Self-replenishment type super-hydrophobic anticorrosive coating and preparation method thereof

Abstract

The invention belongs to the technical field of anti-corrosion materials, and provides a self-supply type super-hydrophobic anti-corrosion coating and a preparation method thereof. The preparation method comprises the following steps: mixing a potassium silicate solution, a self-healing agent and dodecyl polyglucoside to obtain a film-forming material, sequentially coating the film-forming material and hydrophobic particles, and curing; the self-healing agent comprises a long-chain alkyl silane and a hydrophobic siloxane. The self-healing agent is introduced into the film-forming material, on one hand, the film-forming material is endowed with hydrophobicity, and on the other hand, when the coating is damaged and loses hydrophobicity, the self-healing agent can self-migrate to the surface of the coating and self-replenish hydrophobic substances, and the durability of the hydrophobic coating is improved; waste micro powder is used as a raw material, hydrophobic particles are prepared through carbonization and modification, the hydrophobic particles are applied to the self-supply type super-hydrophobic anticorrosive coating, and high value-added application of the waste micro powder is achieved; the self-replenishment type super-hydrophobic anti-corrosion coating can be applied to various base materials including concrete, glass products, metal base materials and the like, and the super-hydrophobic and anti-corrosion effects are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anticorrosive materials, in particular to a self-replenishing super-hydrophobic anticorrosive coating and a preparation method thereof. BACKGROUND

[0002] Coating protection is the most widely used and effective anticorrosive method at present, and the coating acts as a physical barrier to prevent the penetration of corrosive media such as water molecules, dissolved oxygen and chloride ions. Coating protection is simple to operate and has a relatively short construction period, and can be applied to various substrate materials and complex environments. At present, there are still many problems with coatings with anticorrosive effect: the surface of concrete has hydrophilicity and is easily affected by external corrosive media during the coating protection process, resulting in poor protection effect; the coating has adhesion, and corrosive media such as water scale and microbial adhesion corrosion are easily deposited and corroded; the raw materials and preparation process of the coating have problems such as VOC emission which threaten the environment. Based on the above problems, people began to study water-based super-hydrophobic anticorrosive coatings, and the research on super-hydrophobic concrete has also attracted much attention in recent years, and the heat has risen rapidly, becoming the main direction of the development and innovation of building materials.

[0003] Super-hydrophobic anticorrosive coatings mainly undergo five stages of development: ① the proposal of the theoretical basis of super-hydrophobic coatings; ② the use of fluorides to further improve the hydrophobicity of super-hydrophobic coatings by mimicking the microstructure of lotus leaves; ③ the introduction of nanostructures to form micro-nano structures to improve the performance of super-hydrophobic coatings, and the development of multifunctional coatings such as antibacterial and anti-icing coatings; ④ the development of fluoride-free super-hydrophobic coatings to promote the development of green and environmentally friendly technologies; ⑤ the development of intelligent super-hydrophobic coatings that respond to changes in the external environment to expand the application field. At present, super-hydrophobic anticorrosive coatings still have the problems of poor corrosion resistance, easy damage, poor durability and poor environmental adaptability.

[0004] Therefore, it is urgent to develop a new type of intelligent super-hydrophobic anticorrosive coating with high durability and in line with the environmental protection concept to further improve the durability of super-hydrophobic anticorrosive coatings and broaden the application field. SUMMARY

[0005] The present application aims to provide a self-replenishing super-hydrophobic anticorrosive coating and a preparation method thereof to overcome the deficiencies of the prior art.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The present application provides a preparation method of a self-replenishing super-hydrophobic anticorrosive coating, comprising the following steps: 1) mixing a potassium silicate solution, a self-healing agent and dodecyl glucoside to obtain a film-forming material; 2) sequentially coating the film-forming material and hydrophobic particles, and after curing, a self-replenishing super-hydrophobic anticorrosive coating is obtained; The self-healing agent comprises long-chain alkyl silane and hydrophobic siloxane.

[0007] Preferably, the mass ratio of the long-chain alkyl silane and the hydrophobic siloxane is 2-4:1.

