Graphene modified epoxy resin composite anticorrosive paint and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and discloses a graphene modified epoxy resin composite anticorrosive coating which is prepared by the following steps: reacting graphene oxide with epoxy chloropropane to obtain epoxidized graphene, reacting the epoxidized graphene with hydroxyl-terminated styrene-butadiene rubber under the action of a catalyst to obtain hydroxyl-terminated styrene-butadiene rubber modified graphene, and reacting the hydroxyl-terminated styrene-butadiene rubber modified graphene with toluene-2, 4-diisocyanate to obtain the graphene modified epoxy resin composite anticorrosive coating. The graphene modified epoxy resin composite anticorrosive paint is finally prepared by reacting isocyanate esterified styrene-butadiene rubber with graphene to obtain isocyanate esterified styrene-butadiene rubber modified graphene, further reacting the isocyanate esterified styrene-butadiene rubber modified graphene with N, N-carbonyldiimidazole to obtain imidazolyl styrene-butadiene rubber modified graphene, and blending the imidazolyl styrene-butadiene rubber modified graphene with epoxy resin, and graphene can absorb and disperse stress and can also form a physical barrier layer. And imidazole can provide free electrons and can form a stable monomolecular adsorption film on the surface of a matrix to prevent the corrosion process and further play a role in corrosion inhibition, so that the corrosion resistance of the epoxy resin coating is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a graphene-modified epoxy resin composite anti-corrosion coating and a preparation method thereof. Background Art

[0002] Paint refers to a material that can be applied to the surface of an object using different construction techniques to form a continuous solid film with a certain strength, thereby achieving insulation, mildew resistance, heat resistance and other effects. In the modern paint industry, paints made from polymer synthetic resins have the advantages of strong ductility, wear resistance, and washability, and therefore gradually replace traditional vegetable oil paints. Epoxy resin paints have strong adhesion, high thermal stability and excellent electrical insulation properties, and have gradually attracted the attention of major manufacturers in the paint industry. However, the epoxy resin matrix itself is relatively brittle, which makes the prepared paint prone to stress cracking and other phenomena. Therefore, the epoxy resin needs to be modified. In recent years, inorganic nanomaterials with high strength and hardness have been added to organic polymer materials, or polymer materials with excellent toughening effects have been added to improve the toughness of epoxy resins, and by combining the advantages of inorganic nanomaterials and organic polymer materials, the comprehensive performance of epoxy resins has been further improved.

[0003] Graphene is one of the strongest known materials and is considered to be a revolutionary material of the future. With the popularity of organic-inorganic hybrid materials in recent years, the performance of graphene as a functional additive has gradually emerged. Chinese patents CN105837790B and CN105969069A disclose methods for modifying epoxy resins with graphene, but most of these patents use physical mixing methods without modifying graphene, making it difficult to achieve the desired modification effect. Therefore, it is still necessary to improve graphene. After oxidation, the surface of graphene will contain abundant oxygen-containing functional groups such as hydroxyl and carboxyl. Active functional groups can be further introduced through these oxygen-containing functional groups, and then functional molecules can be introduced through these functional groups. Combined with the advantages of functional molecules, the functionality of graphene as an additive can be further broadened, reducing its application difficulty in the field of organic polymer materials.

[0004] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a graphene-modified epoxy resin composite anti-corrosion coating and a preparation method thereof, which solves the problem of poor mechanical properties and corrosion resistance of the epoxy resin coating.

