A water-based self-healing rust-preventing coating and its preparation method

Abstract

This invention belongs to the field of rust-preventive coating material preparation technology, specifically relating to a water-based self-healing rust-preventive coating and its preparation method. First, an unsaturated ester, a fluorinated unsaturated ester, and 1,4-dithiothreitol are prepared into a fluorinated hydrophilic polymer under the conditions of an initiator, a chain extender, and water as a solvent. Then, the obtained fluorinated hydrophilic polymer is reacted in an aqueous phase to prepare a water-based fluorinated acrylic copolymer. Finally, the water-based fluorinated acrylic copolymer is compounded with modified CeO2 nanoparticles, iron oxide, talc, and antioxidant 168 to obtain a water-based self-healing coating material. This invention achieves self-healing of the coating material by introducing a D-A reaction, and uses water as a diluent, is non-toxic, odorless, harmless to humans, and does not pollute the environment. By introducing cerium groups, this coating improves the corrosion resistance of metals, greatly extending the service life of the material and possessing high application value.

Description

Technical Field

[0001] This invention belongs to the field of rust-preventive coating material preparation technology, specifically relating to a water-based self-healing rust-preventive coating and its preparation method. Background Technology

[0002] Metal corrosion is a significant challenge, potentially leading to substantial economic losses and even threatening personal safety. To date, the most effective method for protecting metals from corrosion is the application of protective coatings, which act as a strong barrier to the underlying substrate. However, the long-term corrosion resistance of general coatings is not ideal, requiring further efforts. With increasing corrosion time, corrosive media can penetrate through the micropores of the coating, damaging the substrate. Coating cracks can also allow corrosive media to directly infiltrate the substrate. To address these issues and improve the protective properties of coatings and the service life of metals, corrosion inhibitors need to be introduced into the coating to enhance its self-healing ability and provide more effective corrosion protection.

[0003] Generally, the most common corrosion inhibitors include hexavalent chromium, 8-hydroxyquinoline (8HQ), and benzotriazole (BTA). These inhibitors contain carcinogens and pose potential environmental pollution risks, significantly limiting their practical application. In recent years, lanthanide compounds have attracted widespread attention due to their high protective performance and low toxicity. While cerium-based coatings can improve the corrosion resistance of metals to some extent and extend their service life, their heat resistance is relatively low, and their performance may be affected at high temperatures. Furthermore, cerium-based coatings have poor repairability; once damaged, repair is difficult. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a method for preparing a water-based self-healing rust-preventive coating, using water as a diluent, making it environmentally friendly and pollution-free. The water-based self-healing coating of this invention utilizes a DA reaction self-healing system, significantly extending the material's service life.

[0005] The preparation method of the water-based self-healing anti-rust coating provided by this invention includes the following specific steps:

[0006] (1) Preparation of fluorinated hydrophilic polymers

[0007] Unsaturated esters, fluorinated unsaturated esters, and 1,4-dithiothreitol were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. Under the conditions of initiator, 2,2-dimethylolpropionic acid (chain extender), and water as solvents, and under the condition of magnetic stirring at 75°C to ensure uniform mixing, the reaction was carried out for 8 hours to obtain a fluorinated hydrophilic polymer. The polymer was then placed in a 60°C oven and dried for 12 hours for subsequent use.

[0008] The unsaturated esters include one or a mixture of several of the following: ethylene tert-carbonate, butyl methacrylate, methyl acrylate, glycidyl methacrylate, and 2-methoxyethyl acrylate, with the following structural formula:

[0009] The structural formula of the 1,4-dithiothreitol monomer used is:

[0010]

[0011] The fluorinated unsaturated ester is one or a mixture of several of the following: dodecafluoroheptyl methacrylate, pentafluoropropyl methacrylate, octafluoropentyl methacrylate, pentafluoropropyl acrylate, and perfluorohexylethyl acrylate, with the following structural formula:

[0012]

[0013]

[0014] The initiator is hydrogen peroxide, and its dosage is 0.1-0.3% of the total mass of the unsaturated ester and the fluorinated unsaturated ester.

