Epoxy coating and method for producing the same

Abstract

The present disclosure provides an epoxy coating and a preparation method thereof, the preparation method comprising the following steps: Step 1, preparation of nano-container mesoporous ZSM-5; Step 2, assembly of pH stimulus-responsive intelligent nano-container, mainly including vacuum adsorption of 8-HQ, electrostatic adsorption of PEI and PSS, ion exchange of Ce 3+ and electrostatic adsorption of PSS; Step 3, preparation of an epoxy coating on an aluminum alloy surface. The mesoporous ZSM-5 of the present disclosure itself has a pH stimulus-responsive performance, and after the assembly of the intelligent nano-container, the release amount of the corrosion inhibitor and the fluorescent probe under neutral conditions can be extremely low, the release amount of Ce 3+ is about 1.54E-2 mmol, and the release amount of 8-HQ is about 1.58E-2 mmol, which changes the major defect that ZSM-5 releases a large amount of corrosion inhibitor under neutral conditions, and the prepared epoxy coating has the dual functions of self-warning and self-repair.

Description

Technical Field

[0001] This disclosure relates to the field of chemistry, and more specifically, to epoxy coatings and methods for their preparation. Background Technology

[0002] Currently, there are numerous studies and reports both domestically and internationally on metal surface coatings enhanced by intelligent nanocontainers. Most of these studies involve adding nanocontainers containing corrosion inhibitors to a polymer matrix, and then preparing an anti-corrosion coating on the metal surface. Chen et al. used reduced-pressure adsorption and layer-by-layer self-assembly techniques to simultaneously load 8-hydroxyquinoline and benzotriazole onto mesoporous silica nanoparticles to prepare corrosion inhibitor composite nanocontainers, which were then added to an epoxy coating. Electrochemical tests showed that compared to loading only one corrosion inhibitor into the nanocontainer, simultaneously loading two corrosion inhibitors significantly improved the corrosion inhibition effect. Mohammadloo et al. synthesized conventional spherical capsules filled with linseed oil containing cerium acetate and 8-hydroxyquinoline in an oil-in-water emulsion via in-situ polymerization, and dispersed the microcapsules in an epoxy resin matrix. Under salt spray test conditions, the coating containing 8-hydroxyquinoline microcapsules exhibited better corrosion resistance after immersion for 168 hours compared to the blank sample. Exbraya et al. embedded a rhodamine B derivative into mesoporous silica nanocapsules, dissolved these capsules in polyvinyl butyral (PVB), and prepared a polymer / fluorescent probe composite coating. The coating was then tested on a 304 stainless steel substrate. When corrosion occurred, Fe... 3+ The corrosion inhibitor diffuses into the core through a porous silica capsule shell and chelates with Rhodamine B derivatives, thus providing a corrosion early warning function. Compared with pH-responsive fluorescent probes, corrosion ion-responsive fluorescent probes have better specificity and can predict specific types of corrosion. The coatings reported above either lack stimulus-responsive properties, have not undergone systematic research on the controlled release of corrosion inhibitors, or only possess one function. Therefore, intelligent coatings that integrate both stimulus-responsive properties and functionality are of great significance. Summary of the Invention

[0003] The purpose of this disclosure is to provide an intelligent epoxy coating with integrated self-warning and self-healing functions and its preparation method, so as to solve the problems mentioned in the background art.

[0004] This disclosure provides a method for preparing an epoxy coating, comprising the following steps:

[0005] Step 1, Preparation of mesoporous ZSM-5 nanocontainer: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was added dropwise under stirring. Sodium aluminate was then added, and the mixture was stirred evenly before being placed in a reaction vessel for synthesis. After the reaction, the mixture was centrifuged and dried to obtain ZSM-5 molecular sieve powder. The prepared ZSM-5 molecular sieve powder was then calcined for the first time to remove the template agent tetrapropylammonium hydroxide. After that, the ZSM-5 molecular sieve powder was dispersed in Na2CO3 solution and treated in a water bath, followed by an ice bath treatment. The suspension was then centrifuged, washed, and dried. The product ZSM-5 molecular sieve powder was then calcined for the second time to obtain desilicationized mesoporous ZSM-5 molecular sieve powder.

[0006] Step 2, Assembly of the nanocontainer: 8-hydroxyquinoline was dissolved in ethanol to obtain an 8-hydroxyquinoline solution. Mesoporous ZSM-5 molecular sieve powder prepared in Step 1 was added to the 8-hydroxyquinoline solution, stirred, and then ultrasonically dispersed. The resulting mixed solution was placed in a low-pressure environment below 5000 Pa to allow 8-hydroxyquinoline to adsorb onto ZSM-5. After adsorption, the mixed solution was centrifuged, washed with deionized water, and freeze-dried to obtain the product 8-hydroxyquinoline-ZSM-5. 8-hydroxyquinoline-ZSM-5 was dispersed in deionized water and ultrasonically dispersed. Polyethyleneimine was added under stirring conditions, and the mixture was centrifuged, washed with deionized water, and dried to obtain 8-hydroxyquinoline-ZSM-5 / polyethyleneimine. 8-hydroxyquinoline-ZSM-5 / polyethyleneimine was dispersed in deionized water and ultrasonically dispersed... Disperse the mixture, add sodium polystyrene sulfonate, stir, centrifuge the mixture, wash with deionized water, and dry to obtain 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate; immerse 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate in Ce(NO3)3 solution, stir continuously, filter the obtained sample, wash with distilled water, and dry to obtain product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce; disperse 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce in deionized water, ultrasonically disperse evenly, add polyethyleneimine under stirring, stir, centrifuge the mixture, wash with deionized water, and dry to obtain 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce / polyethyleneimine;

[0007] Step 3: Preparation of intelligent epoxy resin layer on aluminum alloy surface. The product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce / polyethyleneimine obtained in step 2 is ultrasonically dispersed in epoxy resin. After adding curing agent and stirring, it is then coated on aluminum alloy surface and cured to form epoxy coating.

[0008] In some embodiments, in step 1, the molar ratio of tetraethyl orthosilicate, tetrapropylammonium hydroxide, sodium aluminate, and deionized water is 1:0.3–0.4:0.02:90–110, the stirring time is 12–15 hours, the temperature of the reactor is 120–180°C, and the reaction time is 12–24 hours; the concentration of Na₂CO₃ solution is 0.5–0.7 mol / L, the ratio of ZSM-5 molecular sieve powder to Na₂CO₃ solution is 0.5–1.5 g:50–150 mL, the water bath temperature is 60–70°C; the calcination temperature for the first and second calcinations is 500–600°C, the first calcination time is 5–7 hours, and the second calcination time is 4–5 hours.

