Preparation and application of amino acid modified zif-90 composite powder
By modifying the inner wall of the ZIF-90 pore with aldehyde groups and forming a C=N bond with L-histidine, amino acid-modified ZIF-90 composite powder was prepared. This solved the problems of limited interaction between ZIFs and corrosion inhibitors and difficulty in uniformly doping amino acid corrosion inhibitors, thereby achieving efficient and environmentally friendly performance of the self-healing anti-corrosion coating.
Patent Information
- Application Number
- CN202310305180.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-27
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2043-03-27
AI Technical Summary
In the existing technology, the interaction between ZIFs materials and corrosion inhibitors is limited, amino acid corrosion inhibitors are difficult to evenly incorporate into the coating matrix, and traditional corrosion inhibitors are toxic and difficult to degrade, resulting in poor anti-corrosion effect of the anti-corrosion coating.
ZIF-90 with aldehyde functional groups on the inner wall of the pores is used as a carrier. L-histidine is modified onto ZIF-90 through an ammonia-aldehyde condensation reaction to generate a C=N bond, forming an amino acid-modified ZIF-90 composite powder, which is used as a micro-nano container to load corrosion inhibitors and self-repair in response to pH changes in the corrosion micro-area.
The loading amount and type of corrosion inhibitors are increased, the corrosion resistance of the coating is enhanced, and the uniform dispersion and self-repair effect of the environmentally friendly amino acid corrosion inhibitors in the coating are achieved.
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Figure CN116199902B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of metal anticorrosion coating materials, and particularly relates to a preparation method of amino acid modified ZIF-90 composite powder and application thereof in preparation of a self-repairing anticorrosion coating. BACKGROUND
[0002] Metal corrosion problems are increasingly serious and inevitable, and coating anticorrosion is an effective means to cope with metal corrosion. Traditional coatings achieve anticorrosion performance by good physical isolation of metal substrates such as carbon steel from the corrosion environment, but the coating often produces micropores and gaps during the curing process due to poor curing, and cracks and scratches may also occur during use due to external factors, resulting in anticorrosion failure.
[0003] Self-repairing anticorrosion coatings are obtained by adding corrosion inhibitors to coating materials, which endow the coating with the ability to actively repair after damage, thus well compensating for the defects of passive anticorrosion coatings. However, direct addition of corrosion inhibitors to coatings such as epoxy resin may cause the corrosion inhibitors to agglomerate in the coating or interact with the coating matrix, thereby destroying the integrity of the coating. Therefore, many studies have chosen micro-nano containers with good compatibility with the coating matrix to load corrosion inhibitors in order to enhance the anticorrosion performance of epoxy resin coatings.
[0004] Zeolitic imidazolate framework (ZIFs) is a class of metal-organic framework (MOFs) with zeolite-like structure, mainly constructed by zinc ions and imidazole-based ligands. This class of materials generally exhibits permanent porosity, high specific surface area, hydrophobicity and excellent solvent and thermal stability, and has good compatibility with epoxy resin coatings, and can achieve pH-responsive release, so it is a kind of promising micro-nano carrier material for metal corrosion inhibitors. At present, many studies have used ZIFs materials as corrosion inhibitor loading containers in coatings, which have shown good anticorrosion effect. However, the existing related researches mainly use a few materials such as ZIF-7, ZIF-8 and ZIF-67, and the organic ligands of which are generally 2-methylimidazole, benzimidazole and other nitrogen-containing heterocycles. After they form metal-organic frameworks by coordinating with nitrogen atoms, there are no remaining active groups (such as hydroxyl, aldehyde, amino, mercapto, etc.) exposed inside the pores, which makes the guest molecules such as corrosion inhibitors mainly enter the pores by physical adsorption, and the interaction between ZIFs and corrosion inhibitors is limited, which not only makes the loading amount of corrosion inhibitors not high, but also limits the types of loadable corrosion inhibitors to a few such as benzotriazole (BTA). Therefore, how to enhance the interaction between ZIFs framework and corrosion inhibitors, improve the loading amount of corrosion inhibitors, and broaden the types of loadable corrosion inhibitors, is one of the important technical problems to be solved in the existing researches.