[0015] The molar ratio of unsaturated ester, fluorinated unsaturated ester, 1,4-dithiothreitol and 2,2-dimethylolpropionic acid is 2:1:1:1;

[0016] (2) Preparation of fluorinated hydrophilic acrylic copolymer

[0017] The obtained fluorinated hydrophilic polymer was added to a three-necked flask containing 100 mL of water and ultrasonically dispersed for 5 h. Then, methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate and maleimide were added. Benzoyl peroxide was used as an initiator and sodium dodecyl sulfate as an emulsifier. The reaction was carried out at 60 °C with stirring for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0018] The amount of fluorinated hydrophilic polymer added is 50% of the total mass of methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate and maleimide.

[0019] The molar ratio of methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate, and maleimide is 2:1:1:4;

[0020] The amount of initiator benzoyl peroxide is 0.02-0.04% of the total mass of methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate, and maleimide.

[0021] The amount of emulsifier used is 3-4% of the total mass of methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate, and maleimide.

[0022] (3) Preparation of water-based self-healing anti-rust coatings

[0023] The prepared fluorinated hydrophilic acrylic copolymer was mixed with sodium dodecyl sulfonate modified CeO2 nanoparticles, iron oxide, talc, antioxidant 168 and water to finally obtain a water-based self-healing anti-rust coating.

[0024] The amount of sodium dodecyl sulfonate modified CeO2 nanoparticles added is 3%-6% of the mass of the fluorinated hydrophilic acrylic copolymer;

[0025] The amount of iron oxide added is 2%-7% of the mass of the fluorinated hydrophilic acrylic copolymer;

[0026] The amount of talc added is 3%-5% of the mass of the fluorinated hydrophilic acrylic copolymer;

[0027] The amount of antioxidant 168 added is 6%-10% of the mass of sodium dodecyl sulfonate modified CeO2 nanoparticles.

[0028] Beneficial Effects: This invention, through the synergistic effect of fluorinated unsaturated esters and 1,4-dithiothreitol, not only enhances the tensile strength and hydrophilicity of self-healing coating materials, but also uses water as a diluent, making it environmentally friendly, non-toxic, non-flammable, and free of carcinogens such as benzene and formaldehyde, as well as heavy metals. Furthermore, water-based coatings are energy-saving, environmentally friendly, non-flammable, non-explosive, have ultra-low emissions, and are low-carbon and healthy. This invention, through a self-healing system initiating a DA reaction and sodium dodecyl sulfonate-modified CeO2 nanoparticles, significantly extends the service life of the material.

[0029] The water-based self-healing anti-rust coating prepared by this invention contains a polymer with hydrophilic groups and sodium dodecyl sulfonate-modified CeO2 nanoparticles, which gives the coating excellent self-healing and corrosion resistance, greatly extending the service life of the material. It is mainly used in automotive coatings, railway vehicles, bridges and pipelines, steel structures, containers, and other fields. Attached Figure Description

[0030] Figure 1 The infrared spectrum of the water-based self-healing anti-rust coating material prepared in Example 1 is shown.

[0031] Figure 2 The thermogravimetric curve (TG) of the water-based self-healing anti-rust coating material prepared in Example 1.

[0032] Figure 3 The thermogravimetric differential curve (DTG) of the water-based self-healing anti-rust coating material prepared in Example 1 is shown.

[0033] Figure 4 The image shows a comparison of the self-healing and anti-rust coating material prepared in Example 1 before and after self-healing. Detailed Implementation

[0034] The present invention will be further described below with reference to embodiments, but is not limited thereto.

[0035] Example 1

[0036] 3.96 g of ethylene tert-carbonate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0037] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.0 g of methyl methacrylate, 1.44 g of hydroxypropyl methacrylate, 2.38 g of pentafluorophenol acrylate, and 3.88 g of maleimide were added, along with 0.0029 g of benzoyl peroxide as an initiator and 0.34 g of sodium dodecyl sulfate as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0038] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.2g of modified CeO2 nanoparticles, 0.15g of iron oxide, 0.17g of talc, 0.14g of antioxidant 168 and 30mL of water to finally obtain a water-based self-healing anti-rust coating.

