A superhydrophobic anticorrosive material based on silica, its preparation method and application

Abstract

This invention prepares a superhydrophobic material via a one-pot polymerization method. The polymerization reaction generates dodecyl p-isobutyrate and tridecyl p-mercaptopropionate, which have pH-sensitive groups. In an alkaline environment, TEOS is used as a precursor for catalytic hydrolysis to generate SiO2 particles. The addition of PAA dispersant during hydrolysis alters the surface charge of the particles, increasing the electrostatic repulsion and steric hindrance between them, maintaining their suspension in the aqueous solution and thus slowing down the fouling rate within the SG (soil aggregate). Combined with the rough structure of the SiO2 particles, superhydrophobicity and pH responsiveness are achieved, providing corrosion protection in a hydrophobic state while maintaining pH responsiveness. Furthermore, the addition of dimethylethoxyformyloxysilane enhances the adhesion strength between reactants through intermolecular crosslinking, thereby improving the stability of the modified anti-corrosion material and exhibiting excellent corrosion protection effects, which is of great significance for practical industrial applications.

Description

Technical Field

[0001] This invention belongs to the field of metal corrosion protection, specifically involving a superhydrophobic anti-corrosion material based on SiO2, its preparation method, and its application. Background Technology

[0002] Currently, the vast majority of nuclear power units operating worldwide are pressurized water reactors (PWRs). Feedwater carrying corrosion products enters the secondary steam generator (SG) of a PWR, where they deposit on the surface of the U-shaped pipes. These deposits inhibit heat transfer, and blockages in the pipe support plates lead to thermal-hydraulic instability, forming occluded areas. Corrosive substances accumulate at the pipe joints and in the gaps of the support plates (TSP) between pipes, resulting in a relative reduction in internal combustion engine efficiency of approximately 1-5%. Corrosion products flow into the SG with the feedwater and deposit on the heat transfer tubes, not only reducing the water flow velocity in the SG pipes, decreasing heat exchange efficiency, and weakening the mechanical strength of the heat exchanger pipes, but also causing under-deposit corrosion on the heat transfer tubes and support plates. Furthermore, the complex pipe structure of the SG, with many pipes being very narrow, makes it easy for corrosion products to accumulate and become blocked. After long-term operation, the SG will not only suffer from under-deposit pitting corrosion, but in severe cases, it can also cause perforation of the SG heat transfer tube walls.

[0003] To address the aforementioned issues, most power plants employ mechanical methods, such as inter-tube pressure flushing, to remove deposits accumulated on the tube sheet surface. Other methods include chemical cleaning and soft cleaning. Limitations of these methods include: ① It is difficult to maintain a low Fe concentration in the makeup water; ② Chemical cleaning techniques are expensive and cannot guarantee effective cleaning in crevices; ③ The use of corrosive chemicals (such as EDTA) inevitably damages the equipment's base metal, reducing equipment reliability.

[0004] Constructing anti-corrosion coatings on metal surfaces can effectively inhibit chemical or electrochemical reactions, thereby protecting the metal from external environmental corrosion and improving its corrosion resistance and service life. However, contact between the corrosive solution and the metal / coating interface can lead to corrosion of the metal surface. Therefore, applying a coating that reduces interfacial tension or increases surface hydrophobicity would be a more effective protective method. With the rapid development of superwetting materials, there are many applications in the field of functional coatings, such as the application of superhydrophobic coatings in waterproofing and corrosion prevention. Superhydrophobic materials have developed rapidly in the field of corrosion protection, but there are still some noteworthy issues. For example, the preparation process is cumbersome, involving precious metals (such as silver, gold, and copper) and expensive fluorinated materials, posing risks to human health and significantly increasing costs. Furthermore, the prepared materials may not be responsive and require further optimization. In addition, while there are many research reports on superhydrophobic materials, most only involve the separation of simple two-phase mixtures, and few reports demonstrate the ability to achieve in-situ separation of complex multiphase mixtures. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a superhydrophobic anticorrosive material based on silica.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a superhydrophobic anticorrosive material based on silica, comprising,

[0009] Dimethylethoxyformoxysilane, tridecyl 3-mercaptopropionate, dodecyl isobutyrate, anhydrous ethanol and deionized water were mixed evenly, an initiator was added, and the mixture was stirred at room temperature until completely dissolved. The mixture was then transferred to a constant temperature oil bath for polymerization to obtain mixture 1.

[0010] Ammonia solution was slowly added to tetraethyl orthosilicate (TEOS) under stirring, and polyacrylic acid (PAA) was added during the hydrolysis process to obtain mixture 2.