[0009] In some embodiments, in step 2, the volume concentration of the ethanol solution is 75%, the concentration of the 8-hydroxyquinoline solution is 0.1 mol / L, and the ratio of anhydrous ethanol, 8-hydroxyquinoline, and mesoporous ZSM-5 molecular sieve powder is 30 ml–40 ml : 0.581–0.775 g : 0.2 g. The stirring time is 0.5–1 h, the sonication time is 10–15 min, and the settling time is 0.5–1 h. After settling, the mixed solution is centrifuged at 8000–10000 r / min for 5–10 min. After centrifugation, the supernatant is removed, the resulting precipitate is washed with deionized water, dried in a refrigerator, and then refrigerated. The product 8-hydroxyquinoline-ZSM-5 was obtained by drying at a temperature of -5 to 0℃ for 6 to 12 hours. Subsequently, the ratio of 8-hydroxyquinoline-ZSM-5, deionized water, and polyethyleneimine was 200 mg: 100–120 ml: 60–72 mg. Polyethyleneimine was first dissolved in a portion of the deionized water, and then 8-hydroxyquinoline-ZSM-5 was ultrasonically dispersed in the remaining deionized water for 5 minutes. Under stirring, the prepared polyethyleneimine solution was added dropwise, and after stirring for 10 minutes, the mixture was centrifuged to remove the supernatant. The resulting precipitate was washed with deionized water and dried to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine. The ratio of 8-hydroxyquinoline-ZSM-5 / polyethyleneimine, deionized water, and sodium polystyrene sulfonate was 0.2 g: 100–120 mL: 60–72 mg. First, sodium polystyrene sulfonate was dissolved in a portion of the deionized water. Then, 8-hydroxyquinoline-ZSM-5 / polyethyleneimine was ultrasonically dispersed in the remaining deionized water for 5 min. Under stirring, the prepared polyethyleneimine solution was added dropwise. After stirring for 10 min, the mixture was centrifuged, the supernatant was removed, and the resulting precipitate was washed with deionized water and dried to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate. Subsequently, 8-hydroxyquinoline-ZSM-5 / polyethyleneimine… The ratio of amine / sodium polystyrene sulfonate, Ce(NO3)3, and deionized water was 50 mg: 221.14–353.824 mg: 5 ml–8 ml. Ce(NO3)3 was first dissolved in deionized water, then 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate was added and the mixture was stirred continuously for 24 hours. After mixing, the sample was filtered, washed with distilled water, and dried at 80°C to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce. Subsequently, the ratio of 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce, polyethyleneimine, and deionized water was 0.2g: 60-72mg: 100-120ml. First, dissolve polyethyleneimine in a portion of deionized water. Then, ultrasonically disperse 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce in the remaining deionized water for 5 minutes. Under stirring, add the prepared polyethyleneimine solution dropwise. After stirring for 10 minutes, centrifuge the mixture, remove the supernatant, wash the resulting precipitate with deionized water, and dry to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate / sodium polystyrene sulfonate-Ce / polyethyleneimine.

[0010] In some embodiments, in step 3, the ratio of tert-butanol, epoxy resin, curing agent, and nanocontainer 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce / polyethyleneimine is 6-8 ml: 10 g: 3 g: 0.3 g. First, tert-butanol is added to the nanocontainer, and the mixture is stirred for 20-30 min and sonicated for 5 min. Then, epoxy resin is added and stirred evenly for 20-30 min and sonicated for 5 min. Finally, curing agent is added and stirred for 5-15 min. The mixture is placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1-2 min. Then, a coating is prepared by scraping it onto the aluminum alloy surface. The coated aluminum alloy sample is placed in a drying oven and cured at 80-90°C for 12-18 h to obtain the epoxy coating.

[0011] In some embodiments, the curing agent includes at least one of ethylenediamine and triethylenetetramine.

[0012] In some embodiments, this disclosure also provides an epoxy coating prepared by the above-described method for preparing epoxy coatings.

[0013] Compared with the prior art, the beneficial effects of this disclosure are:

[0014] 1. This intelligent epoxy coating has the advantages of self-early warning and self-repair functions, pH stimulation response performance, high corrosion inhibitor loading, short preparation cycle and green environmental protection.

[0015] 2. The intelligent nanocontainer exhibits pH-responsive properties, specifically manifested in low corrosion inhibitor release (Ce) under neutral conditions. 3+ The release amount of 1.54E-2 mmol; the release amount of 8-HQ is approximately 1.58E-2 mmol) has the advantage of Ce 3+ The relationship between the release amounts of both alkaline and acidic corrosion inhibitors and 8-HQ is: alkaline > acidic > neutral; this changes the major defect of ZSM-5 releasing a large amount of corrosion inhibitor under neutral conditions.

[0016] 3. The intelligent nanocontainers in the epoxy coating prepared using the method disclosed herein are coffin-shaped (coffin-shaped intelligent containers have a large specific surface area and Ce...). 3+ It has advantages such as higher loading rate of 8-HQ coating, side length range of 2.8 to 3 micrometers, thickness range of 0.8 to 1 micrometer, and coating thickness of about 200 micrometers. Attached Figure Description

[0017] Figure 1 A schematic flowchart of a method for preparing an epoxy coating according to some embodiments of the present disclosure is shown.

[0018] Figure 2 The fluorescence emission spectra of epoxy coatings according to some embodiments of the present disclosure during a static corrosion process are shown.

[0019] Figure 3 Nyquist plots of epoxy coatings according to some embodiments of the present disclosure during a static corrosion process are shown.

[0020] Figures 4a to 4d 8-HQ and Ce are shown respectively according to some embodiments of the present disclosure. 3+ Release curves before and after encapsulation.

[0021] Figure 5a A scanning electron microscope (SEM) image of a cross-section of a smart nanocontainer according to some embodiments of the present disclosure is shown.

[0022] Figure 5b SEM images of cross-sections of coatings according to some embodiments of the present disclosure are shown. Detailed Implementation

[0023] The following examples are intended to enable those skilled in the art to gain a more comprehensive understanding of this disclosure, but do not limit this disclosure in any way. It should be understood that, unless otherwise specified, the reagents used in this disclosure are all commonly used reagents in the art.

[0024] This disclosure provides an epoxy coating with integrated self-warning and self-healing functions and its preparation method. Figure 1 A schematic flowchart of a method for preparing an epoxy coating according to some embodiments of the present disclosure is shown, the method comprising the following steps:

[0025] Step 1, Preparation of mesoporous ZSM-5 nanocontainers: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was slowly added dropwise under stirring. Finally, sodium aluminate was added, and after stirring evenly, it was placed in a high-temperature and high-pressure reactor for synthesis reaction. After a certain reaction time, it was centrifuged and dried to prepare ZSM-5 molecular sieve powder. Then, the prepared ZSM-5 molecular sieve powder was calcined for the first time to remove the template agent tetrapropylammonium hydroxide. After that, the ZSM-5 molecular sieve powder was dispersed in Na2CO3 solution and treated in a water bath, followed by ice bath treatment. The suspension was then centrifuged, washed, and dried. Finally, the product ZSM-5 powder was calcined for the second time in a muffle furnace to obtain desilicationized mesoporous ZSM-5 molecular sieve powder.