[0005] On the other hand, the existing corrosion inhibitors loaded in various micro-nano containers mainly include chromate, zincate, phosphate and organic amine corrosion inhibitors. Although these types of corrosion inhibitors are highly efficient, they have the disadvantages of toxicity and poor biodegradability. Amino acid corrosion inhibitors have low toxicity, easy degradation, low price, wide sources, and good corrosion inhibition effect in acidic, neutral and alkaline corrosive media, and are excellent substitutes for traditional corrosion inhibitors. However, many amino acids have low solubility in most organic solvents, making it difficult to uniformly dope into the coating matrix, and it is also difficult to use traditional immersion loading methods to load amino acid corrosion inhibitors on inert fillers, which greatly limits the application of amino acid corrosion inhibitors in the field of coating corrosion protection. How to load environmentally friendly amino acid corrosion inhibitors into ZIFs and other micro-nano containers and then dope them into the corrosion protection coating is another technical problem to be solved by existing research.
[0006] The application adopts ZIF-90 with aldehyde functional groups carried on the inner wall of the channel as a corrosion inhibitor carrier, takes natural green and environmentally friendly L-histidine (L-His) and other amino acid corrosion inhibitors as the loading object, and adopts a post-synthesis strategy to modify L-histidine to the skeleton of ZIF-90 through an amino-aldehyde condensation reaction to prepare an amino acid modified ZIF-90 composite powder. The amino acid modified ZIF-90 composite powder can be used as a micro-nano container loaded corrosion inhibitor and doped into an epoxy resin, solving the problem that amino acid corrosion inhibitors are difficult to be applied in organic coatings due to their poor solubility in organic solvents. At the same time, the amino-aldehyde condensation reaction generates a more efficient Schiff base corrosion inhibitor. Once the coating is corroded, ZIF-90 will respond to the pH change of the corrosion microzone and collapse to release the organic ligand, thus improving the corrosion resistance of the coating. SUMMARY
[0007] The application aims to provide a preparation method of an amino acid modified ZIF-90 composite powder and its application in preparing a self-repairing corrosion protection coating. The amino acid modified ZIF-90 composite powder can be used as a micro-nano container loaded corrosion inhibitor and added to an epoxy resin, effectively solving the problem that amino acid corrosion inhibitors are difficult to be applied in organic coatings, and the prepared coating has good corrosion resistance and self-repairing performance.
[0008] To achieve the above-mentioned purpose, the application adopts the following technical solutions:
[0009] A preparation method of an amino acid modified ZIF-90 composite powder, comprising the following steps:
[0010] 1) Synthesis of ZIF-90: 0.3-0.6 parts by mass of zinc nitrate hexahydrate was dissolved in 10-30 parts by mass of tert-butyl alcohol to obtain solution A; 0.4-0.8 parts by mass of imidazole-2-formaldehyde and 0.05-0.15 parts by mass of polyvinylpyrrolidone were dissolved in 10-30 parts by mass of deionized water to obtain solution B; then solution A and B were mixed, stirred in an ultrasonic environment for 5 min, the obtained product was separated by centrifugation, washed with methanol for three times, and then dried at 50-70°C under vacuum for 12h to obtain a light yellow powder of ZIF-90;
[0011] 2) Synthesis of ZIF-90-His: 0.05-0.10 parts by mass of ZIF-90 prepared in step 1) was added to 7.5-15 parts by mass of methanol and ultrasonically dispersed for 10 min to prepare solution C; 0.03-0.06 parts by mass of L-histidine was dissolved in 5-10 parts by mass of methanol to prepare solution D; the obtained solution D was slowly added to solution C at 60°C and refluxed for 14h, the obtained product was separated by centrifugation, washed with excess methanol, and then dried at 50-70°C under vacuum for 12h to obtain the amino acid modified ZIF-90 composite powder.
[0012] The prepared amino acid modified ZIF-90 composite powder is a micro-nano container loaded inhibitor, which can be used for preparing a self-repairing anticorrosive coating. The specific preparation method is that 0.017-0.51 parts by mass of the amino acid modified ZIF-90 inhibitor is ultrasonically dispersed in 1.5-3 parts by mass of epoxy resin, 0.5-1.0 parts by mass of a mixed solution of n-butanol and dimethylbenzene (volume ratio 3:7) is added to adjust the viscosity, then ultrasonic stirring is performed for 0.5h, 0.5-1.5 parts by mass of a polyamide curing agent is added, mechanical stirring is performed for 15 min, and then the mixture is coated on a metal surface in need of corrosion protection, and after solidification and drying, a self-repairing epoxy resin anticorrosive coating is obtained.
