900 mL of deionized water, and stirred uniformly at room temperature (25°C) for at least 24 hours. The mixture was then sonicated for 40 minutes and washed repeatedly with distilled water until the supernatant became clear or its pH reached 6-7. After intercalation, a few-layered Ti3C2T was obtained. x Two-dimensional sheet materials;

[0074] S4. A few layers of Ti3C2T x Two-dimensional sheet materials, polydopamine-modified carbon fibers, and perfluorooctane mercaptan were combined and modified at 25°C for 30 hours to obtain modified fiber / sheet composite materials; among them, few-layer Ti3C2T x The mass ratio of two-dimensional sheet material, polydopamine-modified carbon fiber, and perfluorooctane mercaptan is 0.4:1.0:0.4.

[0075] S5. Add 1 part of modified fiber / sheet composite material, 61.9 parts of oil-based E44 epoxy resin, 37.1 parts of amino-based curing agent, and 0.1 parts of silicone-based defoamer to a mixer and stir at 3500 r / min for 10 min. Apply the resulting mixture to the surface of Q235 steel substrate and then cure at 110℃ for 3 h to obtain a modified fiber / sheet composite anti-corrosion coating.

[0076] The impedance values ​​(Log|Z|) of the modified fiber / sheet material composite anti-corrosion coating after immersion in alternating pressure of 30 MPa for 1200 h in this embodiment are shown in Table 1. Figure 1 This is a morphology image of the original MAX phase (Ti3AlC2) material in Example 1. Figure 2 The image shows the surface morphology of the modified fiber / lamella composite material. The surface morphology of the modified fiber / lamella composite anti-corrosion coating after 600 s of erosion at a SiC content of 10 wt% and an erosion velocity of 4.71 m / s is shown below. Figure 3 As shown.

[0077] Example 2

[0078] S1. The aramid fiber was immersed in a concentrated nitric acid solution for surface oxidation. The solution was stirred at 70°C for 6 hours, then diluted with a large amount of deionized water, filtered and dried to obtain the oxidized aramid fiber.

[0079] S2. Modified aramid fibers were obtained by modifying oxidized aramid fibers with dopamine at 25°C for 25 h; wherein the mass ratio of oxidized aramid fibers to dopamine was 1.0:0.5.

[0080] S3. A composite of few-layer GO, modified aramid fiber, and perfluoroacrylate was formed and modified at 30°C for 30 h to obtain a modified fiber / sheet composite material; wherein the mass ratio of few-layer GO, modified aramid fiber, and perfluoroacrylate was 0.5∶1.2∶0.8.

[0081] S4. Add 1 part of modified fiber / sheet composite material, 61.9 parts of oil-based E44 epoxy resin, 37.1 parts of polyamide curing agent, and 0.1 parts of polyether defoamer to a mixer and stir at 3500 r / min for 10 min. Apply the resulting mixture to the surface of Q235 steel substrate and then cure at 100℃ for 4 h to obtain a modified fiber / sheet composite anti-corrosion coating.

[0082] The impedance values ​​(Log|Z|) of the modified fiber / lamellae composite anti-corrosion coating after immersion in an alternating pressure of 30 MPa for 1200 h in this embodiment are shown in Table 1. The surface morphology of the modified fiber / lamellae composite anti-corrosion coating after 600 s of erosion under conditions of 10 wt% SiC content and an erosion rate of 4.71 m / s is shown in Table 1. Figure 4 As shown.

[0083] Example 3

[0084] S1. The carbon fiber is immersed in a concentrated nitric acid solution for surface oxidation, stirred at 90°C for 4 hours, then diluted with a large amount of deionized water, filtered and dried to obtain the oxidized carbon fiber.

[0085] S2. Stearic acid was used to modify the oxidized carbon fiber at 25°C for 25 h to obtain modified carbon fiber; wherein the mass ratio of the oxidized carbon fiber to stearic acid was 1.0:0.5.

