Preparation method of heat conduction enhanced photo-thermal anti-icing coating

Abstract

The invention discloses a preparation method of a heat-conducting enhanced photo-thermal anti-icing coating, which specifically comprises the following steps: mixing boric acid and urea, calcining to generate BN powder, and carrying out ball milling treatment on the BN powder and benzyl benzoate to prepare BNNSs; the preparation method comprises the following steps: modifying, dispersing and mixing BNNSs and CNTs to prepare a BNNSs (at) CNTs composite material; dissolving AOZ in dichloromethane, dropwise adding the solution into the BNNSs (at) CNTs dispersion liquid, and carrying out a reaction so as to obtain AOZ-BNNSs (at) CNTs; after being modified, the material is mixed with EP and an auxiliary agent to prepare a composite coating; and finally, mixing the composite coating with a curing agent and a curing accelerator, and spraying the mixture on the metal surface to form the heat-conducting enhanced photo-thermal anti-icing coating. The prepared coating is sprayed on the metal surface, efficient light collection, temperature rise and ice prevention can be achieved, the surface is hydrophobic after curing, the low-temperature ice resistance is enhanced, and the coating has wide application prospects in the key fields of electric wires and cables, aerospace, transportation and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of coating preparation, and particularly relates to a preparation method of a heat-conduction-enhanced photo-thermal anti-icing coating. BACKGROUND

[0002] Epoxy resin (EP) coating has become an important choice for the protection of devices such as electric wires and cables due to its excellent insulation performance, good corrosion resistance and weather resistance, strong adhesion, and convenient construction. However, in cold winter, especially in high-latitude areas or cold regions such as high mountains and plateaus, metal surfaces (such as power lines, bridges, aircraft, ships, etc.) are easily covered with ice and snow. This not only affects the normal operation of the equipment, but also can cause serious safety accidents and economic losses. For example, icing of power lines can cause power transmission interruption, and even lead to power grid collapse. Therefore, the research on anti-icing coating for metal surfaces is of great significance.

[0003] Chinese patent "Hydrophobic lubricating type anti-icing coating" (Application No. 202311213376.6, Publication No. CN117264485A, Publication Date: December 22, 2023) discloses a hydrophobic lubricating type anti-icing coating, which contains hydrogel, lubricant and modified micro-nano particles. The micro-nano particles are interwoven into a three-dimensional network in the hydrogel, and the upper surface forms a super-hydrophobic structure. The lubricant penetrates into the network, and the tight bonding between the hydrogel and the micro-nano particles can solve the problem of poor anti-icing effect. However, the coating prepared by this method only has the effect of hydrophobic anti-icing, and the effect is single, and it does not have the photo-thermal effect of absorbing solar light and converting it into heat.

[0004] Chinese patent "Anti-icing coating with photo-thermal effect and fan blade" (Application No. 202311214488.3, Publication No. CN117264493A, Publication Date: December 22, 2023) discloses an anti-icing coating with photo-thermal effect and a fan blade. The anti-icing coating is composed of hydrogel, hydrophobic polymer and photo-thermal micro-nano particles. The two form a double network structure, and the photo-thermal particles are arranged in layers. This structure enhances the hydrophobic anti-icing property, and the layered photo-thermal particles prevent pollution penetration, helping to prevent icing. However, the photo-thermal micro-nano particles in this coating have poor heat conduction effect, and there is an interfacial thermal resistance between the particles, so the heat transfer efficiency is not high during the photo-thermal conversion process.

[0005] Hu et al. (Hu, Du, Dong, Lei. Effect of TiO2 particle size on mechanical stability and anti-icing performance of TiO2 / polyurea superhydrophobic coating [J]. Surface Technology, 2024, 53(12): 240-251.) used organic-inorganic particle blending, modified nano-TiO2 and polyaspartic acid polyurea (PAE polyurea) as materials, and constructed a TiO2 / PAE polyurea superhydrophobic coating by one-step method. When the particle size of TiO2 is 100 nm, the contact angle is 162.4°, the rolling angle is 3.8°, the anti-icing performance and mechanical stability of the sample are better, but the coating does not have photothermal effect. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of a heat-conducting enhanced photothermal anti-icing coating, which solves the problem of poor photothermal deicing effect and easy icing under low temperature conditions in the prior art.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0008] A preparation method of a heat-conducting enhanced photothermal anti-icing coating, which is implemented in the following steps:

