WO2021068506A1

WO2021068506A1 - Water-based anticorrosive coating based on graphene oxide and preparation method therefor

Info

Publication number: WO2021068506A1
Application number: PCT/CN2020/090250
Authority: WO
Inventors: 谢海; 胡明; 钱金均
Original assignee: 江苏冠军科技集团股份有限公司
Priority date: 2019-10-11
Filing date: 2020-05-14
Publication date: 2021-04-15
Also published as: CN110684467A

Abstract

Provided are a water-based anticorrosive coating based on graphene oxide and a preparation method therefor, relating to the field of surface engineering technology. The coating provided in the present invention comprises the following components in parts by mass: 40-45 parts of an aqueous resin, 10-12 parts of graphene oxide, 10-12 parts of silicon carbide, 6-8 parts of a dispersing agent, 3-5 parts of an aluminum powder, and 120-200 parts of water. By means of the combined action of the hexagonal honeycomb structure of graphene oxide and the aluminum powder, the corrosion resistance of the coating layer is improved in the present application. The aluminum powder and the silicon carbide are combined to form an aluminum-silicon hybrid structure, thereby further improving the compactness, high-temperature resistance and corrosion resistance of the coating layer. Therefore, the water-based anticorrosive coating based on graphene oxide provided in the present invention has an excellent anticorrosive capacity, and is water-based, such that same is environmentally friendly and is low in cost. In addition, by means of the preparation method provided in the present invention, the bonding strength of the graphene oxide and the aluminum powder is very high, thereby efficiently improving the anticorrosive capacity of the coating; and the method is simple and easy to control.

Description

Water-based anticorrosive coating based on graphene oxide and preparation method thereof

Technical field

The invention relates to the technical field of surface engineering, in particular to a graphene oxide-based water-based anticorrosive coating and a preparation method thereof.

Background technique

At present, in the process of engineering infrastructure, the anti-corrosion requirements of surface engineering such as buildings, steel frame structures, outdoor facilities, etc. are getting higher and higher, and due to the demand for light weight and high strength, more and more metal structures are used, including energy transportation Pipelines, chemical containers, construction bridges, coastal wharf facilities, etc. have also increased their rust and corrosion resistance requirements.

Traditional anti-corrosion coatings are mainly composed of resin, etc. The principle is to isolate the metal structure after painting and condensing to avoid the intrusion of external corrosive media. However, in the existing corrosion, there is a large part of electric corrosion, ionization decomposition formed by potential difference, etc., which accelerates metal corrosion. However, the traditional anti-corrosion coating has a single anti-corrosion function, which cannot effectively block the electric corrosion and affect the environment. There is pollution.

Graphene-based anti-corrosion coatings are new types of anti-corrosion coatings that are gradually developed, mainly using pure graphene as anti-corrosion fillers. However, the existing graphene-based anticorrosive coatings can only play a certain barrier against electric corrosion, and the anticorrosion performance is not significantly improved, thus limiting the scope of its use. Patent CN105349017B discloses an anticorrosive coating added with graphene/zinc composite material and a preparation method thereof. The anticorrosive coating consists of the following components (in terms of mass percentage): polyurethane 20～90%, graphene/zinc composite Material 5-15%, coloring pigment 1-10%, filler 5-10%, dispersant 0.1-3%, wetting agent 0.1-3%, thickener 0.1-3%, leveling agent 0.1-1%, 0.1 to 1% defoamer, 0.1 to 1% bactericide, and 1 to 35% of water. The anti-corrosion performance of the anti-corrosion coating is improved, but during the preparation process, the zinc powder needs to be vaporized at high temperature into zinc vapor to be compounded on the surface of graphene. This method has insufficient bonding strength between graphene and zinc, and the process is more complicated.

Summary of the invention

In view of this, the purpose of the present invention is to provide a graphene oxide-based water-based anticorrosive coating and a preparation method thereof. The graphene oxide-based water-based anticorrosive coating provided by the invention has excellent corrosion resistance, environmental protection and low cost.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The present invention provides a water-based anticorrosive coating based on graphene oxide, which includes the following components by mass:

Preferably, the dispersant is a polycarboxylic acid ammonium salt dispersant.

