Modified graphene material, preparation method and application thereof, anticorrosive coating material, preparation method and application thereof, anticorrosive coating and application thereof

Abstract

This invention relates to the fields of modified graphene technology and anti-corrosion materials technology, specifically to a modified graphene material and its preparation method, an anti-corrosion coating and its preparation method and application, and an anti-corrosion coating and its application. The modified graphene material includes graphene oxide and ammonium phytate grafted onto the surface of graphene oxide via amide bonds. The structural formula of the ammonium phytate is shown in formula (I). In formula (I), * represents the N-linked site in the amide bond; R1 is selected from one of the groups formed by removing two terminal amine groups from a C2-C10 alkylene group or an n-ethylene(n+1)amine, where n is an integer and 2≤n≤6. The modified graphene of this invention has the advantages of strong dispersibility in water-based coatings and strong adhesion to metal substrates. When applied to water-based anti-corrosion coating resins, it improves the adhesion, high barrier properties, and corrosion resistance of the coating.

Description

Technical Field

[0001] This invention relates to the fields of modified graphene technology and anti-corrosion materials technology, specifically to a modified graphene material and its preparation method and application, an anti-corrosion coating and its preparation method and application, and an anti-corrosion coating and its application. Background Technology

[0002] Coastal oil storage facilities suffer from significant corrosion due to the complex corrosive environment of the ocean. Strengthening research and application of corrosion protection technologies is crucial for ensuring the safe operation of coastal oil and gas storage tank structures. Corrosion protection is a critical issue that must be addressed in marine development and coastal economic growth. It is of great value to my country's energy security and coastal environmental protection. Coastal oil storage facilities are particularly vulnerable to corrosion due to the alternating wet and dry conditions caused by ocean splash and tidal ranges, especially with high oxygen levels. Therefore, the selected anti-corrosion coatings must be able to withstand these changes and possess stringent requirements for wear resistance, impact resistance, and weather resistance.

[0003] Graphene, a promising material that could drive a new industrial revolution, is considered the ideal material for anti-corrosion coatings due to its unique atomic impermeability. Graphene-based anti-corrosion coatings have become one of the future development directions of the industry. In recent years, well-known domestic and foreign coating companies have invested heavily in the development of graphene-based functional coatings.

[0004] CN116694191A discloses a solvent-free epoxy heavy-duty anti-corrosion coating for marine engineering and its application method. It proposes a heavy-duty anti-corrosion, solvent-free epoxy heavy-duty anti-corrosion coating. However, the filler resin used in this invention is still a traditional filler. Only the material ratio and resin structure have been adjusted, and the anti-corrosion effect in high-impact environments is limited.

[0005] CN115746695A discloses a method for preparing a high-adhesion polyamide powder coating. It proposes to use phytic acid to modify hexagonal boron nitride and retrograde it, and then add it to the polyamide resin to improve the adhesion between the polyamide resin and the substrate. The preparation process involves the powder coating preparation process, and the construction process is complicated.

[0006] CN114539877A discloses an anti-corrosion waterborne epoxy coating based on graphene co-modified with divalent zinc ions and phytic acid. It proposes to use zinc ions and phytic acid as precursors to modify graphene and add it as a filler to the filler resin to improve the corrosion resistance of the coating. However, zinc ions have poor stability under acid and alkaline conditions, which leads to poor acid and alkali resistance of the coating. Summary of the Invention

[0007] Currently, the development of high-adhesion, high-barrier water-based coatings for the outer walls of coastal oil storage equipment is a technical challenge in this field, which aims to modify the surface of graphene to enhance its barrier effect and improve its adhesion to the base resin.

[0008] The purpose of this invention is to overcome the problems in existing water-based anti-corrosion coatings. On the one hand, graphene has poor compatibility with resins, making it difficult to utilize its excellent molecular barrier properties. On the other hand, water-based heavy-duty anti-corrosion coatings suffer from weak adhesion to metal substrates and poor impact resistance. The modified graphene described in this invention has the advantages of strong dispersibility in water-based coatings and strong adhesion to metal substrates. When applied to water-based anti-corrosion coating resins, it improves the coating's adhesion, high barrier properties, impact resistance, and corrosion resistance.

[0009] To achieve the above objectives, a first aspect of the present invention provides a modified graphene material, comprising: graphene oxide and an ammonium phytate salt grafted onto the surface of the graphene oxide via amide bonds, wherein the ammonium phytate salt has the structural formula shown in formula (I). (I), In formula (I), * represents the N-linked site in the amide bond; R1 is selected from one of the groups formed by removing two terminal amino groups from C2-C10 alkylene or n-ethylene(n+1)amines, where n is an integer and 2≤n≤6.

