Ti3C2T x MXene@PDA@IL composite corrosion inhibitor, preparation method thereof, composite coating and application

Abstract

The application relates to a composite corrosion inhibitor, a preparation method thereof, and a composite coating and application, and belongs to the technical field of coating corrosion prevention. The preparation method of the composite corrosion inhibitor comprises the following steps: dispersing nanosheets in a Tris-HCl buffer solution, adding dopamine hydrochloride, carrying out a polymerization reaction, and obtaining; adding to an imidazole ionic liquid aqueous solution, uniformly dispersing, stirring and reacting under N2 protection, and obtaining the composite corrosion inhibitor. The composite corrosion inhibitor has good compatibility with epoxy resin by introducing polydopamine and imidazole ionic liquid, and can endow the coating with a self-repairing function, so that long-term and efficient corrosion prevention effect is achieved.

Description

Technical Field

[0001] This invention belongs to the field of coating anti-corrosion technology, and particularly relates to a... Composite corrosion inhibitors, their preparation methods, composite coatings, and applications. Background Technology

[0002] Metal corrosion is widespread in ships, rail transportation, pipelines, and daily life, potentially causing damage to metal components or pipeline leaks. Applying anti-corrosion coatings to metal surfaces is cost-effective, easy to apply, and widely applicable, making it one of the main methods for effectively solving metal corrosion problems. However, cracks or craters often appear during the curing or use of the coating, caused by H2O and Cl... - This provides a pathway for the diffusion of corrosive media, leading to corrosion and coating failure.

[0003] As a novel two-dimensional material, it possesses advantages such as high specific surface area, good mechanical properties, and abundant surface functional groups, and can be used to... Adding it to epoxy coatings can form a dense physical barrier layer, which can fill and repair coating defects, extend the penetration path of corrosive media, and thus improve the anti-corrosion performance of the coating. It has great potential for application in the field of coating anti-corrosion.

[0004] However, directly When added to an epoxy coating, it exhibits poor dispersibility and interfacial compatibility. Furthermore, It is easily oxidized, and reacts with oxygen and water to gradually transform into TiO2 fragments, causing irreversible loss of the coating's long-term durability and functional lifespan. Furthermore, when the coating is damaged, it relies solely on… The physical shielding effect is insufficient to meet corrosion prevention requirements. Therefore, improvement is needed. The dispersibility and interfacial compatibility of epoxy coatings are of great significance in endowing them with active protection functions. Summary of the Invention

[0005] In response to the existing technology, directly using To address the shortcomings of adding it to epoxy coatings, this invention provides... Composite corrosion inhibitors, their preparation methods, composite coatings, and applications. Composite corrosion inhibitors, through The introduction of polydopamine and imidazole ionic liquids improves the effect of polydopamine. The compatibility with epoxy resin is improved by combining polydopamine and imidazole ionic liquids. It has antioxidant properties and also gives the coating a self-healing function, achieving a long-lasting and efficient anti-corrosion effect.

[0006] This invention provides The preparation method of the composite corrosion inhibitor includes the following steps: preparation :Will Nanosheets were dispersed in Tris-HCl buffer solution, and dopamine hydrochloride was added to allow the dopamine hydrochloride to... A polymerization reaction occurs on the surface of the nanosheets to obtain... ; preparation :Will Add to an aqueous solution of imidazole ionic liquid, disperse evenly, and stir under N2 protection to obtain... Composite corrosion inhibitor.

[0007] In some embodiments, preparation In the steps, The mass ratio of nanosheets to dopamine hydrochloride is 1:(0.6~1).

[0008] In some embodiments, preparation In this procedure, the concentration of the Tris-HCl buffer solution is 0.01~0.05 mol / L.

[0009] In some embodiments, preparation In this step, the polymerization reaction is carried out at room temperature for 20-28 hours.

[0010] In some embodiments, preparation In this step, the imidazole ionic liquid is selected from any one of 1-allyl-3-methylimidazolium chloride, 1-aminoethyl-3-methylimidazolium bromide, 1-hydroxyethyl-3-methylimidazolium chloride, and 1-benzyl-3-methylimidazolium chloride.

[0011] In some embodiments, preparation In this procedure, the concentration of the imidazole ionic liquid aqueous solution is 0.3~0.7 mol / L. The ratio of the mass of the ion to the molar mass of the imidazole ionic liquid is 100:(21~25) mg / mmol.

[0012] In some embodiments, preparation In this process, the reaction temperature is 20~28 ℃ and the reaction time is 8~14 h.

[0013] The present invention also provides Composite corrosion inhibitor, as described in any of the above technical solutions The composite corrosion inhibitor was prepared using a specific method.

[0014] The present invention further provides a composite coating comprising component A and component B, wherein component A comprises epoxy resin and the above-described technical solution. The composite corrosion inhibitor, component B includes a curing agent, and the mass ratio of component A to component B is (1.7~2.1):1, wherein component A contains... The mass fraction of the composite corrosion inhibitor is 0.05~0.25 wt%.