The present invention provides a preparation method of the graphene oxide-based water-based anticorrosive coating described in the above scheme, which includes the following steps:

Mixing graphene oxide and water for ultrasonic treatment to obtain a graphene oxide treatment solution;

Ball mill the aluminum powder and mix it with the PVA aqueous solution to obtain PVA modified aluminum powder;

Mixing the PVA modified aluminum powder with water to obtain a powder slurry;

Load an electric field on the outside of the powder slurry, and add the graphene oxide treatment solution to the powder slurry to obtain a composite powder through electrolysis;

The composite powder is sintered in a protective atmosphere, and then mixed with a water-based resin, a dispersant, water and silicon carbide to obtain a graphene oxide-based water-based anticorrosive coating.

Preferably, the frequency of the ultrasonic treatment is 28kHz, the power is 1000W, and the time is 15min.

Preferably, the rotation speed of the ball mill is 330 to 350 rpm, and the particle size of the aluminum powder after ball milling is 3 to 5 μm.

Preferably, the mass concentration of the PVA aqueous solution is 0.5-1.2 mol/L, and the time for mixing the aluminum powder with the PVA aqueous solution after ball milling is 15-20 min.

Preferably, the intensity of the electric field is 60-80V/m.

Preferably, the sintering temperature is 550-600°C, and the time is 1.5-2h.

Preferably, the heating rate of the sintering is 50-70°C/min.

Preferably, after the sintering, it further includes milling the obtained sintered product, and the particle size after milling is 20-30 mesh.

The present invention provides a water-based anticorrosive coating based on graphene oxide, comprising the following components in parts by mass: 40 to 45 parts of water-based resin, 10 to 12 parts of graphene oxide, 10 to 12 parts of silicon carbide, and 6 to 12 parts of dispersant. 8 parts, 3 to 5 parts of aluminum powder, 120 to 200 parts of water. The graphene oxide-based water-based anticorrosive coating provided by the present invention improves the corrosion resistance of the coating through the combined action of the hexagonal honeycomb structure of graphene oxide and aluminum powder, and can effectively inhibit external corrosion; aluminum powder and carbonization Silicon is combined to form an aluminum-silicon mixed structure, which further effectively improves the compactness, high temperature resistance and corrosion resistance of the coating. Therefore, the graphene oxide-based water-based anticorrosive coating provided by the present invention has excellent anticorrosion ability, and adopts water-based, environmental protection and low cost. The results of the examples show that, compared with traditional epoxy resin coatings and existing graphene-based coatings, the graphene oxide-based water-based anticorrosive coating provided by the present invention has good mechanical properties and excellent chemical and corrosion resistance. , Can well protect the matrix from being corroded.

The invention provides a preparation method of the graphene oxide-based water-based anticorrosive coating. The present invention uses PVA as the surface modifier of aluminum powder, and the modified aluminum powder particles form hydrogen-oxygen bonds on the surface, which can be effectively wrapped by graphene oxide; the present invention uses ultrasonic treatment to exfoliate the graphene oxide layer of multi-layer structure. The structure improves the utilization rate of graphene oxide and reduces the thickness of the layer film wrapped outside the aluminum powder particles; the present invention uses the electric field to wrap the graphene oxide on the aluminum powder particles to form a composite powder, which has high bonding strength and is environmentally friendly by the water electrolysis method. , No pollution, high production efficiency; the present invention sinters the graphene oxide-coated aluminum powder particles in a protective atmosphere, which can stabilize the packaging form. Therefore, the preparation method provided by the present invention has a very high bonding strength between the graphene oxide and the aluminum powder, thereby effectively improving the anti-corrosion ability of the coating, and the method is simple and easy to control.

Detailed ways

In terms of parts by mass, the graphene oxide-based water-based anticorrosive coating provided by the present invention includes 40-45 parts of water-based resin, preferably 42-44 parts, and more preferably 43 parts. The present invention has no special requirements on the water-based resin, and water-based resins well-known in the art can be used, such as water-based epoxy resins, water-based acrylic resins, and the like.