[0026] Step 2, Assembly of the Smart Nanocontainer: 8-hydroxyquinoline (8-HQ) was dissolved in an ethanol solution to obtain an 8-HQ solution. Mesoporous ZSM-5 molecular sieve prepared in Step 1 was added to the 8-HQ solution, and the mixture was stirred and then ultrasonically dispersed. The mixture was placed in a low-pressure environment to allow 8-HQ to adsorb onto ZSM-5. After adsorption, the mixture was centrifuged, washed with deionized water, and freeze-dried to obtain the product 8-HQ-ZSM-5. 8-HQ-ZSM-5 was dispersed in deionized water and ultrasonically dispersed. Polyethyleneimine (PEI) was slowly added under stirring conditions. After stirring, the mixture was centrifuged, washed with deionized water, and dried to obtain 8-HQ-ZSM-5 / PEI. 8-HQ-ZSM-5 / PEI was dispersed in deionized water and ultrasonically dispersed. Sodium polystyrene sulfonate (PSS) was slowly added, and the mixture was stirred. The solution was then centrifuged, washed with deionized water, and dried to obtain 8-HQ-ZSM-5 / PEI / PSS. 8-HQ-ZSM-5 / PEI / PSS was then immersed in Ce(NO3)3 solution with continuous stirring. The resulting sample was filtered, washed with distilled water, and dried to obtain the product 8-HQ-ZSM-5 / PEI / PSS-Ce. 8-HQ-ZSM-5 / PEI / PSS-Ce was then dispersed in deionized water and ultrasonically dispersed until homogeneous. PEI was slowly added under stirring conditions. The mixture was then centrifuged, washed with deionized water, and dried to obtain 8-HQ-ZSM-5 / PEI / PSS-Ce / PEI.

[0027] Step 3: Preparation of intelligent epoxy resin layer on aluminum alloy surface. The product obtained in step 2 is ultrasonically dispersed in epoxy resin, a curing agent is added and stirred, the resin is coated on the aluminum alloy surface with a coating rod, and then cured in a drying oven to form intelligent epoxy coating.

[0028] In step 1, the molar ratio of tetraethyl orthosilicate, tetrapropylammonium hydroxide, sodium aluminate, and deionized water is 1:0.3–0.4:0.02:90–110, the stirring time is 12–15 hours, the temperature of the high-temperature and high-pressure reactor is 120–180℃, and the reaction time is 12–24 hours; the concentration of Na2CO3 solution is 0.5–0.7 mol / L, the ratio of ZSM-5 molecular sieve powder to Na2CO3 solution is 0.5–1.5 g:50–150 mL, and the water bath temperature is 60–70℃; the calcination temperature for the first and second calcinations is 500–600℃, the first calcination time is 5–7 hours, and the second calcination time is 4–5 hours.

[0029] In step 2, the volume concentration of the ethanol solution is 75%, and the ratio of anhydrous ethanol, 8-HQ, and ZSM-5 is 30–40 ml: 0.581–0.775 g: 0.2 g. The stirring time is 0.5–1 h, the sonication time is 10–15 min, the low-pressure environment is below 5000 Pa, and the settling time is 0.5–1 h. After settling, the mixed solution is centrifuged at 8000–10000 r / min for 5–10 min. After centrifugation, the supernatant is removed, the precipitate is washed with deionized water, and dried in a refrigerator at -5–0 °C for 6–12 h to obtain the product 8-HQ-ZSM-5. Subsequently, the ratio of 8-HQ-ZSM-5, deionized water, and PEI was 0.2g:100-120mL:60-72mg. PEI was first dissolved in a portion of the deionized water, and then 8-HQ-ZSM-5 was ultrasonically dispersed in the remaining deionized water for 5 minutes. Under stirring conditions, the prepared PEI solution was slowly added dropwise using a dropper. After stirring for 10 minutes, the mixed solution was centrifuged to remove the supernatant. The resulting precipitate was washed with deionized water and dried to obtain the product 8-HQ-ZSM-5 / PEI. The centrifugation speed was 8000-10000 r / min, and the centrifugation time was 5-10 minutes. The ratio of product 8-HQ-ZSM-5 / PEI, deionized water, and PSS was 0.2 g: 100–120 mL: 60–72 mg. First, PSS was dissolved in a portion of deionized water. Then, 8-HQ-ZSM-5 / PEI was ultrasonically dispersed in the deionized water for 5 min. Under stirring, the prepared PEI solution was slowly added dropwise using a dropper. After stirring for 10 min, the mixture was centrifuged, the supernatant was removed, and the resulting precipitate was washed with deionized water and dried to obtain product 8-HQ-ZSM-5 / PEI / PSS. The centrifugation speed was 800 rpm. Centrifuge at 0–10000 r / min for 5–10 min; then, the ratio of 8-HQ-ZSM-5 / PEI / PSS, Ce(NO3)3 and deionized water is 50 mg: 221.14–353.824 mg: 5–8 ml. First, dissolve Ce(NO3)3 in deionized water, then add 8-HQ-ZSM-5 / PEI / PSS and stir continuously for 24 h. After mixing, filter the obtained sample, wash with distilled water, and dry at 80 °C to obtain the product 8-HQ-ZSM-5 / PEI / PSS-Ce.Subsequently, the ratio of 8-HQ-ZSM-5 / PEI / PSS-Ce, PEI, and deionized water was 0.2g:60-72mg:100-120ml. First, PEI was dissolved in a portion of the deionized water. Then, 8-HQ-ZSM-5 / PEI / PSS-Ce was ultrasonically dispersed in the remaining deionized water for 5 minutes. Under stirring, the prepared PEI solution was slowly added dropwise using a dropper. The mixture was stirred for 10 minutes. The mixture was centrifuged, and the supernatant was removed. The resulting precipitate was washed with deionized water and dried to obtain the product 8-HQ-ZSM-5 / PEI / PSS / PSS-Ce / PEI. The centrifugation speed was 8000-10000 r / min, and the centrifugation time was 5-10 minutes.

[0030] In step 3, the ratio of tert-butanol, epoxy resin, curing agent (amine curing agent, such as ethylenediamine, triethylenetetramine, etc.) and nanocontainer 8-HQ-ZSM-5 / PEI / PSS / PSS-Ce / PEI is 6-8 ml: 10 g: 3 g: 0.3 g. After adding tert-butanol to the smart nanocontainer, the stirring time is 30 min, followed by ultrasonication for 5 min. Then, epoxy resin is added and stirred evenly for 20-30 min, followed by ultrasonication for 5 min. Finally, the curing agent is added and stirred for 5-15 min. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1-2 min. A coating (approximately 200 μm thick) is then manually applied to the pre-treated aluminum alloy surface (anodized and cleaned for easier coating) using a scraper. Place the epoxy-coated aluminum alloy sample into a drying oven and cure it at 80-90℃ for 12-18 hours.

[0031] The self-warning effect of this disclosure is caused by the fluorescent probe 8-HQ, which reacts with Al during the corrosion process. 3+ Chelation occurs, forming Alq3, which exhibits a yellow-green fluorescence under ultraviolet light. The self-healing property is due to the corrosion inhibitor Ce. 3+ Caused by Ce during the corrosion process 3+ Combining with OH-, CeO2 is eventually generated at the corrosion micro-area, achieving a self-healing effect. In the first electrostatic adsorption of PEI, the role of PEI adsorption is to adjust the potential of the 8-HQ-ZSM-5 nanocontainer to positive; the role of PSS adsorption is to remove Na from the PSS. + With Ce 3+ The exchange takes place; the second electrostatic adsorption of PEI serves as a seal, ensuring the safety of 8-HQ and Ce. 3+ No leakage.

[0032] The following description, in conjunction with specific embodiments, will provide a better understanding of the solutions disclosed herein.

[0033] Example 1

[0034] A method for preparing an epoxy coating with integrated self-warning and self-healing functions, the method comprising the following steps:

[0035] Step 1, Preparation of the mesoporous ZSM-5 nanocontainer.