[0008] Preferably, the mass ratio of the potassium silicate solution, the self-healing agent and the dodecyl glucoside is 15-25:4:0.1-1. The mass fraction of the potassium silicate solution is 10-30%.

[0009] Preferably, the coating amount of the film-forming material in step 2) is 2-4 kg / m 2 ; The mass ratio of the self-healing agent in step 1) and the hydrophobic particles in step 2) is 0.1-2:5.

[0010] Preferably, the hydrophobic particles are prepared by sequentially carbonizing and modifying waste micro powder. The waste micro powder comprises one or more of recycled concrete micro powder, red mud micro powder and waste glass micro powder.

[0011] Preferably, the carbonization process comprises dispersing the waste micro powder in water and then injecting CO2 to obtain carbonized micro powder.

[0012] Preferably, the mass ratio of the waste micro powder and water is 3-7:100. The flow rate of the injected CO2 is 0.3-0.5 mL / min. The injection of CO2 is performed simultaneously with stirring, and the stirring speed is 200-500 rpm and the stirring time is 1-3 h.

[0013] Preferably, the modification process comprises dispersing the carbonized micro powder in anhydrous ethanol and then adding a silane coupling agent to modify the carbonized micro powder to obtain the hydrophobic particles.

[0014] Preferably, the mass-volume ratio of the carbonized micro powder, the anhydrous ethanol and the silane coupling agent is 1-3 g:50 mL:0.5-2 mL. The modification is stirring modification, and the stirring speed is 400-600 rpm and the stirring time is 10-16 h.

[0015] The application also provides a self-supplying type super-hydrophobic corrosion-resistant coating prepared by the preparation method.

[0016] The application has the following beneficial effects: 1) The present application introduces a self-healing agent into the film-forming material, which on the one hand imparts hydrophobicity to the film-forming material, and on the other hand, when the coating is damaged and loses hydrophobicity, the self-healing agent can self-migrate to the surface of the coating, self-supply hydrophobic substances, and improve the durability of the hydrophobic coating; waste micro powder (recycled concrete micro powder, red mud micro powder or waste glass micro powder) is used as raw material, hydrophobic particles are prepared through carbonization and modification, and are applied to the self-supply type super-hydrophobic corrosion-resistant coating to realize high value-added application of waste micro powder.

[0017] 2) The self-supply type super-hydrophobic corrosion-resistant coating of the present application can be applied to various substrates, including concrete, glass products, etc., to achieve super-hydrophobic and corrosion-resistant effects. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a scanning electron microscope graph of recycled concrete micro powder before and after carbonization in Example 1; Figure 2 It is an X-ray diffraction graph of recycled concrete micro powder before and after carbonization in Example 1; Figure 3 It is a Fourier infrared spectrum graph of recycled concrete micro powder and hydrophobic particles in Example 1, wherein RCP is recycled concrete micro powder and HTDMS-RCP is hydrophobic particles; Figure 4 It is a scanning electron microscope graph of the self-supply type super-hydrophobic corrosion-resistant coating of Example 1 after abrasion before and after heating; Figure 5 It is a Fourier infrared spectrum graph of the self-supply type super-hydrophobic corrosion-resistant coating of Example 1 after abrasion before and after heating, wherein RT is before heating and GT is after heating; Figure 6 It is an X-ray photoelectron spectrum of the self-supply type super-hydrophobic corrosion-resistant coating of Example 1 after abrasion after heating. DETAILED DESCRIPTION

[0019] The present application provides a preparation method of a self-supply type super-hydrophobic corrosion-resistant coating, comprising the following steps: 1) Mixing a potassium silicate solution, a self-healing agent and dodecyl glucoside to obtain a film-forming material; 2) Sequentially coating the film-forming material and the hydrophobic particles, and after curing, a self-supply type super-hydrophobic corrosion-resistant coating is obtained; The self-healing agent comprises long-chain alkyl silane and hydrophobic siloxane.

[0020] In the present application, the mass ratio of the long-chain alkyl silane and the hydrophobic siloxane is preferably 2-4:1, further preferably 2.5-3.5:1, and more preferably 3:1.

