Graphene nano coating and preparation method thereof

Abstract

The invention discloses a graphene nano coating and a preparation method thereof. The preparation method of the graphene nano coating comprises the following steps: S01, modifying graphene oxide; s02, preparing a microcapsule; and S03, taking the modified graphene oxide obtained in the step S01, the microcapsules obtained in the step S02, epoxy modified polyurethane resin and a curing agent, and preparing the graphene nano-coating. The graphene nano coating obtained by the preparation method disclosed by the invention is excellent in adhesive force performance and also has good corrosion resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of corrosion resistance, and in particular relates to a graphene nano coating and a preparation method thereof. Background Art

[0002] Graphene is a single layer of carbon atoms in sp 2 The two-dimensional honeycomb structure material composed of hybrid orbitals has excellent physical and chemical properties, such as super strong mechanical properties, high electrical and thermal conductivity, outstanding chemical stability, etc. These characteristics make graphene have great application potential in the field of anti-corrosion coatings. The two-dimensional sheet structure of graphene can form a dense physical barrier layer in the coating, effectively preventing the penetration of corrosive media such as chloride ions. The ultra-high density of graphene cannot even penetrate the smallest gas molecules, thereby enhancing the physical barrier effect of the coating. Graphene can be directly formed into an anti-corrosion film on the metal surface by chemical vapor deposition (CVD), electrophoretic deposition, spin coating and other methods, or added to the coating as a filler to form a composite coating to improve the corrosion resistance of the coating. Although graphene has broad application prospects in the field of anti-corrosion, there are still some challenges, such as the dispersibility of graphene, the stability of the coating and cost control, which need to be further studied and solved.

[0003] CN114806367A discloses a method for preparing a chitosan-modified graphene oxide composite coating, wherein chitosan (CS) and glutaraldehyde are used as crosslinking components between graphene oxide (GO) and environmentally friendly corrosion inhibitor polyaspartic acid (PASP), and polyaspartic acid and chitosan are grafted on graphene oxide by a two-step method, and PASP-CS-GO is embedded in EP-PU resin to form a high-density composite coating, which effectively improves the dispersion performance of GO nanosheets in the matrix resin coating. However, the adhesion is below 5MPa, which cannot meet the application scenario of high adhesion. Summary of the invention

[0004] In view of the above-mentioned prior art, the present invention proposes a graphene nano-coating and a preparation method thereof. The graphene nano-coating not only has good adhesion, but also does not affect its corrosion resistance. In some embodiments, the corrosion resistance is even significantly improved.

[0005] The first aspect of the present invention is to disclose a method for preparing a graphene nanocoating, comprising the following steps:

[0006] S01, modification of graphene oxide;

[0007] S02, preparing microcapsules;

[0008] S03, taking the modified graphene oxide obtained in step S01 and the microcapsules, epoxy-modified polyurethane resin and curing agent obtained in step S02, to prepare a graphene nano coating.

[0009] In some embodiments of the present invention, S01 includes:

[0010] S11, using chitosan and graphene oxide as main raw materials to prepare chitosan-modified graphene oxide;

[0011] S12, chitosan graphene oxide modified with polyaspartic acid, prepared with polyaspartic acid as the main raw material.

[0012] In some embodiments of the present invention, in S03, microcapsules are prepared using polyvinyl alcohol, urea, vegetable oil, benzotriazole and formaldehyde as main raw materials.

[0013] In some embodiments of the present invention, in S11, chitosan is added to an acetic acid solution and stirred; an aqueous solution of graphene oxide is added, the pH is adjusted, the temperature is increased, stirring is continued, and centrifugation is performed to obtain chitosan-modified graphene oxide.

[0014] In some embodiments of the present invention, in S12, the chitosan-modified graphene oxide obtained in step S11 is added to a polyaspartic acid aqueous solution, stirred, the pH is adjusted, glutaraldehyde is added, stirring is continued, centrifuged, and washed with water to obtain polyaspartic acid-modified chitosan graphene oxide.

[0015] In some embodiments of the present invention, in S02, water is taken, polyvinyl alcohol aqueous solution and urea are added, stirred, and the pH is adjusted; linseed oil and benzotriazole are added, ultrasonic treatment is performed, and stirring is performed to obtain an emulsion; formaldehyde aqueous solution is added dropwise, the temperature is increased, and stirring is continued to obtain microcapsules.

[0016] In some embodiments of the present invention, in S11, the pH is adjusted to 5.0-5.5 and the temperature is raised to 60-65°C.

