Preparation method of sulfate surface-modified graphene oxide composite protective coating

Abstract

The present invention discloses a method for preparing a sulfate-surface-modified graphene oxide composite protective coating. The method first involves adding graphene oxide and a surfactant to deionized water and ultrasonically dispersing the mixture to obtain a suspension. An organic compound containing phenyl and sulfonic acid is then added for surface modification. Surface-modified graphene oxide powder is obtained by centrifugation / redispersion, and drying. The powder is then mixed with a sodium hydroxide solution to obtain a sulfate-surface-modified graphene oxide solution. Finally, the resulting solution is sprayed onto the surface of a cement-based material to form a stable sulfate-surface-modified graphene oxide composite protective coating. The coating exhibits good interfacial adhesion with sulfate cement, significantly preventing the penetration of corrosive media such as water, chloride ions, and sulfate, thereby improving the durability of cement-based materials in corrosive environments such as marine and chemical industries.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and pertains to a novel concrete protective coating material, in particular to a method for preparing a sulfate surface-modified graphene oxide composite protective coating. Background Art

[0002] In the modern building materials field, cement-based materials are widely used in various engineering structures. However, over long-term service, especially when exposed to corrosive environments such as marine and chemical environments, these materials are susceptible to corrosion from corrosive ions such as sulfates and chlorides. These corrosive ions penetrate the cement matrix, causing changes in the material's physical structure and chemical properties, leading to material degradation and strength loss, seriously impacting the durability and safety of engineering structures. Improving the corrosion resistance of cement-based materials, reducing maintenance costs, and extending their service life have become pressing technical challenges in the engineering field.

[0003] As a new type of nanomaterial, graphene oxide (GO) has shown broad application prospects in the fields of composite materials, energy storage, environmental protection, etc. due to its unique two-dimensional lamellar structure, excellent mechanical properties, good conductivity and large specific surface area. The two-dimensional layered structure of graphene oxide can block the penetration of corrosive media to a certain extent, but its interfacial bonding with traditional cement-based materials is poor, which limits its effectiveness in practical applications. In addition, the oxygen-containing functional groups on the surface of graphene oxide make it easy to agglomerate in cement-based materials, affecting its dispersibility and interfacial bonding with the matrix, thereby limiting its application in improving the corrosion resistance of cement-based materials. Therefore, the development of a graphene oxide protective coating that can effectively prevent the penetration of corrosive ions and significantly improve the durability of cement-based materials has important practical application value and broad market prospects. Summary of the Invention

[0004] In view of this, the present invention aims to provide a method for preparing a sulfate-surface-modified graphene oxide composite protective coating, which forms a dense and stable protective coating by spraying on the surface of sulfate cement, supersulfate cement, persulfate cement and sulfoaluminate cement, effectively preventing the intrusion of corrosive media and significantly improving the service life of cement-based materials in harsh environments such as oceans and chemical industries.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A method for preparing a sulfate surface-modified graphene oxide composite protective coating, characterized by comprising the following steps:

[0007] 1) adding graphene oxide and a surfactant to deionized water and performing ultrasonic dispersion to obtain a graphene oxide suspension;

[0008] 2) gradually adding an organic compound containing phenyl groups and sulfonic acid to the graphene oxide suspension, stirring and heating to a certain temperature, so that the phenyl groups in the organic compound and the six-membered honeycomb carbon rings on the graphene oxide structure adsorb each other through π-π stacking, thereby increasing the interlayer spacing of the graphene oxide, and then centrifuging / redispersing and drying the suspension to obtain surface-modified graphene oxide powder;

[0009] 3) mixing the modified graphene oxide powder with a sodium hydroxide solution, heating and stirring to cause the sulfonic acid in the modified graphene oxide to react with the solution to form sodium sulfate, thereby obtaining a sulfate surface-modified graphene oxide solution;

[0010] 4) spraying the sulfate surface-modified graphene oxide solution prepared in step 3) onto the cement surface. Under the action of a strong base, sodium sulfate can further react with the cement surface to form calcium sulfate particles, thereby enhancing the interfacial adhesion between the graphene oxide and the inorganic gelling material, forming a stable sulfate surface-modified graphene composite protective coating on the cement surface, effectively preventing the ingress of moisture and corrosive ions, and improving the durability of marine concrete.

[0011] Optionally, the surfactant in step 1) is one or more of polycarboxylate water reducer, lignin sulfonic acid, polyvinyl alcohol, dodecylbenzene sulfonic acid and polystyrene sulfonic acid.