[0021] In the present application, the long-chain alkyl silane preferably comprises one or more of hexadecyl trimethoxysilane, n-octadecyl trimethoxysilane, dodecyl trimethoxysilane and n-octadecyl triethoxysilane; The hydrophobic siloxane preferably comprises polydimethylsiloxane, which preferably comprises amino-terminated polydimethylsiloxane and / or hydroxyl-terminated polydimethylsiloxane.

[0022] In the present application, the mass ratio of the potassium silicate solution, the self-healing agent and the dodecyl glucoside is preferably 15-25:4:0.1-1, further preferably 17-23:4:0.3-0.8, and more preferably 20:4:0.5. The mass fraction of the potassium silicate solution is preferably 10-30%, further preferably 15-25%, and more preferably 20%.

[0023] In the present application, the mixing in step 1) is preferably stirring mixing, the stirring speed is preferably 300-500 rpm, further preferably 350-450 rpm, and more preferably 400 rpm; the stirring mixing time is preferably 3-5 h, further preferably 3.5-4.5 h, and more preferably 4 h.

[0024] In the present application, the coating amount of the film-forming material in step 2) is preferably 2-4 kg / m 2 , further preferably 2.5-3.5 kg / m 2 , and more preferably 3 kg / m 2 . The mass ratio of the self-healing agent in step 1) to the hydrophobic particles in step 2) is preferably 0.1-2:5, further preferably 0.5-1.5:5, and more preferably 1:5.

[0025] In the present application, the hydrophobic particles are preferably prepared from waste micro-powder by carbonization and modification in sequence. The waste micro-powder preferably comprises one or more of recycled concrete micro-powder, red mud micro-powder and waste glass micro-powder.

[0026] In the present application, the particle size of the waste micro-powder is preferably ≤75 μm, and further preferably ≤65 μm.

[0027] In the present application, the carbonization process preferably comprises dispersing the waste micro-powder in water, and then injecting CO2 to obtain carbonized micro-powder.

[0028] In the present application, the mass ratio of the waste micro-powder to water is preferably 3-7:100, further preferably 4-6:100, and more preferably 5:100. The flow rate of the injected CO2 is preferably 0.3-0.5 mL / min, further preferably 0.35-0.45 mL / min, and more preferably 0.4 mL / min; The stirring is preferably performed simultaneously with the injection of CO2, and the rotation speed of the stirring is preferably 200-500 rpm, further preferably 300-400 rpm, and more preferably 350 rpm; the time of the stirring is preferably 1-3 h, further preferably 1.5-2.5 h, and more preferably 2 h.

[0029] In the present application, after the carbonization, the filtration and freeze-drying are preferably performed in sequence to obtain carbonized particles. The temperature of the freeze-drying is preferably -60--40℃, further preferably -55--45℃, and more preferably -50℃; the time of the freeze-drying is preferably 16-32 h, further preferably 20-28 h, and more preferably 24 h.

[0030] In the present application, the modification process preferably comprises: dispersing the carbonized micro-powder in anhydrous ethanol, and then adding a silane coupling agent for modification, thereby obtaining hydrophobic particles.

[0031] In the present application, the mass-volume ratio of the carbonized micro-powder, the anhydrous ethanol and the silane coupling agent is preferably 1-3 g: 50 mL: 0.5-2 mL, further preferably 1.5-2.5 g: 50 mL: 0.7-1.5 mL, and more preferably 2 g: 50 mL: 1-1.2 mL. The modification is preferably stirring modification, and the rotation speed of the stirring modification is preferably 400-600 rpm, further preferably 450-550 rpm, and more preferably 500 rpm; the time of the stirring modification is preferably 10-16 h, further preferably 11-15 h, and more preferably 12-14 h.

[0032] In the present application, the silane coupling agent preferably comprises one or more of hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, dodecyltrimethoxysilane and n-octadecyltriethoxysilane.

[0033] In the present application, after the modification, the centrifugation, washing and drying are preferably performed in sequence to obtain hydrophobic particles. The rotation speed of the centrifugation is preferably 8000-12000 rpm, further preferably 9000-11000 rpm, and more preferably 10000 rpm; the time of the centrifugation is preferably 5-15 min, and further preferably 10 min. The reagent used for the washing is preferably anhydrous ethanol. The temperature of the drying is preferably 100-140℃, further preferably 110-130℃, and more preferably 120℃; and the time of the drying is preferably 2-4h, further preferably 3h.