[0010] A second aspect of the present invention provides a method for preparing the modified graphene material described herein, the method comprising: (1) In the presence of a first solvent and an amidation catalyst, an organic amine is subjected to an amidation reaction with graphene oxide to obtain amidated graphene. (2) In the presence of a second solvent, phytic acid is contacted with amide graphene, separated, and the solid is dried; the organic amine is selected from one or more of C2-C10 organic diamines and C2-C6 organic polyamines.

[0011] A third aspect of this invention provides the application of the modified graphene material described herein in coatings and coating materials.

[0012] A fourth aspect of the present invention provides an anti-corrosion coating, the anti-corrosion coating comprising: Component A: 0.01-3 parts of the modified graphene material described in this invention, 35-55 parts of waterborne epoxy resin, and 45-80 parts of solvent; Component B: 20-150 parts of water-based epoxy curing agent B; The mass ratio of component A to component B is 0.5-5:1.

[0013] The fifth aspect of this invention provides a method for preparing the anti-corrosion coating of this invention, the method comprising: (I) The modified graphene is dispersed in a solvent to obtain a modified graphene dispersion; (II) Component A is obtained by mixing waterborne epoxy resin with modified graphene dispersion.

[0014] The sixth aspect of the present invention provides an anti-corrosion coating, which is obtained by mixing and coating the anti-corrosion coating components A and B of the present invention.

[0015] The seventh aspect of the present invention provides an application of the anti-corrosion coating or anti-corrosion coating of the present invention in preventing seawater corrosion.

[0016] Compared with the prior art, the beneficial effects of the present invention through the above technical solution are as follows: 1. This invention uses organic amines to undergo an amidation reaction with the carboxyl groups on the surface of graphene oxide under the action of a catalyst to obtain amidated modified graphene. Phytic acid is then combined with the amine groups at the amide end to form ammonium phytate salt, thereby improving the bonding force between phytic acid and graphene and further enhancing the dispersibility of graphene. 2. This invention modifies the functional groups on the graphene surface by co-modifying graphene with phytic acid and amide, thereby grafting phytic acid and amide functional groups onto the graphene surface. This facilitates the formation of steric hindrance between graphene sheets, solving the problem of graphene self-aggregation. When used as a coating component, it allows graphene to expand into a sheet-like structure in water-based anti-corrosion coatings, providing excellent molecular barrier properties and improving the corrosion resistance of the coating.

[0017] 3. Phytic acid and amide co-modified graphene can be used as a coating component to impart bonding force between graphene coating and metal substrate, thereby improving coating adhesion. At the same time, phytic acid, as a grafting agent, can form complexes with metal ions in the substrate, thereby improving the adhesion of the coating on the metal substrate and extending the protection time of the coating. Attached Figure Description

[0018] Figure 1 The infrared spectra of graphene oxide, amidated modified graphene, and modified graphene in Example 1 of this invention are shown. Figure 2 The X-ray photoelectron spectroscopy of the modified graphene in Example 1 of this invention; Figure 3 The N1s X-ray photoelectron spectrum of the modified graphene of Example 1 of this invention; Figure 4 This is the P2p X-ray photoelectron spectrum of the modified graphene of Example 1 of the present invention; Figure 5 These are SEM images of the coating surface in Application Example 1 of this invention; Figure 6 This is a SEM image of the coating surface of Comparative Example 2 of this invention. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] A first aspect of the present invention provides a modified graphene material comprising: graphene oxide and an ammonium phytate salt grafted onto the surface of the graphene oxide via amide bonds, the ammonium phytate salt having the structural formula shown in formula (I). (I), In formula (I), * represents the N-linked site in the amide bond; R1 is selected from one of the groups formed by removing two terminal amino groups from C2-C10 alkylene or n-ethylene(n+1)amines, where n is an integer and 2≤n≤6.

[0021] In this art, the structural formula of graphene oxide is generally considered to be as shown in formula (II). (II).

[0022] In this invention, the ammonium phytate salt in the modified graphene can be grafted onto the surface of graphene oxide via amide bonds. Depending on the number of carboxyl groups on the graphene oxide surface, for example, one, two, three, four, five, six, seven, or eight of the ammonium phytate salts described in this invention can be grafted. Hereinafter, an exemplary structural formula of modified graphene grafted with one ethylene phytate salt (R1) is given, as shown in formula (III). (III) The structural formulas of the remaining phytate ammonium salts of the R1 group and the modified graphene structures grafted with 1, 2, 3, 4, 5, 6, 7 or 8 phytate ammonium salts will not be described in detail.