[0011] Mixture 2 is added to mixture 1 and ultrasonically dispersed, and the reaction continues to obtain the superhydrophobic anticorrosive material.

[0012] In a preferred embodiment of the preparation method described in this invention, the mass ratio of dimethylethoxyformylsilane, tridecyl 3-mercaptopropionate, dodecyl isobutyrate, and AIBME is 1:(1-3):(2-6):(0.05-0.15), the volume ratio of anhydrous ethanol to deionized water is (1-3):1, and the ratio of anhydrous ethanol to dimethylethoxyformylsilane is 20 mL:0.5-1 g.

[0013] As a preferred embodiment of the preparation method described in this invention, the stirring at room temperature until completely dissolved takes 20 to 40 minutes.

[0014] In a preferred embodiment of the preparation method described in this invention, the polymerization reaction is carried out at a constant temperature of 60–80°C for 6–8 hours.

[0015] In a preferred embodiment of the preparation method described in this invention, the volume ratio of ammonia water to TEOS and PAA is (1-3):1:(0.2-0.9).

[0016] In a preferred embodiment of the preparation method described in this invention, the mixture 2 is added to the mixture 1 and ultrasonically dispersed, wherein the ratio of tridecyl 3-mercaptopropionic acid ester in the mixture 1 to tetraethyl orthosilicate in the mixture 2 is 1-3 g: 5-10 mL.

[0017] In a preferred embodiment of the preparation method described in this invention, the ultrasonic dispersion is wherein the ultrasonic reaction time is 15–45 min.

[0018] In a preferred embodiment of the preparation method described in this invention, the superhydrophobic anticorrosive material is obtained by continuing the reaction, wherein the polymerization reaction temperature is 40-60°C and the reaction time is 1-3 hours.

[0019] Another object of the present invention is to overcome the shortcomings of the prior art and provide the application of the product in the field of metal corrosion protection.

[0020] After the surface of the metal material is smoothed with sandpaper, it is cleaned and dried in sequence with deionized water and anhydrous ethanol under ultrasonic conditions.

[0021] The pretreated metal material is immersed in a superhydrophobic anti-corrosion material solution and then dried in an oven.

[0022] As a preferred embodiment of the application described in this invention, the substrate material is soaked for 15 to 45 minutes and dried at 60 to 80°C for 1 to 3 hours.

[0023] Beneficial effects of this invention:

[0024] (1) This invention employs a simple and environmentally friendly one-pot polymerization method to prepare a superhydrophobic anticorrosive material based on SiO2. The polymerization reaction generates pH-sensitive groups, and TEOS is used as a precursor to catalyze hydrolysis to generate SiO2 particles in an alkaline environment. PAA dispersant is added during the hydrolysis process to change the surface charge of the particles, increase the electrostatic repulsion between particles, increase the steric hindrance between particles, and maintain the particles in a suspended state in the aqueous solution, thereby slowing down the accumulation rate of dirt in the SG. Then, combined with the rough structure of SiO2 particles, the superhydrophobicity and pH responsiveness of the material are constructed, so that it has pH responsive performance while being anticorrosive in a hydrophobic state.

[0025] (2) This invention enhances the stability of the modified material by adding dimethylethoxyformyloxysilane and utilizing intermolecular crosslinking to improve the adhesion strength between reactants. The prepared material exhibits good pH-induced surface wetting transition, can reversibly switch between superhydrophobicity and superhydrophilicity multiple times, and also shows excellent mechanical and chemical stability under harsh environmental conditions. In addition to its inherent anti-corrosion properties and high repulsion to corrosive media, the prepared anti-corrosion coating with superhydrophobic properties also has the advantages of self-cleaning and anti-fouling, making the anti-corrosion coating adaptable to more different operating environments. It will not have an adverse effect on materials such as nickel-based alloys, resins, and stainless steel in the secondary loop system, and will not affect the safe and stable operation of the unit. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0027] Figure 1 This is a diagram showing the hydrophobic effect of the material prepared by the cyclic treatment test in an embodiment of the present invention. Detailed Implementation

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0031] Example 1

[0032] (1) Material pretreatment: The surface area is 10±1cm 2 After the surface of the metal material is smoothed with sandpaper, it is cleaned with deionized water and anhydrous ethanol under ultrasonic conditions for 30 minutes in sequence, and then dried before use.

