MXene / PPy composite anticorrosive coating agent, and preparation method and application thereof

Abstract

The application belongs to the technical field of anticorrosive materials, and particularly relates to a MXene / PPy composite anticorrosive coating agent, a preparation method and application thereof, wherein the anticorrosive coating agent at least comprises a composite material of PPy nanospheres and surface-modified MXene. The specific surface area of the MXene is large, and the MXene can block corrosive ions. The conductivity of the composite PPy and MXene is good, and the composite PPy and MXene can improve the self-corrosion potential of steel and reduce the low corrosion current.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion materials technology, and particularly relates to an MXene / PPy composite anti-corrosion coating agent, its preparation method and application. Background Technology

[0002] With the widespread application of steel materials in modern construction and industry, corrosion has become a major concern. Corrosion refers to the chemical or electrochemical interaction between metal and its surrounding environment that renders it unsuitable for practical applications. Phenomena such as oil leaks due to rust in steel transport pipelines and bridge collapses caused by rust not only have a direct impact on the economy but also affect our daily lives. Every year, the international community suffers huge economic losses due to steel corrosion.

[0003] Currently, with the development of research on steel corrosion protection, an increasing number of steel corrosion protection technologies have been reported internationally. These include hot-dip galvanizing, applying inorganic coatings such as chromates, treating steel before use to form a protective layer on the steel surface to improve its corrosion resistance, and adding corrosion inhibitors. However, these technologies all have some significant limitations. For example, using hot-dip galvanizing to improve the corrosion resistance of steel and other metals faces high costs and environmental pollution problems caused by large amounts of waste liquid and fumes generated during construction. The main problem with chromate coatings is that hexavalent chromium ions are highly toxic, posing a significant health risk, and long-term exposure can lead to cancer.

[0004] In recent years, with the advancement of research on conductive polymers, more and more researchers in metal corrosion prevention have focused their attention on conductive polymers. Polypyrrole (PPy) has been favored due to its non-toxicity and easy availability. MXene is a novel two-dimensional transition metal carbide or carbonitride with a unique layered structure similar to graphene. It also has outstanding characteristics such as high electrical conductivity and large specific surface area, making it suitable for composite with other materials, such as MXene and PPy. However, the surface of MXene carries hydrophilic groups, such as -OH and -F, which results in weak interactions between MXene and the hydrophobic PPy, making it difficult to effectively composite MXene and PPy. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, the present invention provides the following technical solution:

[0006] An anti-corrosion coating agent comprising at least a composite material of polypyrrole (PPy) nanospheres and surface-modified MXene.

[0007] Furthermore, the anti-corrosion coating agent also includes a solvent.

[0008] Furthermore, in the anti-corrosion coating agent, the mass ratio of the composite material to the solvent is 1:(5-10).

[0009] Furthermore, in the composite material, the surface-modified MXene has a layered structure, with the PPy nanospheres loaded between and / or on the surface.

[0010] Furthermore, in the composite material, the mass percentage of PPy nanospheres is 45-60%.

[0011] Furthermore, in the composite material, the particle size of the PPy nanospheres is 50 nm to 70 nm.

[0012] Furthermore, in the composite material, the surface-modified MXene modifier is a hydrophobic modifier.

[0013] The present invention also provides a method for preparing the aforementioned anti-corrosion coating agent, the method comprising the following steps:

[0014] S1. Preparation of surface-modified MXene;

[0015] S2. Preparation of PPy nanospheres;

[0016] S3. Mix surface-modified MXene with PPy nanospheres to obtain a composite material of PPy nanospheres and surface-modified MXene.

[0017] Furthermore, the preparation method further includes the following step: S4. Mixing the composite material with a solvent to obtain the anti-corrosion coating agent.

[0018] The present invention also provides the application of the anti-corrosion coating agent in corrosion protection.

[0019] The present invention also provides a steel material comprising a substrate and an anti-corrosion coating on the surface of the substrate, wherein the anti-corrosion coating comprises the aforementioned anti-corrosion coating agent.

[0020] Compared with the prior art, the solution of the present invention achieves the following beneficial effects:

[0021] This invention provides an anti-corrosion coating agent comprising an MXene / PPy composite material, which is a composite anti-corrosion coating agent capable of increasing the self-corrosion potential of steel and reducing corrosion current.