[0036] Preparation of S1, ZSM-5 molecular sieve powder: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was slowly added dropwise under stirring. Finally, sodium aluminate and deionized water were added. The molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate and deionized water was 1:0.3:0.02:90. After stirring for 12 hours, the mixture was placed in a high-temperature and high-pressure reactor at 120℃ for 24 hours for synthesis reaction. Then, the solution after reaction was centrifuged, washed and dried, and calcined at 500℃ for 7 hours to remove the template agent, thus obtaining ZSM-5 powder.

[0037] S2, Preparation of mesoporous ZSM-5 molecular sieve powder: 0.5g ZSM-5 powder was dispersed in 50mL of 0.5mol / L Na2CO3, and the mixture was stirred at 60℃ for 30min, then treated in an ice bath for 10min. The resulting precipitate was centrifuged, washed with deionized water, dried, and calcined at 500℃ for 5 hours to obtain desiliconized ZSM-5 molecular sieve powder.

[0038] Step 2, Assembly of the smart nanocontainer.

[0039] Preparation of S1, 8-HQ-ZSM-5: 0.581 g of 8-HQ was dissolved in a 75% ethanol solution to prepare 30 ml of 8-HQ solution. 0.2 g of desilicationized ZSM-5 was added to the 8-HQ solution. The mixture was stirred for 30 min and then sonicated for 10 min to ensure uniform dispersion of 8-HQ. The mixture was then placed under low pressure (below 5000 Pa) for 30 min to allow 8-HQ to adsorb onto ZSM-5. After adsorption, the product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and freeze-dried at -5℃ for 6 h to obtain the product 8-HQ-ZSM-5.

[0040] Preparation of S2, 8-HQ-ZSM-5 / PEI: First, 60 mg of PEI was dissolved in 30 mL of deionized water to obtain a PEI solution. Then, 0.2 g of 8-HQ-ZSM-5 was dispersed in 70 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, the prepared PEI solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 80 °C for 6 h to obtain the product 8-HQ-ZSM-5 / PEI.

[0041] Preparation of S3, 8-HQ-ZSM-5 / PEI / PSS: First, 60 mg of PSS was dissolved in 30 mL of deionized water to obtain a PSS solution. 0.2 g of 8-HQ-ZSM-5 / PEI was dispersed in 70 mL of deionized water and sonicated for 5 min. The prepared PSS solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 80 °C for 6 h to obtain the product 8-HQ-ZSM-5 / PEI / PSS.

[0042] Preparation of S4, 8-HQ-ZSM-5 / PEI / PSS-Ce: First, 221.14 mg of Ce(NO3)3 was dissolved in 5 ml of deionized water to obtain a Ce(NO3)3 solution. Then, 50 mg of 8-HQ-ZSM-5 / PEI / PSS was immersed in the Ce(NO3)3 solution, and the mixture was stirred continuously for 24 h. After mixing, the sample was filtered, washed with distilled water, and dried at 80 °C for 6 h. The product 8-HQ-ZSM-5 / PEI / PSS-Ce was obtained.

[0043] Preparation of S5, 8-HQ-ZSM-5 / PEI / PSS-Ce / PEI: 0.2 g of 8-HQ-ZSM-5 / PEI / PSS-Ce was dispersed in 100 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, 30 mL of 2 mg / mL PEI was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 80 °C for 6 h to obtain the product 8-HQ-ZSM-5 / PEI / PSS-Ce / PEI.

[0044] Step 3: Preparation of the intelligent epoxy resin layer on the aluminum alloy surface. The ratio of tert-butanol, epoxy resin, curing agent ethylenediamine, and nanocontainer is 6ml:10g:3g:0.3g. First, the product obtained in Step 2 is added to tert-butanol, and the mixture is stirred for 30 minutes and sonicated for 5 minutes. Then, epoxy resin is added and stirred evenly for 30 minutes and sonicated for 5 minutes. Finally, the curing agent is added and stirred for 15 minutes. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1 minute. The coating is then manually applied to the pretreated aluminum alloy surface using a scraper, with a thickness of approximately 200μm. The epoxy-coated aluminum alloy sample is placed in a drying oven and cured at 80℃ for 18 hours.

[0045] Example 2

[0046] A method for preparing an epoxy coating with integrated self-warning and self-healing functions, the method comprising the following steps:

[0047] Step 1, Preparation of the mesoporous ZSM-5 nanocontainer.

[0048] Preparation of S1, ZSM-5 molecular sieve powder: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was slowly added dropwise under stirring. Finally, sodium aluminate and deionized water were added. The molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate and deionized water was 1:0.35:0.02:100. After stirring for 18 hours, the mixture was placed in a high-temperature and high-pressure reactor at 150℃ for 24 hours for synthesis reaction. Then, the reaction solution was centrifuged, washed and dried, and calcined at 550℃ for 6 hours to remove the template agent, thus obtaining ZSM-5 powder.

[0049] S2, Preparation of mesoporous ZSM-5 molecular sieve powder: 1g of ZSM-5 powder was dispersed in 100mL of 0.6mol / L Na2CO3, and the mixture was stirred at 65℃ for 30min, followed by ice bath treatment for 10min. The resulting precipitate was centrifuged, washed with deionized water, dried, and calcined at 550℃ for 4.5h to obtain desiliconized ZSM-5 molecular sieve powder.

[0050] Step 2, Assembly of the smart nanocontainer.

[0051] Preparation of S1, 8-HQ-ZSM-5: 0.678 g of 8-HQ was dissolved in a 75% ethanol solution to prepare 35 ml of 8-HQ solution. 0.2 g of desilicationized ZSM-5 was added to the 8-HQ solution. The mixture was stirred for 45 min and then sonicated for 13 min to ensure uniform dispersion of 8-HQ. The mixture was then placed under low pressure (below 5000 Pa) for 45 min to allow 8-HQ to adsorb onto ZSM-5. After adsorption, the product was separated by centrifugation at 9000 r / min for 9 min, washed with deionized water, and freeze-dried at -3℃ for 9 h to obtain the product 8-HQ-ZSM-5.

[0052] Preparation of S2, 8-HQ-ZSM-5 / PEI: First, 66 mg of PEI was dissolved in 33 mL of deionized water to obtain a PEI solution. Then, 0.2 g of 8-HQ-ZSM-5 was dispersed in 77 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, the prepared PEI solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 85 °C for 5 h to obtain the product 8-HQ-ZSM-5 / PEI.

[0053] Preparation of S3, 8-HQ-ZSM-5 / PEI / PSS: First, 66 mg of PSS was dissolved in 33 mL of deionized water to obtain a PSS solution. 0.2 g of 8-HQ-ZSM-5 / PEI was dispersed in 77 mL of deionized water and sonicated for 5 min. The prepared PSS solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 85 °C for 5 h to obtain the product 8-HQ-ZSM-5 / PEI / PSS.

[0054] Preparation of S4, 8-HQ-ZSM-5 / PEI / PSS-Ce: First, 287.48 mg of Ce(NO3)3 was dissolved in 6.5 ml of deionized water to obtain a Ce(NO3)3 solution. Then, 50 mg of 8-HQ-ZSM-5 / PEI / PSS was immersed in the Ce(NO3)3 solution, and the mixture was stirred continuously for 24 h. After mixing, the sample was filtered, washed with distilled water, and dried at 85 °C for 5 h. The product 8-HQ-ZSM-5 / PEI / PSS-Ce was obtained.