[0033] (2) In a round-bottom flask equipped with a magnetic stirrer, add dimethylethoxyformyloxysilane (0.5g), tridecyl 3-mercaptopropionate (1g), dodecyl isobutyrate (2g) and initiator dimethyl azobisisobutyrate (0.05g) to 20mL of anhydrous ethanol and 10mL of deionized water, and stir at room temperature for 30min until completely dissolved;

[0034] (3) The mixture was transferred to a constant temperature oil bath at 70°C and subjected to polymerization reaction for 7 hours;

[0035] (4) After the reaction, under strong magnetic stirring, 5 mL of TEOS was slowly added to 10 mL of ammonia water, mixed evenly, and then 3 mL of PAA solution was added dropwise. Stirring continued at room temperature, and then added to the above solution and ultrasonically dispersed for 30 min. The reaction continued at 50 °C for 2 h.

[0036] (5) Immerse the pretreated metal material in the above solution for 30 minutes and dry it in an oven at 70°C for 2 hours to obtain the superhydrophobic anticorrosive material.

[0037] Example 2

[0038] (1) Material pretreatment: The surface area is 10±1cm 2 After the surface of the metal material is smoothed with sandpaper, it is cleaned with deionized water and anhydrous ethanol under ultrasonic conditions for 20 minutes in sequence, and then dried before use.

[0039] (2) In a round-bottom flask equipped with a magnetic stirrer, add dimethylethoxyformyloxysilane (0.5g), tridecyl 3-mercaptopropionate (0.5g), dodecyl isobutyrate (1g) and initiator dimethyl azobisisobutyrate (0.025g) to 20mL of anhydrous ethanol and 10mL of deionized water, and stir at room temperature for 30min until completely dissolved;

[0040] (3) The mixture was transferred to a constant temperature oil bath at 60°C for polymerization reaction for 8 hours;

[0041] (4) After the reaction, under strong magnetic stirring, 5 mL of TEOS was slowly added to 5 mL of ammonia water, mixed evenly, and then 4.5 mL of PAA solution was added dropwise. Stirring continued at room temperature, and then added to the above solution and ultrasonically dispersed for 15 min. The reaction continued at 40 °C for 3 h.

[0042] (5) Immerse the pretreated metal material in the above solution for 15 minutes and dry it in an oven at 60°C for 3 hours to obtain the superhydrophobic anticorrosive material.

[0043] Example 3

[0044] (1) Material pretreatment: The surface area is 10±1cm 2 After the surface of the metal material is smoothed with sandpaper, it is cleaned with deionized water and anhydrous ethanol under ultrasonic conditions for 40 minutes in sequence, and then dried before use.

[0045] (2) In a round-bottom flask equipped with a magnetic stirrer, add dimethylethoxyformylsilane (0.5g), tridecyl 3-mercaptopropionate (1.5g), dodecyl isobutyrate (3.0g) and initiator dimethyl azobisisobutyrate (0.15g) to 30mL of anhydrous ethanol and 10mL of deionized water, and stir at room temperature for 40min until completely dissolved;

[0046] (3) The mixture was transferred to a constant temperature oil bath at 80°C for polymerization reaction for 6 hours;

[0047] (4) After the reaction, under strong magnetic stirring, 5 mL of TEOS was slowly added to 15 mL of ammonia water. After uniform mixing, 2 mL of PAA solution was added dropwise. Stirring continued at room temperature. Then, it was added to the above solution and ultrasonically dispersed for 45 min. The reaction continued at 60 °C for 1 h.

[0048] (5) Immerse the pretreated metal material in the above solution for 45 minutes and dry it in an oven at 80°C for 1 hour to obtain the superhydrophobic anticorrosive material.

[0049] Example 4

[0050] (1) Material pretreatment: The surface area is 10±1cm 2 After the surface of the metal material is smoothed with sandpaper, it is cleaned with deionized water and anhydrous ethanol under ultrasonic conditions for 30 minutes in sequence, and then dried before use.

[0051] (2) In a round-bottom flask equipped with a magnetic stirrer, add dimethylethoxyformylsilane (0.5g), tridecyl 3-mercaptopropionate (0.5g), dodecyl isobutyrate (1g), and initiator dimethyl azobisisobutyrate (0.05g) to 20mL of anhydrous ethanol and 10mL of deionized water, and stir at room temperature for 20min until completely dissolved;

[0052] (3) The mixture was transferred to a constant temperature oil bath at 75°C for polymerization reaction for 6.5 h;

[0053] (4) After the reaction, under strong magnetic stirring, 5 mL of TEOS was slowly added to 8 mL of ammonia water. After mixing evenly, 1 mL of PAA solution was added dropwise. Stirring continued at room temperature. Then, the solution was added to the above solution and ultrasonically dispersed for 20 min. The reaction continued at 55 °C for 1.5 h.