[0023] According to a preferred embodiment of the present invention, the modified graphene material has a carbon content of 35-60%, a nitrogen content of 5-15%, a phosphorus content of 5-15%, and an oxygen content of 10-35%.

[0024] In this invention, the modified graphene material has a wide median particle size range. According to a preferred embodiment of this invention, the median particle size of the modified graphene material is 5-15 μm.

[0025] In this invention, the group formed by removing two terminal amino groups from n-ethylene (n+1) amines, for example, triethylenetetramine becomes -CH2CH2NHCH2CH2NHCH2CH2- after removing two terminal amino groups. Other n-ethylene (n+1) amines (such as tetraethylenepentamine, diethylenetriamine, etc.) formed by removing two terminal amino groups are not listed here.

[0026] According to a preferred embodiment of the present invention, R1 is selected from one of the groups formed by removing two terminal amino groups from a C2-C6 alkylene group or an n-ethylene (n+1)amine, wherein n is an integer and 2≤n≤5, preferably R1 is selected from ethylene, hexane, -CH2CH2NHCH2CH2-, -CH2CH2NHCH2CH2NHCH2CH2-、 One of -CH2CH2NHCH2CH2NHCH2CH2NHCH2CH2NHCH2CH2-.

[0027] A second aspect of the present invention provides a method for preparing the modified graphene material described herein, the method comprising: (1) In the presence of a first solvent and an amidation catalyst, an organic amine is subjected to an amidation reaction with graphene oxide to obtain amidated graphene. (2) In the presence of a second solvent, phytic acid is contacted with aminated graphene, separated, and the solid is dried; the organic amine is selected from one or more of C2-C10 organic diamines and C2-C6 organic polyamines. The organic amine described in this invention undergoes an amidation reaction with the carboxyl groups on the surface of graphene oxide under the action of a catalyst to obtain amidated modified graphene. Further, phytic acid is combined with the amine groups at the amide end groups to form ammonium phytate salts to obtain modified graphene materials. The abundant oxygen-containing functional groups in graphene oxide are beneficial for amidation modification and phytic acid grafting on graphene oxide, and are conducive to the functional performance of graphene oxide in coating systems.

[0028] According to a preferred embodiment of the present invention, the organic amine is selected from one or more of triethylenetetramine, hexamethylenediamine, ethylenediamine, tetraethylenepentamine, and diethylenetriamine.

[0029] In this invention, the range of types of amidation catalysts that can be selected in step (1) is relatively wide, as long as they can enable organic amines to undergo amidation reactions with graphene oxide. According to a preferred embodiment of this invention, the amidation catalyst is selected from one or more of methyl orthosilicate, diphenylsilane, carbodiimide, urea cationic / quaternary phosphine salt, benzotriazole, borane, and hydrocarbon-substituted borane.

[0030] In this invention, there is no particular limitation on the amount of the amidation catalyst. According to a preferred embodiment of the invention, the mass ratio of the amidation catalyst to graphene oxide is 0.01-0.05:1.

[0031] According to a preferred embodiment of the present invention, the mass ratio of organic amine to graphene oxide is 0.002-0.1:1.

[0032] In this invention, there is no particular limitation on the type of the first solvent, as long as it can disperse graphene oxide and organic amine. According to a preferred embodiment of the present invention, the first solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, anhydrous ethanol and anhydrous methanol, preferably N,N-dimethylformamide.

[0033] In this invention, there are no particular limitations on the conditions for the amidation reaction. According to a preferred embodiment of the invention, the amidation reaction conditions include: a temperature of 60-150°C; preferably, a reaction time of 30-120 min.

[0034] The present invention also includes a washing process for the solids separated in step (1), such as water washing or alcohol washing.

[0035] According to a preferred embodiment of the present invention, the mass ratio of phytic acid to aminated graphene is 0.1-0.7:1.

[0036] In this invention, the range of selectable contact conditions in step (2) is relatively wide. According to a preferred embodiment of this invention, the contact conditions include: a temperature of 60-100℃; and a preferred reaction time of 3-8h.

[0037] According to a preferred embodiment of the present invention, the second solvent is selected from one or more of water and alcohols, preferably from one or more of ethanol, methanol, glycerol, ethylene glycol and water, and most preferably water.