[0039] The modified CeO2 nanoparticles were prepared as follows: 10g of CeO2 nanoparticles were weighed and placed in a beaker (the beaker was placed in a water bath set to -5℃). 100mL of deionized water was added and stirred for 30 minutes. Then, 0.04g of sodium dodecyl sulfonate dissolved in 2mL of ethanol was added. The mixture was reacted at 70℃ for 6 hours. The mixture was then removed, filtered, washed, and placed in a vacuum drying oven. It was dried at 60℃ for 12 hours to obtain the modified CeO2 nanoparticles.

[0040] To determine the relative molecular weight and molecular weight distribution of the coating, approximately 10 mg of the prepared water-based self-healing rust-preventing coating was dissolved in tetrahydrofuran (2 mL), and the filtered solution was used for GPC (Waters 1515) testing. Tetrahydrofuran was used as the eluent, the flow rate was 1.0 mL / min, and the temperature was 40 °C. The number-average molecular weight of the coating was determined to be 34,800, and the weight-average molecular weight was 48,400.

[0041] To verify the mechanical properties of the coating, the prepared water-based self-healing rust-preventive coating was poured into a dumbbell-shaped mold and dried in an oven at 60°C for 24 hours. The sample was then tested according to ASTM D882 at a test speed of 500 mm / min. The tensile strength was 5.23 MPa and the elongation at break was 708%.

[0042] To verify the hydrophilic properties of the coating, the coating was uniformly applied to the surface of a polytetrafluoroethylene film with a thickness of 5 mm and allowed to dry for 12 hours. Then, the water contact angle of the coating was tested using a JC2000D1 contact angle meter, and the water contact angle of the coating was measured to be 62°.

[0043] To verify the heat resistance of the coating, 10 mg of the obtained coating was taken, heated at a rate of 10℃ / min, with a temperature range of 30-800℃, and tested under a nitrogen atmosphere. The thermal decomposition temperature of the sample with 5% weight loss was determined to be 242℃, and the thermal decomposition temperature with 10% weight loss was determined to be 273℃.

[0044] To verify the self-healing properties of the coating, a 2mm wide incision was made in the prepared tensile specimen with a knife, and the specimen was placed in a 60℃ oven for 6 hours for repair. Afterward, it was observed under an optical microscope. Figure 2 As can be seen, the incision has almost completely healed.

[0045] To verify the corrosion resistance of the coating, it was applied to an iron substrate with a thickness of 5 mm. A salt spray test chamber was prepared, and the temperature (25℃) and relative humidity (50%) were set. The test was started, and after 24 hours, there was no obvious corrosion on the coating surface.

[0046] Example 2

[0047] 1.42 g of butyl methacrylate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0048] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0049] The performance testing method was the same as in Example 1. The number-average molecular weight was 32,500, and the weight-average molecular weight was 43,100. The tensile strength was 5.20 MPa, and the elongation at break was 702%. The water contact angle of the coating was 65°. The thermal decomposition temperature was 232°C for 5% weight loss and 264°C for 10% weight loss. After 22 hours, there was no obvious corrosion on the coating surface.

[0050] Example 3

[0051] In a three-necked flask equipped with nitrogen protection and a magnetic stirrer, 2.0 g of methyl acrylate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0052] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0053] The performance testing method was the same as in Example 1. The number-average molecular weight was 30,500, and the weight-average molecular weight was 41,600. The tensile strength was 5.08 MPa, and the elongation at break was 620%. The water contact angle of the coating was 72°. The thermal decomposition temperature of 5% weight loss was 238°C, and the thermal decomposition temperature of 10% weight loss was 267°C. After 22 hours, there was no obvious corrosion on the coating surface.

[0054] Example 4

[0055] 1.42 g glycidyl methacrylate, 4.0 g dodecafluoroheptyl methacrylate, 1.54 g 1,4-dithiothreitol, 0.09 g hydrogen peroxide, 1.34 g 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0056] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0057] The performance testing method was the same as in Example 1. The number-average molecular weight was 32,900, and the weight-average molecular weight was 46,400. The tensile strength was 5.15 MPa, and the elongation at break was 663%. The water contact angle of the coating was 64°. The thermal decomposition temperature was 228°C for 5% weight loss and 259°C for 10% weight loss. After 20 hours, there was no obvious corrosion on the coating surface.