Based on the mass parts of the water-based resin, the graphene oxide-based water-based anticorrosive coating provided by the present invention includes 10-12 parts of graphene oxide, preferably 10.5-11.5 parts, and more preferably 11 parts. The present invention has no special requirements on the graphene oxide, and graphene oxide well-known in the art can be used. In a specific embodiment of the present invention, the graphene oxide preferably adopts graphene oxide prepared by using graphite paper as a raw material and oxidizing through electrolysis of water. In the present invention, compared with pure graphene, the graphene oxide has more oxygen-containing functional groups, has more active properties, is easier to combine with aluminum powder particles, and improves the performance of the coating.

Based on the mass parts of the water-based resin, the graphene oxide-based water-based anticorrosive coating provided by the present invention includes 10-12 parts of silicon carbide, preferably 10.5-11.5 parts, more preferably 11 parts; the particle size of the silicon carbide Preferably it is 20-35 micrometers. The present invention has no special requirements on the source of the silicon carbide, and commercially available products well known in the art can be used.

Based on the mass parts of the water-based resin, the graphene oxide-based water-based anticorrosive coating provided by the present invention includes 6-8 parts of the dispersant, preferably 6.5-7.5 parts, more preferably 7 parts. In the present invention, the dispersant is preferably a polycarboxylic acid ammonium salt dispersant; the present invention has no special requirements on the source of the polycarboxylic acid ammonium salt dispersant, and a commercially available product well-known in the art may be used.

Based on the mass parts of the water-based resin, the graphene oxide-based water-based anticorrosive coating provided by the present invention includes 3 to 5 parts of aluminum powder, preferably 3.5 to 4.5 parts, and more preferably 4 parts. The present invention has no special requirements on the source of the aluminum powder, and commercial products that are well known in the art can be used.

Based on the mass parts of the water-based resin, the graphene oxide-based water-based anticorrosive coating provided by the present invention includes 120-200 parts of water, preferably 150-200 parts, and more preferably 180 parts. The present invention has no special requirements on the water, and water well known in the art can be used; in the specific embodiment of the present invention, the water is preferably deionized water.

The present invention provides the above-mentioned water-based anticorrosive coating based on graphene oxide. Through the combined action of the hexagonal honeycomb structure of graphene oxide and aluminum powder, the present invention improves the corrosion resistance of the coating and can effectively prevent external corrosion. Inhibition; aluminum powder and silicon carbide combine to form an aluminum-silicon mixed structure, which further effectively improves the compactness, high temperature resistance and corrosion resistance of the coating. Therefore, the graphene oxide-based water-based anticorrosive coating provided by the present invention has excellent anticorrosion ability, and adopts water-based, environmental protection and low cost.

Mixing the PVA modified aluminum powder with water to obtain a powder slurry;

In the present invention, graphene oxide is mixed with water for ultrasonic treatment to obtain a graphene oxide treatment solution. In the present invention, the mass ratio of the graphene oxide to water is preferably 1:8-12, more preferably 1:12. In the present invention, the frequency of the ultrasonic treatment is preferably 28kHz, the power is preferably 1000W, and the time is preferably 15min. After ultrasonic treatment, the aqueous solution of graphene oxide is degraded to brown to obtain the graphene oxide treatment solution. In the present invention, the single-layer structure of the graphene oxide exfoliation layer of the multilayer structure can be improved through the ultrasonic treatment, which can improve the utilization rate of the graphene oxide and reduce the thickness of the layer film wrapped outside the aluminum powder particles.

In the invention, the aluminum powder is ball-milled and mixed with the PVA aqueous solution to obtain the PVA modified aluminum powder. In the present invention, the rotation speed of the ball mill is preferably 330-350 rpm, more preferably 340 rpm; the ball mill is preferably performed by a high-power ball mill; the particle size of the aluminum powder after ball milling is preferably 3 to 5 μm, more preferably 4 μm. After ball milling, the aluminum powder changes from flake or polyhedron to spherical. In the present invention, the mass concentration of the PVA (polyvinyl alcohol) aqueous solution is preferably 0.8-1.2 mol/L, more preferably 0.98 mol/L; the present invention has no special requirements on the amount of the PVA aqueous solution added, which can be Soak the aluminum powder after ball milling completely. In the present invention, the time for mixing the ball-milled aluminum powder with the PVA aqueous solution is preferably 15-20 min, more preferably 17 min. The present invention has no special requirements on the mixing method, and a method well known in the art can be used to ensure that the aluminum powder is fully dispersed in the PVA aqueous solution, specifically, such as stirring and mixing. After mixing, the present invention preferably subject the obtained mixed liquid to solid-liquid separation, and the obtained solid is the PVA modified aluminum powder; the present invention has no special requirements on the solid-liquid separation method, and the method is well known in the art. can. The present invention uses PVA as an aluminum powder surface modifier to form a hydrophilic PVA film on the surface of the spherical aluminum powder after ball milling, and the modified aluminum powder particles form hydrogen-oxygen bonds on the surface, which can be effectively wrapped by graphene oxide.