[0054] (5) Immerse the pretreated metal material in the above solution for 30 minutes and dry it in an oven at 70°C for 2 hours to obtain the superhydrophobic anticorrosive material.

[0055] Specific test conditions for corrosion resistance performance determination:

[0056] The corrosion performance of the pH-responsive superhydrophobic anticorrosive materials prepared based on SiO2 in Examples 1-4 of this invention was tested using an accelerated corrosion experiment (salt water immersion test) with artificial defect coatings. Artificial defect coatings are generally obtained by scratching the coating surface with a scribing tool.

[0057] Refer to ASTM-D1654 (Environmental assessment of corrosion resistance of brush / spray-coated specimens) and ASTM-B117 (Standard operating procedure for salt spray tester).

[0058] The specific experimental steps for preparing a defective coating through scratching are as follows: Using a scalpel and ruler, a straight artificial defect, 1.0 cm long, 50 μm wide, and reaching the substrate, is scratched on the coating surface (whether the scalpel reaches the metal substrate is determined by the contact resistance measured with a multimeter). The force applied for each scratch is kept consistent to ensure the uniformity of the defect. The defective coating sample is then immersed in 60 mL of 3.5 wt.% NaCl solution (100 mL beaker). The corrosion status of the coating surface is observed at regular intervals. After surface treatment, the surface is weighed, and the corrosion rate is calculated.

[0059] The corrosion resistance of the materials obtained in Examples 1-4 is shown in Table 1.

[0060] Table 1

[0061] Sample Corrosion rate Blank example 58.9 μg / d Example 1 8.2 μg / d Example 2 9.7 μg / d Example 3 10.8 μg / d Example 4 11.5 μg / d

[0062] As can be seen from Table 1, the superhydrophobic anticorrosive material prepared by this invention has a good anticorrosive effect.

[0063] Loop processing test:

[0064] The prepared material was immersed in an acidic aqueous solution (pH=1) for 3 minutes and dried. Then, it was immersed in an alkaline solution (pH=8) for 3 minutes and dried. The contact angle was tested by repeating the acid-base conditions for 9 cycles.

[0065] The hydrophobicity of the prepared material was tested by cyclic treatment; see [link to relevant documentation]. Figure 1 As can be seen, the prepared material exhibits good pH-induced surface wetting transition and can reversibly switch between superhydrophobicity and superhydrophilicity multiple times.

[0066] Comparative Example 1

[0067] (1) Material pretreatment: The surface area is 10±1cm 2 After the surface of the metal material is smoothed with sandpaper, it is cleaned with deionized water and anhydrous ethanol under ultrasonic conditions for 30 minutes in sequence, and then dried before use.

[0068] (2) In a round-bottom flask equipped with a magnetic stirring rotor, add dimethylethoxyformyloxysilane (0.5g), dodecyl isobutyrate (3g) and initiator dimethyl azobisisobutyrate (0.05g) to 20mL of anhydrous ethanol and 10mL of deionized water, and stir at room temperature for 30min until completely dissolved.

[0069] (3) The mixture was transferred to a constant temperature oil bath at 70°C and subjected to polymerization reaction for 7 hours;

[0070] (4) After the reaction, under strong magnetic stirring, 5 mL of TEOS was slowly added to 10 mL of ammonia water, mixed evenly, and then 3 mL of PAA solution was added dropwise. Stirring continued at room temperature, and then added to the above solution and ultrasonically dispersed for 30 min. The reaction continued at 50 °C for 2 h.

[0071] (5) Immerse the pretreated metal material in the above solution for 30 minutes and dry it in an oven at 70°C for 2 hours to obtain the material.

[0072] Comparative Example 2

[0073] (1) Material pretreatment: The surface area is 10±1cm 2 After the surface of the metal material is smoothed with sandpaper, it is cleaned with deionized water and anhydrous ethanol under ultrasonic conditions for 30 minutes in sequence, and then dried before use.

[0074] (2) In a round-bottom flask equipped with a magnetic stirrer, add dimethylethoxyformylsilane (0.5g), tridecyl 3-mercaptopropionate (3g) and initiator dimethyl azobisisobutyrate (0.05g) to 20mL of anhydrous ethanol and 10mL of deionized water, and stir at room temperature for 30min until completely dissolved.

[0075] (3) The mixture was transferred to a constant temperature oil bath at 70°C and subjected to polymerization reaction for 7 hours;

[0076] (4) After the reaction, under strong magnetic stirring, 5 mL of TEOS was slowly added to 10 mL of ammonia water, mixed evenly, and then 3 mL of PAA solution was added dropwise. Stirring continued at room temperature, and then added to the above solution and ultrasonically dispersed for 30 min. The reaction continued at 50 °C for 2 h.