[0015] In addition, the present invention also provides the application of the composite coating described in the above technical solution in the corrosion protection of metal surfaces. When applying, the A component and B component of the composite coating are mixed evenly and then coated on the metal surface. After standing to allow the coated composite coating to self-level, it is cured at 55°C.

[0016] 1. The present invention provides The preparation method of composite corrosion inhibitors first involves... Nanosheets are coated with polydopamine to improve... The compatibility with epoxy resin is further enhanced by grafting imidazole ionic liquids, allowing the imidazole ionic liquids to interact with Fe on the metal matrix surface. 2+ or Fe 3+ The coating forms a protective film, giving it a certain degree of self-healing properties and achieving a long-lasting and highly effective anti-corrosion effect. 2. The present invention provides Composite corrosion inhibitor, through The introduction of polydopamine and imidazole ionic liquids improves the effect of polydopamine. The compatibility with epoxy resin is improved by combining polydopamine and imidazole ionic liquids. It has antioxidant properties and also gives the coating a self-healing function; 3. The composite coating provided by this invention, by adding... Composite corrosion inhibitors, when applied to metal surface corrosion protection, form composite coatings with excellent long-term corrosion protection performance. Attached Figure Description

[0017] Figure 1 Provided by the embodiments of the present invention Flowchart of the preparation method of composite corrosion inhibitor; Figure 2 In Embodiment 1 of the present invention, Ti3AlC2, , and SEM images of the composite corrosion inhibitor, where (a) corresponds to Ti3AlC2, and (b) corresponds to (c) corresponds to (d) corresponds to ; Figure 3 Prepared as described in Example 1 of this invention XPS characterization images of the composite corrosion inhibitor, where (a) is the XPS spectrum, (b) is the C 1s spectrum, (c) is the Ti 2p spectrum, (d) is the O 1s spectrum, (e) is the F 1s spectrum, and (f) is the N 1s spectrum; Figure 4 In Embodiment 1 of the present invention , and Zeta potential diagram of composite corrosion inhibitor; Figure 5 In Embodiment 1 of the present invention and Photographs showing the dispersion stability test results of the composite corrosion inhibitor in water and epoxy resin; Figure 6 For pure epoxy resin coating, the following additives are used in Example 1 of this invention: coating and Bode diagrams of the coatings, where (a) corresponds to pure epoxy resin, and (b) corresponds to... (c) corresponds to ; Figure 7 For pure epoxy resin scratch coating and adding the coating of Example 1 of this invention Bode diagrams of scratched coatings, where (a) corresponds to pure epoxy resin, and (b) corresponds to... . Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 As shown, an embodiment of the present invention provides a The preparation method of the composite corrosion inhibitor includes the following steps: preparation :Will Nanosheets were dispersed in Tris-HCl buffer solution, and dopamine hydrochloride was added to allow the dopamine hydrochloride to... A polymerization reaction occurs on the surface of the nanosheets to obtain... ; preparation :Will Add to an aqueous solution of imidazole ionic liquid, disperse evenly, and stir under N2 protection to obtain... Composite corrosion inhibitor.

[0020] The above In the preparation method of composite corrosion inhibitors, it should be noted that the preparation must be carried out in accordance with the following steps: Post-preparation The two steps must be performed simultaneously (i.e., dopamine hydrochloride and imidazole ionic liquid cannot be added at the same time).

[0021] The above The preparation method of composite corrosion inhibitors first involves... Nanosheets are coated with polydopamine to improve... The compatibility with epoxy resin is further enhanced by grafting imidazole ionic liquids, allowing the imidazole ionic liquids to interact with Fe on the metal matrix surface. 2+ or Fe 3+ The coating forms a protective film, giving it a certain self-healing property and achieving a long-lasting and efficient anti-corrosion effect.

[0022] Specifically, the preparation method described above yielded... Composite corrosion inhibitors, in The effects and synergistic properties of the polydopamine and imidazole ionic liquid introduced onto the surface are as follows: 1. Polydopamine can be firmly attached to [the target organism] through hydrogen bonding, π-π stacking, or Michael addition. On the surface, an organically functionalized interface is formed, which acts as a physical barrier to isolate oxygen and water, thereby improving... Its antioxidant properties; the phenolic hydroxyl and amino functional groups in polydopamine can react with the epoxy groups (-O-CH2-CH-) in epoxy resin to form a three-dimensional polymer, enhancing its antioxidant properties. The coating exhibits good compatibility with epoxy resins, and the phenolic hydroxyl and amino functional groups can improve the adhesion strength between the coating and the substrate, thereby enhancing the coating's corrosion resistance; polydopamine and Fe 3+ The chelating effect can form a coating film on the metal surface, thereby resisting further corrosion and giving the coating a self-healing function, which can effectively protect the metal substrate; polydopamine can provide active sites for subsequent grafting of imidazole ionic liquids, improving the modification efficiency.

