Anti-corrosion self-repairing polyphenylene sulfide coating and preparation method thereof

Abstract

The invention discloses a preparation method of an anti-corrosion self-repairing polyphenylene sulfide coating. The preparation method comprises the following steps: synthesizing carboxyl functionalized polyphenylene sulfide; mixing and dispersing the carboxyl-functionalized polyphenylene sulfide and the amino-functionalized nanoparticles to form a suspension; spraying the suspension to form a film; curing the film at high temperature; and repeatedly and alternately putting the high-temperature cured film into a polyacrylamide solution and a polyacrylic acid solution for dip-coating, thereby finally obtaining the anticorrosive self-repairing polyphenylene sulfide coating. The anti-corrosion self-repairing polyphenylene sulfide coating is prepared by adopting the method. The composite coating prepared through the method has good corrosion resistance and self-repairing capacity, the corrosion resistance of the metal material can be effectively improved, and the service life of the metal material can be effectively prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polyphenylene sulfide modification, in particular to an anticorrosive self-repairing polyphenylene sulfide coating and a preparation method thereof. BACKGROUND

[0002] Metal materials are widely used in industrial production and daily life, but metal corrosion has always been an important factor affecting their service life and performance. Traditional metal anticorrosive coatings, such as paint coatings and electroplated layers, can play a certain anticorrosive role, but they are difficult to repair themselves after being mechanically damaged or chemically eroded, thereby causing the metal substrate to continue to be corroded and reducing the reliability and safety of metal components. Therefore, developing an anticorrosive coating with self-repairing function is of great significance for improving the corrosion resistance and prolonging the service life of metal materials. Polyphenylene sulfide (PPS) has excellent chemical stability, high-temperature resistance and mechanical properties, and has potential application value in the field of anticorrosive coatings. However, pure PPS coating has poor affinity with the metal surface and limited self-repairing ability. By functionalizing PPS and compounding it with other materials with self-repairing function, an anticorrosive self-repairing composite coating with excellent performance can be prepared. SUMMARY

[0003] In view of the above-mentioned defects of the prior art, the purpose of the present application is to provide an anticorrosive self-repairing polyphenylene sulfide coating and a preparation method. The composite coating prepared by the method has good anticorrosive performance and self-repairing ability, and can effectively improve the corrosion resistance and service life of metal materials.

[0004] The purpose of the present application is achieved by the following technical solutions:

[0005] The preparation method of the anticorrosive self-repairing polyphenylene sulfide coating comprises the following steps:

[0006] Synthesizing carboxyl-functionalized polyphenylene sulfide;

[0007] Mixing and dispersing the carboxyl-functionalized polyphenylene sulfide and the amino-functionalized nanoparticles to form a suspension;

[0008] Spraying the suspension into a film;

[0009] High-temperature curing the film;

[0010] Repeating and alternatingly immersing and pulling the high-temperature cured film in polyacrylamide solution and polyacrylic acid solution to coat the film, and finally obtaining the anticorrosive self-repairing polyphenylene sulfide coating.

[0011] Further, the step of "synthesizing carboxyl-functionalized polyphenylene sulfide" comprises the following steps:

[0012] Preparation of PPS prepolymer by oxidative polymerization;

[0013] Oxidizing the hydroxyl group of the PPS prepolymer into a carboxyl group.

[0014] Further, the step of "preparing a PPS prepolymer by oxidative polymerization" comprises the following steps:

[0015] N-methyl-2-pyrrolidone, sodium polysulfide, sodium hydroxide and a catalyst are sequentially mixed, and heated under N2 protection until the sodium polysulfide is completely dehydrated to obtain a preliminary reactant; the catalyst is one or more of sodium carbonate, sodium acetate, lithium chloride, lithium acetate and lithium bromide; the weight ratio of the amounts of N-methyl-2-pyrrolidone, sodium polysulfide, sodium hydroxide is 23-27:0.25-0.35:0.08-0.1; the molar ratio of the amounts of sodium polysulfide in the sodium polysulfide and the catalyst is 3.9:20-23;

[0016] p-dichlorobenzene, p-chlorobenzoic acid, N-methyl-2-pyrrolidone are sequentially added to the preliminary reactant, and then heated to 210-230℃, kept at this temperature for 1.8-2.2h, and then heated to 250-275℃, kept at this temperature for 2.5-3.5h to obtain the PPS prepolymer; the weight ratio of the amounts of the preliminary reactant, p-dichlorobenzene, p-chlorobenzoic acid, N-methyl-2-pyrrolidone is 25-27:6.9-7.2:0.35-0.4:4.7-5.1.