[0086] S3. A modified fiber / sheet composite material was obtained by combining few-layer MoS2, modified carbon fiber and perfluorooctane mercaptan, and modifying it at 25°C for 28 hours; wherein the mass ratio of few-layer MoS2, modified carbon fiber and perfluorooctane mercaptan was 0.5∶1.2∶0.5.

[0087] S4. Add 1 part of modified fiber / sheet composite material, 61.9 parts of oil-based E44 epoxy resin, 37.1 parts of polyamide curing agent, and 0.1 parts of polyether defoamer to a mixer and stir at 3500 r / min for 10 min. Apply the resulting mixture to the surface of Q235 steel substrate and then cure at 120℃ for 1 h to obtain a modified fiber / sheet composite anti-corrosion coating.

[0088] In this embodiment, the impedance value (Log|Z|) of the modified fiber / lamellae composite anti-corrosion coating after immersion in alternating pressure at 30 MPa for 1200 h is shown in Table 1. The surface morphology of the modified fiber / lamellae composite anti-corrosion coating after 600 s of erosion under conditions of 10 wt% SiC content and an erosion rate of 4.71 m / s is shown in Table 1. Figure 5 As shown.

[0089] Comparative Example 1

[0090] The method is the same as in Example 1, except that Ti3C2T is missing. x Two-dimensional sheet materials;

[0091] S1. The carbon fiber is immersed in a concentrated nitric acid solution for surface oxidation, stirred at 80°C for 5 hours, then diluted with a large amount of deionized water, filtered and dried to obtain the oxidized carbon fiber.

[0092] S2. Oxidized carbon fiber and polydopamine are mixed and reacted at 30°C for 30 hours to obtain polydopamine-modified carbon fiber, wherein the thickness of the surface active molecular layer is 50 nm and the mass ratio of oxidized carbon fiber to polydopamine is 1.2:0.8.

[0093] S3. Polydopamine-modified carbon fiber is compounded with perfluorooctane mercaptan and modified at 25°C for 30 hours to obtain modified fiber;

[0094] S4. Add 1 part of modified fiber, 61.9 parts of oil-based E44 epoxy resin, 37.1 parts of amino-based curing agent, and 0.1 parts of silicone-based defoamer to a mixer and stir at 3500 r / min for 10 min. Apply the resulting mixture to the surface of Q235 steel substrate and then cure at 110℃ for 3 h to obtain a composite coating.

[0095] The impedance values ​​(Log|Z|) of the composite coating in this comparative example after immersion in an alternating pressure of 30 MPa for 1200 h are shown in Table 1. The surface morphology of the composite coating after 600 s of erosion at a SiC content of 10 wt% and an erosion velocity of 4.71 m / s is shown in Table 1. Figure 6 As shown.

[0096] Comparative Example 2

[0097] The method is the same as in Example 1, except that the modified fibers are not used.

[0098] S1. Preparation of few-layer two-dimensional sheet material Ti3C2T x The MAX phase material (Ti3AlC2) was etched using HF solution at a mass ratio of 1:6 to MAX at 80°C for at least 24 hours to obtain multilayered MXene material. 500 mg of the multilayered MXene material was then immersed in 100 mL of tetrabutylammonium hydroxide, 900 mg / L ascorbic acid, and 900 mL of deionized water, and stirred uniformly at room temperature (25°C) for at least 24 hours. The mixture was then sonicated for 40 minutes and washed repeatedly with distilled water until the supernatant became clear or its pH reached 6-7. After intercalation, a few-layered Ti3C2T was obtained. x Two-dimensional sheet materials;

[0099] S2. Few layers of Ti3C2T x Two-dimensional sheet material was compounded with perfluorooctane mercaptan and modified at 25°C for 30 h to obtain modified sheet material;

[0100] S5. Add 1 part of modified sheet material, 61.9 parts of oil-based E44 epoxy resin, 37.1 parts of amino-based curing agent, and 0.1 parts of silicone-based defoamer to a mixer and stir at 3500 r / min for 10 min. Apply the resulting mixture to the surface of Q235 steel substrate and then cure at 110℃ for 3 h to obtain a composite coating.