[0023] 2. Imidazole ionic liquids contain an imidazole ring in their structure. The imidazole ring has reactive oxygen species scavenging ability and can capture oxidants such as hydroxyl radicals. When combined with polydopamine, it can enhance... Antioxidant effect, delays The conversion to TiO2 maintains the long-term function of the coating; the imidazole ionic liquid can form a coordination bond between the electron-rich nitrogen atom on the imidazole ring and the empty d orbital on the metal surface, adsorb onto the metal surface to form a hydrophobic protective film, and inhibit anodic dissolution and cathodic reaction.

[0024] In a preferred embodiment, The preparation steps of the nanosheets are as follows: LiF is added to HCl, and after the reaction is complete, Ti3AlC2 is added and the reaction is stirred; after the reaction is completed, the precipitate is collected and washed with deionized water by centrifugation until the pH of the supernatant is >6, thus obtaining multilayer nanosheets. ; will have multiple layers Redispersed in distilled water and ultrasonically exfoliated under N2 atmosphere to obtain Nanosheets.

[0025] In a preferred embodiment, preparation In the steps, The mass ratio of nanosheets to dopamine hydrochloride is 1:(0.6~1). This preferred embodiment further defines... The preferred ratio range of polydopamine and dopamine hydrochloride, within which the polydopamine can be ensured to... A uniform and dense coating layer is formed on the surface, which avoids insufficient dosage leading to insignificant improvement in compatibility and limited enhancement of antioxidant properties, and also prevents excessive dosage from causing agglomeration.

[0026] In a preferred embodiment, preparation In this step, the concentration of the Tris-HCl buffer solution is 0.01~0.05 mol / L. This preferred embodiment further specifies the concentration of the Tris-HCl buffer solution. Within this preferred concentration range, the Tris-HCl buffer solution can stabilize the pH of the reaction system, providing a suitable environment for the polymerization reaction of dopamine hydrochloride. This avoids excessively high concentrations leading to excessively rapid polymerization and uneven coating layers, or excessively low concentrations leading to incomplete polymerization and failure to form an effective coating layer. It should be noted that the amount of Tris-HCl buffer solution used must be ensured... Nanosheets and dopamine hydrochloride can be fully dispersed when When the total mass of nanosheets and dopamine hydrochloride is 1.6 to 2.0 g, the preferred amount of Tris-HCl buffer solution is 40 to 100 mL.

[0027] In a preferred embodiment, preparation In this step, the polymerization reaction is carried out at room temperature for 20-28 hours. This preferred embodiment further specifies the preferred polymerization temperature and reaction time, allowing dopamine hydrochloride to fully polymerize and firmly adhere to the [product / material]. The surface treatment eliminates the need for high-temperature energy consumption, balancing manufacturing costs and product performance.

[0028] In a preferred embodiment, preparation In this step, the imidazole ionic liquid is selected from any one of 1-allyl-3-methylimidazolium chloride, 1-aminoethyl-3-methylimidazolium bromide, 1-hydroxyethyl-3-methylimidazolium chloride, and 1-benzyl-3-methylimidazolium chloride. The imidazole ionic liquids listed above have cation rings that can form an adsorption film on the metal surface, preventing corrosive media (such as water, Cl-) from forming. - When in contact with metals, different types of imidazole ionic liquids can optimize corrosion inhibition performance through the combined action of cation rings and functional groups. For example, amino groups can form coordination bonds with metals to improve chemical adsorption capacity; hydroxyl groups can form hydrogen bonds to improve the adhesion between the adsorption film and the metal surface; and aromatic π electrons can form π-coordination with metal d orbitals to increase adsorption strength.

[0029] In a preferred embodiment, preparation In this procedure, the concentration of the imidazole ionic liquid aqueous solution is 0.3~0.7 mol / L. The mass ratio of the imidazole ionic liquid to the molar amount of the imidazole ionic liquid is 100:(21~25) mg / mmol. This preferred embodiment further defines the preferred concentration range of the imidazole ionic liquid aqueous solution and... The optimal ratio of imidazole ionic liquid to the solution, the suitable concentration of the imidazole ionic liquid aqueous solution, and An appropriate ratio with imidazole ionic liquids can ensure that the imidazole ionic liquids are fully and uniformly grafted onto the surface. On the surface, to avoid the imidazole ionic liquid from agglomerating due to excessively high concentration or dosage, or from insufficient grafting of imidazole ionic liquid due to excessively low concentration or dosage, thus failing to achieve effective active protection function.

[0030] In a preferred embodiment, preparation In this step, the reaction temperature is 20–28 °C, and the reaction time is 8–14 h. This preferred embodiment further defines the preferred reaction temperature and reaction time ranges for grafting imidazole ionic liquids, achieving the desired reaction between imidazole ionic liquids and imidazole ionic liquids under mild conditions. The highly efficient grafting avoids the decomposition of ionic liquids caused by high temperatures. Oxidation was achieved while controlling the reaction time, thus balancing grafting efficiency.