[0022] This invention also provides a method for preparing the above-mentioned anti-corrosion coating agent. Specifically, MXene is reacted with a surface modifier (such as a hydrophobic modifier, specifically TBAOH). The surface modifier (such as a hydrophobic ion, specifically TBAOH) +The insertion of PPy nanospheres into MXene increases the interlayer spacing of MXene, thereby increasing the specific surface area and enabling uniform dispersion in organic solvents. PPy nanospheres, especially those with nonpolar groups on their surface, can be uniformly dispersed in organic solvents. Furthermore, PPy nanospheres can be uniformly intercalated into MXene with larger interlayer spacing. MXene has a large specific surface area, which provides some barrier effect against corrosive ions in the solution. The combined PPy and MXene exhibit good conductivity, which can increase the self-corrosion potential of steel and reduce corrosion current.

[0023] Meanwhile, the oxidant that reacts with PPy in this invention cannot be completely removed by centrifugation. The oxidant remaining in the PPy nanosphere powder can insert into the MXene interlayer, further increasing the MXene spacing, increasing the amount of PPy nanospheres loaded on MXene, and further improving the conductivity of the composite material. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the composite material formed by PPy nanospheres and surface-modified MXene in this invention; wherein, the small spheres represent PPy nanospheres and the flat plate represents surface-modified MXene.

[0025] Figure 2 The dynamic potential polarization analysis curves of PPy / MXene-Q235 steel plate and MXene-Q235 steel plate in Test 1 of this invention are shown. Detailed Implementation

[0026] [Anti-corrosion coating agent]

[0027] As previously stated, the present invention provides an anti-corrosion coating agent comprising at least a composite material of PPy nanospheres and surface-modified MXene.

[0028] According to an embodiment of the present invention, the anti-corrosion coating agent further includes a solvent.

[0029] According to an embodiment of the present invention, in the anti-corrosion coating agent, the mass ratio of the composite material to the solvent is 1:(5-10), and can be 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, for example.

[0030] According to an embodiment of the present invention, the solvent is selected from at least one of phenolic resin, polyurethane, ethylene resin, and epoxy resin, for example, selected from liquid epoxy resin.

[0031] According to an embodiment of the present invention, in the composite material, the surface-modified MXene has a layered structure, and the PPy nanospheres are loaded between the layers and / or on the surface.

[0032] According to an embodiment of the present invention, the mass percentage of PPy nanospheres in the composite material is 45% to 60%, and exemplaryly it can be 48%, 50%, 52%, 55%, 57%, 59% or 60%.

[0033] According to an embodiment of the present invention, the particle size of the PPy nanospheres in the composite material is 50nm to 70nm, and can be 50nm, 55nm, 60nm, 65nm, or 70nm, for example.

[0034] According to an embodiment of the present invention, in the composite material, the surface-modified MXene modifier is a hydrophobic modifier, such as at least one selected from TBAOH (tetrabutylammonium hydroxide), TBAB (tetrabutylammonium bromide) or CTAB (hexadecyltrimethylammonium bromide).

[0035] According to an embodiment of the present invention, the MXene in the surface-modified MXene is selected from Ti2C and / or Ti3C2, for example, Ti3C2.

[0036] According to an embodiment of the present invention, the PPy nanospheres are PPy nanospheres with nonpolar groups on their surface, and the nonpolar groups are derived from a surface modifier.

[0037] According to an embodiment of the present invention, the PPy nanospheres also contain trace amounts of oxidant.

[0038] In some specific embodiments, the oxidant is selected from at least one of ammonium persulfate, ferric chloride, hydrogen peroxide, and potassium permanganate, for example, ammonium persulfate.

[0039] [Preparation method of anti-corrosion coating agent]

[0040] As mentioned above, the present invention also provides a method for preparing the above-mentioned anti-corrosion coating agent, comprising the following steps:

[0041] S1. Preparation of surface-modified MXene;

[0042] S2. Preparation of PPy nanospheres;

[0043] S3. Mix surface-modified MXene with PPy nanospheres to obtain a composite material of PPy nanospheres and surface-modified MXene.

[0044] According to an embodiment of the present invention, the preparation method further includes the following steps:

[0045] S4. Mix the composite material with a solvent to obtain the anti-corrosion coating agent.

[0046] According to an embodiment of the present invention, step S1 specifically includes the following steps: mixing and reacting MXene with a surface modifier solution to obtain surface-modified MXene.

[0047] According to an embodiment of the present invention, step S1 specifically includes the following steps: mixing and reacting MXene with a surface modifier solution, centrifuging and washing to obtain powdered surface-modified MXene.

[0048] According to an embodiment of the present invention, the MXene is selected from Ti2C and / or Ti3C2, for example Ti3C2.