[0101] The impedance values ​​(Log|Z|) of the composite coating in this comparative example after immersion in an alternating pressure of 30 MPa for 1200 h are shown in Table 1. The surface morphology of the composite coating after 600 s of erosion at a SiC content of 10 wt% and an erosion velocity of 4.71 m / s is shown in Table 1. Figure 7 As shown.

[0102] Comparative Example 3

[0103] The method is the same as in Example 1, except that: carbon fiber and Ti3C2T are directly mixed. x Two-dimensional sheet materials are coated with a coating.

[0104] S1. Preparation of few-layer two-dimensional sheet material Ti3C2T x The MAX phase material (Ti3AlC2) was etched using HF solution at a mass ratio of 1:6 to MAX at 80°C for more than 24 hours to obtain multilayer MXene material. 500 mg of the multilayer MXene material was immersed in 100 mL of tetrabutylammonium hydroxide, 900 mg / L ascorbic acid and 900 mL of deionized water and stirred uniformly at room temperature (25°C) for more than 24 hours. The mixture was ultrasonically reacted for 40 min and washed repeatedly with distilled water until the supernatant was clear or until its pH value was 6-7. After intercalation, a few-layer Ti3C2Tx two-dimensional sheet material was obtained.

[0105] S2. Few layers of Ti3C2T x One part of two-dimensional sheet material and carbon fiber (few-layer Ti3C2T) x The two-dimensional sheet material and carbon fiber were mixed in a mass ratio of 0.5:1.2. 61.9 parts of oily E44 epoxy resin, 37.1 parts of amino curing agent and 0.1 parts of silicone defoamer were added to a mixer and stirred at 3500 r / min for 10 min. The resulting mixture was applied to the surface of Q235 steel substrate and then cured at 110℃ for 3 h to obtain a composite coating.

[0106] The impedance values ​​(Log|Z|) of the composite coating in this comparative example after immersion in an alternating pressure of 30 MPa for 1200 h are shown in Table 1. The surface morphology of the composite coating after 600 s of erosion at a SiC content of 10 wt% and an erosion velocity of 4.71 m / s is shown in Table 1. Figure 8 As shown.

[0107] Comparative Example 4

[0108] The method is the same as in Example 1, except that the modified fibers and sheet materials are not combined.

[0109] S1. The carbon fiber is immersed in a concentrated nitric acid solution for surface oxidation, stirred at 80°C for 5 hours, then diluted with a large amount of deionized water, filtered and dried to obtain the oxidized carbon fiber.

[0110] S2. Oxidized carbon fiber and polydopamine are mixed and reacted at 30°C for 30 hours to obtain polydopamine-modified carbon fiber, wherein the thickness of the surface active molecular layer is 50 nm and the mass ratio of oxidized carbon fiber to polydopamine is 1.2:0.8.

[0111] S3. Preparation of few-layer two-dimensional sheet material Ti3C2T x The MAX phase material (Ti3AlC2) was etched using HF solution at a mass ratio of 1:6 to MAX at 80°C for more than 24 hours to obtain multilayer MXene material. 500 mg of the multilayer MXene material was immersed in 100 mL of tetrabutylammonium hydroxide, 900 mg / L ascorbic acid and 900 mL of deionized water and stirred uniformly at room temperature (25°C) for more than 24 hours. The mixture was ultrasonically reacted for 40 min and washed repeatedly with distilled water until the supernatant was clear or until its pH value was 6-7. After intercalation, a few-layer Ti3C2Tx two-dimensional sheet material was obtained.