[0055] Preparation of S5, 8-HQ-ZSM-5 / PEI / PSS-Ce / PEI: First, 66 mg of PEI was dissolved in 33 mL of deionized water to obtain a PEI solution. Then, 0.2 g of 8-HQ-ZSM-5 / PEI / PSS-Ce was dispersed in 77 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, the prepared PEI solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 85 °C for 5 h to obtain the product 8-HQ-ZSM-5 / PEI.

[0056] Step 3: Preparation of the intelligent epoxy resin layer on the aluminum alloy surface. The ratio of tert-butanol, epoxy resin, curing agent ethylenediamine, and nanocontainer is 7ml:10g:3g:0.3g. First, the product obtained in Step 2 is added to tert-butanol, and the mixture is stirred for 25 minutes followed by ultrasonication for 5 minutes. Then, epoxy resin is added and stirred evenly for 25 minutes, followed by ultrasonication for 5 minutes. Finally, the curing agent is added and stirred for 10 minutes. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1.5 minutes. The coating is then manually applied to the pre-treated aluminum alloy surface using a scraper, with a thickness of approximately 200μm. The epoxy-coated aluminum alloy sample is placed in a drying oven and cured at 85℃ for 15 hours.

[0057] Example 3

[0058] A method for preparing an epoxy coating with integrated self-warning and self-healing functions, the method comprising the following steps:

[0059] Step 1, Preparation of the mesoporous ZSM-5 nanocontainer.

[0060] Preparation of S1, ZSM-5 molecular sieve powder: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was slowly added dropwise under stirring. Finally, sodium aluminate and deionized water were added. The molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate and deionized water was 1:0.4:0.02:110. After stirring for 24 hours, the mixture was placed in a high-temperature and high-pressure reactor at 180℃ for 12 hours for synthesis reaction. Then, the reaction solution was centrifuged, washed and dried, and calcined at 600℃ for 5 hours to remove the template agent, thus obtaining ZSM-5 powder.

[0061] S2, Preparation of mesoporous ZSM-5 molecular sieve powder: 1.5g ZSM-5 powder was dispersed in 150mL of 0.7mol / L Na2CO3, and the mixture was stirred at 70℃ for 30min, followed by ice bath treatment for 10min. The resulting precipitate was centrifuged, washed with deionized water, dried, and calcined at 600℃ for 4 hours to obtain desiliconized ZSM-5 molecular sieve powder.

[0062] Step 2, Assembly of the smart nanocontainer.

[0063] Preparation of S1, 8-HQ-ZSM-5: 0.775 g of 8-HQ was dissolved in a 75% ethanol solution to prepare 40 ml of 8-HQ solution. 0.2 g of desilicationized ZSM-5 was added to the 8-HQ solution. The mixture was stirred for 60 min and then sonicated for 10 min to ensure uniform dispersion of 8-HQ. The mixture was then placed under low pressure (below 5000 Pa) for 30 min to allow 8-HQ to adsorb onto ZSM-5. After adsorption, the product was separated by centrifugation at 10000 r / min for 5 min, washed with deionized water, and freeze-dried at 0 °C for 12 h to obtain the product 8-HQ-ZSM-5.

[0064] Preparation of S2, 8-HQ-ZSM-5 / PEI: First, 72 mg of PEI was dissolved in 36 mL of deionized water to obtain a PEI solution. Then, 0.2 g of 8-HQ-ZSM-5 was dispersed in 84 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, the prepared PEI solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 10000 r / min for 5 min, washed with deionized water, and dried at 90 °C for 2 h to obtain the product 8-HQ-ZSM-5 / PEI.

[0065] Preparation of S3, 8-HQ-ZSM-5 / PEI / PSS: First, 72 mg of PSS was dissolved in 36 mL of deionized water to obtain a PSS solution. 0.2 g of 8-HQ-ZSM-5 / PEI was dispersed in 84 mL of deionized water and sonicated for 5 min. The prepared PSS solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 10000 r / min for 5 min, washed with deionized water, and dried at 90 °C for 2 h to obtain the product 8-HQ-ZSM-5 / PEI / PSS.

[0066] Preparation of S4, 8-HQ-ZSM-5 / PEI / PSS-Ce: First, 353.824 mg of Ce(NO3)3 was dissolved in 8 ml of deionized water to obtain a Ce(NO3)3 solution. Then, 50 mg of 8-HQ-ZSM-5 / PEI / PSS was immersed in the Ce(NO3)3 solution, and the mixture was stirred continuously for 24 h. After mixing, the sample was filtered, washed with distilled water, and dried at 90 °C for 2 h. The product 8-HQ-ZSM-5 / PEI / PSS-Ce was obtained.

[0067] Preparation of S5, 8-HQ-ZSM-5 / PEI / PSS-Ce / PEI: First, 72 mg of PEI was dissolved in 36 mL of deionized water to obtain a PEI solution. 0.2 g of 8-HQ-ZSM-5 / PEI / PSS-Ce was dispersed in 84 mL of deionized water and sonicated for 5 min. The prepared PSS solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 10000 r / min for 5 min, washed with deionized water, and dried at 90 °C for 2 h to obtain the product 8-HQ-ZSM-5 / PEI / PSS-Ce / PEI.

[0068] Step 3: Preparation of the intelligent epoxy resin layer on the aluminum alloy surface. The ratio of tert-butanol, epoxy resin, triethylenetetramine curing agent, and nanocontainer is 8 ml: 10 g: 3 g: 0.3 g. First, the product obtained in Step 2 is added to tert-butanol, and the mixture is stirred for 20 min followed by ultrasonication for 5 min. Then, epoxy resin is added and stirred evenly for 20 min, followed by ultrasonication for 5 min. Finally, the curing agent is added and stirred for 5 min. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1 min. The coating is then manually applied to the pre-treated aluminum alloy surface using a scraper, with a thickness of approximately 200 μm. The epoxy-coated aluminum alloy sample is placed in a drying oven and cured at 90℃ for 12 h.

[0069] Comparative Example 1

[0070] A method for preparing an epoxy coating with integrated self-warning and self-healing functions, the method comprising the following steps:

[0071] Step 1, Preparation of the mesoporous ZSM-5 nanocontainer.

[0072] Preparation of S1, ZSM-5 molecular sieve powder: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was slowly added dropwise under stirring. Finally, sodium aluminate and deionized water were added. The molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate and deionized water was 1:0.3:0.02:90. After stirring for 12 hours, the mixture was placed in a high-temperature and high-pressure reactor at 120℃ for 24 hours for synthesis reaction. Then, the solution after reaction was centrifuged, washed and dried, and calcined at 500℃ for 7 hours to remove the template agent, thus obtaining ZSM-5 powder.

[0073] S2, Preparation of mesoporous ZSM-5 molecular sieve powder: 0.5g ZSM-5 powder was dispersed in 50mL of 0.5mol / L Na2CO3, and the mixture was stirred at 60℃ for 30min, then treated in an ice bath for 10min. The resulting precipitate was centrifuged, washed with deionized water, dried, and calcined at 500℃ for 5 hours to obtain desiliconized ZSM-5 molecular sieve powder.