[0005] (II) Technical solution To achieve the above object, the present invention provides the following technical solution: a graphene-modified epoxy resin composite anti-corrosion coating, wherein the preparation method of the graphene-modified epoxy resin composite anti-corrosion coating comprises the following steps: (1) Add tetrahydrofuran solvent and graphene oxide to the reactor, and after ultrasonic dispersion, continue to add potassium fluoride, potassium iodide and epichlorohydrin to the system, stir evenly and transfer to an oil bath, raise the temperature to 90-110° C., react in a nitrogen atmosphere for 12-24 hours, centrifuge after the reaction, wash and dry to obtain epoxidized graphene; (2) adding toluene solvent and epoxidized graphene into a reactor, and after ultrasonic dispersion, adding hydroxylated styrene butadiene rubber and a catalyst, and after mixing, transferring to an oil bath, raising the temperature to react, and after the reaction is completed, centrifuging, washing and drying to obtain hydroxylated styrene butadiene rubber modified graphene; (3) adding anhydrous toluene solvent and hydroxy-terminated styrene butadiene rubber modified graphene to the reactor, and after ultrasonic dispersion, adding toluene-2,4-diisocyanate and a catalyst, mixing them evenly and transferring them to an oil bath pot, reacting them at 60-80° C. for 6-12 hours, centrifuging, washing and drying after the reaction to obtain isocyanate-modified styrene butadiene rubber modified graphene; (4) Add xylene, ethanol and isocyanate-modified styrene butadiene rubber-modified graphene to the reactor, disperse them uniformly by ultrasonication, continue to add N,N-carbonyldiimidazole and catalyst, stir them uniformly, transfer them to an oil bath, react at 70-90°C for 4-8h under nitrogen protection, continue to increase the temperature to 100-120°C, react for 2-6h, filter the product after cooling, wash, purify and dry it to obtain imidazole-based styrene butadiene rubber-modified graphene; (5) Add epoxy resin emulsion, imidazole-based styrene-butadiene rubber modified graphene, 0.5-4% of polyether defoaming agent, and 1-3% of polyacrylate leveling agent into the reactor, mix them evenly at high speed, and obtain a graphene-modified epoxy resin composite anti-corrosion coating.

[0006] Preferably, in step (1), the mass ratio of tetrahydrofuran, graphene oxide, potassium fluoride, potassium iodide and epichlorohydrin is 1500-12000:1:120-260:20-55:60-150.

[0007] Preferably, in step (2), the mass ratio of toluene, epoxidized graphene, hydroxy-terminated styrene butadiene rubber and catalyst is 800-6500:1:15-50:0.06-0.1.

[0008] Preferably, the reaction temperature in step (2) is 110-130° C., and the reaction is carried out for 4-12 hours with constant temperature stirring in a nitrogen atmosphere.

[0009] Preferably, the catalyst in step (2) is 2,4,6-tris(dimethylaminomethyl)phenol.

[0010] Preferably, in step (3), the mass ratio of anhydrous toluene, hydroxy-terminated styrene butadiene rubber modified graphene, toluene-2,4-diisocyanate and catalyst is 240-600:1:0.2-0.8:0.01-0.03.

[0011] Preferably, the catalyst in step (3) is dibutyltin dilaurate.

[0012] Preferably, in step (4), the mass ratio of xylene, ethanol, isocyanate-treated styrene-butadiene rubber-modified graphene, N,N-carbonyldiimidazole and catalyst is 120-350:60-150:1:0.4-0.8:0.1-0.3.

[0013] Preferably, the catalyst in step (4) is benzoyl peroxide.

[0014] Preferably, in step (5), the mass ratio of the epoxy resin emulsion to the imidazole-based styrene-butadiene rubber modified graphene is 100:2-6.

[0015] 3. Beneficial technical effects Compared with the prior art, the present invention has the following beneficial technical effects: The invention discloses a graphene-modified epoxy resin composite anticorrosive coating. The graphene oxide contains a large number of epoxy groups on its surface after being modified by epichlorohydrin. Under the catalytic action of a catalyst, 2,4,6-tris(dimethylaminomethyl)phenol, the graphene oxide undergoes a ring-opening reaction with the hydroxyl groups in the hydroxy-terminated styrene butadiene rubber to obtain hydroxy-terminated styrene butadiene rubber-modified graphene. Under the catalytic action of a catalyst, dibutyltin dilaurate, the hydroxyl groups in the hydroxy-terminated styrene butadiene rubber-modified graphene can undergo a carbamate reaction with the isocyanate groups in toluene-2,4-diisocyanate to obtain isocyanate-modified styrene butadiene rubber-modified graphene. Under the catalytic action of benzoyl peroxide, the graphene oxide further reacts with the carbonyl groups in N,N-carbonyldiimidazole to obtain imidazolyl styrene butadiene rubber-modified graphene. Thus, active functional groups such as epoxy groups, hydroxyl groups and isocyanate groups and functional molecules such as styrene butadiene rubber and carbonyldiimidazole are covalently bonded to the graphene surface by chemical grafting, thereby effectively improving the application range of graphene.