After obtaining the PVA modified aluminum powder, the present invention mixes the PVA modified aluminum powder with water to obtain a powder slurry. In the present invention, the mass ratio of the PVA modified aluminum powder to water is preferably 1:0.5-0.8, more preferably 1:0.6. The present invention has no special requirements on the mixing method, as long as it can ensure that the PVA modified aluminum powder and water are uniformly mixed.

After the powder slurry is obtained, the present invention loads an electric field on the outside of the powder slurry, and adds the graphene oxide treatment solution to the powder slurry, and electrolysis obtains a composite powder. In the present invention, the intensity of the electric field is preferably 60 to 80 V/m, and more preferably 70 V/m. The present invention does not have any special requirements for the specific application method of the electric field, and a method well known in the art may be used. The present invention preferably stirs the mixed slurry during the electrolysis process to promote the dispersion of graphene oxide and PVA modified aluminum powder. In the present invention, the electrolysis time is based on the fading of the brown color of the mixed slurry; after electrolysis, the present invention preferably washes the electrolyzed mixed slurry with water to obtain a composite powder. In the present invention, graphene oxide is wrapped on aluminum powder particles to form a composite powder through the action of an electric field (ie, water electrolysis). The surface of the aluminum powder is positively charged, and the graphene oxide is negatively charged due to the ionization of carboxyl and hydroxyl groups. It adsorbs each other with graphene oxide, has high bonding strength, and the water electrolysis method is environmentally friendly, pollution-free, and high in production efficiency.

After the composite powder is obtained, the present invention sinters the composite powder in a protective atmosphere, and then mixes it with water-based resin, dispersant, water and silicon carbide to obtain a graphene oxide-based water-based anticorrosive coating. In the present invention, the sintering temperature is preferably 550-600°C, more preferably 570°C, and the time is preferably 1.5-2h, more preferably 1.7h. In the present invention, the heating rate of the sintering is preferably 50-70°C/min, more preferably 60°C/min. In the present invention, the protective atmosphere is continuously introduced during the sintering process; the protective atmosphere is preferably argon or nitrogen; when the protective atmosphere is preferably argon, the flow rate of the argon is preferably 50cc/min When the protective atmosphere is preferably nitrogen, the flow rate of the nitrogen is preferably 100 cc/min. In the present invention, after the sintering, it also preferably includes milling the obtained sintered product, and the particle size after milling is preferably 20-30 mesh. The present invention does not have any special requirements for the specific method of milling, as long as the method is well known in the art. The present invention sinters the graphene oxide-coated aluminum powder particles, that is, the composite powder, in a protective atmosphere, so that the package shape can be stabilized. After the composite powder is sintered in a protective atmosphere, it is mixed with an aqueous resin, a dispersant, water and silicon carbide. In the present invention, the mixing sequence is preferably: after sintering the composite powder, first mix with the water-based resin and the dispersant, then add water to it for mixing; finally, add silicon carbide to the resulting mixed aqueous solution for mixing. In the present invention, mixing is preferably carried out under stirring conditions. The present invention has no special requirements on the stirring speed and time, as long as the components are uniformly mixed. After mixing, the graphene oxide-based water-based anticorrosive coating is obtained.

The graphene oxide-based water-based anticorrosive coating and the preparation method thereof provided by the present invention will be described in detail below with reference to examples, but they should not be understood as limiting the protection scope of the present invention.