[0077] (5) Immerse the pretreated metal material in the above solution for 30 minutes and dry it in an oven at 70°C for 2 hours to obtain the superhydrophobic anticorrosive material.

[0078] Comparative Example 3

[0079] (1) Material pretreatment: The surface area is 10±1cm 2 After the surface of the metal material is smoothed with sandpaper, it is cleaned with deionized water and anhydrous ethanol under ultrasonic conditions for 30 minutes in sequence, and then dried before use.

[0080] (2) In a round-bottom flask equipped with a magnetic stirrer, add dimethyl ethoxyformyl silane (0.5 g), ethylene glycol diisobutyrate (3 g) and initiator dimethyl azobisisobutyrate (0.05 g) to 20 mL of anhydrous ethanol and 10 mL of deionized water, and stir at room temperature for 30 min until completely dissolved.

[0081] (3) The mixture was transferred to a constant temperature oil bath at 70°C and subjected to polymerization reaction for 7 hours;

[0082] (4) After the reaction, under strong magnetic stirring, 5 mL of TEOS was slowly added to 10 mL of ammonia water, mixed evenly, and then 3 mL of PAA solution was added dropwise. Stirring continued at room temperature, and then added to the above solution and ultrasonically dispersed for 30 min. The reaction continued at 50 °C for 2 h.

[0083] (5) Immerse the pretreated metal material in the above solution for 30 minutes and dry it in an oven at 70°C for 2 hours to obtain the superhydrophobic anticorrosive material.

[0084] Table 2

[0085] Sample Corrosion rate Example 1 8.2 μg / d Comparative Example 1 12.7 μg / d Comparative Example 2 13.3 μg / d Comparative Example 3 14.6 μg / d

[0086] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a superhydrophobic anticorrosive material based on silica, characterized in that: include, Dimethylethoxyformylsilane, tridecyl 3-mercaptopropionate, dodecyl isobutyrate, anhydrous ethanol and deionized water were mixed evenly, and initiator AIBME was added. The mixture was stirred at room temperature until completely dissolved, and then transferred to a constant temperature oil bath for polymerization to obtain mixture 1. Ammonia solution was slowly added to tetraethyl orthosilicate (TEOS) under stirring, and polyacrylic acid (PAA) was added during the hydrolysis process to obtain mixture 2. Mixture 2 is added to mixture 1 and ultrasonically dispersed, and the reaction continues to obtain the superhydrophobic anticorrosive material.

2. The preparation method according to claim 1, characterized in that: The mass ratio of dimethylethoxyformylsilane, tridecyl 3-mercaptopropionate, dodecyl isobutyrate, and AIBME is 1:(1~3):(2~6):(0.05~0.15), the volume ratio of anhydrous ethanol to deionized water is (1~3):1, and the ratio of anhydrous ethanol to dimethylethoxyformylsilane is 20mL:0.5~1g.

3. The preparation method according to claim 1, characterized in that: Stir at room temperature until completely dissolved, for 20-40 minutes.

4. The preparation method according to claim 1, characterized in that: The polymerization reaction is carried out in a constant temperature oil bath at 60-80°C for 6-8 hours.

5. The preparation method according to claim 1, characterized in that: The volume ratio of ammonia water to TEOS and PAA is (1~3):1:(0.2~0.9).

6. The preparation method according to claim 1, characterized in that: The mixture 2 is added to the mixture 1 and ultrasonically dispersed, wherein the ratio of tridecyl 3-mercaptopropionate in the mixture 1 to tetraethyl orthosilicate in the mixture 2 is 1~3g:5~10mL.

7. The preparation method according to claim 1, characterized in that: The ultrasonic dispersion, wherein the ultrasonic reaction time is 15~45 min.

8. The preparation method according to claim 1, characterized in that: The superhydrophobic anticorrosive material is obtained by continuing the reaction, wherein the polymerization reaction temperature is 40~60℃ and the reaction time is 1~3h.

9. The application of the superhydrophobic anticorrosive material prepared by any one of claims 1 to 8 in the field of metal corrosion protection, characterized in that: include, After the surface of the metal material is smoothed with sandpaper, it is cleaned and dried in sequence with deionized water and anhydrous ethanol under ultrasonic conditions. The pretreated metal material is immersed in a superhydrophobic anti-corrosion material solution and then dried in an oven.

10. The application as described in claim 9, characterized in that: The soaking time is 15-45 minutes, and the drying time is 1-3 hours at 60-80℃.

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