[0009] Step 1: ball milling method for preparing boron nitride nanosheet:

[0010] After mixing boric acid and urea, deionized water is added, heated and evaporated, and calcined to generate BN powder. The BN powder is ball milled with benzyl benzoate, washed and dried to obtain boron nitride nanosheet BNNSs;

[0011] Step 2: preparation of carbon nanotubes loaded with boron nitride nanosheet:

[0012] The BNNSs prepared in step 1 are modified by NaOH solution and dispersed in ethanol to obtain solution A. The carbon nanotubes are modified by an acidic solution and dispersed in ethanol to obtain solution B. Solution A and solution B are mixed and stirred, and after washing and drying, carbon nanotubes loaded with boron nitride nanosheet BNNSs@CNTs are obtained;

[0013] Step 3: preparation of azobenzene grafted BNNSs@CNTs:

[0014] The BNNSs@CNTs prepared in step 2 are modified by silane coupling agent and dispersed in dichloromethane to obtain a BNNSs@CNTs dispersion. Azobenzene AOZ is dissolved in dichloromethane and added dropwise to the BNNSs@CNTs dispersion. The reaction is carried out under nitrogen protection, and after washing and drying, azobenzene grafted BNNSs@CNTs, namely AOZ-BNNSs@CNTs, are obtained;

[0015] Step 4: preparation of AOZ-BNNSs@CNTs / EP composite coating:

[0016] The AOZ-BNNSs@CNTs obtained in step 3 is modified by silane coupling agent, then the modified AOZ-BNNSs@CNTs, leveling agent and defoaming agent are added into the epoxy resin EP and stirred to obtain the AOZ-BNNSs@CNTs / EP composite coating;

[0017] Step 5, preparing the heat-conducting enhanced photothermal anti-icing coating by spraying method:

[0018] The AOZ-BNNSs@CNTs / EP composite coating obtained in step 4 is mixed with curing agent and curing accelerator, and then sprayed on the surface of the metal substrate after stirring to obtain the heat-conducting enhanced photothermal anti-icing coating.

[0019] Further, the molar ratio of boric acid to urea in step 1 is 1:6-12.

[0020] Further, the calcination atmosphere in step 1 is nitrogen, the calcination temperature is 900-1200℃, the calcination time is 3-6h; the ball milling speed is 200-400rpm, the ball milling time is 8h, and the washing uses ethanol and deionized water.

[0021] Further, the concentration of NaOH solution in step 2 is 4mol / L, and the acid solution is prepared by mixing sulfuric acid, hydrogen peroxide and nitric acid in a volume ratio of 3:2:1.

[0022] Further, the mass ratio of solution A to solution B in step 2 is 3:7-6:4, solution A and solution B are stirred at 80℃ for 12h, and deionized water is used for washing.

[0023] Further, the silane coupling agent in step 3 is KH-550.

[0024] Further, the specific method of step 3 is as follows:

[0025] 3g of BNNSs@CNTs modified by KH-550 is dispersed in 10ml of dichloromethane to obtain a BNNSs@CNTs dispersion liquid, 0.5ml of azobenzene AOZ is dissolved in 4ml of dichloromethane, then it is added to the BNNSs@CNTs dispersion liquid at a drop rate of 0.5ml / min, and the reaction is carried out under nitrogen protection for 72h, and then the azobenzene grafted BNNSs@CNTs, namely AOZ-BNNSs@CNTs, is obtained after washing and drying with ethanol and acetone.

[0026] Further, the silane coupling agent in step 4 is selected from any one of KH-550, KH-560 and KH-570, the leveling agent is fluorocarbon surfactant, the defoaming agent is silicone defoaming agent, the modified AOZ-BNNSs@CNTs accounts for 8-14% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, the leveling agent accounts for 1% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, the defoaming agent accounts for 1% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, the stirring time is 5 min, and the stirring temperature is 60 DEG C.

[0027] Further, the curing agent in step 5 is dicyandiamide, and the addition amount is 10-20% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, the curing agent and the curing accelerator, and the curing accelerator is 2-methylimidazole, and the addition amount is 3% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, the curing agent and the curing accelerator.