[0012] Optionally, the mass percentage of graphene oxide in the graphene oxide suspension in step 1) is 0.1-10%, the mass ratio of graphene oxide to surfactant is 5:1-1:5, the ultrasonic dispersion treatment time is 5-60 min, and the power is 100-600 W.

[0013] Furthermore, the mass percentage of graphene oxide in the graphene oxide suspension is preferably 0.5-3%, the mass ratio of graphene oxide to surfactant is preferably 2:1-1:3, the ultrasonic dispersion treatment time is preferably 5-30 min, and the power is preferably 100-300 W.

[0014] Optionally, the organic compound in step 2) is one or more of benzenesulfonic acid, polystyrenesulfonic acid, naphthalenesulfonic acid, m-phenylenedisulfonic acid, dodecylbenzenesulfonic acid, sodium p-toluenesulfonate and diaminobenzenesulfonic acid.

[0015] Furthermore, in step 2), the organic compound is one or more of benzenesulfonic acid, polystyrenesulfonic acid and dodecylbenzenesulfonic acid.

[0016] Optionally, the mass percentage of the organic compound added in step 2) is 0.05% to 2% of the graphene oxide suspension.

[0017] Optionally, the heating temperature in step 2) ranges from 30 to 80° C., and the stirring time is from 1 to 6 hours.

[0018] Optionally, the concentration of the sodium hydroxide solution in step 3) is 0.01 to 0.1 mol / L, the heating and stirring temperature range is 40 to 90° C., and the stirring time is 0.1 to 5 hours.

[0019] Optionally, in step 3), the mass ratio of the modified graphene oxide powder to the sodium hydroxide solution is 1:50 to 1:5.

[0020] Optionally, in step 4), the types of cement include sulfate cement, supersulfate cement, persulfate cement and sulfoaluminate cement.

[0021] Compared with the prior art, the sulfate surface-modified graphene oxide composite protective coating of the present invention has the following advantages:

[0022] 1. Sulfate-surface-modified graphene oxide has an ultra-stable two-dimensional layered structure, significantly blocking the penetration of aggressive media such as moisture, chloride ions, and sulfate ions. This composite protective coating not only effectively blocks the direct penetration of aggressive ions but also increases the tortuosity of their migration, further enhancing the coating's protective effectiveness and significantly extending the service life of cement-based materials in corrosive environments such as marine and chemical industries.

[0023] 2. Sulfate is grafted onto the graphene oxide surface through the π-π stacking effect of the phenyl groups in the organic compound and the six-membered honeycomb carbon rings in the graphene oxide structure. This not only improves the dispersion of graphene oxide in water and on the cement surface through steric hindrance, ensuring the uniformity and coverage of the coating, but also exhibits improved chemical compatibility with sulfate cement, supersulfated cement, persulfated cement, and sulfoaluminate cement, significantly enhancing the interfacial adhesion between the modified graphene oxide and the cement matrix, forming a more stable protective coating and improving its adhesion and durability.

[0024] 3. The method of the present invention is simple and easy to operate, and can be achieved through conventional steps such as ultrasonic dispersion, heated stirring, and spraying. It not only improves the impermeability and corrosion resistance of cement-based materials, but also enhances the mechanical properties of the materials to a certain extent, extending the service life of the materials. Furthermore, the protective coating is suitable for sulfate cement, supersulfated cement, persulfated cement, and sulfoaluminate cement, and has broad practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 Schematic diagram of a preparation method of a sulfate surface-modified graphene oxide composite protective coating. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0029] Example 1

[0030] A method for preparing a sulfate surface-modified graphene oxide composite protective coating comprises the following steps:

[0031] 1) adding 1 mg of graphene oxide and 1 mg of a surfactant to 100 mL of deionized water and performing ultrasonic dispersion, wherein the surfactant is a polycarboxylate water reducer, and the ultrasonic dispersion treatment time is 30 min at a power of 150 W to obtain a graphene oxide suspension;

[0032] 2) gradually adding 1 mg of benzenesulfonic acid to 100 mL of the graphene oxide suspension, heating to 50° C. and stirring for 2 h, then centrifuging / redispersing at 2000 rpm and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0033] 3) mixing 1 mg of modified graphene oxide powder with 50 mL of 0.01 mol / L sodium hydroxide solution, heating to 40° C. and stirring for 1 h to obtain a sulfate surface-modified graphene oxide solution;

[0034] 4) spraying the sulfate surface modified graphene oxide solution prepared in step 3) onto the surface of sulfate cement to obtain the sulfate surface modified graphene composite protective coating.