[0038] In this invention, there is no particular limitation on the drying method in step (2). According to a preferred embodiment of this invention, the drying method is freeze drying.

[0039] According to a preferred embodiment of the present invention, step (2) further includes washing the separated solids, for example, by washing with deionized water; and then performing the drying.

[0040] A third aspect of this invention provides the application of the modified graphene material described herein in coatings and coating materials.

[0041] A fourth aspect of the present invention provides an anti-corrosion coating, the water-based anti-corrosion coating comprising: Component A: 0.01-3 parts of the modified graphene material described in this invention, 35-55 parts of waterborne epoxy resin, and 45-80 parts of solvent; Component B: 20-150 parts of water-based epoxy curing agent B; the mass ratio of component A to component B is 0.5-5:1. The modified graphene described in this invention has the advantage of strong dispersibility. As a component of water-based anti-corrosion coatings, it can improve the adhesion, barrier properties, impact resistance, and corrosion resistance of the coating.

[0042] According to a preferred embodiment of the present invention, the solvent is selected from one or more of water, propylene glycol monomethyl ether, propylene glycol monobutyl ether, and ethylene glycol monobutyl ether.

[0043] According to a preferred embodiment of the present invention, the waterborne epoxy resin is selected from one or more of waterborne polyurethane modified epoxy resin and waterborne bisphenol A epoxy resin.

[0044] In this invention, there are no special requirements for the type of waterborne epoxy curing agent. The waterborne epoxy curing agent is selected from curing agents corresponding to epoxy resins.

[0045] The fifth aspect of this invention provides a method for preparing the anti-corrosion coating of this invention, the method comprising: (I) The modified graphene is dispersed in a solvent to obtain a modified graphene dispersion; (II) Component A is obtained by mixing waterborne epoxy resin with modified graphene dispersion.

[0046] According to a preferred embodiment of the present invention, in step (I), the modified graphene of the present invention is first formed into a modified graphene dispersion. There is no particular limitation on the dispersion method. According to a preferred embodiment of the present invention, it is dispersed by ultrasonication. Preferably, the ultrasonic treatment time is 1-5 hours and the ultrasonic power is 5-20 kW.

[0047] According to a preferred embodiment of the present invention, the mass concentration of modified graphene in the modified graphene dispersion is 5-15 wt%.

[0048] In this invention, components A and B are mixed and applied to a substrate material, then cured and dried to form a coating. The anti-corrosion coating of this invention can be applied at room temperature. According to a preferred embodiment of this invention, the drying temperature is 5-80°C.

[0049] A sixth aspect of the present invention provides an anti-corrosion coating, which is obtained by mixing and applying the anti-corrosion coating components A and B described in the present invention. The coating method includes, for example, spraying, roller coating, brushing, or dip coating.

[0050] According to one embodiment of the present invention, components A and B are mixed and then applied to the surface of a metal substrate by spraying, roller coating, brushing or dipping, and then dried to form an anti-corrosion coating.

[0051] According to a preferred embodiment of the present invention, the coating thickness is 80-300 μm.

[0052] A seventh aspect of the present invention provides the application of the anti-corrosion coating or anti-corrosion layer described herein in preventing seawater corrosion, preferably in the prevention of seawater corrosion in coastal storage tanks, coastal platforms, pipelines, and other similar installations. For example, it can be used for the external surface corrosion protection of coastal oil depots.

[0053] In the context of this invention specification, including the following embodiments, the content of each element was obtained by X-ray photoelectron spectroscopy (XPS) using an ESCALAB 250Xi XPS instrument from Thermo Fisher Scientific, USA. Test conditions: room temperature 25°C, vacuum degree less than 5 × 10⁻⁶. -10 The mba operates at 15KV and uses Al Kα as the radiation source.

[0054] The morphology of the material was characterized using a scanning electron microscope (SEM) in the following embodiments, as described in this specification. Specifically, the scanning electron microscope was a TECNALG2F20 (200kV) from FEI Corporation, USA. The test conditions were as follows: the sample was pressed directly onto a sample stage containing conductive tape, and then the electron microscope was inserted for observation.

[0055] In the context of this invention specification, including the following embodiments, the median particle size of the modified graphene was obtained by dynamic light scattering characterization using a Malvern Panalytical MS-3000 laser particle size analyzer. Test conditions: The sample was dispersed in deionized water at a concentration of 0.01 mg / ml, and tested after sonication for 10 minutes. The instrument's light-blocking setting was set between 5% and 20%.