[0058] Example 5

[0059] In a three-necked flask equipped with nitrogen protection and a magnetic stirrer, 2.6 g of 2-methoxyethyl acrylate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0060] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0061] The performance testing method was the same as in Example 1. The number-average molecular weight was 29,800, and the weight-average molecular weight was 39,700. The tensile strength was 5.02 MPa, and the elongation at break was 703%. The water contact angle of the coating was 76°. The thermal decomposition temperature of 5% weight loss was 217°C, and the thermal decomposition temperature of 10% weight loss was 246°C. After 22 hours, there was no obvious corrosion on the coating surface.

[0062] Example 6

[0063] 3.96 g of ethylene tert-carbonate, 1.64 g of pentafluoropropyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0064] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0065] The performance testing method was the same as in Example 1. The number-average molecular weight was 31,100, and the weight-average molecular weight was 42,300. The tensile strength was 5.22 MPa, and the elongation at break was 685%. The water contact angle of the coating was 68°. The thermal decomposition temperature was 239°C for 5% weight loss and 270°C for 10% weight loss. After 20 hours, there was no obvious corrosion on the coating surface.

[0066] Example 7

[0067] 3.96 g of ethylene tert-carbonate, 3.0 g of octafluoroamyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0068] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0069] The performance testing method was the same as in Example 1. The number-average molecular weight was 30,900, and the weight-average molecular weight was 41,700. The tensile strength was 5.04 MPa, and the elongation at break was 613%. The water contact angle of the coating was 82°. The thermal decomposition temperature was 217°C for 5% weight loss and 246°C for 10% weight loss. After 22 hours, there was no obvious corrosion on the coating surface.

[0070] Example 8

[0071] 3.96 g of ethylene tert-carbonate, 2.04 g of pentafluoropropyl acrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0072] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0073] The performance testing method was the same as in Example 1. The number-average molecular weight was 32,700, and the weight-average molecular weight was 42,500. The tensile strength was 5.16 MPa, and the elongation at break was 696%. The water contact angle of the coating was 67°. The thermal decomposition temperature was 225°C for 5% weight loss and 254°C for 10% weight loss. After 20 hours, there was no obvious corrosion on the coating surface.

[0074] Example 9

[0075] 3.96 g of ethylene tert-carbonate, 4.18 g of perfluorohexyl ethyl acrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0076] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0077] The performance testing method was the same as in Example 1. The number-average molecular weight was 32,200, and the weight-average molecular weight was 46,000. The tensile strength was 5.03 MPa, and the elongation at break was 648%. The water contact angle of the coating was 85°. The thermal decomposition temperature was 209°C for 5% weight loss and 239°C for 10% weight loss. After 20 hours, there was no obvious corrosion on the coating surface.

[0078] Example 10

[0079] In a three-necked flask equipped with nitrogen protection and a magnetic stirrer, 2.82 g of butyl methacrylate, 1.64 g of pentafluoropropyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0080] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0081] The performance testing method was the same as in Example 1. The number-average molecular weight was 33,200, and the weight-average molecular weight was 42,900. The tensile strength was 5.17 MPa, and the elongation at break was 673%. The water contact angle of the coating was 72°. The thermal decomposition temperature was 234°C for 5% weight loss and 265°C for 10% weight loss. After 18 hours, there was no obvious corrosion on the coating surface.

[0082] Example 11

[0083] In a three-necked flask equipped with nitrogen protection and a magnetic stirrer, 2.82 g of butyl methacrylate, 3.0 g of octafluoropentyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0084] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0085] The performance testing method was the same as in Example 1. The number-average molecular weight was 31,300, the weight-average molecular weight was 40,700, the tensile strength was 4.97 MPa, the elongation at break was 698%, the water contact angle of the coating was 77°, the thermal decomposition temperature of 5% weight loss was 226°C, and the thermal decomposition temperature of 10% weight loss was 261°C. After 22 hours, there was no obvious corrosion on the coating surface.

[0086] Example 12

[0087] In a three-necked flask equipped with nitrogen protection and a magnetic stirrer, 2.82 g of butyl methacrylate, 2.04 g of pentafluoropropyl acrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0088] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0089] The performance testing method was the same as in Example 1. The number-average molecular weight was 31,100, and the weight-average molecular weight was 45,400. The tensile strength was 4.87 MPa, and the elongation at break was 701%. The water contact angle of the coating was 79°. The thermal decomposition temperature was 215°C for 5% weight loss and 247°C for 10% weight loss. After 20 hours, there was no obvious corrosion on the coating surface.