[0031] The present invention also provides a Composite corrosion inhibitor, through the above The composite corrosion inhibitor was prepared using a specific method. Composite corrosion inhibitor, through The introduction of polydopamine and imidazole ionic liquids improves the effect of polydopamine. The compatibility with epoxy resin is improved by combining polydopamine and imidazole ionic liquids. It has antioxidant properties and also gives the coating a self-healing function.

[0032] This invention further provides a composite coating, comprising component A and component B, wherein component A comprises epoxy resin and the above-mentioned... The composite corrosion inhibitor, component B includes a curing agent, and the mass ratio of component A to component B is (1.7~2.1):1, wherein component A contains... The composite corrosion inhibitor has a mass fraction of 0.05~0.25wt%. The epoxy resin of this composite coating contains the above-mentioned... The composite corrosion inhibitor, with an addition amount of 0.05~0.25wt%, ensures uniform dispersion within the epoxy resin matrix, fully leveraging its anti-corrosion and self-healing properties while avoiding issues like abnormal viscosity and reduced workability caused by excessive addition. Simultaneously, the A:B component mass ratio of (1.7~2.1):1 in this composite coating ensures complete curing and the formation of a dense coating.

[0033] Furthermore, this invention also provides the application of the aforementioned composite coating in metal surface corrosion protection. In application, components A and B of the composite coating are mixed evenly, then applied to the metal surface. After allowing the coating to self-level, it is cured at 55°C. This method of applying the composite coating to metal surface corrosion protection is simple and easy to implement, requiring no complex equipment, and is suitable for large-scale industrial applications. It allows the composite coating to form a protective layer on the metal surface that combines physical barrier and self-healing functions, effectively blocking contact between corrosive media and the metal surface, inhibiting metal corrosion, significantly extending the service life of metal equipment, and avoiding safety hazards caused by corrosion. It is suitable for metal protection in various complex corrosive environments. When applying the composite coating to metal surface corrosion protection, a curing temperature of 55°C is used to avoid the problems of excessively high curing temperatures leading to coating cracking and excessively low temperatures leading to incomplete curing. It should be noted that to ensure uniform mixing of components A and B, a mixing scheme of "stirring for 5 minutes first, then sonicating for 10 minutes" can be adopted. It should also be noted that to ensure sufficient curing of the composite coating, the preferred curing time is 14 hours.

[0034] To more clearly and in detail describe the embodiments provided by the present invention The composite corrosion inhibitor, its preparation method, composite coating, and application will be described below with reference to specific embodiments.

[0035] Example 1 (1) Preparation Nanosheets 1.6 g LiF was added to 20 mL of 9 mol / L HCl. After the reaction was complete, 1 g Ti3AlC2 was added to the reaction system, and the mixture was stirred at 39 °C for 24 h. After the reaction was completed, the precipitate was collected and washed with deionized water by centrifugation until the pH of the supernatant was >6, resulting in a multilayered product. ; will have multiple layers The solution was redispersed in distilled water and ultrasonically exfoliated under N2 atmosphere. The solution was centrifuged to collect the precipitate, which was then freeze-dried to obtain the desired product. Nanosheets.

[0036] (2) Preparation

[0037] 1 g of the product obtained in step (1) Nanosheets were dispersed in 100 mL of 0.01 mol / L Tris-HCl buffer solution, and 0.8 g of dopamine hydrochloride was added. The mixture was stirred at room temperature for 24 h, and the lower precipitate was freeze-dried to obtain... .

[0038] (3) Preparation

[0039] 50 mL of 0.5 mol / L 1-hydroxyethyl-3-methylimidazole chloride was ultrasonically dispersed in deionized water until uniformly dispersed; 100 mg of the solution prepared in step (2) was then added. The mixture was added to an aqueous solution of imidazole ionic liquid, ultrasonically dispersed to ensure uniform dispersion, and stirred for 12 h under N2 protection at 20 °C. After the reaction was completed, the lower precipitate was collected by centrifugation, washed, filtered, freeze-dried, and ground to obtain the desired product. Composite corrosion inhibitor.

[0040] (4) Preparation of composite coating The preparation obtained in step (3) The composite corrosion inhibitor was added to the epoxy resin at a mass fraction of 0.05 wt%. The mixture was then mixed with BHC807-2 type curing agent at a mass ratio of 1.7:1, stirred for 5 min, and ultrasonicated for 10 min to obtain the composite coating. The composite coating was applied to a Q235 steel plate, allowed to stand for 13 h to allow it to self-level, and then placed in an oven at 55 ℃ for 14 h to cure fully.