[0017] Further, the step of "oxidizing the hydroxyl group of the PPS prepolymer into a carboxyl group" comprises the following steps:

[0018] The temperature of the PPS prepolymer is controlled at 145-155℃, and the PPS prepolymer is acidified with dilute hydrochloric acid, and then centrifuged to collect the solid substance; the solid substance is washed with desalted water, and finally vacuum dried to obtain the carboxyl-functionalized polyphenylene sulfide.

[0019] Further, the step of "mixing and dispersing the carboxyl-functionalized polyphenylene sulfide and the amino-functionalized nanoparticles to form a suspension" comprises the following steps:

[0020] The carboxyl-functionalized polyphenylene sulfide and the amino-functionalized nanoparticles are dispersed in anhydrous ethanol, and ultrasonically treated for 25-35min to form a uniformly dispersed suspension; the weight ratio of the amounts of the carboxyl-functionalized polyphenylene sulfide, the amino-functionalized nanoparticles and the anhydrous ethanol is 1:0.9-1.1:90-110;

[0021] The amino-functionalized nanoparticles are one or more of NH2-TiO2, NH2-ZrO2 and NH2-ZnO.

[0022] Further, the film thickness sprayed in the step of "spraying the suspension into a film" is 20-25 μm; the curing temperature in the step of "high-temperature curing the film" is 28-310℃, and the curing time is 2.8-3.2 h.

[0023] Further, in the step of "immersing and pulling the high-temperature cured film alternately in polyacrylamide solution and polyacrylic acid solution for coating, and finally obtaining the corrosion-resistant self-repairing polyphenylene sulfide coating", the concentration of the polyacrylamide solution is 1.8-2.2 g / L, and the immersion time in the polyacrylamide solution is 15-25 min; the concentration of the polyacrylic acid solution is 1.8-2.2 g / L, and the immersion time in the polyacrylic acid solution is 15-25 min.

[0024] Further, in the step of "spraying the suspension into a film", the suspension is sprayed on the pretreated metal surface to form a film; and the pretreated metal surface is rich in a hydroxyl film layer.

[0025] Further, the metal surface is rich in a hydroxyl film layer after the following steps:

[0026] polishing the surface to be sprayed to bright;

[0027] immersing the surface to be sprayed in anhydrous ethanol for ultrasonic cleaning for 8-12 min;

[0028] immersing the cleaned surface to be sprayed in an aqueous solution of one or a mixture of multiple LiOH, NaOH and KOH with a concentration of 0.08-0.12 mol / L, and hydrothermally treating at 160-200℃ for 1.8-2.2 h;

[0029] removing the surface to be sprayed from the aqueous solution, cooling to room temperature, cleaning the surface to be sprayed with deionized water, and quickly air-drying the surface to be sprayed.

[0030] The corrosion-resistant self-repairing polyphenylene sulfide coating is characterized in that it is prepared by any of the above-mentioned methods.

[0031] Due to the above technical solutions, the present application has the following advantages:

[0032] 1. The present application forms a hydroxyl film layer rich in negative charges on the metal surface by KOH hydrothermal treatment, enhances the adhesion between the carboxyl functionalized polyphenylene sulfide coating and the metal substrate, and enables the coating to firmly adhere to the metal surface and not to easily fall off.

[0033] 2. The PPS coating layer formed by spraying carboxyl functionalized PPS and high temperature treatment to form cross-linked structure, endows the composite coating layer with excellent chemical stability and high temperature resistance, and the introduction of amino functionalized zirconium dioxide nanoparticles effectively enhances the wear resistance of the coating layer.