[0016] The graphene-modified epoxy resin composite anti-corrosion coating is prepared by blending epoxy resin with imidazole-based styrene-butadiene rubber modified graphene. When the composite coating is impacted by external force, stress can be transferred from the epoxy resin matrix to the graphene. The graphene absorbs part of the energy through its own high strength, and then disperses the stress to the styrene-butadiene rubber segment, thereby effectively enhancing the mechanical properties of the epoxy resin matrix such as impact and tensile strength. At the same time, the styrene-butadiene rubber can buffer and store energy, avoid stress concentration, and inhibit the expansion of cracks, thereby further enhancing the toughness of the epoxy resin matrix. In addition, the stably dispersed graphene can form a physical barrier layer to hinder the corrosion of water molecules, small organic molecules and gas molecules in the air, and at the same time extend the diffusion path of the corrosive medium. The diimidazole grafted on the graphene surface can provide more free electrons, and can form a stable single-molecule adsorption film on the surface of the matrix, further react with the ions of the corrosive medium, prevent the corrosion process, and then play a corrosion inhibition role, thereby effectively improving the anti-corrosion performance of the epoxy resin coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the reaction between epoxidized graphene and hydroxy-terminated styrene butadiene rubber.

[0018] Figure 2 Schematic diagram of the reaction of hydroxy-terminated styrene butadiene rubber modified graphene and toluene-2,4-diisocyanate.

[0019] Figure 3 This is a schematic diagram of the reaction of isocyanate-modified styrene-butadiene rubber-modified graphene and N,N-carbonyldiimidazole. DETAILED DESCRIPTION

[0020] To achieve the above object, the present invention provides the following specific implementation methods and examples: A graphene-modified epoxy resin composite anti-corrosion coating, the preparation method of which comprises the following steps: Example 1

[0021] (1) Add 170 mL of tetrahydrofuran solvent and 0.1 g of graphene oxide to the reactor, and after ultrasonic dispersion, continue to add 12 g of potassium fluoride, 2 g of potassium iodide and 55 mL of epichlorohydrin to the system, stir evenly and transfer to an oil bath, raise the temperature to 90 ° C, react in a nitrogen atmosphere for 12 h, centrifuge after the reaction, wash and dry to obtain epoxy graphene; (2) Add 95 mL of toluene solvent and 0.1 g of epoxidized graphene into the reactor, and after ultrasonic dispersion, continue to add 1.5 g of terminal hydroxyl styrene butadiene rubber and 0.006 g of 2,4,6-tris(dimethylaminomethyl)phenol. After mixing, transfer to an oil bath pot, and react at a constant temperature of 110°C for 4 h in a nitrogen atmosphere. After the reaction is completed, centrifuge, wash and dry to obtain terminal hydroxyl styrene butadiene rubber modified graphene; (3) Add 290 mL of anhydrous toluene solvent and 1 g of hydroxy-terminated styrene butadiene rubber modified graphene into the reactor, and after uniform ultrasonic dispersion, continue to add 0.2 g of toluene-2,4-diisocyanate and 0.01 g of dibutyltin dilaurate, mix well and transfer to an oil bath pot, react at 60 ° C for 6 h, centrifuge after the reaction, wash and dry to obtain isocyanate styrene butadiene rubber modified graphene; (4) Add 140 mL of xylene, 80 mL of ethanol and 1 g of isocyanate-modified styrene butadiene rubber-modified graphene to the reactor, disperse them uniformly by ultrasonication, continue to add 0.4 g of N,N-carbonyldiimidazole and 0.1 g of benzoyl peroxide, stir them uniformly, transfer them to an oil bath, react at 70 ° C for 4 h under nitrogen protection, continue to increase the temperature to 100 ° C, react for 2 h, filter the product after cooling, wash, purify and dry it to obtain imidazole-based styrene butadiene rubber-modified graphene; (5) Add 100 g of epoxy resin emulsion, 2 g of imidazole-based styrene-butadiene rubber modified graphene, 0.5% of polyether defoamer, and 1% of polyacrylate leveling agent into the reactor, mix them evenly at high speed, and obtain a graphene-modified epoxy resin composite anti-corrosion coating.