[0017] In some embodiments of the present invention, in S12, the pH is adjusted to 5.0-5.5;

[0018] In some embodiments of the present invention, in S02, the pH is adjusted to 3.0-3.5; after the formaldehyde aqueous solution is added dropwise, the temperature is raised to 60-65°C.

[0019] In some embodiments of the present invention, in S01, the ratio of chitosan, graphene oxide, polyaspartic acid and glutaraldehyde is 0.10-0.20g chitosan: 15-25mL 0.1% (w / v) graphene oxide aqueous solution: 40-60mL 0.5% (w / v) polyaspartic acid aqueous solution: 0.5-1.5mL glutaraldehyde; preferably, 0.10-0.20g chitosan: 15-25mL 0.1% (w / v) graphene oxide aqueous solution: 40-60mL 0.5% (w / v) polyaspartic acid aqueous solution: 0.8-1.0mL glutaraldehyde.

[0020] In some embodiments of the present invention, in S02, the ratio of polyvinyl alcohol, urea, linseed oil, benzotriazole and formaldehyde aqueous solution is 1-10mL 5% (w / v) polyvinyl alcohol aqueous solution: 1-10g urea: 10-20g linseed oil: 1-5g benzotriazole: 10-20mL 30% (v / v) formaldehyde aqueous solution; preferably 1-10mL 5% (w / v) polyvinyl alcohol aqueous solution: 1-10g urea: 10-20g linseed oil: 2-3g benzotriazole: 10-20mL 30% (v / v) formaldehyde aqueous solution. When urea is less than 0.5g or linseed oil is greater than 15g and benzotriazole is less than 1g, the adhesion improvement performance of the microcapsule is significantly reduced.

[0021] In some embodiments of the present invention, in S03, the weight ratio of epoxy-modified polyurethane resin, curing agent, polyaspartic acid-modified chitosan graphene oxide and microcapsules is (40-60): (10-30): (0.01-0.5): (1-10), preferably (40-60): (10-30): (0.01-0.5): (5-10).

[0022] The second aspect of the present invention is to disclose the graphene nanocoating obtained by the preparation method described in the first aspect.

[0023] Beneficial effects:

[0024] The present invention studies and improves the adhesion of coatings prepared from graphene oxide modified with chitosan and polyaspartic acid. It is found that microcapsules prepared by adding vegetable oil and polyvinyl alcohol can significantly improve adhesion without affecting corrosion resistance, and even in some embodiments, improve corrosion resistance. The graphene nanocoating obtained by the preparation method of the present invention has excellent adhesion performance and good corrosion resistance.

[0025] In the preparation method of the present invention, the microcapsules are dispersed in the coating, and their surfaces may form a mechanical anchor with the matrix material. This anchoring effect increases the contact area between the coating and the matrix, thereby improving the adhesion of the coating. The microcapsules can be filled in the tiny gaps between the coating and the matrix, play a bridging role, reduce the stress concentration points in the coating, and thus improve the overall adhesion of the coating. When the coating is subjected to external forces, the elasticity and toughness of the microcapsules help to disperse the stress and prevent the formation and expansion of cracks, which also helps to improve the adhesion of the coating. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] Unless otherwise specified, the examples and comparative examples are parallel tests with the same parameters such as components, component contents, preparation steps, preparation parameters, and dimensions.

[0028] In the following examples and comparative examples, the emulsion was dripped with formaldehyde solution, cooled to room temperature, vacuum filtered, washed with deionized water, ethanol and acetone in sequence, and dried naturally in the air, and the residual ethanol and acetone were completely volatilized to obtain microcapsules. The molecular weight of the polyvinyl alcohol is 2400-2500, and the alcohol solubility is 98%-99%.

[0029] Example 1

[0030] A method for preparing a graphene nano coating:

[0031] 1) 0.15 g chitosan CTS was added to 50 mL 2% (w / v) acetic acid solution and stirred at 200 rpm for 10 min;

[0032] Add 20 mL of 0.1% (w / v) graphene oxide GO aqueous solution (treated with 200 W ultrasound for 10 min) and stir at 500 rpm for 30 min;

[0033] Add NaOH aqueous solution to adjust the pH to 5.0, raise the temperature to 60°C, continue stirring for 20 hours, and centrifuge to obtain chitosan-modified graphene oxide GC for later use;

[0034] 2) Take chitosan-modified graphene oxide GC, add it to 60 mL of 0.5% (w / v) polyaspartic acid aqueous solution, and stir at 200 rpm for 10 min;

[0035] Add NaOH aqueous solution to adjust the pH to 5.0.