[0041] Example 2 (1) Preparation Nanosheets 1.4 g LiF was added to 26 mL of 10 mol / L HCl. After the reaction was complete, 1 g Ti3AlC2 was added to the reaction system, and the mixture was stirred at 37 °C for 26 h. After the reaction was completed, the precipitate was collected and washed with deionized water by centrifugation until the pH of the supernatant was >6, resulting in a multilayered product. ; will have multiple layers The solution was redispersed in distilled water and ultrasonically exfoliated under N2 atmosphere. The solution was centrifuged to collect the precipitate, which was then freeze-dried to obtain the desired product. Nanosheets.

[0042] (2) Preparation

[0043] 1 g of the product obtained in step (1) Nanosheets were dispersed in 50 mL of 0.02 mol / L Tris-HCl buffer solution, and 0.7 g of dopamine hydrochloride was added. The mixture was stirred at room temperature for 20 h, and the lower precipitate was freeze-dried to obtain... .

[0044] (3) Preparation

[0045] 60 mL of 0.4 mol / L 1-allyl-3-methylimidazole chloride was ultrasonically dispersed in deionized water until uniformly dispersed; 100 mg of the solution prepared in step (2) was then added. The mixture was added to an aqueous solution of imidazole ionic liquid, ultrasonically dispersed to ensure uniform dispersion, and stirred for 10 h under N2 protection. After the reaction was complete, the lower precipitate was collected by centrifugation, washed, filtered, freeze-dried, and ground to obtain the desired product. Composite corrosion inhibitor.

[0046] (4) Preparation of composite coating The preparation obtained in step (3) The composite corrosion inhibitor was added to the epoxy resin at a mass fraction of 0.1 wt%. The mixture was then mixed with BHC807-2 type curing agent at a mass ratio of 1.8:1, stirred for 5 min, and ultrasonicated for 10 min to obtain the composite coating. The composite coating was applied to a Q235 steel plate, allowed to stand for 13 h to allow it to self-level, and then placed in an oven at 55 ℃ for 14 h to cure fully.

[0047] Example 3 (1) Preparation Nanosheets 1.8 g LiF was added to 19 mL of 11 mol / L HCl. After the reaction was complete, 1 g Ti3AlC2 was added to the reaction system, and the mixture was stirred at 36 °C for 20 h. After the reaction was completed, the precipitate was collected and washed with deionized water by centrifugation until the pH of the supernatant was >6, resulting in a multilayered product. ; will have multiple layers The solution was redispersed in distilled water and ultrasonically exfoliated under N2 atmosphere. The solution was centrifuged to collect the precipitate, which was then freeze-dried to obtain the desired product. Nanosheets.

[0048] (2) Preparation

[0049] 1 g of the product obtained in step (1) Nanosheets were dispersed in 80 mL of 0.03 mol / L Tris-HCl buffer solution, and 0.9 g of dopamine hydrochloride was added. The mixture was stirred at room temperature for 28 h, and the lower precipitate was freeze-dried to obtain... .

[0050] (3) Preparation

[0051] 40 mL of 0.6 mol / L 1-aminoethyl-3-methylimidazolium bromide was ultrasonically dispersed in deionized water to ensure uniform dispersion; 100 mg of the solution prepared in step (2) was then added. The mixture was added to an aqueous solution of imidazole ionic liquid, ultrasonically dispersed to ensure uniform dispersion, and stirred for 8 h under N2 protection at 24 ℃. After the reaction was completed, the lower precipitate was collected by centrifugation, washed, filtered, freeze-dried, and ground to obtain the desired product. Composite corrosion inhibitor.

[0052] (4) Preparation of composite coating The preparation obtained in step (3) The composite corrosion inhibitor was added to the epoxy resin at a mass fraction of 0.15 wt%. The mixture was then mixed with BHC807-2 type curing agent at a mass ratio of 1.9:1, stirred for 5 min, and ultrasonicated for 10 min to obtain the composite coating. The composite coating was applied to a Q235 steel plate, allowed to stand for 13 h to allow it to self-level, and then cured in a 55 ℃ oven for 14 h to ensure full curing.

[0053] Example 4 (1) Preparation Nanosheets 1.2 g LiF was added to 29 mL of 8 mol / L HCl. After the reaction was complete, 1 g Ti3AlC2 was added to the reaction system, and the mixture was stirred at 36 °C for 30 h. After the reaction was completed, the precipitate was collected and washed with deionized water by centrifugation until the pH of the supernatant was >6, resulting in a multilayered product. ; will have multiple layers The solution was redispersed in distilled water and ultrasonically exfoliated under N2 atmosphere. The solution was centrifuged to collect the precipitate, which was then freeze-dried to obtain the desired product. Nanosheets.

[0054] (2) Preparation

[0055] 1 g of the product obtained in step (1) Nanosheets were dispersed in 60 mL of 0.04 mol / L Tris-HCl buffer solution, and 0.6 g of dopamine hydrochloride was added. The mixture was stirred at room temperature for 26 h, and the lower precipitate was freeze-dried to obtain... .