[0022] Example 2

[0023] (1) Add 350 mL of tetrahydrofuran solvent and 0.1 g of graphene oxide to the reactor, and after ultrasonic dispersion, continue to add 18 g of potassium fluoride, 3 g of potassium iodide and 7 mL of epichlorohydrin to the system, stir evenly and transfer to an oil bath, raise the temperature to 95 ° C, react in a nitrogen atmosphere for 16 hours, centrifuge after the reaction, wash and dry to obtain epoxy graphene; (2) Add 200 mL of toluene solvent and 0.1 g of epoxidized graphene into the reactor, and after ultrasonic dispersion, continue to add 2.4 g of terminal hydroxyl styrene butadiene rubber and 0.007 g of 2,4,6-tris(dimethylaminomethyl)phenol. After mixing, transfer to an oil bath pot, and react at a constant temperature of 115 ° C for 6 h in a nitrogen atmosphere. After the reaction is completed, centrifuge, wash and dry to obtain terminal hydroxyl styrene butadiene rubber modified graphene; (3) Add 350 mL of anhydrous toluene solvent and 1 g of hydroxy-terminated styrene butadiene rubber modified graphene into the reactor, and after ultrasonic dispersion, continue to add 0.4 g of toluene-2,4-diisocyanate and 0.015 g of dibutyltin dilaurate. After mixing evenly, transfer to an oil bath pot and react at 65 ° C for 8 h. After the reaction is completed, centrifuge, wash and dry to obtain isocyanate styrene butadiene rubber modified graphene; (4) Add 180 mL of xylene, 120 mL of ethanol and 1 g of isocyanate-modified styrene butadiene rubber-modified graphene to the reactor, disperse them uniformly by ultrasonication, continue to add 0.5 g of N,N-carbonyldiimidazole and 0.15 g of benzoyl peroxide, stir them uniformly, transfer them to an oil bath, react at 75 °C for 5 h under nitrogen protection, continue to increase the temperature to 105 °C, react for 3 h, cool the product, filter it, wash, purify and dry it to obtain imidazole-based styrene butadiene rubber-modified graphene; (5) Add 100 g of epoxy resin emulsion, 3 g of imidazole-based styrene-butadiene rubber modified graphene, 1.5% of polyether defoamer, and 2% of polyacrylate leveling agent to the reactor, and mix them evenly at high speed to obtain a graphene-modified epoxy resin composite anti-corrosion coating. Example 3