[0112] S5. Few layers of Ti3C2T x One part of two-dimensional sheet material and polydopamine-modified carbon fiber (few-layer Ti3C2T) x The two-dimensional sheet material and polydopamine-modified carbon fiber were mixed in a mass ratio of 0.5:1.2. 61.9 parts of oily E44 epoxy resin, 37.1 parts of amino curing agent, and 0.1 parts of silicone defoamer were added to a mixer and stirred at 3500 r / min for 10 min. The resulting mixture was applied to the surface of a Q235 steel substrate and then cured at 110℃ for 3 h to obtain a modified fiber / sheet material composite anti-corrosion coating.

[0113] The impedance values ​​(Log|Z|) of the composite coating in this comparative example after immersion in an alternating pressure of 30 MPa for 1200 h are shown in Table 1. The surface morphology of the composite coating after 600 s of erosion at a SiC content of 10 wt% and an erosion velocity of 4.71 m / s is shown in Table 1. Figure 9 As shown.

[0114] Test experiment:

[0115] The corresponding test substrates were selected according to the test items. For salt spray resistance, corrosion resistance, and erosion resistance, Q235 steel plates with dimensions of 5cm x 10cm x 0.1cm, Q235 steel blocks with dimensions of 1cm x 1cm x 1cm, and Q235 steel plates with dimensions of 5cm x 5cm x 1cm were used, respectively. Each sample was coated with a composite coating with a thickness of 100±10μm. The acid salt spray resistance time was tested according to GB / T 1731-1993. The test results of the corrosion resistance of the composite coating are shown in Table 1.

[0116] Table 1. Performance test results of the composite coatings in Examples 1-3 and Comparative Examples 1-4

[0117]

[0118] A comparison of Examples 1-3 with Comparative Examples 1-4 shows that the selection of surface modifiers, two-dimensional sheet materials, epoxy resins, and curing agents plays a crucial role in improving product performance. The surface treatment of carbon fibers and the composite of two-dimensional sheets determine the corrosion resistance and erosion resistance of the composite coating. Compared to Comparative Examples 1-4, the modified carbon fiber / Ti3C2T in Example 1... x The Log|Z| value of the layered material composite anti-corrosion coating decreased by only 0.30 after immersion in 30 MPa for 1800 h, indicating that the modified carbon fiber grafted with Ti3C2T... x The dual treatment with perfluorooctane mercaptan significantly improved the surface roughness of the fiber and the chemical bonding between it and the resin. This helps to enhance the interfacial bonding between the modified fiber and the epoxy resin. Therefore, the introduction of the modified fiber / two-dimensional sheet composite material helps to improve the corrosion resistance of the epoxy resin-based composite coating. The Log|Z| value of the modified aramid fiber / GO composite coating obtained in Example 2 decreased by 1.27 after immersion in high pressure of 30 MPa for 1800 h. This indicates that the corrosion resistance of aramid fiber is relatively weak compared to carbon fiber. However, the GO grafting on the surface of the aramid fiber effectively enhances the mechanical interlocking between the fiber and the epoxy resin. In addition, the surface treatment with perfluoroacrylate also improves the corrosion resistance of the composite coating. The modified carbon fiber / MoS2 composite coating obtained in Example 3 showed a 0.80 decrease in Log|Z| value after immersion in 30 MPa for 1800 h. This is because the introduction of the two-dimensional lamellar material hindered the diffusion of the corrosive medium and blocked its diffusion at the interface, thereby delaying the contact between the corrosive medium and the metal substrate and inhibiting the corrosion process. Therefore, the surface-modified carbon fiber / two-dimensional lamellar material composite coating provided by this invention exhibits superior salt spray and high-pressure corrosion resistance, and its corrosion resistance is long-lasting.