[0056] (3) Preparation

[0057] 70 mL of 0.3 mol / L 1-benzyl-3-methylimidazolium chloride was ultrasonically dispersed in deionized water to ensure uniform dispersion; 100 mg of the solution prepared in step (2) was then added. The mixture was added to an aqueous solution of imidazole ionic liquid, ultrasonically dispersed to ensure uniform dispersion, and stirred for 14 h under N2 protection at 26 ℃. After the reaction was completed, the lower precipitate was collected by centrifugation, washed, filtered, freeze-dried, and ground to obtain the desired product. Composite corrosion inhibitor.

[0058] (4) Preparation of composite coating The preparation obtained in step (3) The composite corrosion inhibitor was added to the epoxy resin at a mass fraction of 0.2 wt%. The mixture was then mixed with BHC807-2 type curing agent at a mass ratio of 2.0:1, stirred for 5 min, and ultrasonicated for 10 min to obtain the composite coating. The composite coating was applied to a Q235 steel plate, allowed to stand for 13 h to allow it to self-level, and then placed in an oven at 55 ℃ for 14 h to cure fully.

[0059] Example 5 (1) Preparation Nanosheets 2.0 g LiF was added to 22 mL of 7 mol / L HCl. After the reaction was complete, 1 g Ti3AlC2 was added to the reaction system, and the mixture was stirred at 40 °C for 28 h. After the reaction was completed, the precipitate was collected and washed with deionized water by centrifugation until the pH of the supernatant was >6, resulting in a multilayered product. ; will have multiple layers The solution was redispersed in distilled water and ultrasonically exfoliated under N2 atmosphere. The solution was centrifuged to collect the precipitate, which was then freeze-dried to obtain the desired product. Nanosheets.

[0060] (2) Preparation

[0061] 1 g of the product obtained in step (1) Nanosheets were dispersed in 40 mL of 0.05 mol / L Tris-HCl buffer solution, and 1.0 g of dopamine hydrochloride was added. The mixture was stirred at room temperature for 22 h, and the lower precipitate was freeze-dried to obtain... .

[0062] (3) Preparation

[0063] 30 mL of 0.7 mol / L 1-hydroxyethyl-3-methylimidazole chloride was ultrasonically dispersed in deionized water until uniformly dispersed; 100 mg of the solution prepared in step (2) was then added. The mixture was added to an aqueous solution of imidazole ionic liquid, ultrasonically dispersed to ensure uniform dispersion, and stirred for 10 h under N2 protection at 28 ℃. After the reaction was completed, the lower precipitate was collected by centrifugation, washed, filtered, freeze-dried, and ground to obtain the desired product. Composite corrosion inhibitor.

[0064] (4) Preparation of composite coating The preparation obtained in step (3) The composite corrosion inhibitor was added to the epoxy resin at a mass fraction of 0.25 wt%. The mixture was then mixed with BHC807-2 type curing agent at a mass ratio of 2.1:1, stirred for 5 min, and ultrasonicated for 10 min to obtain the composite coating. The composite coating was applied to a Q235 steel plate, allowed to stand for 13 h to allow it to self-level, and then placed in an oven at 55 ℃ for 14 h to cure fully.

[0065] Comparative Example 1 Epoxy resin and BHC807-2 curing agent were mixed at a mass ratio of 1.8:1, stirred for 5 min, and ultrasonicated for 10 min to obtain a composite coating. The composite coating was applied to a Q235 steel plate, allowed to stand for 13 h to allow it to self-level, and then placed in an oven at 55 ℃ for 14 h to cure fully.

[0066] Comparative Example 2 The preparation obtained in Example 2 Nanosheets were added to epoxy resin at a mass fraction of 0.1 wt%. The mixture was then mixed with BHC807-2 curing agent at a mass ratio of 1.8:1, stirred for 5 min, and sonicated for 10 min to obtain a composite coating. The composite coating was applied to a Q235 steel plate, allowed to stand for 13 h to allow it to self-level, and then cured in an oven at 55 ℃ for 14 h to ensure full curing.

[0067] Performance testing 1. Morphological characteristics Figure 2 The example shown is Ti3AlC2, Nanosheets and SEM image of the composite corrosion inhibitor. Figure 2It can be seen that the precursor Ti3AlC2 has a multi-layered stacked structure, which is further revealed after etching. It has a two-dimensional sheet-like structure, after being coated with polydopamine PDA polymers can be observed on the surface after grafting imidazole ionic liquids. The composite corrosion inhibitor exhibits a relatively smooth two-dimensional flake-like state, and the introduction of imidazole ionic liquid did not change this. The sheet-like structure.

[0068] 2. Structural characterization Figure 3 The preparation of Example 1 is shown. XPS spectra and elemental nuclear-level spectra of the composite corrosion inhibitor. Figure 3 As can be seen in (a) the five elements C, Ti, O, F and N are observed, and in (c) the peak at 455.9 eV corresponds to the Ti-N bond on the Ti 2p orbital, indicating that the PDA was successfully grafted onto the Ti-N bond. On the surface, the peaks at 400.1 eV and 400.9 eV in Figure (f) correspond to N-C3 and NH bonds, respectively, indicating that the imidazole ionic liquid was successfully introduced.