[0034] 3. The self-repairing coating layer has fast repair speed, high repair degree, and can be repeatedly repaired, thereby effectively improving the protection performance.

[0035] Other advantages, objects, and features of the application will be in part apparent and in part pointed out hereinafter in the specification, and in part will be learned from the practice of the application. DETAILED DESCRIPTION

[0036] The application will be further described below in conjunction with examples.

[0037] Example 1:

[0038] The steps for preparing the coating layer include:

[0039] 1. A piece of Q235 steel with a size of 1 cm x 1 cm was selected, and the surface was polished to brightness successively using 400 mesh and 800 mesh sandpaper, and then ultrasonic cleaning in anhydrous ethanol for 10 min.

[0040] 2. The polished Q235 steel was placed in a 0.1 mol / L KOH aqueous solution and hydrothermally treated at 180℃ for 2h. After cooling to room temperature, it was rinsed with deionized water and quickly air dried.

[0041] 3. 1.00g of PPS-COOH and 0.01g of amino functionalized zirconium dioxide (NH2-ZrO2) nanoparticles were dispersed in 100mL of anhydrous ethanol, and ultrasonic treatment was performed for 30min to form a uniformly dispersed suspension. The suspension was uniformly sprayed on the pretreated metal surface using an airbrush, and the spraying distance was maintained at 15-20cm, and the spraying thickness was 20μm. The sprayed Q235 steel was placed in a muffle furnace and solidified at 300℃ for 3h to form a wear-resistant and corrosion-resistant primer, which was denoted as PPS-COOH@NH2-ZrO2.

[0042] 4. The Q235 steel coated with the PPS-COOH@NH2-ZrO2 primer was immersed in a 2.0g / L polyacrylamide (PAM) solution for 20min, and then immersed in a 2.0g / L polyacrylic acid (PAA) solution for 20min. The above process was repeated for 20 times alternately, and finally dried at room temperature to obtain a corrosion-resistant self-repairing composite coating, which was denoted as PAM@PAA / PPS-COOH@NH2-ZrO2 / Fe.

[0043] Example 2

[0044] The steps for preparing the coating layer include:

[0045] 1. Select a piece of AZ31 magnesium alloy with a size of 1 cm x 1 cm, polish the surface to a bright finish using 400 mesh and 800 mesh sandpaper in turn, and then ultrasonically clean it in anhydrous ethanol for 10 min.

[0046] 2. Place the polished AZ31 magnesium alloy in a 0.1 mol / L aqueous KOH solution and hydrothermally treat it at 180°C for 2 h. Cool to room temperature, rinse with deionized water, and quickly air dry.

[0047] 3. Disperse 1.00 g of PPS-COOH and 0.01 g of amino-functionalized zirconium dioxide (NH2-ZrO2) nanoparticles in 100 mL of anhydrous ethanol, ultrasonically treat for 30 min to form a uniformly dispersed suspension. Use an airbrush to evenly spray the suspension onto the pretreated metal surface, maintain a spraying distance of 15-20 cm, and the spraying thickness is 20 μm. Place the sprayed AZ31 magnesium alloy in a muffle furnace and solidify it at 300°C for 3 h to form a wear-resistant and corrosion-resistant primer, denoted as PPS-COOH@NH2-ZrO2.

[0048] 4. Soak the AZ31 magnesium alloy coated with the PPS-COOH@NH2-ZrO2 primer in a 2.0 g / L polyacrylamide (PAM) solution for 20 min, and then in a 2.0 g / L polyacrylic acid (PAA) solution for 20 min. Repeat the above process for 20 times alternately, and finally dry it at room temperature to obtain a corrosion-resistant self-repairing composite coating, denoted as PAM@PAA / PPS-COOH@NH2-ZrO2 / Mg.

[0049] Comparative Example 1

[0050] 1. Select a piece of Q235 steel with a size of 1 cm x 1 cm, polish the surface to a bright finish using 400 mesh and 800 mesh sandpaper in turn, and then ultrasonically clean it in anhydrous ethanol for 10 min.

[0051] 2. Place the polished Q235 steel in a 0.1 mol / L aqueous KOH solution and hydrothermally treat it at 180°C for 2 h. Cool to room temperature, rinse with deionized water, and quickly air dry.