[0035] Example 2

[0036] A method for preparing a sulfate surface-modified graphene oxide composite protective coating comprises the following steps:

[0037] 1) adding 1 mg of graphene oxide and 3 mg of a surfactant to 100 mL of deionized water and performing ultrasonic dispersion, wherein the surfactant is a polycarboxylate water reducer, and the ultrasonic dispersion treatment time is 15 min and the power is 150 W to obtain a graphene oxide suspension;

[0038] 2) gradually adding 1 mg of polystyrene sulfonic acid to 100 mL of the graphene oxide suspension, heating to 50° C. and stirring for 2 h, then centrifuging / redispersing at 2000 rpm and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0039] 3) mixing 1 mg of modified graphene oxide powder with 50 mL of 0.03 mol / L sodium hydroxide solution, heating to 40° C. and stirring for 2 h to obtain a sulfate surface-modified graphene oxide solution;

[0040] 4) spraying the sulfate surface modified graphene oxide solution prepared in step 3) onto the surface of sulfate cement to obtain the sulfate surface modified graphene composite protective coating.

[0041] Example 3

[0042] A method for preparing a sulfate surface-modified graphene oxide composite protective coating comprises the following steps:

[0043] 1) adding 1 mg of graphene oxide and 2 mg of a surfactant to 100 mL of deionized water and performing ultrasonic dispersion, wherein the surfactant is lignin sulfonic acid, and the ultrasonic dispersion treatment time is 30 min at a power of 150 W to obtain a graphene oxide suspension;

[0044] 2) gradually adding 1 mg of polystyrene sulfonic acid to 100 mL of the graphene oxide suspension, heating to 50° C. and stirring for 2 h, then centrifuging / redispersing at 2000 rpm and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0045] 3) mixing 1 mg of modified graphene oxide powder with 50 mL of 0.05 mol / L sodium hydroxide solution, heating to 40° C. and stirring for 2 h to obtain a sulfate surface-modified graphene oxide solution;

[0046] 4) spraying the sulfate surface-modified graphene oxide solution prepared in step 3) onto the surface of sulphoaluminate cement to obtain a sulfate surface-modified graphene composite protective coating.

[0047] Example 4

[0048] A method for preparing a sulfate surface-modified graphene oxide composite protective coating comprises the following steps:

[0049] 1) adding 1 mg of graphene oxide and 0.5 mg of a surfactant to 100 mL of deionized water and performing ultrasonic dispersion, wherein the surfactant is polystyrene sulfonic acid, and the ultrasonic dispersion treatment time is 30 min at a power of 150 W to obtain a graphene oxide suspension;

[0050] 2) gradually adding 1.5 mg of polystyrene sulfonic acid to the 100 mL graphene oxide suspension, heating to 50° C. and stirring for 1 h, then centrifuging / redispersing at 2000 rpm and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0051] 3) 1 mg of modified graphene oxide powder was mixed with 20 mL of 0.05 mol / L sodium hydroxide solution, heated to 40° C. and stirred for 2 h to obtain a sulfate surface-modified graphene oxide solution;

[0052] 4) spraying the sulfate surface modified graphene oxide solution prepared in step 3) onto the surface of sulfate cement to obtain the sulfate surface modified graphene composite protective coating.

[0053] Example 5

[0054] A method for preparing a sulfate surface-modified graphene oxide composite protective coating comprises the following steps:

[0055] 1) adding 1 mg of graphene oxide and 1 mg of a surfactant to 100 mL of deionized water and performing ultrasonic dispersion, wherein the surfactant is dodecylbenzenesulfonic acid, and the ultrasonic dispersion treatment time is 20 min at a power of 150 W to obtain a graphene oxide suspension;

[0056] 2) gradually adding 3 mg of dodecylbenzenesulfonic acid to the 100 mL graphene oxide suspension, heating to 50° C. and stirring for 2 h, then centrifuging / redispersing at 2000 rpm and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0057] 3) mixing 1 mg of modified graphene oxide powder with 50 mL of 0.01 mol / L sodium hydroxide solution, heating to 40° C. and stirring for 1 h to obtain a sulfate surface-modified graphene oxide solution;

[0058] 4) spraying the sulfate surface modified graphene oxide solution prepared in step 3) onto the surface of sulfate cement to obtain the sulfate surface modified graphene composite protective coating.