[0056] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0057] Example 1 (1) Take 50g of graphene oxide powder and add it to 1kg of N,N-dimethylformamide. Disperse it by ultrasonication to obtain a graphene oxide dispersion. Add 1.5g of diphenylsilane to the dispersion in step (1), stir evenly, and slowly add 3g of tetraethylenepentamine to the mixture. Control the reaction temperature at 100℃ and the reflux reaction time at 60min. Filter the reacted material, wash with alcohol and water to obtain aminated graphene. (2) Take 50g of the amide graphene from step (1) and disperse it in deionized water. Sonicate it to obtain a uniform dispersion. Add 18g of phytic acid to the dispersion and reflux it at 80℃ for 5h. Then wash and filter it with water and freeze dry to obtain phytic acid and amide co-modified graphene powder. According to X-ray photoelectron spectroscopy, the modified graphene contains 48.1% carbon, 7.6% nitrogen, 12.6% phosphorus, and 31.7% oxygen.

[0058] The median particle size of the modified graphene is 12 μm.

[0059] In Example 1, the infrared spectra of graphene oxide, amide graphene, and modified graphene are as follows: Figure 1 As shown. From Figure 1 It can be seen that, compared to graphene oxide, amide graphene has a lower content of 3461 cm⁻¹. -1 and 952 cm -1 Stretching vibration peaks belonging to NH and C-NH2 appeared at 1470 cm⁻¹, indicating that amide groups were successfully grafted onto the graphene. Meanwhile, at 1470 cm⁻¹... -1 The presence of a characteristic peak for vinyl groups at this location indicates that organic amines are grafted onto graphene oxide via amide bonds. A peak at 3390 cm⁻¹ appears on the modified graphene. -1 A hydroxyl peak of a phosphate group appears at 1641 cm⁻¹. -1 The characteristic peak of the six-membered carbon ring of phytic acid appears at 1555 cm⁻¹; simultaneously, at 1555 cm⁻¹... -1 The presence of an ammonium salt peak indicates that phosphate groups were grafted onto the surface of ammonium-treated graphene in the form of ammonium salts.

[0060] Figure 2 The image shows the X-ray photoelectron spectrum of the modified graphene in Example 1. The image confirms the presence of the N1s signal peak and the P1p signal peak generated by phytic acid grafting in the modified graphene. Both the surface amide functional group and the P element were grafted onto the graphene oxide.

[0061] Figure 3This is the N1s X-ray photoelectron spectrum of the modified graphene in Example 1. The figure confirms the presence of the amide functional group O=C-NH (399.8 eV), as well as C-NH-C (399.1 eV), -C=NH (398.9 eV), and NC (395.7 eV) functional groups.

[0062] Figure 4 This is the P2p X-ray photoelectron spectrum of the modified graphene in Example 1. The figure confirms the presence of both the P(O)-N (135.8 eV) functional group and the -P=O (135 eV) and OPO (133.8 eV) functional groups.

[0063] The above spectral structures collectively demonstrate that graphene oxide was modified and grafted with organic amines to form amidated graphene, and then the combination of phytic acid and organic amines formed a stable modified graphene structure. This structure not only ensures the uniform dispersion of graphene in the coating solvent, but also leverages the combined effect of phytic acid groups and graphene to improve the overall performance of the coating.

[0064] Example 2 (1) Take 50g of graphene oxide powder, add it to 1kg of N-methylpyrrolidone, and disperse it by ultrasonication to obtain a graphene oxide dispersion; add 1.5g of phenyltriazole to the dispersion in step (1), stir evenly, slowly add 1g of ethylenediamine to the mixture, control the reaction temperature at 60℃, and reflux the reaction for 30min; filter the reacted material, wash with alcohol and water to obtain aminated graphene; (2) Take 50g of the amide graphene from step (1) and disperse it in deionized water. Sonicate it to obtain a uniform dispersion. Add 5g of phytic acid to the dispersion and reflux it at 60℃ for 3h. Then wash and filter it with water and freeze dry to obtain phytic acid and amide co-modified graphene powder. The median particle size of the modified graphene is 5 micrometers.

[0065] According to X-ray photoelectron spectroscopy, the modified graphene contains 59.3% carbon, 5.6% nitrogen, 7.4% phosphorus, and 27.7% oxygen.