[0024] (1) Add 800 mL of tetrahydrofuran solvent and 0.1 g of graphene oxide to the reactor, and after ultrasonic dispersion, continue to add 20 g of potassium fluoride, 3.8 g of potassium iodide and 9 mL of epichlorohydrin to the system, stir evenly and transfer to an oil bath, raise the temperature to 100 ° C, react for 18 hours in a nitrogen atmosphere, centrifuge after the reaction, wash and dry to obtain epoxy graphene; (2) Add 380 mL of toluene solvent and 0.1 g of epoxidized graphene into the reactor, and after ultrasonic dispersion, continue to add 4.2 g of terminal hydroxyl styrene butadiene rubber and 0.008 g of 2,4,6-tris(dimethylaminomethyl)phenol. After mixing, transfer to an oil bath pot, and react at a constant temperature of 120°C in a nitrogen atmosphere for 9 h. After the reaction is completed, centrifuge, wash and dry to obtain terminal hydroxyl styrene butadiene rubber modified graphene; (3) Add 320 mL of anhydrous toluene solvent and 1 g of hydroxy-terminated styrene butadiene rubber modified graphene into the reactor, and after ultrasonic dispersion, continue to add 0.5 g of toluene-2,4-diisocyanate and 0.02 g of dibutyltin dilaurate. After mixing evenly, transfer to an oil bath pot and react at 70 ° C for 9 h. After the reaction is completed, centrifuge, wash and dry to obtain isocyanate styrene butadiene rubber modified graphene; (4) Add 250 mL of xylene, 160 mL of ethanol and 1 g of isocyanate-modified styrene butadiene rubber-modified graphene to the reactor, disperse them uniformly by ultrasonication, continue to add 0.6 g of N,N-carbonyldiimidazole and 0.2 g of benzoyl peroxide, stir them uniformly, transfer them to an oil bath, react at 80 ° C for 6 h under nitrogen protection, continue to increase the temperature to 110 ° C, react for 4 h, cool the product, filter it, wash, purify and dry it to obtain imidazole-based styrene butadiene rubber-modified graphene; (5) Add 100 g of epoxy resin emulsion, 4 g of imidazole-based styrene-butadiene rubber modified graphene, 2.5% of polyether defoamer, and 2% of polyacrylate leveling agent into the reactor, and mix them evenly at high speed to obtain a graphene-modified epoxy resin composite anti-corrosion coating. Example 4

[0025] (1) Add 1200 mL of tetrahydrofuran solvent and 0.1 g of graphene oxide to the reactor, and after ultrasonic dispersion, continue to add 23 g of potassium fluoride, 4.6 g of potassium iodide and 10 mL of epichlorohydrin to the system, stir evenly and transfer to an oil bath, raise the temperature to 105 ° C, react in a nitrogen atmosphere for 20 hours, centrifuge after the reaction, wash and dry to obtain epoxy graphene; (2) Add 600 mL of toluene solvent and 0.1 g of epoxidized graphene into the reactor, and after ultrasonic dispersion, continue to add 4 g of terminal hydroxyl styrene butadiene rubber and 0.009 g of 2,4,6-tris(dimethylaminomethyl)phenol. After mixing, transfer to an oil bath pot, and react at a constant temperature of 125 ° C for 10 h in a nitrogen atmosphere. After the reaction is completed, centrifuge, wash and dry to obtain terminal hydroxyl styrene butadiene rubber modified graphene; (3) Add 580 mL of anhydrous toluene solvent and 1 g of hydroxy-terminated styrene butadiene rubber modified graphene into the reactor, and after ultrasonic dispersion, continue to add 0.6 g of toluene-2,4-diisocyanate and 0.025 g of dibutyltin dilaurate. After mixing evenly, transfer to an oil bath pot and react at 75°C for 10 h. After the reaction is completed, centrifuge, wash and dry to obtain isocyanate-modified styrene butadiene rubber modified graphene; (4) Add 350 mL of xylene, 200 mL of ethanol and 1 g of isocyanate-modified styrene butadiene rubber-modified graphene into the reactor, disperse them uniformly by ultrasonication, continue to add 0.7 g of N,N-carbonyldiimidazole and 0.25 g of benzoyl peroxide, stir them uniformly, transfer them to an oil bath, react at 85 ° C for 7 h under nitrogen protection, continue to increase the temperature to 115 ° C, react for 5 h, cool the product, filter it, wash, purify and dry it to obtain imidazole-based styrene butadiene rubber-modified graphene; (5) Add 100 g of epoxy resin emulsion, 5 g of imidazole-based styrene-butadiene rubber modified graphene, 2.5% of polyether defoamer, and 2% of polyacrylate leveling agent into the reactor, and mix them evenly at high speed to obtain a graphene-modified epoxy resin composite anti-corrosion coating. Example 5