[0052] 3. 1.00 g of PPS and 0.01 g of amino-functionalized zirconium dioxide (NH2-ZrO2) nanoparticles were dispersed in 100 mL of anhydrous ethanol, ultrasonically treated for 30 min to form a uniformly dispersed suspension. The suspension was uniformly sprayed on the pretreated metal surface using an airbrush, maintaining a spraying distance of 15-20 cm and a spraying thickness of 20 μm. The sprayed Q235 steel was placed in a muffle furnace and cured at 300 °C for 3 h to form a wear-resistant and corrosion-resistant primer film, denoted as PPS@NH2-ZrO2.

[0053] 4. The Q235 steel coated with the PPS@NH2-ZrO2 primer film was immersed in a 2.0 g / L polyacrylamide (PAM) solution for 20 min, and then immersed in a 2.0 g / L polyacrylic acid (PAA) solution for 20 min. The above process was repeated for 20 times of alternate deposition, and finally dried at room temperature to obtain a corrosion-resistant self-repairing coating, denoted as PAM@PAA / PPS@NH2-ZrO2 / Fe.

[0054] Comparative Example 2:

[0055] 1. A piece of AZ31 magnesium alloy with a size of 1 cm x 1 cm was selected, and the surface was polished to a bright finish using 400 mesh and 800 mesh sandpaper in turn, and then ultrasonically cleaned in anhydrous ethanol for 10 min.

[0056] 2. The polished AZ31 magnesium alloy was placed in a 0.1 mol / L aqueous KOH solution and hydrothermally treated at 180 °C for 2 h. After cooling to room temperature, it was rinsed with deionized water and quickly air-dried.

[0057] 3. 1.00 g of PPS and 0.01 g of amino-functionalized zirconium dioxide (NH2-ZrO2) nanoparticles were dispersed in 100 mL of anhydrous ethanol, ultrasonically treated for 30 min to form a uniformly dispersed suspension. The suspension was uniformly sprayed on the pretreated metal surface using an airbrush, maintaining a spraying distance of 15-20 cm and a spraying thickness of 20 μm. The sprayed AZ31 magnesium alloy was placed in a muffle furnace and cured at 300 °C for 3 h to form a wear-resistant and corrosion-resistant primer film, denoted as PPS@NH2-ZrO2.

[0058] 4. The AZ31 magnesium alloy coated with the PPS@NH2-ZrO2 primer film was immersed in a 2.0 g / L polyacrylamide (PAM) solution for 20 min, and then immersed in a 2.0 g / L polyacrylic acid (PAA) solution for 20 min. The above process was repeated for 20 times of alternate deposition, and finally dried at room temperature to obtain a corrosion-resistant self-repairing coating, denoted as PAM@PAA / PPS@NH2-ZrO2 / Mg.

[0059] Comparative Example 3:

[0060] 1. A piece of Q235 steel with a size of 1 cm x 1 cm was selected, and its surface was polished to brightness successively using 400-mesh and 800-mesh sandpaper, and then ultrasonic cleaning in anhydrous ethanol for 10 min.

[0061] 2. The polished Q235 steel was placed in a 0.1 mol / L aqueous KOH solution and hydrothermally treated at 180°C for 2 h. After cooling to room temperature, it was rinsed with deionized water and quickly air-dried.

[0062] 3. 1.00 g of PPS-COOH was dispersed in 100 mL of anhydrous ethanol and ultrasonic treated for 30 min to form a uniformly dispersed suspension. The suspension was uniformly sprayed on the pretreated metal surface using an airbrush, with a spraying distance of 15-20 cm and a spraying thickness of 20 μm. The sprayed Q235 steel was placed in a muffle furnace and solidified at 300°C for 3 h to form a PPS-COOH primer film.

[0063] 4. The Q235 steel coated with the PPS-COOH primer film was immersed in a 2.0 g / L polyacrylamide (PAM) solution for 20 min, and then immersed in a 2.0 g / L polyacrylic acid (PAA) solution for 20 min. The above process was repeated for 20 times alternately, and finally dried at room temperature to obtain a corrosion-resistant self-repairing composite coating, denoted as PAM@PAA / PPS-COOH / Fe.