[0090] Example 13

[0091] 2.82 g of butyl methacrylate, 4.18 g of perfluorohexyl ethyl acrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0092] The preparation of the water-based self-healing rust-preventive coating is the same as in Example 1.

[0093] The performance testing method was the same as in Example 1. The number-average molecular weight was 32,700, and the weight-average molecular weight was 41,400. The tensile strength was 5.09 MPa, and the elongation at break was 673%. The water contact angle of the coating was 73°. The thermal decomposition temperature was 227°C for 5% weight loss and 258°C for 10% weight loss. After 22 hours, there was no obvious corrosion on the coating surface.

[0094] Example 14

[0095] 3.96 g of ethylene tert-carbonate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0096] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.0 g of methyl methacrylate, 1.44 g of hydroxypropyl methacrylate, 2.38 g of pentafluorophenol acrylate and 3.88 g of maleimide were added as monomers, 0.0029 g of benzoyl peroxide was added as an initiator and 0.34 g of sodium dodecyl sulfate was added as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0097] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.15g of modified CeO2 nanoparticles, 0.15g of iron oxide, 0.17g of talc, 0.14g of antioxidant 168 and 30mL of water to finally obtain a water-based self-healing anti-rust coating.

[0098] The performance testing method was the same as in Example 1. The number-average molecular weight was 31,800, and the weight-average molecular weight was 46,500. The tensile strength was 5.13 MPa, and the elongation at break was 694%. The water contact angle of the coating was 65°. The thermal decomposition temperature was 232°C for 5% weight loss and 266°C for 10% weight loss. After 22 hours, there was no obvious corrosion on the coating surface.

[0099] Example 15

[0100] 3.96 g of ethylene tert-carbonate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0101] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.0 g of methyl methacrylate, 1.44 g of hydroxypropyl methacrylate, 2.38 g of pentafluorophenol acrylate and 3.88 g of maleimide were added as monomers, 0.0029 g of benzoyl peroxide was added as an initiator and 0.34 g of sodium dodecyl sulfate was added as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0102] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.25g of modified CeO2 nanoparticles, 0.15g of iron oxide, 0.17g of talc, 0.14g of antioxidant 168 and 30mL of water to finally obtain a water-based self-healing anti-rust coating.

[0103] The performance testing method was the same as in Example 1. The number-average molecular weight was 32,200, and the weight-average molecular weight was 46,900. The tensile strength was 5.11 MPa, and the elongation at break was 701%. The water contact angle of the coating was 67°. The thermal decomposition temperature was 240°C for 5% weight loss and 268°C for 10% weight loss. After 20 hours, there was no obvious corrosion on the coating surface.

[0104] Example 16

[0105] 3.96 g of ethylene tert-carbonate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0106] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.0 g of methyl methacrylate, 1.44 g of hydroxypropyl methacrylate, 2.38 g of pentafluorophenol acrylate and 3.88 g of maleimide were added as monomers, 0.0029 g of benzoyl peroxide was added as an initiator and 0.34 g of sodium dodecyl sulfate was added as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0107] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.3g of modified CeO2 nanoparticles, 0.15g of iron oxide, 0.17g of talc, 0.14g of antioxidant 168 and 30mL of water to finally obtain a water-based self-healing anti-rust coating.

[0108] The performance testing method was the same as in Example 1. The number-average molecular weight was 31,200, and the weight-average molecular weight was 47,300. The tensile strength was 5.18 MPa, and the elongation at break was 692%. The water contact angle of the coating was 66°. The thermal decomposition temperature was 241°C for 5% weight loss and 267°C for 10% weight loss. After 18 hours, there was no obvious corrosion on the coating surface.