[0119] Furthermore, the Log|Z| values ​​of the composite coating in this embodiment after immersion in a high pressure of 30MPa for 1800h are shown in Table 1. Figure 1 This is a morphology diagram of the original MAX phase material in Example 1. Figure 2 For modified fiber / two-dimensional sheet material Ti3C2T x Surface morphology of composite coating. Figure 3-9 These are surface images of the composite coatings in Examples 1-3 and Comparative Examples 1-4 after erosion tests. It can be seen that the composite coatings in Comparative Examples 1-4 expose the underlying metal substrate after the erosion test, while the epoxy resin-based coating incorporates the modified fiber / two-dimensional sheet composite material Ti3C2T. xThe damage was minor, and the coating surface remained intact. This indicates that surface grafting of the sheet material helps to solidify the resin matrix around the carbon fiber, disperse stress at the carbon fiber interface, and enhance the interfacial bonding strength between the carbon fiber and the resin, thereby improving the mechanical properties and erosion resistance of the modified fiber / sheet material composite coating.

[0120] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0121] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing a modified fiber / sheet material composite anti-corrosion coating, characterized in that, include: Two-dimensional sheet materials are provided; the two-dimensional sheet materials include MoS2, GO, and Ti3C2T. x Any one or more of the following; the sheet diameter of the two-dimensional sheet material is 0.5-2μm; the number of layers of the two-dimensional sheet material is single or few layers, wherein the fewest layers are no more than 5 layers; Fibers are modified using a surface-modifying substance A to form at least a surface-active molecular layer on the surface of the fibers, thereby obtaining modified fibers. The surface-modifying substance A is grown and bonded to the fiber surface via physical and / or chemical adsorption, resulting in a uniform coating of active groups on the fiber surface to form the surface-active molecular layer, the thickness of which is greater than 10 nm. The fiber has a diameter of 6–110 μm and a length of 90–110 μm. The surface-modifying substance A is polydopamine. The mass ratio of fiber to surface-modifying substance A is 1.0–1.2:0.4–0.

8. The two-dimensional sheet material, modified fiber, and surface modifier B are mixed and modified to obtain a modified fiber / sheet composite material; wherein, the surface modifier B is any one or more combinations of perfluoroacrylate and perfluorooctane mercaptan; the mass ratio of the two-dimensional sheet material, modified fiber, and surface modifier B is 0.4~0.5:1.0~1.2:0.4~0.8; Furthermore, the modified fiber / sheet composite material is mixed with an epoxy resin-based composite coating system and applied to the surface of a substrate to obtain a modified fiber / sheet composite anti-corrosion coating; wherein the mass ratio of the modified fiber / sheet composite material to the epoxy resin-based composite coating system is 0.5~5:

100.

2. The preparation method according to claim 1, characterized in that: The fibers include organic fibers and / or inorganic fibers.

3. The preparation method according to claim 1, characterized in that, Specifically, it includes: The fiber is first oxidized, and then surface modifier A is used to modify the obtained fiber at 25~30℃ for 24~30h to obtain modified fiber.

4. The preparation method according to claim 1, characterized in that, Specifically, it includes: The two-dimensional sheet material, modified fiber, and surface modifier B are mixed and modified at 25-30°C for 24-30 hours to obtain a modified fiber / sheet composite material.

5. The preparation method according to claim 1, characterized in that, Specifically, it includes: The modified fiber / sheet composite material is mixed with an epoxy resin-based composite coating system and applied to the substrate surface, and then cured at 100~120℃ for 1~4h to obtain a modified fiber / sheet composite anti-corrosion coating.

6. The preparation method according to claim 5, characterized in that: The epoxy resin-based composite coating system includes component A and component B; wherein, component A includes epoxy resin, and component B includes a curing agent and a defoamer.

7. The preparation method according to claim 5, characterized in that: The substrate includes steel pipe piles and / or submarine pipelines.

8. A modified fiber / sheet composite anti-corrosion coating prepared by any one of claims 1-7.

9. The modified fiber / sheet composite anti-corrosion coating according to claim 8, characterized in that: The thickness of the modified fiber / sheet material composite anti-corrosion coating is 160~230μm.

10. The application of the modified fiber / sheet composite anti-corrosion coating as described in claim 8 or 9 in the field of metal material protection for marine engineering equipment serving in extreme marine environments.

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