[0036] Add 1.0 mL of glutaraldehyde, continue stirring for 24 h, centrifuge, and wash with water three times to obtain chitosan graphene oxide GCP modified with polyaspartic acid for later use;

[0037] 3) Take 200 mL of water, add 5 mL of 5% (w / v) polyvinyl alcohol aqueous solution and 5 g of urea, stir at 200 rpm for 10 min, and add NaOH aqueous solution to adjust the pH to 3.0;

[0038] Add 15 g of linseed oil and 3 g of benzotriazole, treat with 200 W ultrasound for 10 min, and then stir at 500 rpm for 30 min to obtain emulsion EM for later use;

[0039] 4) Take the emulsion, add 15 mL of 30% (v / v) formaldehyde aqueous solution, heat to 60°C, and continue stirring for 5 hours to obtain microcapsules MP for later use;

[0040] 5) Take 50 g of epoxy-modified polyurethane resin, 20 g of curing agent, 0.1 g of chitosan graphene oxide modified with polyaspartic acid, and 7 g of microcapsules, stir and mix to obtain a composite coating.

[0041] Example 2

[0042] A method for preparing a graphene nano coating:

[0043] 1) 0.10 g chitosan CTS was added to 50 mL 2% (w / v) acetic acid solution and stirred at 200 rpm for 10 min;

[0044] Add 20 mL of 0.1% (w / v) graphene oxide GO aqueous solution (treated with 200 W ultrasound for 10 min) and stir at 500 rpm for 30 min;

[0045] NaOH aqueous solution was added to adjust the pH to 5.2, the temperature was raised to 65°C, stirring was continued for 10 h, and centrifuged to obtain chitosan-modified graphene oxide GC for later use;

[0046] 2) Take chitosan-modified graphene oxide GC, add it to 50 mL of 0.5% (w / v) polyaspartic acid aqueous solution, and stir at 200 rpm for 10 min;

[0047] Add NaOH aqueous solution to adjust the pH to 5.0.

[0048] Add 1.0 mL of glutaraldehyde, continue stirring for 24 h, centrifuge, and wash with water three times to obtain chitosan graphene oxide GCP modified with polyaspartic acid for later use;

[0049] 3) Take 200 mL of water, add 5 mL of 5% (w / v) polyvinyl alcohol aqueous solution and 5 g of urea, stir at 200 rpm for 10 min, and add NaOH aqueous solution to adjust the pH to 3.0;

[0050] Add 13 g of linseed oil and 3 g of benzotriazole, treat with 200 W ultrasound for 10 min, and then stir at 500 rpm for 30 min to obtain emulsion EM, which is set aside;

[0051] 4) Take the emulsion, add 15 mL of 30% (v / v) formaldehyde aqueous solution, heat to 60°C, and continue stirring for 5 hours to obtain microcapsules MP for later use;

[0052] 5) Take 50 g of epoxy-modified polyurethane resin, 20 g of curing agent, 0.1 g of chitosan graphene oxide modified with polyaspartic acid, and 7 g of microcapsules, stir and mix to obtain a composite coating.

[0053] Example 3

[0054] A method for preparing a graphene nano coating:

[0055] 1) 0.20 g chitosan CTS was added to 50 mL 2% (w / v) acetic acid solution and stirred at 200 rpm for 10 min;

[0056] Add 20 mL of 0.1% (w / v) graphene oxide GO aqueous solution (treated with 200 W ultrasound for 10 min) and stir at 500 rpm for 30 min;

[0057] Add NaOH aqueous solution to adjust the pH to 5.0, raise the temperature to 60°C, continue stirring for 20 hours, and centrifuge to obtain chitosan-modified graphene oxide GC for later use;

[0058] 2) Take chitosan-modified graphene oxide GC, add it to 60 mL of 0.5% (w / v) polyaspartic acid aqueous solution, and stir at 200 rpm for 10 min;

[0059] Add NaOH aqueous solution to adjust the pH to 5.0.