[0109] Comparative Example 1

[0110] 3.96 g of ethylene tert-carbonate, 1.54 g of trifluoroethyl acrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0111] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.0 g of methyl methacrylate, 1.44 g of hydroxypropyl methacrylate, 2.38 g of pentafluorophenol acrylate, and 3.88 g of maleimide were added, along with 0.0029 g of benzoyl peroxide as an initiator and 0.34 g of sodium dodecyl sulfate as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0112] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.2g of modified CeO2 nanoparticles, 0.15g of iron oxide, 0.17g of talc, 0.14g of antioxidant 168 and 30mL of water to finally obtain a water-based self-healing anti-rust coating.

[0113] The performance testing method was the same as in Example 1. The number-average molecular weight was 21,200, and the weight-average molecular weight was 28,500. The tensile strength was 3.16 MPa, and the elongation at break was 413%. The water contact angle of the coating was 60°. The thermal decomposition temperature of 5% weight loss was 167°C, and the thermal decomposition temperature of 10% weight loss was 198°C. After 12 hours, there was no obvious corrosion on the coating surface.

[0114] Comparative Example 2

[0115] 3.96 g of ethylene tert-carbonate, 4.0 g of dodecafluoroheptyl methacrylate, 0.78 g of mercaptoethanol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0116] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.0 g of methyl methacrylate, 1.44 g of hydroxypropyl methacrylate, 2.38 g of pentafluorophenol acrylate, and 3.88 g of maleimide were added, along with 0.0029 g of benzoyl peroxide as an initiator and 0.34 g of sodium dodecyl sulfate as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0117] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.2g of modified CeO2 nanoparticles, 0.15g of iron oxide, 0.17g of talc, 0.14g of antioxidant 168 and 30mL of water to finally obtain a water-based self-healing anti-rust coating.

[0118] The performance testing method was the same as in Example 1. The number-average molecular weight was 23,600, and the weight-average molecular weight was 29,300. The tensile strength was 4.65 MPa, and the elongation at break was 473%. The water contact angle of the coating was 88°. The thermal decomposition temperature was 169°C for 5% weight loss and 187°C for 10% weight loss. After 10 hours, there was no obvious corrosion on the coating surface.

[0119] Comparative Example 3

[0120] 3.96 g of ethylene tert-carbonate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0121] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.0 g of methyl methacrylate, 1.44 g of hydroxypropyl methacrylate, 2.38 g of pentafluorophenol acrylate, and 3.88 g of maleimide were added, along with 0.0029 g of benzoyl peroxide as an initiator and 0.34 g of sodium dodecyl sulfate as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0122] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.2g CeO2 nanoparticles, 0.15g iron oxide, 0.17g talc, 0.14g antioxidant 168 and 30mL water to finally obtain a water-based self-healing anti-rust coating.

[0123] The performance testing method was the same as in Example 1. The number-average molecular weight was 33,700, the weight-average molecular weight was 42,900, the tensile strength was 4.97 MPa, the elongation at break was 593%, the water contact angle of the coating was 75°, the thermal decomposition temperature of 5% weight loss was 203°C, and the thermal decomposition temperature of 10% weight loss was 235°C. After 12 hours, there was no obvious corrosion on the coating surface.

[0124] Comparative Example 4

[0125] 3.96 g of ethylene tert-carbonate, 4.0 g of dodecafluoroheptyl methacrylate, 1.54 g of 1,4-dithiothreitol, 0.09 g of hydrogen peroxide, 1.34 g of 2,2-dimethylolpropionic acid, and 50 mL of water were added to a three-necked flask equipped with nitrogen protection and a magnetic stirrer. The mixture was stirred magnetically at 75 °C until homogeneous. After reacting for 8 h, a fluorinated hydrophilic polymer was obtained and dried in a 60 °C oven for 12 h for subsequent use.

[0126] 4.85 g of the fluorinated hydrophilic polymer was added to a three-necked flask containing 30 mL of water and ultrasonically dispersed for 5 h. Then, 2.64 g of methyl methacrylate, 1.88 g of hydroxypropyl methacrylate, and 5.18 g of maleimide were added, along with 0.0029 g of benzoyl peroxide as an initiator and 0.34 g of sodium dodecyl sulfate as an emulsifier. The mixture was stirred at 60 °C for 8 h to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution.

[0127] 5g of the prepared fluorinated hydrophilic acrylic copolymer was mixed with 0.2g of modified CeO2 nanoparticles, 0.15g of iron oxide, 0.17g of talc, 0.14g of antioxidant 168 and 30mL of water to finally obtain a water-based self-healing anti-rust coating.