[0013] The significant advantages of the present application are:
[0014] (1) Different from the ZIF materials (ZIF-7, ZIF-8, ZIF-67) with no active functional groups on the inner wall of the pore channel commonly used in existing researches, the present application uses ZIF-90 with aldehyde functional groups on the inner wall of the pore channel as a carrier, so that it can be firmly connected with the guest in the form of C=N chemical bond, thereby widening the range of the loaded inhibitor to amino acid inhibitors and the like which are rarely involved in the existing MOF carriers, and effectively avoiding the early loss of the inhibitor.
[0015] (2) Unlike the traditional corrosion inhibitors used in the prior art, which have biological toxicity, environmental toxicity and are difficult to degrade, the amino acid corrosion inhibitor L-histidine is used as the loading object in the present application, which is cheap and easy to obtain, and has the characteristics of environmental friendliness, and the molecule has alkaline amino and acidic carboxyl groups, which can be applied to acidic, neutral and alkaline media.
[0016] (3) The amino group of L-histidine (L-His) and the aldehyde group of ZIF-90 are connected by aldehyde-amine condensation reaction to form C=N bond in the present application, when corrosion occurs, ZIF-90 can respond to the pH change of the corrosion micro area, and the structure collapses to release organic ligand and metal ion Zn 2+ , and the imidazole group and carboxyl group on the histidine molecule, and the C=N bond in the Schiff base can be coordinated with metal ions to form a film, and the synergistic self-repairing behavior occurs to improve the corrosion resistance of the coating.
[0017] (4) The L-ZIF-90-His composite powder prepared in the present application has uniform size (precisely controlled at about 400-500 nm), good compatibility with the coating matrix, can be uniformly dispersed in the coating matrix, not easy to agglomerate, and its structure is stable in weak acidic to alkaline environment, easy to save. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 XRD powder diffraction pattern of ZIF-90 prepared in Example 1.
[0019] Figure 2 XRD powder diffraction comparison chart of ZIF-90 and ZIF-90-His prepared in Example 1.
[0020] Figure 3 Scanning electron microscope images of ZIF-90 (a) and ZIF-90-His (b) prepared in Example 1.
[0021] Figure 4 Fourier transform infrared spectrum of ZIF-90 and ZIF-90-His prepared in Example 1.
[0022] Figure 5 Electrochemical impedance spectrogram of epoxy resin coating (a) without adding ZIF-90-His and epoxy resin coating (b) prepared in Example 1 by adding ZIF-90-His after being soaked in different time sodium chloride solution. DETAILED DESCRIPTION
[0023] In order to make the content described in the present application more convenient to understand, the technical solutions described in the present application will be further described below in combination with specific embodiments, but the present application is not limited thereto.
[0024] Imidazole-2-carboxaldehyde (purity 99%) used in the embodiments was produced by Adamas Reagent Co., Ltd., histidine (purity 99%) was produced by Aladdin Reagent Co., Ltd., zinc nitrate hexahydrate, tert-butyl alcohol, polyvinylpyrrolidone, methanol, n-butanol, dimethylbenzene, etc. were produced by National Pharmaceutical Group Chemical Reagent Co., Ltd.
[0025] The pretreatment method of the Q235 carbon steel sheet is as follows: the Q235 carbon steel sheet is polished smooth with 600 mesh, 1000 mesh and 1500 mesh sandpaper in turn, then taken out after ultrasonic treatment in anhydrous ethanol for 10 min, and dried for standby use.
[0026] Example 1
[0027] (1) Synthesis of ZIF-90: 0.37 g of zinc nitrate hexahydrate was dissolved in 15 g of tert-butyl alcohol to obtain solution A; 0.48 g of imidazole-2-carboxaldehyde and 0.05 g of polyvinylpyrrolidone were dissolved in 15 g of deionized water to obtain solution B; then solution A and B were mixed, stirred in an ultrasonic environment for 5 min, centrifuged at a speed of 12000 rpm, washed with methanol three times, and dried in a vacuum drying oven at 65°C for 12 h to obtain a light yellow powder, which was ZIF-90.