[0034] In the present application, the temperature of the curing in step 2) is preferably 20-30℃, further preferably 25℃; and the time of the curing is preferably 35-55min, further preferably 45min.

[0035] The present application also provides a self-replenishing super-hydrophobic corrosion-resistant coating prepared by the preparation method.

[0036] The technical solutions provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0037] In the embodiments of the present application, the recycled concrete micro powder is prepared by crushing waste concrete, the waste glass powder is prepared by crushing waste glass bottles and waste glass cups, and the red mud micro powder is purchased from Henan Yixiang New Material.

[0038] Example 1

[0039] In this embodiment, the self-healing agent is hexadecyl trimethoxysilane and polydimethylsiloxane (the molecular weight of polydimethylsiloxane is 500Da) with a mass ratio of 3:1.

[0040] 20g of potassium silicate solution (20% by mass fraction), 4g of self-healing agent and 0.5g of dodecyl glucoside were mixed, stirred at a speed of 400rpm for 4h to obtain a film-forming material.

[0041] At room temperature, 5g of recycled concrete micro powder with a particle size of ≤75μm was dispersed into 100mL of deionized water, then CO2 with a volume fraction of 99.999% was injected into the dispersion at a flow rate of 0.4mL / min, while stirring at a speed of 300rpm for 2h for carbonization. After carbonization, the solid particles were obtained by filtration, and the solid particles were freeze-dried at-50℃ for 24h to obtain carbonized micro powder. 2g of carbonized micro powder was dispersed into 50mL of anhydrous ethanol, and ultrasonic treatment was carried out at a frequency of 38Hz for 30min to obtain a dispersion system. 1mL of hexadecyl trimethoxysilane was added to the dispersion system, and then stirring modification was carried out at a speed of 500rpm for 12h. After stirring modification, the product was centrifuged at a speed of 10000rpm for 10min, and then washed with anhydrous ethanol for 3 times, and then dried at 120℃ for 3h to obtain hydrophobic particles.

[0042] Concrete test blocks were prepared using PO42.5 ordinary Portland cement (purchased from Henan Jiuqi Building Materials). Concrete mortar was prepared with a water-cement ratio of 0.35. The mortar was poured into 40mm×40mm×40mm molds, compacted to remove air bubbles, covered with a thin film, and allowed to stand for 24 hours before demolding. The molds were then cured in a standard curing environment at 20±2℃ and relative humidity ≥95% for 28 days to obtain the concrete test blocks. A film-forming material was brushed onto the surface of the concrete test blocks at a coating amount of 3kg / m². 2 Subsequently, hydrophobic particles were immediately sprayed onto the surface of the film-forming material. After spraying, the concrete test block was allowed to cure naturally at 25°C for 45 minutes to obtain a self-healing superhydrophobic anti-corrosion coating. The mass ratio of self-healing agent to hydrophobic particles in the film-forming material was 1:5.

[0043] In this embodiment, the contact angle of the self-supplementing superhydrophobic anti-corrosion coating on the surface of the concrete test block is 152°.

[0044] Figure 1 The images shown are scanning electron microscope (SEM) images of the recycled concrete powder before and after carbonation in Example 1.

[0045] Figure 2 The images show X-ray diffraction patterns of recycled concrete powder before and after carbonation in Example 1, where CRP represents the powder after carbonation and RP represents the powder before carbonation. Figure 2 It can be seen that after carbonation, calcium carbonate with calcite crystal form is the main peak, thus confirming that carbonation transforms recycled concrete powder into a homogeneous system dominated by calcite, improving stability and promoting its application in superhydrophobic coatings.

[0046] Figure 3 The image shows the Fourier transform infrared (FTIR) spectra of the recycled concrete powder and hydrophobic particles in Example 1, where RCP represents the recycled concrete powder and HTDMS-RCP represents the hydrophobic particles. Figure 3 It can be seen that the infrared spectrum curves of the hydrophobic particles show obvious CH vibration peaks, indicating that hexadecyltrimethoxysilane has been successfully introduced into recycled concrete powder.