[0128] The performance testing method was the same as in Example 1. The number-average molecular weight was 30,200, and the weight-average molecular weight was 37,400. The tensile strength was 4.77 MPa, and the elongation at break was 573%. The water contact angle of the coating was 77°. The thermal decomposition temperature of 5% weight loss was 209°C, and the thermal decomposition temperature of 10% weight loss was 241°C. After 14 hours, there was no obvious corrosion on the coating surface.

Claims

1. A method for preparing a water-based self-healing rust-preventive coating, characterized in that: The preparation method steps are as follows: (1) Preparation of fluorinated hydrophilic polymers Unsaturated ester, fluorinated unsaturated ester and 1,4-dithiothreitol were added to a three-necked flask equipped with nitrogen protection and magnetic stirring. The reaction was carried out at 75°C with initiator, chain extender and water as solvent and magnetic stirring for 8 hours to obtain fluorinated hydrophilic polymer. The polymer was then placed in an oven at 60°C and dried for 12 hours for subsequent use. (2) Preparation of fluorinated hydrophilic acrylic copolymer The obtained fluorinated hydrophilic polymer was added to a three-necked flask containing water and ultrasonically dispersed for 5 hours. Then, methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate and maleimide were added. Benzoyl peroxide was used as an initiator and sodium dodecyl sulfate as an emulsifier. The reaction was carried out at 60°C with stirring for 8 hours to obtain a fluorinated hydrophilic acrylic copolymer with controllable molecular weight distribution. (3) Preparation of water-based self-healing anti-rust coatings The prepared fluorinated hydrophilic acrylic copolymer was mixed with sodium dodecyl sulfonate modified CeO2 nanoparticles, iron oxide, talc, antioxidant 168 and water to finally obtain a water-based self-healing anti-rust coating.

2. The method for preparing the water-based self-healing anti-rust coating according to claim 1, characterized in that: In step (1), the unsaturated ester is one or a mixture of several of the following: ethylene tert-carbonate, butyl methacrylate, methyl acrylate, glycidyl methacrylate, and 2-methoxyethyl acrylate.

3. The method for preparing the water-based self-healing anti-rust coating according to claim 1, characterized in that: In step (1), the fluorinated unsaturated ester is one or a mixture of several of the following: dodecafluoroheptyl methacrylate, pentafluoropropyl methacrylate, octafluoropentyl methacrylate, pentafluoropropyl acrylate, and perfluorohexyl ethyl acrylate.

4. The method for preparing the water-based self-healing anti-rust coating according to claim 1, characterized in that: In step (1), the amount of hydrogen peroxide as the initiator is 0.1%-0.3% of the total mass of the unsaturated ester and the fluorinated unsaturated ester.

5. The method for preparing the water-based self-healing anti-rust coating according to claim 1, characterized in that: In step (1), the molar ratio of unsaturated ester, fluorinated unsaturated ester, 1,4-dithiothreitol and chain extender is 2:1:1:

1.

6. The method for preparing the water-based self-healing anti-rust coating according to claim 1, characterized in that: In step (2), the molar ratio of methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate and maleimide is 2:1:1:4; the amount of fluorinated hydrophilic polymer used is 50% of the total mass of methyl methacrylate, hydroxypropyl methacrylate, pentafluorophenol acrylate and maleimide.

7. The method for preparing the water-based self-healing anti-rust coating according to claim 1, characterized in that: In step (3), the amount of sodium dodecyl sulfonate modified CeO2 nanoparticles added is 3%-6% of the mass of the fluorinated hydrophilic acrylic copolymer.

8. The method for preparing the water-based self-healing anti-rust coating according to claim 1, characterized in that: In step (3), the amount of iron oxide added is 2%-7% of the mass of the fluorinated hydrophilic acrylic copolymer, the amount of talc added is 3%-5% of the mass of the fluorinated hydrophilic acrylic copolymer, and the amount of antioxidant 168 added is 6%-10% of the mass of sodium dodecyl sulfonate modified CeO2 nanoparticles.

9. A water-based self-healing rust-preventive coating prepared by the method according to any one of claims 1-8.

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