Example 1

A water-based anticorrosive coating based on graphene oxide, comprising: 45 parts of water-based resin, 10 parts of graphene oxide, 12 parts of silicon carbide, 8 parts of polycarboxylate dispersant, 3 parts of aluminum powder, and 200 parts of deionized water, The above-mentioned components are in parts by mass. The preparation method is as follows:

1) Put the graphene oxide in the above components into deionized water, the mass ratio of graphene oxide to deionized water is 1:12, and the solution is degraded by ultrasonic until it is brown;

2) Ball mill the aluminum powder to refine it to 5 μm; the aluminum powder ball mill is performed by a high-power ball mill with a rotation speed of 330 rpm;

3) The spherical aluminum powder after ball milling in step 2) is treated with a PVA aqueous solution to form a hydrophilic PVA film on the surface;

4) Put the modified aluminum powder in step 3) into deionized water for mixing, and the mass ratio of the modified aluminum powder to the deionized water is 1:0.6 to form a powder slurry;

5) Load an electric field on the outside of the powder slurry in step 4), the electric field can make the aluminum powder and graphene oxide charge and attract each other;

6) The solution obtained in step 1) is gradually added to the powder slurry placed in the electric field, and dispersed and stirred, and mechanically stirred until the slurry fades from the brown color;

7) Wash and clean the powder slurry obtained in step 6), and heat it to 550 degrees Celsius at a heating rate of 50 degrees Celsius per minute, and keep it warm. During the heating process, continue to inject argon for 2 hours; argon flows at a constant speed State, the flow rate is 50cc per minute;

8) The sintered product in step 7) is milled into a powder, and mixed with the water-based resin and dispersant by mechanical stirring, and water is added for mixing and stirring;

9) Add silicon carbide to the solution obtained in step 8), continue to stir and mix, to obtain a graphene oxide-based water-based anticorrosive coating.

Example 2

A water-based anticorrosive coating based on graphene oxide, comprising: 40 parts of water-based resin, 12 parts of graphene oxide, 10 parts of silicon carbide, 6 parts of polycarboxylate dispersant, 5 parts of aluminum powder, and 180 parts of deionized water, The above-mentioned components are in parts by mass. The preparation method is as follows:

2) Ball mill the aluminum powder and refine it to 3 μm; the aluminum powder ball mill is performed by a high-power ball mill with a rotation speed of 350 rpm;

4) Put the modified aluminum powder in step 3) into deionized water for mixing, and the mass ratio of the modified aluminum powder to deionized water is 1:0.6 to form a powder slurry;

5) Load an electric field on the outside of the powder slurry in step 4);

7) Wash and clean the powder slurry obtained in step 6), and heat it to 600 degrees Celsius at a heating rate of 50 degrees Celsius per minute, keep it warm, and continue to inject nitrogen during the heating process at a flow rate of 100cc/min and a duration of 1.5 hours;

8) The sintered product in step 7) is ground into powder, and mixed with the water-based resin and dispersant by mechanical stirring, and deionized water is added to the stirring and mixing;

Example 3

A water-based anticorrosive coating based on graphene oxide, comprising: 42 parts of water-based resin, 11 parts of graphene oxide, 11 parts of silicon carbide, 7 parts of polycarboxylate dispersant, 4 parts of aluminum powder, and 120 parts of deionized water, The above-mentioned components are in parts by mass. The preparation method is as follows:

2) Ball mill the aluminum powder and refine it to 3.5 μm; the aluminum powder ball mill is performed by a high-power ball mill with a rotation speed of 340 rpm;

4) In step 3), the modified aluminum powder is poured into deionized water for mixing, and the mass ratio of the modified aluminum powder to the deionized water is 1:0.6 to form a powder slurry;

5) Load an electric field on the outside of the powder slurry in step 4);

7) Wash and clean the powder slurry obtained in step 6), and heat it to 580 degrees Celsius at a heating rate of 60 degrees Celsius per minute, keep it warm, and continue to inject inert protective gas during the heating process for 1.8 hours;

The graphene oxide-based water-based anticorrosive coatings prepared in Examples 1 to 3 are silver-grey after curing into a film, with a grainy surface and metallic luster; observing their microstructures, it is found that there are independent coatings coated with graphene oxide Aluminum powder particles are uniformly distributed everywhere under the action of the dispersant, forming a spherical granular composite coating.