[0074] Step 2, Assembly of the smart nanocontainer.

[0075] Preparation of S1, ZSM-5 / PEI: First, 60 mg of PEI was dissolved in 30 mL of deionized water to obtain a PEI solution. Then, 0.2 g of ZSM-5 was dispersed in 70 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, the prepared PEI solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 80 °C for 6 h to obtain the product ZSM-5 / PEI.

[0076] Preparation of S2, ZSM-5 / PEI / PSS: First, 60 mg of PSS was dissolved in 30 mL of deionized water to obtain a PSS solution. 0.2 g of ZSM-5 / PEI was dispersed in 70 mL of deionized water and sonicated for 5 min. The prepared PSS solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min and washed with deionized water. The product was dried at 80 °C for 6 h to obtain ZSM-5 / PEI / PSS.

[0077] Preparation of S3, ZSM-5 / PEI / PSS-Ce: First, 221.14 mg of Ce(NO3)3 was dissolved in 5 ml of deionized water to obtain a Ce(NO3)3 solution. Then, 50 mg of ZSM-5 / PEI / PSS was immersed in the Ce(NO3)3 solution, and the mixture was stirred continuously for 24 h. After mixing, the sample was filtered, washed with distilled water, and dried at 80 °C for 6 h. The product ZSM-5 / PEI / PSS-Ce was obtained.

[0078] Preparation of S4, ZSM-5 / PEI / PSS-Ce / PEI: 0.2 g ZSM-5 / PEI / PSS-Ce was dispersed in 100 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, 30 mL of 2 mg / mL PEI was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 80 °C for 6 h to obtain the product ZSM-5 / PEI / PSS-Ce / PEI.

[0079] Step 3: Preparation of the intelligent epoxy resin layer on the aluminum alloy surface. The ratio of tert-butanol, epoxy resin, curing agent ethylenediamine, and nanocontainer is 6ml:10g:3g:0.3g. First, the product obtained in Step 2 is added to tert-butanol, and the mixture is stirred for 30 minutes and sonicated for 5 minutes. Then, epoxy resin is added and stirred evenly for 30 minutes and sonicated for 5 minutes. Finally, the curing agent is added and stirred for 15 minutes. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1 minute. The coating is then manually applied to the pretreated aluminum alloy surface using a scraper, with a thickness of approximately 200μm. The epoxy-coated aluminum alloy sample is placed in a drying oven and cured at 80℃ for 18 hours.

[0080] Comparative Example 2

[0081] A method for preparing an epoxy coating with integrated self-warning and self-healing functions, the method comprising the following steps:

[0082] Step 1, Preparation of the mesoporous ZSM-5 nanocontainer.

[0083] Preparation of S1, ZSM-5 molecular sieve powder: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was slowly added dropwise under stirring. Finally, sodium aluminate and deionized water were added. The molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate and deionized water was 1:0.35:0.02:100. After stirring for 18 hours, the mixture was placed in a high-temperature and high-pressure reactor at 150℃ for 24 hours for synthesis reaction. Then, the reaction solution was centrifuged, washed and dried, and calcined at 550℃ for 6 hours to remove the template agent, thus obtaining ZSM-5 powder.

[0084] S2, Preparation of mesoporous ZSM-5 molecular sieve powder: 1g of ZSM-5 powder was dispersed in 100mL of 0.6mol / L Na2CO3, and the mixture was stirred at 65℃ for 30min, followed by ice bath treatment for 10min. The resulting precipitate was centrifuged, washed with deionized water, dried, and calcined at 550℃ for 4.5h to obtain desiliconized ZSM-5 molecular sieve powder.

[0085] Step 2, Assembly of the smart nanocontainer.

[0086] Preparation of S1, 8-HQ-ZSM-5: 0.678 g of 8-HQ was dissolved in a 75% ethanol solution to prepare 35 ml of 8-HQ solution. 0.2 g of desilicationized ZSM-5 was added to the 8-HQ solution. The mixture was stirred for 45 min and then sonicated for 13 min to ensure uniform dispersion of 8-HQ. The mixture was then placed under low pressure (below 5000 Pa) for 45 min to allow 8-HQ to adsorb onto ZSM-5. After adsorption, the product was separated by centrifugation at 9000 r / min for 9 min, washed with deionized water, and freeze-dried at -3℃ for 9 h to obtain the product 8-HQ-ZSM-5.

[0087] Preparation of S2, 8-HQ-ZSM-5 / PEI: First, 66 mg of PEI was dissolved in 33 mL of deionized water to obtain a PEI solution. Then, 0.2 g of 8-HQ-ZSM-5 was dispersed in 77 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, the prepared PEI solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 8000 r / min for 10 min, washed with deionized water, and dried at 85 °C for 5 h to obtain the product 8-HQ-ZSM-5 / PEI.

[0088] Step 3: Preparation of the intelligent epoxy resin layer on the aluminum alloy surface. The ratio of tert-butanol, epoxy resin, curing agent ethylenediamine, and nanocontainer is 7ml:10g:3g:0.3g. First, the product obtained in Step 2 is added to tert-butanol, and the mixture is stirred for 25 minutes followed by ultrasonication for 5 minutes. Then, epoxy resin is added and stirred evenly for 25 minutes, followed by ultrasonication for 5 minutes. Finally, the curing agent is added and stirred for 10 minutes. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1.5 minutes. The coating is then manually applied to the pre-treated aluminum alloy surface using a scraper, with an average coating thickness of 200μm. The epoxy-coated aluminum alloy sample is placed in a drying oven and cured at 85℃ for 15 hours.

[0089] Comparative Example 3

[0090] A method for preparing an epoxy coating with integrated self-warning and self-healing functions, the method comprising the following steps:

[0091] Step 1, Preparation of the mesoporous ZSM-5 nanocontainer.

[0092] Preparation of S1, ZSM-5 molecular sieve powder: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was slowly added dropwise under stirring. Finally, sodium aluminate and deionized water were added. The molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate and deionized water was 1:0.4:0.02:110. After stirring for 24 hours, the mixture was placed in a high-temperature and high-pressure reactor at 180℃ for 12 hours for synthesis reaction. Then, the reaction solution was centrifuged, washed and dried, and calcined at 600℃ for 5 hours to remove the template agent, thus obtaining ZSM-5 powder.

[0093] S2, Preparation of mesoporous ZSM-5 molecular sieve powder: 1.5g ZSM-5 powder was dispersed in 150mL of 0.7mol / L Na2CO3, and the mixture was stirred at 70℃ for 30min, followed by ice bath treatment for 10min. The resulting precipitate was centrifuged, washed with deionized water, dried, and calcined at 600℃ for 4 hours to obtain desiliconized ZSM-5 molecular sieve powder.

[0094] Step 2, Assembly of the smart nanocontainer.

