Preparation method of sulfate surface modified graphene oxide composite protective coating

Abstract

The invention discloses a preparation method of a sulfate surface modified graphene oxide composite protective coating. The method comprises the following steps: firstly, adding graphene oxide and a surfactant into deionized water, and carrying out ultrasonic dispersion to obtain a suspension; then adding an organic compound containing phenyl and sulfonic acid to carry out surface modification, and carrying out centrifugation / redispersion and drying to obtain surface-modified graphene oxide powder; then mixing the sulfate surface modified graphene oxide with a sodium hydroxide solution to obtain a sulfate surface modified graphene oxide solution; and finally, spraying the obtained solution to the surface of a cement-based material to form a stable sulfate surface modified graphene oxide composite protective coating. The coating has good interface cohesiveness with sulfate cement, can remarkably prevent corrosive media such as water, chloride ions and sulfate radicals from permeating, and improves the durability of a cement-based material in corrosive environments such as ocean and chemical engineering.

Description

Technical Field

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

[0002] In the field of modern building materials, cement-based materials are widely used in various engineering structures. However, these materials are susceptible to corrosion by corrosive ions such as sulfates and chloride ions during long-term service, especially when exposed to corrosive environments such as the ocean and chemical industry. These corrosive ions will penetrate into the cement matrix, causing changes in the physical structure and chemical properties of the material, which in turn causes the material to deteriorate and lose strength, seriously affecting the durability and safety of the engineering structure. How to improve the corrosion resistance of cement-based materials, reduce maintenance costs, and extend service life has become a technical problem that needs to be solved urgently 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 interface bonding with traditional cement-based materials is poor, which limits its effect 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 interface 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 invasion of corrosive media and significantly improving the service life of cement-based materials in harsh environments such as ocean and chemical industry.

[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 in that it comprises the following steps:

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

[0008] 2) gradually adding an organic compound containing phenyl and sulfonic acid to the graphene oxide suspension, stirring and heating to a certain temperature, so that the phenyl in the organic compound and the six-membered honeycomb carbon ring 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 it 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 generate 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, wherein sodium sulfate can further react with the cement surface under the action of a strong alkali 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 entry of moisture and corrosive ions, and improving the durability of marine engineering 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 100-600W.

[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, isophenylenedisulfonic 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 ranges 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 temperature range of heating and stirring 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, which has a significant barrier effect on the penetration of corrosive media such as water, chloride ions and sulfate ions. This composite protective coating can not only effectively prevent the direct penetration of corrosive ions, but also increase the tortuosity of the migration of corrosive ions, thereby further enhancing the protective effect of the coating and significantly improving the service life of cement-based materials in corrosive environments such as the ocean and chemical industry.

[0023] 2. Sulfate is grafted onto the surface of graphene oxide through the π-π stacking effect of the phenyl group in the organic compound and the six-membered honeycomb carbon ring on the graphene oxide structure, which can not only improve the dispersion of graphene oxide in water and on the cement surface through the steric hindrance effect, ensuring the uniformity and coverage of the coating. In addition, sulfate can also have better chemical compatibility with sulfate cement, supersulfate cement, persulfate cement and sulfoaluminate cement, significantly enhancing the interfacial adhesion between modified graphene oxide and cement matrix, forming a more stable protective coating, and improving the adhesion and durability of the protective coating.

[0024] 3. The method of the present invention is simple in process and easy to operate. It can be realized through conventional steps such as ultrasonic dispersion, heating and stirring, and spraying. It can not only improve the impermeability and corrosion resistance of cement-based materials, but also enhance the mechanical properties of materials to a certain extent and extend the service life of materials. At the same time, the protective coating is suitable for sulfate cement, supersulfate cement, persulfate cement and sulphoaluminate cement, and has a wide range of practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0026] Figure 1 Schematic diagram of a method for preparing 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, the ultrasonic dispersion treatment time is 30 min, the power is 150 W, and a graphene oxide suspension is obtained;

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

[0033] 3) 1 mg of modified graphene oxide powder was mixed with 50 mL of 0.01 mol / L sodium hydroxide solution, heated to 40° C. and stirred for 1 h, thereby obtaining 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, the ultrasonic dispersion treatment time is 15 min, the power is 150 W, and a graphene oxide suspension is obtained;

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

[0039] 3) 1 mg of modified graphene oxide powder was mixed with 50 mL of 0.03 mol / L sodium hydroxide solution, heated to 40° C. and stirred for 2 h, thereby obtaining 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, the ultrasonic dispersion treatment time is 30 min, the power is 150 W, and a graphene oxide suspension is obtained;

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

[0045] 3) 1 mg of modified graphene oxide powder was mixed with 50 mL of 0.05 mol / L sodium hydroxide solution, heated to 40° C. and stirred for 2 h, thereby obtaining 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 the 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, the ultrasonic dispersion treatment time is 30 min, the power is 150 W, and a graphene oxide suspension is obtained;

[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 r / min 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, thereby obtaining 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, the ultrasonic dispersion treatment time is 20 min, the power is 150 W, and a graphene oxide suspension is obtained;

[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 r / min and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0057] 3) 1 mg of modified graphene oxide powder was mixed with 50 mL of 0.01 mol / L sodium hydroxide solution, heated to 40° C. and stirred for 1 h, thereby obtaining 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, the ultrasonic dispersion treatment time is 30 min, the power is 200 W, and a graphene oxide suspension is obtained;

[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 r / min and drying at 80° C. to obtain surface-modified graphene oxide powder;

[0063] 3) 1 mg of modified graphene oxide powder was mixed with 50 mL of 0.01 mol / L sodium hydroxide solution, heated to 40° C. and stirred for 3 h, thereby obtaining 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 surface of sulfate cement.

[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 substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope 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 into deionized water and performing ultrasonic dispersion to obtain a graphene oxide suspension; 2) gradually adding an organic compound containing phenyl and sulfonic acid to the graphene oxide suspension, stirring and heating to a certain temperature, so that the phenyl in the organic compound and the six-membered honeycomb carbon ring 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 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 generate 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, wherein sodium sulfate can further react with the cement surface under the action of a strong alkali 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 entry of moisture and corrosive ions, and improving the durability of marine engineering concrete.

2. The method for preparing the sulfate surface modified graphene oxide composite protective coating according to claim 1, characterized in that: 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, characterized in that: 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 minutes, and the power is 100-600W.

4. The method for preparing the sulfate surface modified graphene oxide composite protective coating according to claim 1, characterized in that: In step 2), the organic compound is one or more of benzenesulfonic acid, polystyrenesulfonic acid, naphthalenesulfonic acid, isophenylenedisulfonic acid, dodecylbenzenesulfonic acid, sodium p-toluenesulfonate and diaminobenzenesulfonic acid.

5. The method for preparing the sulfate surface modified graphene oxide composite protective coating according to claim 1, characterized in that: The mass percentage of the organic compound added in step 2) is 0.05% to 2% of the graphene oxide suspension.

6. The method for preparing the sulfate surface modified graphene oxide composite protective coating according to claim 1, characterized in that: 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.

7. The method for preparing the sulfate surface modified graphene oxide composite protective coating according to claim 1, characterized in that: The heating temperature in step 2) ranges from 30 to 80° C., and the stirring time ranges from 1 to 6 hours.

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

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

5.

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

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