[0047] Example 2

[0048] The concrete test block in Example 1 was replaced with a Sailboat brand glass slide with a size of 25.4mm × 76.2mm, and everything else was the same as in Example 1.

[0049] In this embodiment, the contact angle of the self-supplementing superhydrophobic anti-corrosion coating on the glass surface is 155°.

[0050] Example 3

[0051] The self-healing agent in Example 1 was replaced with octadecyltrimethoxysilane and hydroxyl-terminated polydimethylsiloxane in a mass ratio of 3:1, and the rest was the same as in Example 1.

[0052] In this embodiment, the contact angle of the self-replenishing superhydrophobic anti-corrosion coating on the surface of the concrete test block is 151°.

[0053] Example 4

[0054] In this embodiment, the self-healing agent is octadecyltrimethoxysilane and hydroxyl-terminated polydimethylsiloxane in a mass ratio of 3:1.

[0055] 23g of potassium silicate solution (25% by mass), 4g of self-healing agent and 0.7g of dodecyl glucoside were mixed and stirred at 380 rpm for 3.5h to obtain the film-forming material.

[0056] At room temperature, 6 g of waste glass powder (particle size ≤75 μm) was dispersed in 100 mL of deionized water. Then, 99.999% CO2 (volume fraction) was injected into the dispersion at a flow rate of 0.5 mL / min, while stirring at 400 rpm for 1.5 h for carbonization. After carbonization, the suspended solid particles were collected by filtration and freeze-dried at -60℃ for 30 h to obtain carbonized microparticles. 3 g of the carbonized microparticles were dispersed in 50 mL of anhydrous ethanol and sonicated at 30 Hz for 30 min to obtain a dispersion system. 2 mL of n-octadecyltrimethoxysilane was added to the dispersion system, and then stirred at 550 rpm for 15 h for stirring modification. After stirring modification, the mixture was centrifuged at 8000 rpm for 15 min. The product obtained by centrifugation was washed three times with anhydrous ethanol and then dried at 120℃ for 3 h to obtain hydrophobic particles.

[0057] The concrete test blocks were prepared in the same manner as in Example 1. The film-forming material was brushed onto the surface of the concrete test block at a coating weight of 2 kg / m². 2 Subsequently, hydrophobic particles were immediately sprayed onto the surface of the film-forming material. After spraying, the concrete test block was allowed to cure naturally at 25°C for 45 minutes to obtain a self-healing superhydrophobic anti-corrosion coating. The mass ratio of self-healing agent to hydrophobic particles in the film-forming material was 1.8:5.

[0058] In this embodiment, the contact angle of the self-supplementing superhydrophobic anti-corrosion coating on the surface of the concrete test block is 152°.

[0059] Comparative Example 1

[0060] The self-healing agent in Example 1 is omitted, and everything else is the same as in Example 1.

[0061] In this comparative example, the contact angle of the superhydrophobic anti-corrosion coating on the surface of the concrete specimen is 145°.

[0062] Comparative Example 2

[0063] The mass ratio of hexadecyltrimethoxysilane and polydimethylsiloxane in the self-healing agent of Example 1 was modified to 5:1, and other aspects were the same as in Example 1.

[0064] In this comparative example, the contact angle of the superhydrophobic anti-corrosion coating on the surface of the concrete specimen is 150°.

[0065] Comparative Example 3

[0066] The mass ratio of the self-healing agent to the hydrophobic particles in Example 1 was modified to 3:5, and the rest was the same as in Example 1.

[0067] In this comparative example, the contact angle of the superhydrophobic anti-corrosion coating on the surface of the concrete specimen is 146°.

[0068] The superhydrophobic anticorrosive coatings of Examples 1 and 1-3 were subjected to abrasion tests to measure their contact angles. They were then heated at 60°C for 15 minutes and allowed to cool naturally to room temperature before measuring the contact angles again. The abrasion test conditions were as follows: the superhydrophobic anticorrosive coating was repeatedly rubbed 20 times with 800-grit sandpaper under 100g pressure. The contact angle measurement results are shown in Table 1.