[0028] (2) Synthesis of ZIF-90-His: 0.05 g of ZIF-90 was ultrasonically dispersed in 7.5 g of methanol for 10 min to prepare solution C; 0.03 g of L-histidine was dissolved in 5.0 g of methanol to prepare solution D; the obtained solution D was slowly added to solution C at a speed of 0.5 mL per hour at 60°C and refluxed for 14 h, and the obtained product was centrifuged at a speed of 10000 rpm to obtain a light yellow powder, which was then washed with excess methanol and dried in a vacuum drying oven at 65°C for 12 h to obtain ZIF-90-His.
[0029] (3) Preparation of ZIF-90-His-containing epoxy resin coating: 0.035 g of ZIF-90-His powder was ultrasonically dispersed in 1.75 g of epoxy resin, 0.52 g of a mixed solution of n-butanol and dimethylbenzene (volume ratio 3:7) was added to adjust the viscosity, and then ultrasonic stirring was performed for 0.5 h, 1.0 g of polyamide curing agent was added, mechanical stirring was performed for 15 min, and then the mixture was coated on the pretreated Q235 carbon steel sheet using a four-sided film applicator, and after curing at room temperature for 2 days and drying in an oven at 80°C for 4 h, a ZIF-90-His-containing epoxy resin composite coating (based on the mass of the epoxy resin) with a thickness of 50±3 μm was successfully prepared.
[0030] Example 2
[0031] (1) Synthesis of ZIF-90: 0.37 g of zinc nitrate hexahydrate was dissolved in 15 g of t-butyl alcohol to obtain solution A; 0.48 g of imidazole-2-formaldehyde and 0.10 g of polyvinylpyrrolidone were dissolved in 15 g of deionized water to obtain solution B; then solution A and B were mixed, stirred in an ultrasonic environment for 5 min, centrifuged at a speed of 12000 rpm, washed with methanol for three times, and dried in a vacuum drying oven at 60 ℃ for 12 h to obtain a light yellow powder, which was ZIF-90.
[0032] (2) Synthesis of ZIF-90-His: 0.05 g of the obtained ZIF-90 was dispersed in 15 g of methanol by ultrasonic for 10 min to obtain solution C; 0.03 g of L-histidine was dissolved in 7.5 g of methanol to obtain solution D; solution D was slowly added to solution C at a speed of 0.5 mL per hour at 60 ℃ and refluxed for 14 h, and the obtained product was centrifuged at a speed of 10000 rpm to obtain a light yellow powder, which was washed with excess methanol and dried in a vacuum drying oven at 60 ℃ for 12 h to obtain ZIF-90-His.
[0033] (3) Preparation of ZIF-90-His-containing epoxy resin coating: 0.0175 g of ZIF-90-His powder was ultrasonically dispersed in 1.75 g of epoxy resin, 0.52 g of a mixed solution of n-butanol and dimethylbenzene (volume ratio of 3:7) was added to adjust the viscosity, and then ultrasonic stirring was performed for 0.5 h; 1.0 g of a polyamide curing agent was added, and mechanical stirring was performed for 15 min; then the mixture was coated on a pretreated Q235 carbon steel sheet using a four-side coating machine, and cured at room temperature for 2 days, and then dried in an oven at 80 ℃ for 4 h to successfully prepare a ZIF-90-His-containing epoxy resin composite coating (50±3 μm in thickness, based on the mass of the epoxy resin).
[0034] Figure 1 XRD powder diffraction pattern of ZIF-90 prepared in Example 1. As shown in the figure, ZIF-90 has strong diffraction peaks at 2θ = 7.2°, 10.2°, 12.5° and 17.8°, which correspond to the (011), (002), (112) and (222) crystal planes of ZIF-90, respectively.
[0035] Figure 2 XRD powder diffraction comparison chart of ZIF-90 and ZIF-90-His prepared in Example 1. As shown in the figure, the diffraction spectrum of the modified sample is similar to that before modification, indicating that the synthesis method after modification can maintain the main framework of ZIF-90 without being destroyed.