[0066] Example 3 (1) Take 50g of graphene oxide powder, add it to 1kg of N,N-dimethylacetamide, and disperse it by ultrasonication to obtain a graphene oxide dispersion; add 2.5g of methyl-substituted borane to the dispersion in step (1), stir evenly, slowly add 5g of tetraethylenepentamine to the mixture, control the reaction temperature at 150℃, and reflux the reaction for 120min; filter the reacted material, wash with alcohol and water to obtain aminated graphene; (2) Take 50g of the amide graphene from step (1) and disperse it in deionized water. Sonicate it to obtain a uniform dispersion. Add 35g of phytic acid to the dispersion and reflux it at 100℃ for 8h. Then wash and filter it with water and freeze dry it to obtain phytic acid and amide co-modified graphene powder. Infrared spectrum of modified graphene and Figure 1 Similarly, this indicates that tetraethylenepentamine is grafted onto graphene oxide in the form of amide bonds, and phosphate groups are grafted onto the surface of amide graphene in the form of ammonium salts.

[0067] The median particle size of the modified graphene is 15 micrometers.

[0068] According to X-ray photoelectron spectroscopy, the modified graphene contains 49.2% carbon, 12.4% nitrogen, 14.8% phosphorus, and 23.6% oxygen.

[0069] Example 4 (1) Take 50g of graphene oxide powder, add it to 1kg of N,N-dimethylformamide, and disperse it by ultrasonication to obtain a graphene oxide dispersion; add 2g of methyl orthosilicate to the dispersion in step (1), stir evenly, slowly add 3.5g of diethylenetriamine to the mixture, control the reaction temperature at 90℃, and reflux the reaction for 120min; filter the reaction mixture, wash with alcohol and water to obtain aminated graphene; (2) Take 50g of the amide graphene from step (1) and disperse it in deionized water. Sonicate it to obtain a uniform dispersion. Add 30g of phytic acid to the dispersion and reflux it at 80℃ for 6h. Then wash and filter it with water and freeze dry it to obtain phytic acid and amide co-modified graphene powder. Infrared spectrum of modified graphene and Figure 1 Similarly, this indicates that diethylenetriamine is grafted onto graphene oxide in the form of amide bonds, and phosphate groups are grafted onto the surface of ammonium-based graphene oxide in the form of ammonium salts.

[0070] The median particle size of the modified graphene is 5 micrometers.

[0071] According to X-ray photoelectron spectroscopy, the modified graphene contains 57.3% carbon, 11.6% nitrogen, 14.6% phosphorus, and 16.5% oxygen.

[0072] Comparative Example 1 (1) Take 50g of graphene oxide powder and add it to 1kg of N,N-dimethylformamide. Disperse it by ultrasonication to obtain a graphene oxide dispersion. Add 1.5g of diphenylsilane to the dispersion in step (1), stir evenly, and slowly add 3g of tetraethylenepentamine to the mixture. Control the reaction temperature at 100℃ and the reflux reaction time at 60min. Filter the reacted material, wash with alcohol and water to obtain aminated graphene.

[0073] Application Example 1 Weigh 50g of the phytic acid and amide co-modified graphene powder prepared in Example 1 and add it to 500g of propylene glycol monomethyl ether. Ultrasonic power is 15kw, and ultrasonic treatment is carried out for 2h to obtain a uniform dispersion. Weigh 20g of modified graphene dispersion and add it to 100g of Jotun waterborne epoxy paint Penguard WF-07A (53%) component. Mix well and then add 50g of the corresponding component B WF-07B (70%). After mixing well, a waterborne anti-corrosion coating is obtained. Spray the coating onto a carbon steel substrate. After the paint film is fully dried, the thickness of the paint film is 200μm.

[0074] Figure 5 This is a SEM image of the coating surface in Application Example 1 of the present invention. It can be seen that the graphene is evenly spread in the anti-corrosion coating, achieving uniform dispersion, which can better play the role of blocking corrosive media.

[0075] The modified graphene anticorrosive coating has a tensile strength of 10 MPa.

[0076] According to GB / T1771-2007, GB / T4157-2017, and GB / T 5210-2006, we tested the coating's resistance to neutral salt spray, hydrogen sulfide, and film adhesion. The test results showed that after immersion in hydrogen sulfide solution for 1000 hours, the substrate surface showed no blistering or peeling. After 3000 hours of neutral salt spray testing, only the scribing lines showed corrosion marks, and the corrosion did not spread to either side, meeting the requirements.

[0077] The abrasion loss of the coating was tested according to ASTM D4060, which involves measuring the mass loss of the coating after 1000 revolutions on a 1kg standard abrasion wheel. The abrasion loss in Example 1 was 10mg.