[0069] Figure 4 Example 1 is shown , and Zeta potential of the composite corrosion inhibitor. Figure 4 It can be seen that, due to The surface contains abundant oxygen-containing functional groups, with a Zeta potential of -33.27 mV; positively charged polydopamine is grafted onto... After surface treatment, The zeta potential value is 5.17 mV, changing from negative to positive; The zeta potential value was 10.9 mV, compared to The zeta potential increases due to the positively charged imidazole ionic liquid reacting with... A reaction occurred, and the graft reached... surface.

[0070] 3. Dispersion stability test In Example 1 and preparation The composite corrosion inhibitor was ultrasonically dispersed in water and epoxy resin, respectively. Photos were taken after standing for 0 h, 1 h, 3 h, and 72 h, as shown below. Figure 5 As shown. By Figure 5 It can be seen that in the first hour, and After ultrasonic treatment, it was completely and uniformly dispersed in water and epoxy resin. After 72 hours, It can maintain uniform dispersion in water, but due to the presence of hydrophilic end groups (-OH, -O, -F), it precipitates rapidly in epoxy resin. In contrast, Composite corrosion inhibitors showed superior performance compared to unmodified ones in epoxy resins. The stability is due to: on the one hand, after the PDA is modified, it makes... The interlayer spacing is significantly increased, effectively expanding the layers and avoiding the tight stacking of nanosheets; on the other hand, PDA is rich in active groups such as phenolic hydroxyl groups, which can generate strong intermolecular forces with epoxy resin molecules, making... It bonds more tightly to organic resins, enhancing interfacial compatibility. Therefore, Compare It is more suitable for use in epoxy coatings.

[0071] 4. Coating corrosion resistance test In Example 1 and preparation Composite corrosion inhibitors were added to epoxy resin at a mass fraction of 0.1 wt% and coated onto Q235 steel plates as experimental groups, while Q235 steel plates coated with pure epoxy resin served as blank control groups. The electrochemical impedance spectroscopy of the coated steel plates in the experimental and blank control groups after immersion in 3.5 wt% NaCl solution for different times was measured using an electrochemical workstation. A three-electrode system was used for the tests (coated steel plate as the working electrode, saturated calomel electrode as the reference electrode, and platinum sheet electrode as the counter electrode). The test results are as follows: Figure 6 As shown.

[0072] Depend on Figure 6 It can be seen that in the initial stage of immersion: the impedance value of the pure epoxy resin coating is 10. 7 Ω·cm 2 ;Add to The coating has an impedance value of 10. 8 Ω·cm 2 It is an order of magnitude higher than that of pure epoxy resin coating, which is due to It acts as a physical barrier in the coating, delaying the intrusion of corrosive media; while adding The impedance value of the coating with the composite corrosion inhibitor is 10. 10 Ω·cm 2 It is three orders of magnitude higher than pure epoxy resin coating, and higher than added... The coating is also an order of magnitude higher, due to the reaction of imidazole ionic liquid with polydopamine, grafted onto... The surface enhances the density of the coating and improves... Dispersion in epoxy coatings. Figure 6 It is evident that, with prolonged soaking time, the effects of pure epoxy resin coatings and added... The impedance values ​​of the coatings all decreased, while the added... The resistivity of the coating with the composite corrosion inhibitor remained essentially unchanged and remained at 10. 10 Ω·cm 2 As can be seen from the above, [the following was added] The coating of the composite corrosion inhibitor has good corrosion resistance.

[0073] For pure epoxy resin coatings and additives The composite corrosion inhibitor coating was subjected to a scratch test. The electrochemical impedance spectroscopy results of the scratch-coated steel plate after immersion in 3.5 wt% NaCl solution for different times are as follows: Figure 7 As shown.

[0074] Depend on Figure 7 It can be seen that, in the initial stage of immersion, the impedance value of the pure epoxy resin scratch coating is 10. 4 Ω·cm 2 As the immersion time increased, its impedance value decreased rapidly, indicating that the scratches on the pure epoxy resin coating underwent severe corrosion in the 3.5 wt% NaCl solution; Figure 7 It is evident that adding [something] during the initial soaking stage... The scratch resistance value of the composite corrosion inhibitor-coated coating is higher than that of the pure epoxy resin-coated coating. With prolonged immersion time, its resistance value decreases relatively slowly. Even after immersion in 3.5 wt% NaCl solution for 72 h, its resistance value remains higher than that of the pure epoxy resin-coated coating. This is because... The imidazole ionic liquid in the composite corrosion inhibitor is released from the composite corrosion inhibitor and chelates with iron ions at the corrosion site to form a slow-release film, which reduces the corrosion rate and inhibits the corrosion reaction.