[0049] Specifically, the surface modifier solution is selected from hydrophobic modifier solutions, such as TBAOH solution, TBAB solution or CTAB solution.

[0050] According to an embodiment of the present invention, step S1, the mixing and reaction of MXene with the surface modifier solution includes the following steps: dispersing MXene in water to form a suspension, adding the surface modifier solution, and reacting at room temperature for 1 to 6 hours.

[0051] Preferably, the reaction time between MXene and the surface modifier solution is 2 to 5 hours, for example, 4 hours.

[0052] Preferably, the reaction between MXene and the surface modifier solution is carried out under stirring.

[0053] According to an embodiment of the present invention, step S1, dispersing MXene in water to form a suspension includes the following steps: dispersing MXene in deionized water to prepare a suspension with a concentration of 0.3 g / L to 0.8 g / L, and then performing ultrasonic dispersion to obtain the suspension.

[0054] According to an embodiment of the present invention, in step S1, the mass concentration of the surface modifier solution is 20% to 30%, exemplarily 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%.

[0055] According to an embodiment of the present invention, step S2 specifically includes the following steps: reacting pyrrole with an oxidant to obtain PPy nanospheres.

[0056] According to an embodiment of the present invention, step S2 specifically includes the following steps: reacting pyrrole with an oxidant, centrifuging, and obtaining PPy nanosphere powder.

[0057] According to an embodiment of the present invention, step S2, the reaction of pyrrole with the oxidant includes the following steps: dissolving pyrrole in a solvent to form a pyrrole solution, adding an oxidant dropwise to the pyrrole solution and reacting for 10h to 30h, preferably the reaction time of the oxidant with the pyrrole solution is 20h to 25h, for example 24h.

[0058] According to an embodiment of the present invention, in step S2, pyrrole is dissolved in the emulsion at a temperature of 0–5°C. In some embodiments, the emulsion is selected from one of PVA (polyvinyl alcohol) solution, PVP (polyvinylpyrrolidone) solution, and sodium dodecyl sulfate solution, preferably a PVA solution. The mass fraction of the PVA solution is 1%–10%, exemplarily 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0059] According to an embodiment of the present invention, in step S2, the concentration of pyrrole in the pyrrole solution is (0.1 to 0.3) g / 100 mL, preferably (0.1 to 0.2) g / 100 mL, for example, 0.14 g / 100 mL.

[0060] According to an embodiment of the present invention, in step S2, the oxidant is selected from at least one of ammonium persulfate, ferric chloride, hydrogen peroxide, and potassium permanganate, for example, ammonium persulfate.

[0061] According to an embodiment of the present invention, in step S2, the oxidant is first prepared into a solution and then added dropwise, preferably with a concentration of 0.1–0.2 mol·L⁻¹. -1 .

[0062] According to an embodiment of the present invention, in step S2, the molar ratio of the oxidant to pyrrole is (0.25 to 1):1, for example, 0.25:1, 0.5:1, 0.75:1, or 1:1.

[0063] According to an embodiment of the present invention, step S3 specifically includes: dispersing surface-modified MXene and PPy nanospheres in an organic solvent to form a reaction solution and reacting to obtain a composite material of PPy nanospheres and surface-modified MXene.

[0064] According to an embodiment of the present invention, in the reaction solution of step S3, the molar ratio of pyrrole to MXene, based on pyrrole and MXene, is 2:1 to 4:1, preferably 2.5:1 to 3.5:1, for example 11:4.

[0065] According to an embodiment of the present invention, in step S3, the organic solvent is selected from at least one of DMF (N,N-dimethylformamide), PC (polycarbonate), and DMAC (dimethylacetamide), for example, DMF.

[0066] According to an embodiment of the present invention, in step S3, dispersing the surface-modified MXene and PPy nanospheres in an organic solvent to form a reaction solution and reacting includes the following steps: adding the surface-modified MXene and PPy nanospheres to the organic solvent and stirring for 1 h to 2 h, and then placing the reaction solution in an ice-water bath and sonicating for 30 min to 60 min.

[0067] According to an embodiment of the present invention, in step S3, the temperature of the reaction solution in the ultrasound is 30-40°C, preferably 34-36°C.

[0068] According to an embodiment of the present invention, in step S3, after the sonication step, the following steps are further included: filtering, washing and drying the sonicated reaction product.

[0069] Preferably, the drying process includes the following steps: drying the washing product at a temperature below 60°C for 12 to 36 hours, preferably at a temperature below 50°C, for example, drying the reaction product at 40°C for 24 hours.