[0078] Application Example 2 Weigh 50g of the phytic acid and amide co-modified graphene powder prepared in Example 2 and add it to 950g of deionized water. Ultrasonic power 5kw, ultrasonic treatment for 5h, to obtain a uniform dispersion. Weigh 12g of modified graphene dispersion and add it to 100g of Jotun waterborne epoxy paint HEMPEL 48509A (49%) component. Mix well and then add 150g of the corresponding B component HEMPEL 98721B (60%) component. Mix well to obtain a waterborne anti-corrosion coating. Apply the coating to a carbon steel substrate by spraying. After the paint film is fully dried, the thickness of the paint film is 150μm.

[0079] The coating formed by the above-mentioned modified graphene anti-corrosion coating was tested and found to have a tensile strength of 10 MPa. It can withstand hydrogen sulfide solution for 800 hours and neutral salt spray for 2600 hours. The wear loss is 25mg.

[0080] Application Example 3 30g of the phytic acid and amide co-modified graphene powder prepared in Example 3 was weighed and added to 200g of propylene glycol monomethyl ether. The mixture was ultrasonically treated with an ultrasonic power of 10kw for 1h to obtain a uniform dispersion. Weigh 20g of modified graphene dispersion and add it to 100g of Jotun waterborne epoxy paint JT-233M (42%) component A. After mixing evenly, add 20g of the corresponding component B JT-233M (80%) component B. After mixing evenly, a waterborne anti-corrosion coating is obtained. The coating is applied to a carbon steel substrate by spraying and roller coating. After the paint film is fully dried, the thickness of the paint film is 80μm.

[0081] The coating formed by the above-mentioned modified graphene anti-corrosion coating was tested and found to have a tensile strength of 8 MPa; It can withstand hydrogen sulfide solution for 850 hours and neutral salt spray for 3200 hours. The wear loss is 20mg.

[0082] Application Example 4 Weigh 50g of the phytic acid and amide co-modified graphene powder prepared in Example 4 and add it to 500g of propylene glycol monomethyl ether. Ultrasonic power 12kw, ultrasonic treatment for 1h, to obtain a uniform dispersion. Weigh 20g of modified graphene dispersion and add it to 100g of Jotun waterborne epoxy paint Penguard WF-06DA (65%) component. After mixing evenly, add 70g of the corresponding component B WF-06DB (70%) and mix evenly to obtain a waterborne anti-corrosion coating. Apply the coating to a carbon steel substrate by spraying. After the paint film is fully dried, the thickness of the paint film is 300μm.

[0083] The coating formed by the above-mentioned modified graphene anti-corrosion coating was tested and found to have a tensile strength of 8 MPa; It can withstand hydrogen sulfide solution for 1200 hours and neutral salt spray for 3000 hours. The wear loss is 35mg.

[0084] Application Comparative Example 1 Compared with Application Example 1, the difference between Application Example 1 and Application Example 1 is that in Application Example 1, aminated graphene was used to replace modified graphene in the preparation of the dispersion, while in the coating, aminated graphene dispersion was added to replace modified graphene dispersion.

[0085] The adhesion of the above-mentioned graphene-containing anti-corrosion coating is 7 MPa.

[0086] Subsequently, we tested the coating's resistance to neutral salt spray and hydrogen sulfide. The test results showed that after 200 hours of immersion in hydrogen sulfide solution, the substrate exhibited blistering and peeling. After 600 hours of neutral salt spray testing, the corrosion at the scribe lines was severe, and the corrosion spread significantly to both sides, meeting the requirements. The wear loss of Comparative Example 1 was 85 mg.

[0087] Figure 6 The SEM image of the coating surface used in Comparative Example 1 shows that unmodified graphene exhibits significant aggregation in the coating, which leads to wrinkles and voids in the coating and is detrimental to the coating's anti-corrosion performance.

[0088] Application Comparative Example 2 Compared with Application Example 1, Application Comparative Example 2 uses unmodified graphene instead of modified graphene, and in the coating, unmodified graphene dispersion is added instead of modified graphene dispersion.

[0089] The adhesion of the above-mentioned graphene-containing anti-corrosion coating is 5 MPa.

[0090] Subsequently, we tested the coating's resistance to neutral salt spray and hydrogen sulfide. The test results showed that after immersion in hydrogen sulfide solution for 300 hours, the substrate exhibited blistering and peeling. After 400 hours of neutral salt spray testing, the corrosion at the scribe lines was severe, and the corrosion spread significantly to both sides, meeting the requirements. The wear loss of Comparative Example 2 was 125 mg.