[0095] Preparation of S1, 8-HQ-ZSM-5: 0.775 g of 8-HQ was dissolved in a 75% ethanol solution to prepare 40 ml of 8-HQ solution. 0.2 g of desilicationized ZSM-5 was added to the 8-HQ solution. The mixture was stirred for 60 min and then sonicated for 10 min to ensure uniform dispersion of 8-HQ. The mixture was then placed under low pressure (below 5000 Pa) for 30 min to allow 8-HQ to adsorb onto ZSM-5. After adsorption, the product was separated by centrifugation at 10000 r / min for 5 min, washed with deionized water, and freeze-dried at 0 °C for 12 h to obtain the product 8-HQ-ZSM-5.

[0096] Preparation of S2, 8-HQ-ZSM-5 / PEI: First, 72 mg of PEI was dissolved in 36 mL of deionized water to obtain a PEI solution. Then, 0.2 g of 8-HQ-ZSM-5 was dispersed in 84 mL of deionized water and sonicated for 5 min to ensure uniform dispersion. Under stirring, the prepared PEI solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 10000 r / min for 5 min, washed with deionized water, and dried at 90 °C for 2 h to obtain the product 8-HQ-ZSM-5 / PEI.

[0097] Preparation of S3, 8-HQ-ZSM-5 / PEI / PSS: First, 72 mg of PSS was dissolved in 36 mL of deionized water to obtain a PSS solution. 0.2 g of 8-HQ-ZSM-5 / PEI was dispersed in 84 mL of deionized water and sonicated for 5 min. The prepared PSS solution was slowly added and stirred for 10 min to obtain a mixed solution. The product was separated by centrifugation at 10000 r / min for 5 min, washed with deionized water, and dried at 90 °C for 2 h to obtain the product 8-HQ-ZSM-5 / PEI / PSS.

[0098] Preparation of S4, 8-HQ-ZSM-5 / PEI / PSS-Ce: First, 353.824 mg of Ce(NO3)3 was dissolved in 8 ml of deionized water to obtain a Ce(NO3)3 solution. Then, 50 mg of 8-HQ-ZSM-5 / PEI / PSS was immersed in the Ce(NO3)3 solution, and the mixture was stirred continuously for 24 h. After mixing, the sample was filtered, washed with distilled water, and dried at 90 °C for 2 h. The product 8-HQ-ZSM-5 / PEI / PSS-Ce was obtained.

[0099] Step 3: Preparation of the intelligent epoxy resin layer on the aluminum alloy surface. The ratio of tert-butanol, epoxy resin, triethylenetetramine curing agent, and nanocontainer is 8 ml: 10 g: 3 g: 0.3 g. First, the product obtained in Step 2 is added to tert-butanol, and the mixture is stirred for 20 min followed by ultrasonication for 5 min. Then, epoxy resin is added and stirred evenly for 20 min, followed by ultrasonication for 5 min. Finally, the curing agent is added and stirred for 5 min. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1 min. The coating is then manually applied to the pre-treated aluminum alloy surface using a scraper, with an average coating thickness of 200 μm. The epoxy-coated aluminum alloy sample is placed in a drying oven and cured at 90℃ for 12 h.

[0100] Figure 2 The fluorescence emission spectrum of the epoxy coating prepared in Example 2 during static corrosion is shown. The fluorescence intensity of the corrosion solution was measured for 30 days using a fluorescence spectrophotometer to obtain the fluorescence emission spectrum of the smart coating during static corrosion. Figure 3 The Nyquist plot of the epoxy coating prepared in Example 2 during the static corrosion process is shown. Electrochemical impedance spectroscopy (EIS) was performed on the smart coating, with the sample as the working electrode, AgCl / KCl as the reference electrode, and Pb as the counter electrode. The EIS test frequency range was 100kHz-10mHz, and the corresponding Nyquist plot was obtained. Figures 4a to 4d The 8-HQ and Ce of Example 2 are shown respectively. 3+ Release curves before and after encapsulation; UV-Vis spectroscopy was used to study 8-HQ and Ce. 3+ Release behavior under acidic, neutral, and alkaline conditions; analysis of 8-HQ and Ce at specific time points. 3+ The absorbance corresponding to the excitation wavelength, specifically, weighing the 8-HQ and Ce-loaded... 3+ 0.015 g of each nanocontainer was dispersed in solutions with different pH values ​​(pH = 4, 7, 10). The supernatant was removed periodically, and its absorbance was measured. The results were compared with 8-HQ and Ce... 3+ Standard curves were obtained to show the release curves of the two corrosion inhibitors at different pH values. Figure 5a A scanning electron microscope (SEM) image of the cross-section of the smart nanocontainer of Example 2 is shown. Figure 5b A cross-sectional SEM image of the epoxy coating of Example 2 is shown.

[0101] refer to Figures 2 to 5b The epoxy coating prepared in this disclosure has advantages such as fluorescent self-warning function and self-healing performance, pH stimulation response performance, high corrosion inhibitor loading, short preparation cycle, and green environmental protection; the pH stimulation response performance is specifically manifested in: low corrosion inhibitor release (Ce) under neutral conditions. 3+The release amount of 1.54E-2 mmol; the release amount of 8-HQ is approximately 1.58E-2 mmol) has the advantage of Ce 3+ The order of 8-HQ release was: alkaline > acidic > neutral; this overcomes the major defect of ZSM-5 releasing a large amount of corrosion inhibitor under neutral conditions. Furthermore, the smart nanocontainers in the epoxy coating prepared by this method are coffin-shaped (coffin-shaped smart containers have a large specific surface area and Ce...). 3+ It has advantages such as higher loading rate of 8-HQ coating, side length range of 2.8 to 3 micrometers, thickness range of 0.8 to 1 micrometer, and coating thickness of about 200 micrometers.

[0102] The self-warning effect of this disclosure is caused by the fluorescent probe 8-HQ, which reacts with Al during the corrosion process. 3+ Chelation occurs, forming Alq3, which exhibits a yellow-green fluorescence under ultraviolet light. The self-healing property is due to the corrosion inhibitor Ce. 3+ Caused by Ce during the corrosion process 3+ Combining with OH-, CeO2 is eventually generated at the corrosion micro-area, achieving a self-healing effect. In the first electrostatic adsorption of PEI, the role of PEI adsorption is to adjust the potential of the 8-HQ-ZSM-5 nanocontainer to positive; the role of PSS adsorption is to remove Na from the PSS. + With Ce 3+ The exchange takes place; the second electrostatic adsorption of PEI serves as a seal, ensuring the safety of 8-HQ and Ce. 3+ No leakage.

[0103] In Comparative Example 1, the prepared epoxy coating lacked a fluorescent self-warning function; in Comparative Example 2, the prepared epoxy coating lacked a self-healing function, and the self-warning function was not durable. This was due to the absence of the corrosion inhibitor Ce. 3+ Furthermore, the lack of PEI sealing led to rapid leakage of 8-HQ, and the self-warning function was not durable. In Comparative Example 3, the prepared epoxy coating had both self-warning and self-healing functions, but neither was durable. Due to the lack of PEI sealing, the corrosion inhibitor Ce... 3+ Rapid and large-volume release; the fluorescent probe 8-HQ is rapidly released.

[0104] Those skilled in the art should understand that the above embodiments are merely exemplary embodiments, and various changes, substitutions, and modifications can be made without departing from the spirit and scope of this disclosure.