[0060] Add 0.8 mL of glutaraldehyde, continue stirring for 24 h, centrifuge, and wash with water three times to obtain chitosan graphene oxide GCP modified with polyaspartic acid for later use;

[0061] 3) Take 200 mL of water, add 5 mL of 5% (w / v) polyvinyl alcohol aqueous solution and 5 g of urea, stir at 200 rpm for 10 min, and add NaOH aqueous solution to adjust the pH to 3.0;

[0062] Add 15 g of linseed oil and 2.5 g of benzotriazole, treat with 200 W ultrasound for 10 min, and then stir at 500 rpm for 30 min to obtain emulsion EM, which is set aside;

[0063] 4) Take the emulsion, add 15 mL of 30% (v / v) formaldehyde aqueous solution, heat to 60°C, and continue stirring for 5 hours to obtain microcapsules MP for later use;

[0064] 5) Take 50 g of epoxy-modified polyurethane resin, 20 g of curing agent, 0.1 g of chitosan graphene oxide modified with polyaspartic acid, and 7 g of microcapsules, stir and mix to obtain a composite coating.

[0065] Example 4

[0066] A method for preparing a graphene nano coating:

[0067] 1) 0.15 g chitosan CTS was added to 50 mL 2% (w / v) acetic acid solution and stirred at 200 rpm for 10 min;

[0068] Add 20 mL of 0.1% (w / v) graphene oxide GO aqueous solution (treated with 200 W ultrasound for 10 min) and stir at 500 rpm for 30 min;

[0069] Add NaOH aqueous solution to adjust the pH to 5.0, raise the temperature to 60°C, continue stirring for 20 hours, and centrifuge to obtain chitosan-modified graphene oxide GC for later use;

[0070] 2) Take chitosan-modified graphene oxide GC, add it to 60 mL of 0.5% (w / v) polyaspartic acid aqueous solution, and stir at 200 rpm for 10 min;

[0071] Add NaOH aqueous solution to adjust the pH to 5.0.

[0072] Add 1.0 mL of glutaraldehyde, continue stirring for 24 h, centrifuge, and wash with water three times to obtain chitosan graphene oxide GCP modified with polyaspartic acid for later use;

[0073] 3) Take 200 mL of water, add 5 mL of 5% (w / v) polyvinyl alcohol aqueous solution and 5 g of urea, stir at 200 rpm for 10 min, and add NaOH aqueous solution to adjust the pH to 3.0;

[0074] Add 15 g of linseed oil and 3 g of benzotriazole, treat with 200 W ultrasound for 10 min, and then stir at 500 rpm for 30 min to obtain emulsion EM for later use;

[0075] 4) Take the emulsion, add 15 mL of 30% (v / v) formaldehyde aqueous solution, heat to 60°C, and continue stirring for 5 hours to obtain microcapsules MP for later use;

[0076] 5) Take 50 g of epoxy-modified polyurethane resin, 20 g of curing agent, 0.1 g of polyaspartic acid-modified chitosan graphene oxide, and 5 g of microcapsules, stir and mix to obtain a composite coating.

[0077] Example 5

[0078] A method for preparing a graphene nano coating:

[0079] 1) 0.15 g chitosan CTS was added to 50 mL 2% (w / v) acetic acid solution and stirred at 200 rpm for 10 min;

[0080] Add 20 mL of 0.1% (w / v) graphene oxide GO aqueous solution (treated with 200 W ultrasound for 10 min) and stir at 500 rpm for 30 min;

[0081] Add NaOH aqueous solution to adjust the pH to 5.0, raise the temperature to 60°C, continue stirring for 20 hours, and centrifuge to obtain chitosan-modified graphene oxide GC for later use;

[0082] 2) Take chitosan-modified graphene oxide GC, add it to 60 mL of 0.5% (w / v) polyaspartic acid aqueous solution, and stir at 200 rpm for 10 min;

[0083] Add NaOH aqueous solution to adjust the pH to 5.0.

[0084] Add 1.0 mL of glutaraldehyde, continue stirring for 24 h, centrifuge, and wash with water three times to obtain chitosan graphene oxide GCP modified with polyaspartic acid for later use;

[0085] 3) Take 200 mL of water, add 5 mL of 5% (w / v) polyvinyl alcohol aqueous solution and 5 g of urea, stir at 200 rpm for 10 min, and add NaOH aqueous solution to adjust the pH to 3.0;

[0086] Add 15 g of linseed oil and 3 g of benzotriazole, treat with 200 W ultrasound for 10 min, and then stir at 500 rpm for 30 min to obtain emulsion EM for later use;

[0087] 4) Take the emulsion, add 15 mL of 30% (v / v) formaldehyde aqueous solution, heat to 60°C, and continue stirring for 5 hours to obtain microcapsules MP for later use;

[0088] 5) Take 50 g of epoxy-modified polyurethane resin, 20 g of curing agent, 0.1 g of polyaspartic acid-modified chitosan graphene oxide, and 10 g of microcapsules, stir and mix to obtain a composite coating.