[0091] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A modified graphene material, characterized in that, include: Graphene oxide and ammonium phytate grafted onto the surface of graphene oxide via amide bonds, the structural formula of which is shown in formula (I). （I）， In formula (I), * represents the N-linked site in the amide bond; R1 is selected from one of the groups formed by removing two terminal amino groups from C2-C10 alkylene or n-ethylene(n+1)amines, where n is an integer and 2≤n≤6.

2. The modified graphene material according to claim 1, wherein, The modified graphene material contains 35-60% carbon, 5-15% nitrogen, 5-15% phosphorus, and 10-35% oxygen; and / or The median particle size of the modified graphene material is 5-15 μm.

3. The modified graphene material according to claim 1 or 2, wherein, R1 is selected from one of the groups formed by removing two terminal amino groups from a C2-C6 alkylene group or an n-ethylene(n+1)amine, where n is an integer and 2≤n≤5. R1 is selected from ethylene, hexylene, ... -CH2CH2NHCH2CH2-, -CH2CH2NHCH2CH2NHCH2CH2-, One of -CH2CH2NHCH2CH2NHCH2CH2NHCH2CH2NHCH2CH2-.

4. The method for preparing the modified graphene material according to any one of claims 1-3, characterized in that, The method includes: (1) In the presence of a first solvent and an amidation catalyst, an organic amine is subjected to an amidation reaction with graphene oxide to obtain amidated graphene. (2) In the presence of a second solvent, phytic acid is contacted with amide graphene, separated, and the solid is dried; the organic amine is selected from one or more of C2-C10 organic diamines and C2-C6 organic polyamines.

5. The preparation method according to claim 4, wherein, The organic amine is selected from one or more of triethylenetetramine, hexamethylenediamine, ethylenediamine, tetraethylenepentamine, and diethylenetriamine; and / or In step (1), the amidation catalyst is selected from one or more of methyl orthosilicate, diphenylsilane, carbodiimide, urea cationic / quaternary phosphine salt, benzotriazole, borane, and alkyl-substituted borane; and / or The mass ratio of the amidation catalyst to graphene oxide is 0.01-0.05:1; and / or The mass ratio of organic amine to graphene oxide is 0.02-0.1:1; and / or The first solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, anhydrous ethanol, and anhydrous methanol, preferably N,N-dimethylformamide; and / or The amidation reaction conditions include: a temperature of 60-150℃; and / or a reaction time of 30-120 min.

6. The preparation method according to claim 4, wherein, The mass ratio of phytic acid to amide graphene is 0.1-0.7:1; and / or Contact conditions include: a temperature of 60-100℃; and / or a reaction time of 3-8 hours; and / or The second solvent is selected from one or more of water and alcohols, preferably one or more of ethanol, methanol, glycerol, ethylene glycol, and water, preferably water; and / or The drying method is freeze drying.

7. The application of the modified graphene material according to any one of claims 1-3 in coatings and coating materials.

8. An anti-corrosion coating, characterized in that, The anti-corrosion coating includes: Component A: 0.01-3 parts of the modified graphene material according to any one of claims 1-3, 35-55 parts of waterborne epoxy resin, and 45-80 parts of solvent; Component B: 20-150 parts of water-based epoxy curing agent B; The mass ratio of component A to component B is 0.5-5:1; Preferably, the solvent is selected from one or more of water, propylene glycol monomethyl ether, propylene glycol monobutyl ether, and ethylene glycol monobutyl ether.

9. The method for preparing the anti-corrosion coating according to claim 8, characterized in that, The method includes: (I) The modified graphene is dispersed in a solvent to obtain a modified graphene dispersion; (II) Component A is obtained by mixing aqueous epoxy resin with modified graphene dispersion; Preferably, in step (I), dispersion is achieved by ultrasonic treatment, and preferably, the ultrasonic treatment time is 1-5 hours and the ultrasonic power is 5-20 kW. Preferably, the mass concentration of modified graphene in the modified graphene dispersion is 5-15 wt%.

10. An anti-corrosion coating, characterized in that, The coating is obtained by mixing and applying the anti-corrosion coating components A and B as described in claim 8; preferably, the coating thickness is 80-300 μm.

11. The application of the anti-corrosion coating of claim 8 or the anti-corrosion coating of claim 10 in preventing seawater corrosion, preferably in preventing seawater corrosion of coastal storage tanks, coastal platforms or coastal pipelines.

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