[0070] According to an embodiment of the present invention, in step S3, after drying the reaction product, the following step is further included: pulverizing the dried material into powder, for example, grinding the dried material into powder.

[0071] According to an embodiment of the present invention, in step S4, the solvent is selected from at least one of phenolic resin, polyurethane, and ethylene resin, for example, from liquid epoxy resin.

[0072] According to an embodiment of the present invention, in step S4, the mass ratio of the composite material to the solvent is 1:(5-10), which can be 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, for example.

[0073] Application of anti-corrosion coating agents

[0074] As mentioned above, the present invention also provides the application of the above-mentioned anti-corrosion coating agent in corrosion protection, preferably for metal corrosion protection, such as for steel corrosion protection.

[0075] [Steel with anti-corrosion coating]

[0076] As mentioned above, the present invention also provides a steel material comprising a substrate and an anti-corrosion coating on the surface of the substrate, wherein the anti-corrosion coating comprises the aforementioned anti-corrosion coating agent.

[0077] According to an embodiment of the present invention, the thickness of the anti-corrosion coating is 1mm to 4mm, for example, 1.0mm, 1.1mm, 1.5mm, 1.8mm, 1.9mm, 1.98mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm or 4.0mm.

[0078] The following detailed description, in conjunction with specific embodiments, illustrates the general formula compounds of the present invention, their preparation methods, and applications in further detail. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0079] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0080] Comparative Example 1

[0081] (1) 0.1223 g of Ti3C2 (an MXene) was dispersed in 300 mL of deionized water to prepare a suspension with a concentration of about 0.4 g / L, and then subjected to low-temperature ultrasonic dispersion for 1 h to obtain a suspension.

[0082] (2) Add 50 ml of TBAOH solution to the suspension and stir for 4 h to obtain the modified MXene suspension.

[0083] (3) The modified MXene suspension was centrifuged at 3500 r / min, and the precipitate was washed to obtain the modified MXene powder.

[0084] (4) Add 0.1223g of modified MXene powder to 20ml of organic solvent DMF, stir at 5℃ for 2h, and sonicate in an ice bath for 30min. After sonication, filter and wash. The resulting solid is the reaction product.

[0085] (5) Place the washed reaction product into an oven and dry it at 40°C for 24 hours. After drying, grind the product into powder using a mortar and pestle to obtain MXene anti-corrosion coating agent, and put it into a sample bottle for later use.

[0086] Example 1

[0087] (1) 0.1223 g of Ti3C2 (an MXene) was dispersed in 300 mL of deionized water to prepare a suspension with a concentration of about 0.4 g / L, and then subjected to low-temperature ultrasonic dispersion for 1 h to obtain a suspension.

[0088] (2) Add 50 ml of TBAOH solution to the suspension and stir for 4 h to obtain the modified MXene suspension.

[0089] (3) The modified MXene suspension was centrifuged at 3500 r / min, and the precipitate was washed to obtain the modified MXene powder.

[0090] (4) Pour 20 ml of 2% PVA solution into a double-walled flask connected to a circulating cooling pump. Set the temperature to 2°C. After the temperature stabilizes, add 0.134 g (about 0.14 mL) of pyrrole to the double-walled flask.

[0091] (5) Add 0.228g of oxidant ammonium persulfate to a beaker containing 100ml of deionized water and stir well to obtain a transparent ammonium persulfate solution.

[0092] (6) Add ammonium persulfate solution to a constant pressure dropping funnel, and slowly add it dropwise into a flask containing pyrrole, controlling the knob to do so over a period of 30 min. Continue the reaction in a double-layered flask for 24 h, maintaining the reaction temperature at 0–5 °C. After the reaction is complete, centrifuge at 16000 r / min, and wash the precipitate with a 1:1 volume ratio of ethanol / deionized water by vacuum filtration. Repeat centrifugation and washing multiple times to obtain PPy nanosphere powder product (hereinafter referred to as PPy nanospheres).

[0093] (7) Add 0.1223g of modified MXene powder and 0.134g of PPy nanospheres to 20ml of organic solvent DMF, stir at 5℃ for 2h, and sonicate in an ice bath for 30min. After sonication, filter and wash. The resulting solid is the reaction product.

[0094] (8) Place the cleaned reaction product into an oven and dry it at 40°C for 24 hours. After drying, grind the product into powder using a mortar and pestle to obtain the MXene / PPy composite anti-corrosion coating agent, and place it into a sample bottle for later use.