The performances of the graphene oxide-based water-based anticorrosive coatings prepared in Examples 1 to 3 were tested. During the test, the epoxy resin coatings commonly used for anticorrosion and the graphene-based coatings of a certain manufacturer (Jinling Coatings HGM- 10) As a comparative example.

(1) Corrosion resistance test

The paint prepared in Examples 1 to 3, the epoxy resin paint as a comparative example and the graphene-based paint (Jinling paint HGM-10) of a certain manufacturer were respectively coated on the surface of carbon steel with a coating thickness of 220 μm. After curing and forming a film The corrosion potential of carbon steel was tested respectively, and the results are shown in Table 1:

Table 1 Corrosion resistance of graphene oxide-based water-based anticorrosive coatings prepared in Examples 1 to 3

(2) Physical and chemical performance test

Physical and chemical performance tests were carried out on the paint prepared in Examples 1 to 3, the epoxy resin paint as a comparative example and the paint film formed by a graphene-based paint (Jinling Paint HGM-10) from a certain manufacturer, respectively, according to GB/T13452.2- In 2008, the thickness of the paint film was measured, the adhesion of the paint film was measured in accordance with GB/T 9286-1998, the flexibility of the paint film was measured in accordance with GB/T 6742-2007, and the impact resistance of the paint film was measured in accordance with GB/T 1732-1993, in accordance with GB/T The water resistance of the paint film was measured in 1733-1993, the hardness of the paint film was determined in accordance with GB/T 6739-2006, and the neutral salt spray resistance of the paint film was determined in accordance with GB/T 1771-2007; the test results are shown in Table 2: Table 2 Example 1 ～3 Physical and chemical properties of water-based anticorrosive coating based on graphene oxide prepared

It can be seen from Table 1 and Table 2 that compared with traditional epoxy resin coatings and existing graphene-based coatings, the graphene oxide-based water-based anticorrosive coatings provided by the present invention have good mechanical properties and excellent resistance. Chemical and corrosion resistance, can well protect the matrix from being corroded.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also It should be regarded as the protection scope of the present invention.

Claims

A water-based anticorrosive coating based on graphene oxide, which is characterized in that it comprises the following components by mass:
The graphene oxide-based water-based anticorrosive coating according to claim 1, wherein the dispersant is a polycarboxylic acid ammonium salt dispersant.
The method for preparing a graphene oxide-based water-based anticorrosive coating according to claim 1 or 2, characterized in that it comprises the following steps:

Mixing graphene oxide and water for ultrasonic treatment to obtain a graphene oxide treatment solution;

Ball mill the aluminum powder and mix it with the PVA aqueous solution to obtain PVA modified aluminum powder;

Mixing the PVA modified aluminum powder with water to obtain a powder slurry;

Load an electric field on the outside of the powder slurry, and add the graphene oxide treatment solution to the powder slurry to obtain a composite powder through electrolysis;

The composite powder is sintered in a protective atmosphere, and then mixed with a water-based resin, a dispersant, water and silicon carbide to obtain a graphene oxide-based water-based anticorrosive coating.
The preparation method according to claim 3, wherein the frequency of the ultrasonic treatment is 28kHz, the power is 1000W, and the time is 15min.
The preparation method according to claim 3, wherein the rotation speed of the ball mill is 330-350 rpm, and the particle size of the aluminum powder after ball milling is 3-5 μm.
The preparation method according to claim 3, wherein the mass concentration of the PVA aqueous solution is 0.5 to 1.2 mol/L, and the time for mixing the aluminum powder with the PVA aqueous solution after ball milling is 15 to 20 minutes.
The preparation method according to claim 3, wherein the intensity of the electric field is 60-80 V/m.
The preparation method according to claim 3, wherein the sintering temperature is 550-600°C, and the time is 1.5-2h.
The preparation method according to claim 3 or 8, characterized in that the heating rate of the sintering is 50-70°C/min.
The preparation method according to claim 3, characterized in that, after the sintering, it further comprises grinding the obtained sintered product, and the particle size after grinding is 20-30 mesh.