[0075] 5. Coating performance tests of Examples 1-5 and Comparative Examples 1-2 Table 1. Coating performance test results of Examples 1-5 and Comparative Examples 1-2

[0076] The static water contact angles of the coatings prepared in Examples 1-5 and Comparative Examples 1-2 were tested, and the results are shown in Table 1. As can be seen from Table 1, compared to the pure epoxy resin coating prepared in Comparative Example 1 and the directly added coating prepared in Comparative Example 2... The coating, prepared in Examples 1-5, with added... The coating of the composite corrosion inhibitor has better hydrophobicity, indicating that an appropriate amount... Composite corrosion inhibitors can effectively improve the surface hydrophobicity of coatings.

[0077] The adhesion strength of the coatings prepared in Examples 1-5 and Comparative Examples 1-2 was tested after immersion in 3.5 wt% NaCl solution for 110 days, and the results are shown in Table 1. As can be seen from Table 1, the pure epoxy resin coating prepared in Comparative Example 1 exhibited the lowest adhesion strength, indicating that the coating underwent significant degradation due to water absorption and interfacial weakening; compared to Comparative Example 1, the coating prepared in Comparative Example 2 with added... The adhesion strength of the coating was improved; compared with Comparative Example 2, the additives prepared in Examples 1-5 showed improved adhesion strength. The coating with the composite corrosion inhibitor exhibits higher adhesion strength.

[0078] The coatings prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to scratch and salt spray resistance tests, and the results are shown in Table 1. It should be noted that the salt spray resistance test method was as follows: according to GB / T 10125-2021 salt spray test standard, a 5% sodium chloride neutral solution was used, at 35℃±2℃, and a pH value of 6.5~7.2. As can be seen from Table 1, the pure epoxy resin coating prepared in Comparative Example 1 had the shortest salt spray resistance time, while the coating prepared in Comparative Example 2 with added... The salt spray resistance time of the coating prepared in Examples 1-5 was increased compared to Comparative Example 1. The coating with the composite corrosion inhibitor has a longer salt spray resistance time compared to Comparative Examples 1-2, demonstrating a long-lasting and highly effective anti-corrosion effect.

Claims

1. A method for preparing a composite corrosion inhibitor, characterized in that, Includes the following steps: preparation :Will Nanosheets were dispersed in Tris-HCl buffer solution, and dopamine hydrochloride was added to allow the dopamine hydrochloride to... A polymerization reaction occurs on the surface of the nanosheets to obtain... ; preparation :Will Add to an aqueous solution of imidazole ionic liquid, disperse evenly, and stir under N2 protection to obtain... Composite corrosion inhibitor.

2. As described in claim 1 A method for preparing a composite corrosion inhibitor, characterized in that, The preparation In the steps, The mass ratio of nanosheets to dopamine hydrochloride is 1:(0.6~1).

3. As described in claim 1 A method for preparing a composite corrosion inhibitor, characterized in that, The preparation In this procedure, the concentration of the Tris-HCl buffer solution is 0.01~0.05 mol / L.

4. As described in claim 1 A method for preparing a composite corrosion inhibitor, characterized in that, The preparation In this step, the polymerization reaction is carried out at room temperature for 20-28 hours.

5. The method according to claim 1 A method for preparing a composite corrosion inhibitor, characterized in that, The preparation In this step, the imidazole ionic liquid is selected from any one of 1-allyl-3-methylimidazolium chloride, 1-aminoethyl-3-methylimidazolium bromide, 1-hydroxyethyl-3-methylimidazolium chloride, and 1-benzyl-3-methylimidazolium chloride.

6. As described in claim 1 or 5 A method for preparing a composite corrosion inhibitor, characterized in that, The preparation In this procedure, the concentration of the imidazole ionic liquid aqueous solution is 0.3~0.7 mol / L. The ratio of the mass of the ion to the molar mass of the imidazole ionic liquid is 100:(21~25) mg / mmol.

7. The method according to claim 1 A method for preparing a composite corrosion inhibitor, characterized in that, The preparation In this process, the reaction temperature is 20~28 ℃ and the reaction time is 8~14 h.

8. Composite corrosion inhibitor, characterized in that, By any one of claims 1-7 The composite corrosion inhibitor was prepared using a specific method.

9. A composite coating, characterized in that, It includes component A and component B, wherein component A comprises epoxy resin and the product described in claim 8. The composite corrosion inhibitor, component B includes a curing agent, and the mass ratio of component A to component B is (1.7~2.1):1, wherein component A contains... The mass fraction of the composite corrosion inhibitor is 0.05~0.25 wt%.

10. The application of the composite coating according to claim 9 in corrosion protection of metal surfaces, characterized in that, After the components A and B of the composite coating are mixed evenly, the mixture is applied to the metal surface and allowed to stand to allow the coated composite coating to self-level before curing at 55°C.

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