[0089] Example 6

[0090] A method for preparing a graphene nano coating:

[0091] 1) 0.15 g chitosan CTS was added to 50 mL 2% (w / v) acetic acid solution and stirred at 200 rpm for 10 min;

[0092] Add 20 mL of 0.1% (w / v) graphene oxide GO aqueous solution (treated with 200 W ultrasound for 10 min) and stir at 500 rpm for 30 min;

[0093] Add NaOH aqueous solution to adjust the pH to 5.0, raise the temperature to 60°C, continue stirring for 20 hours, and centrifuge to obtain chitosan-modified graphene oxide GC for later use;

[0094] 2) Take chitosan-modified graphene oxide GC, add it to 60 mL of 0.5% (w / v) polyaspartic acid aqueous solution, and stir at 200 rpm for 10 min;

[0095] Add NaOH aqueous solution to adjust the pH to 5.0.

[0096] Add 1.0 mL of glutaraldehyde, continue stirring for 24 h, centrifuge, and wash with water three times to obtain chitosan graphene oxide GCP modified with polyaspartic acid for later use;

[0097] 3) Take 200 mL of water, add 5 mL of 5% (w / v) polyvinyl alcohol aqueous solution and 5 g of urea, stir at 200 rpm for 10 min, and add NaOH aqueous solution to adjust the pH to 3.0;

[0098] Add 15 g of linseed oil and 3 g of benzotriazole, treat with 200 W ultrasound for 10 min, and then stir at 500 rpm for 30 min to obtain emulsion EM for later use;

[0099] 4) Take the emulsion, add 15 mL of 30% (v / v) formaldehyde aqueous solution, heat to 60°C, and continue stirring for 5 hours to obtain microcapsules MP for later use;

[0100] 5) Take 50 g of epoxy-modified polyurethane resin, 20 g of curing agent, 0.1 g of chitosan graphene oxide modified with polyaspartic acid, and 1 g of microcapsule, stir and mix to obtain a composite coating.

[0101] Comparative Example 1

[0102] A method for preparing a graphene nano coating:

[0103] 1) 0.15 g chitosan CTS was added to 50 mL 2% (w / v) acetic acid solution and stirred at 200 rpm for 10 min;

[0104] Add 20 mL of 0.1% (w / v) graphene oxide GO aqueous solution (treated with 200 W ultrasound for 10 min) and stir at 500 rpm for 30 min;

[0105] Add NaOH aqueous solution to adjust the pH to 5.0, raise the temperature to 60°C, continue stirring for 20 hours, and centrifuge to obtain chitosan-modified graphene oxide GC for later use;

[0106] 2) Take chitosan-modified graphene oxide GC, add it to 60 mL of 0.5% (w / v) polyaspartic acid aqueous solution, and stir at 200 rpm for 10 min;

[0107] Add NaOH aqueous solution to adjust the pH to 5.0.

[0108] Add 1.0 mL of glutaraldehyde, continue stirring for 24 h, centrifuge, and wash with water three times to obtain chitosan graphene oxide GCP modified with polyaspartic acid for later use;

[0109] 3) Take 50 g of epoxy-modified polyurethane resin, 20 g of curing agent, and 0.1 g of chitosan graphene oxide modified with polyaspartic acid, and stir and mix to obtain a composite coating.

[0110] Performance Testing

[0111] Q235 carbon steel was polished with 600, 800, and 1200 mesh sandpapers, and degreased with an organic agent. Then, the composite coating obtained in the embodiment and the comparative example was applied, dried at room temperature for 3 days, and then cured at 90°C for 12 hours, and the dry film thickness was 35±2μm. The dry adhesion was measured using the method of CN114806367A.

[0112] The results show that the dry adhesion of comparative example 1 is 4.64MPa, which is equivalent to CN114806367A. Examples 1-6 are higher than 5.00MPa, which are significantly higher than comparative example 1, among which Example 1 is 5.51MPa, Example 2 is 5.36MPa, and Example 3 is 5.33MPa; Example 4 is 5.17MPa, Example 5 is 5.28MPa, and Example 6 is 4.86MPa. It can be seen that Examples 1-3 are significantly better than Examples 4 and 5, and Examples 4 and 5 are better than Example 6.

[0113] The corrosion rate was determined using the method of CN114806367A.