[0036] Figure 3Scanning electron microscope images of ZIF-90 (a) and ZIF-90-His (b) prepared in Example 1. As can be seen from the images, the main morphology of ZIF-90 is dodecahedron structure, the particle size of ZIF-90 is uniform, and the average particle size is about 460 nm (obtained by ImageJ image analysis software); and the morphology of ZIF-90-His has no obvious difference from that of ZIF-90, which indicates that the post-modification process does not destroy the appearance morphology of the material.
[0037] Figure 4 Fourier transform infrared spectra of ZIF-90 and ZIF-90-His prepared in Example 1. As can be seen from the images, the C=O bond (1680 cm -1 ) on ZIF-90 is gradually converted to the C=N bond (1640 cm -1 ) of ZIF-90-His, which proves that L-histidine (L-His) is successfully modified on ZIF-90 through imine condensation reaction. At the same time, there is still an aldehyde group characteristic peak at 1680 -1 cm-1, which is due to the fact that the equivalent of the amino group in the added histidine is half of the equivalent of the aldehyde group in ZIF-90.
[0038] Performance experiment:
[0039] The epoxy resin coating added with ZIF-90-His obtained in Example 1 was immersed in a 3.5% NaCl solution, and the electrochemical impedance spectra of the coating at different immersion times were collected, and an epoxy resin coating without ZIF-90-His was used as a comparison, as shown in Figure 5 .
[0040] By comparing the electrochemical impedance spectra of the surfaces of the samples after immersion in the sodium chloride solution for different times, it can be seen that the electrochemical impedance value of the corrosion-resistant coating added with ZIF-90-His is higher than that of the corrosion-resistant coating without ZIF-90-His after immersion for 1 day, and after immersion for 7 days and 14 days, the electrochemical impedance value of the corrosion-resistant coating added with ZIF-90-His decreases at a significantly lower rate than that of the corrosion-resistant coating without ZIF-90-His, which proves that the incorporation of ZIF-90-His into the epoxy resin can significantly improve the corrosion resistance of the epoxy resin to carbon steel sheets.
[0041] The above only describes the preferred embodiments of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be included in the scope of the present application.
Claims
1. Application of an amino acid-modified ZIF-90 composite powder in the preparation of a self-repairing anti-corrosion coating, characterized in that: Amino acid-modified ZIF-90 composite powder was used as a corrosion inhibitor loaded in micro-nano containers to prepare a self-repairing epoxy resin anti-corrosion coating. The preparation method of the amino acid-modified ZIF-90 composite powder comprises the following steps: 1) Synthesis of ZIF-90: 0.3-0.6 parts by weight of zinc nitrate hexahydrate was dissolved in 10-30 parts by weight of tert-butanol to obtain solution A. 0.4-0.8 parts by weight of imidazole-2-carboxaldehyde and 0.05-0.15 parts by weight of polyvinylpyrrolidone were dissolved in 10-30 parts by weight of deionized water to obtain solution B. Solutions A and B were then mixed and stirred under ultrasonication for 5 minutes. The resulting product was centrifuged, washed three times with methanol, and then dried under vacuum at 50-70°C for 12 hours to obtain a light yellow powder of ZIF-90. 2) Synthesis of ZIF-90-His: 0.05-0.10 parts by mass of ZIF-90 prepared in step 1) was added to 7.5-15 parts by mass of methanol and ultrasonically dispersed for 10 minutes to prepare solution C; 0.03-0.06 parts by mass of L-histidine was dissolved in 5-10 parts by mass of methanol to prepare solution D; the resulting solution D was slowly added dropwise to solution C at 60°C and refluxed for 14 hours. The resulting product was centrifuged, washed with excess methanol, and then vacuum dried at 50-70°C for 12 hours to obtain the amino acid-modified ZIF-90 composite powder.
2. The use according to claim 1, characterized in that: Specifically, 0.017-0.051 parts by mass of the amino acid-modified ZIF-90 composite powder is ultrasonically dispersed in 1.5-3 parts by mass of epoxy resin, 0.5-1.0 parts by mass of a mixed solution of n-butanol and xylene are added to adjust the viscosity, ultrasonic stirring is performed for 0.5 hours, and then 0.5-1.5 parts by mass of a polyamide curing agent is added. After mechanical stirring for 15 minutes, it is coated on the metal surface and cured and dried to obtain the self-repairing epoxy resin anti-corrosion coating.
3. The use according to claim 2, characterized in that: The volume ratio of n-butanol to xylene in the mixed solution is 3:7.