[0069] Table 1. Contact angles of the superhydrophobic anti-corrosion coating after wear and heating.

[0070] Figure 4 Scanning electron microscope (SEM) images of the self-replenishing superhydrophobic anti-corrosion coating of Example 1 after wear, before and after heating. Figure 4 It can be seen that after heating, the self-healing agent in the self-replenishing superhydrophobic anti-corrosion coating has increased fluidity, making the coating more uniform and dense.

[0071] Figure 5 The image shows the Fourier transform infrared (FTIR) spectra of the self-replenishing superhydrophobic anti-corrosion coating of Example 1 after wear, before and after heating. RT represents the coating before heating, and GT represents the coating after heating. Figure 5 It can be seen that obvious CH bond vibration peaks appear after heating, indicating that the self-healing agent migrates to the coating surface and endows the coating with self-replenishing hydrophobicity.

[0072] Figure 6 X-ray photoelectron spectroscopy (XPS) of the self-replenishing superhydrophobic anti-corrosion coating of Example 1 after wear and heating. Figure 6 It can be seen that after heating, the coating exhibits peaks corresponding to Si-CH / CH and Si-O-Si. This result indicates that a silicon-oxygen hydrophobic chain network structure was synthesized after heating, further increasing the hydrophobicity.

[0073] As can be seen from the above embodiments, the present invention provides a self-replenishing superhydrophobic anti-corrosion coating and its preparation method. By adding a self-healing agent to the film-forming material, the coating is endowed with hydrophobicity on the one hand, and on the other hand, when the coating loses its superhydrophobicity due to wear or other damage, it can self-replenish hydrophobic substances to ensure the superhydrophobicity of the coating, thereby improving the durability of the hydrophobic coating.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-supplementing superhydrophobic anti-corrosion coating, characterized in that, It includes the following steps: 1) A film-forming material is obtained by mixing potassium silicate solution, self-healing agent and dodecyl glucoside; 2) Sequentially coat the film-forming material and hydrophobic particles, and after curing, a self-replenishing superhydrophobic anti-corrosion coating is obtained; The self-healing agent comprises long-chain alkylsilanes and hydrophobic siloxanes.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the long-chain alkylsilane to the hydrophobic siloxane is 2~4:

1.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the potassium silicate solution, the self-healing agent, and the dodecyl glucoside is 15~25:4:0.1~1; The potassium silicate solution has a mass fraction of 10-30%.

4. The preparation method according to any one of claims 1 to 3, characterized in that, Step 2) The coating amount of the film-forming material is 2~4 kg / m³. 2 ; The mass ratio of the self-healing agent in step 1) to the hydrophobic particles in step 2) is 0.1~2:

5.

5. The preparation method according to claim 4, characterized in that, The hydrophobic particles are obtained by sequentially carbonizing and modifying waste micro powder; The waste powder includes one or more of recycled concrete powder, red mud powder, and waste glass powder.

6. The preparation method according to claim 5, characterized in that, The carbonization process includes: dispersing waste micro powder in water, and then injecting CO2 to obtain carbonized micro powder.

7. The preparation method according to claim 6, characterized in that, The mass ratio of the waste powder to water is 3~7:100; The CO2 injection rate is 0.3~0.5 mL / min; The CO2 is injected while stirring, and the stirring speed is 200~500 rpm, and the stirring time is 1~3 hours.

8. The preparation method according to any one of claims 5 to 7, characterized in that, The modification process includes: dispersing carbonized micropowder in anhydrous ethanol, and then adding a silane coupling agent for modification to obtain hydrophobic particles.

9. The preparation method according to claim 8, characterized in that, The mass-to-volume ratio of the carbonized micro powder, anhydrous ethanol, and silane coupling agent is 1-3 g: 50 mL: 0.5-2 mL; The modification is a stirring modification, with a stirring speed of 400~600 rpm and a stirring time of 10~16 h.

10. The self-supplementing superhydrophobic anti-corrosion coating prepared by the preparation method according to any one of claims 1 to 9.

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