[0064] Comparative Example 4:

[0065] 1. A piece of AZ31 magnesium alloy with a size of 1 cm x 1 cm was selected, and its surface was polished to brightness successively using 400-mesh and 800-mesh sandpaper, and then ultrasonic cleaning in anhydrous ethanol for 10 min.

[0066] 2. The polished AZ31 magnesium alloy was placed in a 0.1 mol / L aqueous KOH solution and hydrothermally treated at 180°C for 2 h. After cooling to room temperature, it was rinsed with deionized water and quickly air-dried.

[0067] 3. 1.00 g of PPS-COOH was dispersed in 100 mL of anhydrous ethanol and ultrasonic treated for 30 min to form a uniformly dispersed suspension. The suspension was uniformly sprayed on the pretreated metal surface using an airbrush, with a spraying distance of 15-20 cm and a spraying thickness of 20 μm. The sprayed AZ31 magnesium alloy was placed in a muffle furnace and solidified at 300°C for 3 h to form a PPS-COOH primer film.

[0068] 4. The PPS-COOH bottom film coated AZ31 magnesium alloy was immersed in a 2.0 g / L polyacrylamide (PAM) solution for 20 min, and then immersed in a 2.0 g / L polyacrylic acid (PAA) solution for 20 min. The above process was repeated for 20 times alternately, and finally dried at room temperature to obtain a corrosion-resistant self-repairing composite coating, denoted as PAM@PAA / PPS-COOH / Mg.

[0069] Comparative Example 5:

[0070] 1. A piece of Q235 steel with a size of 1 cm x 1 cm was selected, and its surface was polished to brightness successively using 400-mesh and 800-mesh sandpaper, and then ultrasonically cleaned in anhydrous ethanol for 10 min.

[0071] 2. The polished Q235 steel was placed in a 0.1 mol / L KOH aqueous solution and hydrothermally treated at 180°C for 2 h. After cooling to room temperature, it was rinsed with deionized water and quickly air-dried.

[0072] 3. 1.00 g of PPS-COOH and 0.01 g of amino-functionalized zirconium dioxide (NH2-ZrO2) nanoparticles were dispersed in 100 mL of anhydrous ethanol, and ultrasonically treated for 30 min to form a uniformly dispersed suspension. The suspension was uniformly sprayed on the pretreated metal surface using an airbrush, with a spraying distance of 15-20 cm and a spraying thickness of 20 μm. The sprayed Q235 steel was placed in a muffle furnace and solidified at 300°C for 3 h to form a wear-resistant and corrosion-resistant bottom film, denoted as PPS-COOH@NH2-ZrO2 / Fe.

[0073] Comparative Example 6:

[0074] 1. A piece of AZ31 magnesium alloy with a size of 1 cm x 1 cm was selected, and its surface was polished to brightness successively using 400-mesh and 800-mesh sandpaper, and then ultrasonically cleaned in anhydrous ethanol for 10 min.

[0075] 2. The polished AZ31 magnesium alloy was placed in a 0.1 mol / L KOH aqueous solution and hydrothermally treated at 180°C for 2 h. After cooling to room temperature, it was rinsed with deionized water and quickly air-dried.

[0076] 3. 1.00 g of PPS-COOH and 0.01 g of amino-functionalized zirconium dioxide (NH2-ZrO2) nanoparticles were dispersed in 100 mL of anhydrous ethanol, and ultrasonic treatment was performed for 30 min to form a uniformly dispersed suspension. The suspension was uniformly sprayed on the pretreated metal surface using a spray gun, and the spraying distance was maintained at 15-20 cm, and the spraying thickness was 20 μm. The sprayed AZ31 magnesium alloy was placed in a muffle furnace and cured at 300 °C for 3 h to form a wear-resistant and corrosion-resistant primer film, which was denoted as PPS-COOH@NH2-ZrO2 / Fe.