[0114] The results show that the corrosion rates of Examples 4-6 and Comparative Example 1 are around 1.600 mm / year, which is comparable to CN114806367A. Examples 2 and 3 are 1.587 mm / year and 1.574 mm / year, respectively. Although there are improvements, they are not statistically significant (P>0.05). Example 1 is 1.448 mm / year, which is a significant improvement.

[0115] The preferred specific implementation modes and embodiments of the present invention are described in detail above, but the present invention is not limited to the above implementation modes and embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the concept of the present invention.

Claims

1. A method for preparing a graphene nanocoating, characterized in that: The following steps are involved: S01, modification of graphene oxide; S02, preparing microcapsules; S03, taking the modified graphene oxide obtained in step S01 and the microcapsules, epoxy-modified polyurethane resin and curing agent obtained in step S02, to prepare a graphene nano coating.

2. The method for preparing a graphene nano coating according to claim 1, characterized in that: S01 includes: S11, using chitosan and graphene oxide as main raw materials to prepare chitosan-modified graphene oxide; S12, chitosan graphene oxide modified with polyaspartic acid, prepared with polyaspartic acid as the main raw material.

3. The method for preparing a graphene nanocoating according to claim 1 or 2, characterized in that: In S03, microcapsules are prepared using polyvinyl alcohol, urea, vegetable oil, benzotriazole and formaldehyde as main raw materials.

4. The method for preparing a graphene nanocoating according to any one of claims 1 to 3, characterized in that: In S11, chitosan is added to an acetic acid solution and stirred; an aqueous solution of graphene oxide is added, the pH is adjusted, the temperature is increased, stirring is continued, and centrifugation is performed to obtain chitosan-modified graphene oxide.

5. The method for preparing a graphene nanocoating according to any one of claims 1 to 4, characterized in that: In S12, the chitosan-modified graphene oxide obtained in step S11 is taken and added to the polyaspartic acid aqueous solution, stirred, the pH is adjusted, glutaraldehyde is added, the stirring is continued, centrifuged, and washed with water to obtain the polyaspartic acid-modified chitosan graphene oxide.

6. The method for preparing a graphene nanocoating according to any one of claims 1 to 5, characterized in that: In S02, water is taken, polyvinyl alcohol aqueous solution and urea are added, stirred, and the pH is adjusted; linseed oil and benzotriazole are added, ultrasonic treatment is performed, and stirring is performed to obtain an emulsion; formaldehyde aqueous solution is added dropwise, the temperature is increased, and stirring is continued to obtain microcapsules.

7. The method for preparing a graphene nanocoating according to any one of claims 1 to 6, characterized in that: In S11, the pH is adjusted to 5.0-5.5 and the temperature is raised to 60-65°C; In S12, the pH is adjusted to 5.0-5.5; In S02, the pH is adjusted to 3.0-3.5; after adding formaldehyde aqueous solution dropwise, the temperature is raised to 60-65°C.

8. The method for preparing a graphene nanocoating according to any one of claims 1 to 7, characterized in that: In S01, the ratio of chitosan, graphene oxide, polyaspartic acid and glutaraldehyde is 0.10-0.20g chitosan: 15-25mL 0.1% (w / v) graphene oxide aqueous solution: 40-60mL 0.5% (w / v) polyaspartic acid aqueous solution: 0.5-1.5mL glutaraldehyde; preferably, 0.10-0.20g chitosan: 15-25mL 0.1% (w / v) graphene oxide aqueous solution: 40-60mL 0.5% (w / v) polyaspartic acid aqueous solution: 0.8-1.0mL glutaraldehyde; In S02, the ratio of polyvinyl alcohol, urea, linseed oil, benzotriazole and formaldehyde aqueous solution is 1-10 mL 5% (w / v) polyvinyl alcohol aqueous solution: 1-10 g urea: 10-20 g linseed oil: 1-5 g benzotriazole: 10-20 mL 30% (v / v) formaldehyde aqueous solution; preferably 1-10 mL 5% (w / v) polyvinyl alcohol aqueous solution: 1-10 g urea: 10-20 g linseed oil: 2-3 g benzotriazole: 10-20 mL 30% (v / v) formaldehyde aqueous solution.

9. The method for preparing a graphene nano coating according to any one of claims 1 to 8, characterized in that: In S03, the weight ratio of epoxy-modified polyurethane resin, curing agent, polyaspartic acid-modified chitosan graphene oxide and microcapsules is (40-60): (10-30): (0.01-0.5): (1-10), preferably (40-60): (10-30): (0.01-0.5): (5-10).

10. A graphene nanocoating obtained according to the preparation method according to any one of claims 1 to 9.