Claims

1. A method for preparing an epoxy coating, characterized in that, Includes the following steps: Step 1, Preparation of mesoporous ZSM-5 nanocontainer: Tetrapropylammonium hydroxide was dissolved in deionized water, and then tetraethyl orthosilicate was added dropwise under stirring. Sodium aluminate was then added, and the mixture was stirred evenly before being placed in a reaction vessel for synthesis. After the reaction, the mixture was centrifuged and dried to obtain ZSM-5 molecular sieve powder. The prepared ZSM-5 molecular sieve powder was then calcined for the first time to remove the template agent tetrapropylammonium hydroxide. After that, the ZSM-5 molecular sieve powder was dispersed in Na2CO3 solution and treated in a water bath, followed by an ice bath treatment. The suspension was then centrifuged, washed, and dried. The product ZSM-5 molecular sieve powder was then calcined for the second time to obtain desilicationized mesoporous ZSM-5 molecular sieve powder. Step 2, assembly of nanocontainers: Dissolve 8-hydroxyquinoline in ethanol solution to obtain 8-hydroxyquinoline solution, add mesoporous ZSM-5 molecular sieve powder prepared in step 1 to 8-hydroxyquinoline solution, stir first, and then disperse by ultrasonication. The obtained mixed solution was placed in a low-pressure environment below 5000 Pa to allow 8-hydroxyquinoline to adsorb onto ZSM-5. After adsorption, the mixed solution was centrifuged, washed with deionized water, and freeze-dried to obtain the product 8-hydroxyquinoline-ZSM-5. 8-hydroxyquinoline-ZSM-5 was dispersed in deionized water and ultrasonically dispersed. Polyethyleneimine was added under stirring conditions. After stirring, the mixed solution was centrifuged, washed with deionized water, and dried to obtain 8-hydroxyquinoline-ZSM-5 / polyethyleneimine. 8-hydroxyquinoline-ZSM-5 / polyethyleneimine was dispersed in deionized water and ultrasonically dispersed. Sodium polystyrene sulfonate was added. After stirring, the mixed solution was centrifuged, washed with deionized water, and dried to obtain 8-hydroxyquinoline-ZSM-5 / polyethyleneimine. 8-Hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate; 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate was soaked in Ce(NO3)3 solution with continuous stirring, and the resulting sample was filtered, washed with distilled water, and dried to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce; 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce was dispersed in deionized water, ultrasonically dispersed evenly, and under stirring conditions, polyethyleneimine was added. After stirring, the mixed solution was centrifuged, washed with deionized water, and dried to obtain 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce / polyethyleneimine; Step 3: Preparation of intelligent epoxy resin layer on aluminum alloy surface. The product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce / polyethyleneimine obtained in step 2 is ultrasonically dispersed in epoxy resin. After adding curing agent and stirring, it is then coated on aluminum alloy surface and cured to form epoxy coating. In step 1, the molar ratio of tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate, and deionized water is 1:0.3–0.4:0.02:90–110; the stirring time is 12–15 hours; the temperature of the reactor is 120–180℃; and the reaction time is 12–24 hours. The concentration of the Na₂CO₃ solution is 0.5–0.7 mol / L; the ratio of ZSM-5 molecular sieve powder to Na₂CO₃ solution is 0.5–1.5 g:50–150 mL; and the water bath temperature is 60–70℃. The calcination temperatures for the first and second calcinations are 500–600℃; the first calcination time is 5–7 hours; and the second calcination time is 4–5 hours. In step 2, the ethanol solution concentration is 75%, the 8-hydroxyquinoline solution concentration is 0.1 mol / L, and the ratio of anhydrous ethanol, 8-hydroxyquinoline, and mesoporous ZSM-5 molecular sieve powder is 30 ml–40 ml: 0.581–0.775 g: 0.2 g. The stirring time is 0.5–1 h, the sonication time is 10–15 min, and the settling time is 0.5–1 h. After settling, the mixed solution is centrifuged at 8000–10000 r / min for 5–10 min. After centrifugation, the supernatant is removed, the precipitate is washed with deionized water, and dried in a refrigerator at -5–0℃ for 6–12 h to obtain the product 8-hydroxyquinoline-ZSM-5. Subsequently, 8-hydroxyquinoline-ZSM-5, deionized water, and poly(hydroxyquinoline-ZSM-5) are reacted. The ratio of ethyleneimine used was 200 mg: 100-120 mL: 60-72 mg. First, polyethyleneimine was dissolved in a portion of deionized water. Then, 8-hydroxyquinoline-ZSM-5 was ultrasonically dispersed in the remaining deionized water for 5 min. Under stirring, the prepared polyethyleneimine solution was added dropwise. After stirring for 10 min, the mixture was centrifuged, the supernatant was removed, and the resulting precipitate was washed with deionized water and dried to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine. The ratio of 8-hydroxyquinoline-ZSM-5 / polyethyleneimine, deionized water, and sodium polystyrene sulfonate was 0.2 g: 100-120 mL: 60-72 mg. First, sodium polystyrene sulfonate was dissolved in a portion of deionized water. Then, 8-hydroxyquinoline-ZSM-5 / polyethyleneimine was ultrasonically dispersed in the remaining deionized water for 5 min. Under stirring, the prepared polyethyleneimine solution was added dropwise. After stirring for 10 min, the mixture was centrifuged, the supernatant was removed, and the resulting precipitate was washed with deionized water. The product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate was obtained by washing and drying. Subsequently, the ratio of 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate, Ce(NO3)3, and deionized water was 50 mg: 221.14–353.824 mg: 5 ml–8 ml. Ce(NO3)3 was first dissolved in deionized water, then 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate was added and the mixture was stirred continuously for 24 h. After mixing, the sample was filtered, washed with distilled water, and dried at 80 °C to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce. Subsequently, the ratio of 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce, polyethyleneimine, and deionized water was 0.2g: 60-72mg: 100-120ml. First, dissolve polyethyleneimine in a portion of deionized water. Then, ultrasonically disperse 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce in the remaining deionized water for 5 minutes. Under stirring, add the prepared polyethyleneimine solution dropwise. After stirring for 10 minutes, centrifuge the mixture, remove the supernatant, wash the resulting precipitate with deionized water and dry it to obtain the product 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate / sodium polystyrene sulfonate-Ce / polyethyleneimine. In step 3, the ratio of tert-butanol, epoxy resin, curing agent, and nanocontainer 8-hydroxyquinoline-ZSM-5 / polyethyleneimine / sodium polystyrene sulfonate-Ce / polyethyleneimine is 6-8 ml: 10 g: 3 g: 0.3 g. First, tert-butanol is added to the nanocontainer, and the mixture is stirred for 20-30 minutes followed by ultrasonication for 5 minutes. Then, epoxy resin is added and stirred evenly for 20-30 minutes, followed by ultrasonication for 5 minutes. Finally, curing agent is added and stirred for 5-15 minutes. The mixture is then placed in a vacuum drying oven to remove air bubbles at a pressure of 5000 Pa for 1-2 minutes. A coating is then prepared by scraping it onto the aluminum alloy surface. The coated aluminum alloy sample is placed in a drying oven and cured at 80-90℃ for 12-18 hours to obtain the epoxy coating.

2. The method for preparing the epoxy coating according to claim 1, characterized in that, The curing agent includes at least one of ethylenediamine and triethylenetetramine.

3. The epoxy coating prepared by the method for preparing epoxy coating according to claim 1 or 2.

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