[0077] The coatings prepared in Examples 1-2 and Comparative Examples 1-6 above were subjected to performance tests for coating thickness, adhesion strength, Young's modulus, film layer resistance, and self-repairing time. Specifically:

[0078] The coating thickness was tested by scanning electron microscopy (SEM);

[0079] The adhesion strength of the coating on the metal substrate was tested by cross-cut tape peeling test according to ASTM D3359 standard;

[0080] The indentation load curve of the coating was tested by atomic force microscopy (AFM), and the Young's modulus was calculated by Hertz model fitting;

[0081] The film layer resistance of the film layer sample was tested by electrochemical impedance spectroscopy (EIS);

[0082] The coating surface was scratched with a needle tip to form a scratch with a width of 100-110 μm, and was placed in a 90% RH environment, and the scratch disappearance time was recorded to test the self-repairing time of the coating.

[0083] The test results of the above indicators are shown in Table 1.

[0084] Table 1. Performance test results

[0085]

[0086] From the performance test results in Table 1, the following conclusions can be drawn:

[0087] 1. From the control examples of Examples 1-2, Comparative Examples 1-2, Comparative Examples 3-4, and Comparative Examples 5-6, it can be concluded that the use of different materials of metal as the adhesion substrate of the coating has no significant effect on the various index data of the finally prepared coating.

[0088] 2、From the two groups of experimental examples 1-2, Comparative Examples 1-2, it can be concluded that whether the polyphenylene sulfide is carboxyl functionalized has a great influence on the adhesion strength of the finally prepared coating to the metal material, and the carboxyl functionalized polyphenylene sulfide can greatly improve the adhesion strength of the coating to the metal material; whether the polyphenylene sulfide is carboxyl functionalized has a great influence on the self-repairing ability of the finally prepared coating, and the carboxyl functionalized polyphenylene sulfide can greatly improve the self-repairing time of the coating, which can be shortened by 33.3% compared with the coating prepared by using the non-carboxyl functionalized polyphenylene sulfide as raw material.

[0089] 3、From the two groups of experimental examples 1-2, Comparative Examples 3-4, it can be concluded that when the carboxyl functionalized polyphenylene sulfide is sprayed, the addition of the amino functionalized nanoparticles can greatly improve the Young's modulus of the coating, and the Young's modulus of the coating with the addition of the amino functionalized nanoparticles is about 3 times that without the addition, and the scratch resistance is greatly improved; the addition of the amino functionalized nanoparticles can greatly improve the film layer resistance of the coating, and the electric protection performance of the coating is more than 7 times that of the coating without the addition of the nanoparticles.

[0090] 4、From the two groups of experimental examples 1-2, Comparative Examples 5-6, it can be concluded that the coating prepared by the immersion pulling coating method does not have self-repairing ability at all.

[0091] In summary, the coating prepared by the experimental examples 1-2 has high adhesion strength, high Young's modulus (strong scratch resistance), high electric protection performance, self-repairing ability and relatively short self-repairing time under the condition of the same coating thickness.

[0092] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not limiting, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing an anti-corrosion self-repairing polyphenylene sulfide coating, characterized in that: The following steps are involved: Synthesis of carboxyl-functionalized polyphenylene sulfide; mixing and dispersing carboxyl-functionalized polyphenylene sulfide and amino-functionalized nanoparticles to form a suspension; spraying the suspension into a film; Curing the film at high temperature; The high-temperature cured film is repeatedly and alternately placed in a polyacrylamide solution and a polyacrylic acid solution for immersion and pulling to form a coating, and finally an anti-corrosion self-repairing polyphenylene sulfide coating is obtained.

2. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 1, characterized in that: The step of "synthesizing carboxyl-functionalized polyphenylene sulfide" comprises the following steps: Preparation of PPS prepolymer by oxidative polymerization; The hydroxyl groups of the PPS prepolymer are oxidized to carboxyl groups.

3. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 2, characterized in that: The step of "preparing a PPS prepolymer by oxidative polymerization" comprises the following steps: N-methyl-2-pyrrolidone, sodium sulfide polyhydrate, sodium hydroxide and a catalyst are sequentially mixed, and the temperature is increased under nitrogen protection until the sodium sulfide polyhydrate is completely dehydrated to obtain a preliminary reactant; the catalyst is one or more of sodium carbonate, sodium acetate, lithium chloride, lithium acetate and lithium bromide; the weight ratio of N-methyl-2-pyrrolidone to sodium sulfide polyhydrate and sodium hydroxide is 23-27:0.25-0.35:0.08-0.1; the molar ratio of sodium sulfide to catalyst in sodium sulfide polyhydrate is 3.9:20-23; p-Dichlorobenzene, p-chlorobenzoic acid and N-methyl-2-pyrrolidone are added to the preliminary reactants in sequence, and then the temperature is raised to 210-230°C and kept constant at the temperature for 1.8-2.2 hours. Subsequently, the temperature is further raised to 250-275°C and kept constant at the temperature for 2.5-3.5 hours to obtain a PPS prepolymer; the weight ratio of the preliminary reactants, p-dichlorobenzene, p-chlorobenzoic acid and N-methyl-2-pyrrolidone is 25-27:6.9-7.2:0.35-0.4:4.7-5.

1.

4. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 2, characterized in that: The step of "oxidizing the hydroxyl groups of the PPS prepolymer into carboxyl groups" comprises the following steps: The temperature of the PPS prepolymer is controlled at 145-155° C., and it is acidified with dilute hydrochloric acid. The solid matter is then collected by centrifugation. The solid matter is fully washed with desalted water, and finally vacuum dried to obtain carboxyl-functionalized polyphenylene sulfide.

5. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 1, characterized in that: The step of "mixing and dispersing the carboxyl-functionalized polyphenylene sulfide and the amino-functionalized nanoparticles to form a suspension" comprises the following steps: The carboxyl-functionalized polyphenylene sulfide and the amino-functionalized nanoparticles are dispersed in anhydrous ethanol and ultrasonically treated for 25 to 35 minutes to form a uniformly dispersed suspension; the weight ratio of the carboxyl-functionalized polyphenylene sulfide, the amino-functionalized nanoparticles, and the anhydrous ethanol is 1:0.9 to 1.1:90 to 110; The amino-functionalized nanoparticles are a mixture of one or more of NH2-TiO2, NH2-ZrO2, and NH2-ZnO.

6. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 1, characterized in that: The thickness of the film sprayed in the step of "spraying the suspension into a film" is 20 to 25 μm; the curing temperature in the step of "curing the film at a high temperature" is 28 to 310° C., and the curing time is 2.8 to 3.2 hours.

7. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 1, characterized in that: In the step of "repeatedly and alternately placing the high-temperature cured film into a polyacrylamide solution and a polyacrylic acid solution for immersion and pulling the coating to finally obtain an anti-corrosion self-repairing polyphenylene sulfide coating", the concentration of the polyacrylamide solution is 1.8 to 2.2 g / L, and the immersion time in the polyacrylamide solution is 15 to 25 minutes; the concentration of the polyacrylic acid solution is 1.8 to 2.2 g / L, and the immersion time in the polyacrylic acid solution is 15 to 25 minutes.

8. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 1, characterized in that: In the step of "spraying the suspension into a film", the suspension is sprayed onto the pretreated metal surface to form a film; the pretreated metal surface is rich in a hydroxyl film layer.

9. The method for preparing the anti-corrosion self-repairing polyphenylene sulfide coating according to claim 8, characterized in that: The metal surface is rich in hydroxyl film after the following steps: Sand the surface to be sprayed until it is bright; Place the surface to be sprayed in anhydrous ethanol and ultrasonically clean it for 8 to 12 minutes; Immerse the cleaned surface to be sprayed in an aqueous solution of LiOH, NaOH, or KOH with a concentration of 0.08 to 0.12 mol / L or a mixed aqueous solution thereof, and perform hydrothermal treatment at 160 to 200°C for 1.8 to 2.2 hours; The surface to be sprayed is separated from the aqueous solution, cooled to room temperature, cleaned with deionized water, and quickly air-dried.

10. Anti-corrosion self-repairing polyphenylene sulfide coating, characterized in that: The anti-corrosion self-repairing polyphenylene sulfide coating is prepared by any one of the preparation methods of claims 1-9.

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