[0026] (1) Add 1350 mL of tetrahydrofuran solvent and 0.1 g of graphene oxide to the reactor, and after ultrasonic dispersion, continue to add 26 g of potassium fluoride, 5.5 g of potassium iodide and 12 mL of epichlorohydrin to the system, stir evenly and transfer to an oil bath, raise the temperature to 110 ° C, react in a nitrogen atmosphere for 24 hours, centrifuge after the reaction, wash and dry to obtain epoxy graphene; (2) Add 750 mL of toluene solvent and 0.1 g of epoxidized graphene into the reactor, and after ultrasonic dispersion, continue to add 5 g of terminal hydroxyl styrene butadiene rubber and 0.01 g of 2,4,6-tris(dimethylaminomethyl)phenol. After mixing, transfer to an oil bath pot, and react at a constant temperature of 130 ° C in a nitrogen atmosphere for 12 h. After the reaction is completed, centrifuge, wash and dry to obtain terminal hydroxyl styrene butadiene rubber modified graphene; (3) Add 690 mL of anhydrous toluene solvent and 1 g of hydroxy-terminated styrene butadiene rubber modified graphene into the reactor, and after ultrasonic dispersion, continue to add 0.8 g of toluene-2,4-diisocyanate and 0.03 g of dibutyltin dilaurate. After mixing evenly, transfer to an oil bath pot and react at 80°C for 12 h. After the reaction is completed, centrifuge, wash and dry to obtain isocyanate-modified styrene butadiene rubber modified graphene; (4) Add 400 mL of xylene, 240 mL of ethanol and 1 g of isocyanate-modified styrene butadiene rubber-modified graphene into the reactor, disperse them uniformly by ultrasonication, continue to add 0.8 g of N,N-carbonyldiimidazole and 0.3 g of benzoyl peroxide, stir them uniformly, transfer them to an oil bath, react at 90 ° C for 8 h under nitrogen protection, continue to increase the temperature to 120 ° C, react for 6 h, filter the product after cooling, wash, purify and dry it to obtain imidazole-based styrene butadiene rubber-modified graphene; (5) Add 100 g of epoxy resin emulsion, 6 g of imidazole-based styrene-butadiene rubber modified graphene, 4% of polyether defoaming agent, and 3% of polyacrylate leveling agent in a mass ratio into a reactor, and mix them evenly at a high speed to obtain a graphene-modified epoxy resin composite anti-corrosion coating.

[0027] Comparative Example 1 (1) Add 2000 mL of tetrahydrofuran solvent and 0.1 g of graphene oxide to the reactor, and after ultrasonic dispersion, continue to add 15 g of potassium fluoride, 2.5 g of potassium iodide and 7 mL of epichlorohydrin to the system, stir evenly and transfer to an oil bath, raise the temperature to 90 ° C, react in a nitrogen atmosphere for 12 h, centrifuge after the reaction, wash and dry to obtain epoxy graphene; (2) Add 120 mL of toluene solvent and 0.1 g of epoxidized graphene into the reactor, and after ultrasonic dispersion, continue to add 2 g of terminal hydroxyl styrene butadiene rubber and 0.007 g of 2,4,6-tris(dimethylaminomethyl)phenol. After mixing, transfer to an oil bath pot, and react at a constant temperature of 110 ° C for 4 h in a nitrogen atmosphere. After the reaction is completed, centrifuge, wash and dry to obtain terminal hydroxyl styrene butadiene rubber modified graphene; (3) Add 100 g of epoxy resin emulsion, 3 g of hydroxy-terminated styrene-butadiene rubber modified graphene, 2% of polyether defoaming agent, and 2% of polyacrylate leveling agent in a mass ratio into a reactor, and mix them evenly at high speed to obtain a graphene-modified epoxy resin composite anti-corrosion coating.

[0028] The composite coatings in the examples and comparative examples were placed in a mold for curing and prepared into samples with a specification of 2 mm×8 mm×8 mm. The tensile strength and elongation at break were tested using a HTS-LLY9100C tensile strength testing machine.

[0029] The composite coatings in the examples and comparative examples were placed in a mold for curing and prepared into samples with a size of 2 mm×8 mm×8 mm. The impact strength of the samples was tested using a KRT-2022C impact strength testing machine.