[0059] Example 6

[0060] A method for preparing a sulfate surface-modified graphene oxide composite protective coating comprises the following steps:

[0061] 1) adding 1 mg of graphene oxide and 1 mg of a surfactant to 100 mL of deionized water and performing ultrasonic dispersion, wherein the surfactant is polystyrene sulfonic acid, and the ultrasonic dispersion treatment time is 30 min at a power of 200 W to obtain a graphene oxide suspension;

[0062] 2) gradually adding 3 mg of naphthalenesulfonic acid to the 100 mL graphene oxide suspension, heating to 50° C. and stirring for 2 h, then centrifuging / redispersing at 2000 rpm and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0063] 3) mixing 1 mg of modified graphene oxide powder with 50 mL of 0.01 mol / L sodium hydroxide solution, heating to 40° C. and stirring for 3 h to obtain a sulfate surface-modified graphene oxide solution;

[0064] 4) spraying the sulfate surface modified graphene oxide solution prepared in step 3) onto the surface of sulfate cement to obtain the sulfate surface modified graphene composite protective coating.

[0065] Comparative Example 1

[0066] No protective coating was sprayed on the sulfate cement surface.

[0067] Table 1: Properties of composite protective coatings

[0068]

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a sulfate surface-modified graphene oxide composite protective coating, characterized in that: The following steps are involved: 1) adding graphene oxide and a surfactant to deionized water and performing ultrasonic dispersion to obtain a graphene oxide suspension; 2) gradually adding an organic compound containing phenyl groups and sulfonic acid to the graphene oxide suspension, stirring and heating to a certain temperature so that the phenyl groups in the organic compound and the six-membered honeycomb carbon rings on the graphene oxide structure adsorb each other through π-π stacking, thereby increasing the interlayer spacing of the graphene oxide, and then centrifuging or redispersing it, and then drying it to obtain surface-modified graphene oxide powder; 3) mixing the modified graphene oxide powder with a sodium hydroxide solution, heating and stirring to cause the sulfonic acid in the modified graphene oxide to react with the solution to form sodium sulfate, thereby obtaining a sulfate-surface-modified graphene oxide solution; 4) spraying the sulfate surface-modified graphene oxide solution prepared in step 3) onto the cement surface. Under the action of a strong base, sodium sulfate can further react with the cement surface to form calcium sulfate particles, thereby enhancing the interfacial adhesion between the graphene oxide and the inorganic gelling material, and forming a stable sulfate surface-modified graphene composite protective coating on the cement surface, effectively preventing the ingress of moisture and corrosive ions, and improving the durability of marine concrete. In step 2), the organic compound is one or more of benzenesulfonic acid, polystyrenesulfonic acid, naphthalenesulfonic acid, m-phenylenedisulfonic acid, dodecylbenzenesulfonic acid, sodium p-toluenesulfonate and diaminobenzenesulfonic acid; The mass percentage of the organic compound added in step 2) is 0.05% to 2% of the graphene oxide suspension.

2. The method for preparing the sulfate surface-modified graphene oxide composite protective coating according to claim 1, wherein: The surfactant in step 1) is one or more of polycarboxylate water reducer, lignin sulfonic acid, polyvinyl alcohol, dodecylbenzene sulfonic acid and polystyrene sulfonic acid.

3. The method for preparing the sulfate surface-modified graphene oxide composite protective coating according to claim 1, wherein: The mass percentage of graphene oxide in the graphene oxide suspension in step 1) is 0.1-10%, the mass ratio of graphene oxide to surfactant is 5:1-1:5, the ultrasonic dispersion treatment time is 5-60 min, and the power is 100-600 W.

4. The method for preparing the sulfate surface-modified graphene oxide composite protective coating according to claim 1, wherein: In step 2), the organic compound is polystyrene sulfonic acid, and the mass percentage of the added amount is 0.1-0.5% of the graphene oxide suspension.

5. The method for preparing the sulfate surface-modified graphene oxide composite protective coating according to claim 1, wherein: In step 2), the heating temperature range is 30-80°C, and the stirring time is 1-6 h.

6. The method for preparing the sulfate surface-modified graphene oxide composite protective coating according to claim 1, wherein: The concentration of the sodium hydroxide solution in step 3) is 0.01 to 0.1 mol / L, the heating and stirring temperature range is 40 to 90° C., and the stirring time is 0.1 to 5 hours.

7. The method for preparing the sulfate surface-modified graphene oxide composite protective coating according to claim 1, wherein: In step 3), the mass ratio of the modified graphene oxide powder to the sodium hydroxide solution is 1:50 to 1:

5.

8. The method for preparing the sulfate surface-modified graphene oxide composite protective coating according to claim 1, wherein: The types of cement used in step 4) include supersulfate cement, persulfate cement and sulfoaluminate cement.

Images