[0095] Test Example 1

[0096] The MXene / PPy composite anti-corrosion coating agent prepared in Example 1 was mixed with liquid epoxy resin at a mass ratio of 1:7 and stirred evenly before being coated onto a Q235 steel plate with a coating thickness of 1.98 mm, resulting in a PPy / MXene-Q235 steel plate. After 30 days, dynamic potential polarization analysis was performed on the PPy / MXene-Q235 steel plate.

[0097] The MXene anti-corrosion coating agent prepared in Comparative Example 1 and liquid epoxy resin were mixed at a mass ratio of 1:7 and stirred evenly before being coated onto a Q235 steel plate with a coating thickness of 1.98 mm, resulting in an MXene-Q235 steel plate. After 30 days, dynamic potential polarization analysis was performed on the MXene-Q235 steel plate.

[0098] Based on the polarization curves of each sample, the corrosion potential E was calculated using the Tafel extrapolation method. corr and corrosion current I corr Based on this, the corrosion rate (CR) can be calculated using the following formula:

[0099]

[0100] The EW of Q235 is 28g, and the d value is 7.86g / cm³. 3

[0101] See Figure 1 As shown, MXene-Q235 steel plate (corresponding to Figure 1 Corrosion potential E of MXene corr It is -0.631V, while the corrosion potential E of PPy / MXene-Q235 steel plate (corresponding to MXene / ppy in the figure) is... corr The value is -0.631V, indicating that PPy has little effect on the self-corrosion potential of Q235 steel; furthermore, the corrosion current of the MXene-Q235 steel plate is 3.16 nA cm⁻¹. -2 The calculated corrosion rate was 0.411 μm / y, while the corrosion current of the PPy / MXene-Q235 steel plate was 0.0351 nA cm⁻¹. -2 The calculated corrosion rate was 4.61 nm / y, indicating that the PPy / MXene-Q235 steel plate has significantly improved corrosion resistance. That is, the anti-corrosion coating agent of the present invention can significantly improve the corrosion resistance of the steel plate compared with MXene.

[0102] The specific embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an anti-corrosion coating agent, characterized in that, The preparation method includes the following steps: S1. Preparation of surface-modified Mxene: Disperse MXene in water to form a suspension with a concentration of 0.3 g / L to 0.8 g / L, add a surface modifier solution with a mass concentration of 20% to 30%, and react at room temperature for 1 h to 6 h; The MXene is Ti3C2; The surface modifier solution is a TBAOH solution; S2. Preparation of PPy nanospheres: Pyrrole is dissolved in PVA (polyvinyl alcohol) solution to form pyrrole solution, oxidant is added dropwise to pyrrole solution and the reaction is carried out for 10h~30h; The molar ratio of the oxidant to pyrrole is (0.25~1):1; The oxidant is ammonium persulfate; S3. Surface-modified MXene and PPy nanospheres are dispersed in an organic solvent to form a reaction solution and react to obtain a composite material of PPy nanospheres and surface-modified MXene; in the reaction solution, the molar ratio of pyrrole to MXene is 2.5:1 to 3.5:1, based on pyrrole and MXene.

2. The preparation method according to claim 1, characterized in that, The anti-corrosion coating agent comprises at least a composite material of PPy nanospheres and surface-modified MXene, and the anti-corrosion coating agent also includes a solvent.

3. The method for preparing the anti-corrosion coating agent according to claim 2, characterized in that, In the anti-corrosion coating agent, the mass ratio of the composite material to the solvent is 1:(5~10).

4. The method for preparing the anti-corrosion coating agent according to any one of claims 1-3, characterized in that, In the composite material, the surface-modified MXene has a layered structure, with the PPy nanospheres loaded between and / or on the surface.

5. The method for preparing the anti-corrosion coating agent according to any one of claims 1-3, characterized in that, In the composite material, the mass percentage of PPy nanospheres is 45-60%; And / or, in the composite material, the particle size of the PPy nanospheres is 50nm~70nm.

6. The preparation method according to any one of claims 1-3, characterized in that, The preparation method further includes the following step: S4. Mixing the composite material with a solvent to obtain the anti-corrosion coating agent.

7. The application of an anti-corrosion coating agent prepared by the method of any one of claims 1-6 in corrosion protection.

8. A type of steel, characterized in that, The steel material includes a substrate and an anti-corrosion coating on the surface of the substrate, wherein the anti-corrosion coating includes an anti-corrosion coating agent prepared by the method according to any one of claims 1-6.

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