[0030]

[0031] The composite coating in the embodiment and the comparative example was evenly coated on the surface of the stainless steel electrode, cured at 80°C, and used as the working electrode, a platinum electrode as the auxiliary electrode, a calomel electrode as the reference electrode, and a 3.5% sodium chloride solution as the electrolyte. The corrosion current density and corrosion potential were tested using a PGSTAT 302N electrochemical workstation.

Claims

1. A graphene-modified epoxy resin composite anti-corrosion coating, characterized in that: The following steps are involved: (1) Adding graphene oxide to tetrahydrofuran solvent, and after ultrasonic dispersion, adding potassium fluoride, potassium iodide and epichlorohydrin to the system, stirring evenly, transferring to an oil bath, raising the temperature to 90-110° C., reacting in a nitrogen atmosphere for 12-24 hours, centrifuging, washing and drying after the reaction to obtain epoxidized graphene; (2) adding epoxidized graphene to toluene solvent, and after ultrasonic dispersion, adding hydroxylated styrene butadiene rubber and catalyst, and after mixing, transferring to an oil bath, raising the temperature to react, and after the reaction is completed, centrifuging, washing and drying to obtain hydroxylated styrene butadiene rubber modified graphene; (3) Adding hydroxy-terminated styrene butadiene rubber modified graphene to anhydrous toluene solvent, and after ultrasonic dispersion, continue to add toluene-2,4-diisocyanate and a catalyst, mix well and transfer to an oil bath pot, react at 60-80°C for 6-12h, centrifuge after the reaction, wash and dry to obtain isocyanate styrene butadiene rubber modified graphene; (4) Adding isocyanate-modified styrene butadiene rubber-modified graphene to a mixed solvent of xylene and ethanol, uniformly dispersing by ultrasonication, continuing to add N,N-carbonyldiimidazole and a catalyst, stirring evenly, transferring to an oil bath, reacting at 70-90° C. for 4-8 h under nitrogen protection, continuing to increase the temperature to 100-120° C., reacting for 2-6 h, and filtering, washing, purifying and drying the product after cooling to obtain imidazole-based styrene butadiene rubber-modified graphene; (5) Add epoxy resin emulsion, imidazole-based styrene-butadiene rubber modified graphene, 0.5-4% of polyether defoaming agent, and 1-3% of polyacrylate leveling agent into the reactor, mix them evenly at high speed, and obtain a graphene-modified epoxy resin composite anti-corrosion coating.

2. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: In the step (1), the mass ratio of tetrahydrofuran, graphene oxide, potassium fluoride, potassium iodide and epichlorohydrin is 1500-12000:1:120-260:20-55:60-150.

3. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: In the step (2), the mass ratio of toluene, epoxidized graphene, hydroxylated styrene butadiene rubber and catalyst is 800-6500:1:15-50:0.06-0.

1.

4. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: The reaction temperature in step (2) is 110-130° C., and the reaction is carried out for 4-12 hours under constant temperature stirring in a nitrogen atmosphere.

5. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: The catalyst in step (2) is 2,4,6-tris(dimethylaminomethyl)phenol.

6. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: In the step (3), the mass ratio of anhydrous toluene, hydroxy-terminated styrene butadiene rubber modified graphene, toluene-2,4-diisocyanate and catalyst is 240-600:1:0.2-0.8:0.01-0.

03.

7. The graphene-modified epoxy resin composite anticorrosive coating according to claim 1, characterized in that: The catalyst in step (3) is dibutyltin dilaurate.

8. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: In the step (4), the mass ratio of xylene, ethanol, isocyanate-treated styrene-butadiene rubber-modified graphene, N,N-carbonyldiimidazole and catalyst is 120-350:60-150:1:0.4-0.8:0.1-0.

3.

9. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: The catalyst in step (4) is benzoyl peroxide.

10. The graphene-modified epoxy resin composite anti-corrosion coating according to claim 1, characterized in that: In the step (5), the mass ratio of the epoxy resin emulsion to the imidazole-based styrene-butadiene rubber modified graphene is 100:2-6.

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