[0028] Further, in step 5, the AOZ-BNNSs@CNTs / EP composite coating, the curing agent and the curing accelerator are stirred at room temperature for 8 min, and the spraying rate is 5-10 cm / s.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The preparation method of the heat-conducting enhanced photothermal anti-icing coating provided by the present application can obtain an epoxy resin composite coating interconnected by carbon nanotubes and boron nitride nanosheets, and the epoxy resin composite coating is grafted with azobenzene containing a photothermal group. Through the unique light-induced reversible structure transformation characteristics of azobenzene, the photothermal group efficiently absorbs and releases photon energy in the cis-trans isomerization process. At the same time, the excellent heat-conducting performance of the boron nitride nanosheet and the carbon nanotube further synergistically improves the heat absorption and release efficiency of the photothermal group. The carbon nanotube not only has excellent performance itself, but also serves as a regulating factor to effectively regulate the cis-trans isomerization process of azobenzene, thereby optimizing the overall performance of the composite coating. After the composite coating is sprayed on the metal surface, it can efficiently absorb sunlight and convert it into heat energy, significantly increasing the surface temperature and effectively preventing icing. The uneven surface structure formed after the coating is cured endows the coating with excellent hydrophobic properties, further enhancing the anti-icing ability in low-temperature environments, and the coating has wide application prospects in key fields such as power lines and cables, aerospace and transportation. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The structure diagram of the heat-conducting enhanced photothermal anti-icing coating prepared by the present application.

[0032] In the figure, 1 is a substrate, 2 is a boron nitride nanosheet, 3 is azobenzene, 4 is a carbon nanotube, and 5 is an epoxy resin coating base. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0034] The technical solution adopted in this invention is: a method for preparing a thermally enhanced photothermal anti-icing coating, specifically implemented according to the following steps:

[0035] Step 1: Preparation of boron nitride nanosheets by ball milling:

[0036] Boric acid (H3BO3) and urea (CH4N2O) are mixed in a molar ratio of 1:6-12, then deionized water is added, the mixture is heated to evaporate, and calcined at 900-1200℃ for 3-6 hours to produce BN powder. 2g of BN powder is then mixed with 20ml of benzyl benzoate (C... 14 H 12 Boron nitride nanosheets (BNNSs) were prepared by ball milling O2 at 200-400 rpm for 8 hours, followed by washing and drying with ethanol and deionized water.

[0037] Step 2, Preparation of carbon nanotubes loaded with boron nitride nanosheets:

[0038] The BNNSs obtained in step 1 were modified with 4 mol / L NaOH solution and then dispersed in 20 ml of ethanol to obtain solution A. The carbon nanotubes (CNTs) were modified with an acidic solution and then dispersed in 20 ml of ethanol to obtain solution B. The acidic solution was prepared by sulfuric acid, hydrogen peroxide and nitric acid in a volume ratio of 3:2:1. The solutions A and B in a mass ratio of 3:7 to 6:4 were mixed and stirred at 80℃ for 12 h. After washing and drying with deionized water, carbon nanotubes loaded with boron nitride nanosheets (BNNSs@CNTs) were obtained.

[0039] Step 3, Preparation of azobenzene-grafted BNNSs@CNTs:

[0040] The BNNSs@CNTs obtained in step 2 were modified with KH-550. 3g of the modified BNNSs@CNTs were dispersed in 10ml of dichloromethane to obtain a BNNSs@CNTs dispersion. 0.5ml of azobenzene (AOZ) was dissolved in 4ml of dichloromethane and then added dropwise to the BNNSs@CNTs dispersion at a rate of 0.5ml / min. The reaction was carried out under nitrogen protection for 72h. After washing and drying with ethanol and acetone, azobenzene-grafted BNNSs@CNTs (AOZ-BNNSs@CNTs) were obtained.

[0041] Step 4, prepare AOZ-BNNSs@CNTs / EP composite coating:

[0042] The AOZ-BNNSs@CNTs obtained in step 3 were modified with a silane coupling agent (any one of KH-550, KH-560, and KH-570). Then, the modified AOZ-BNNSs@CNTs, fluorocarbon surfactants, and silicone defoamers were added to epoxy resin (EP) and mixed and stirred at 60°C for 5 minutes to obtain an AOZ-BNNSs@CNTs / EP composite coating. The modified AOZ-BNNSs@CNTs accounted for 8-14% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, the leveling agent accounted for 1% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, and the defoamer accounted for 1% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating.

[0043] Step 5: Prepare a thermally enhanced photothermal anti-icing coating using a spraying method.

[0044] The AOZ-BNNSs@CNTs / EP composite coating obtained in step 4 is stirred with dicyandiamide (DICY) and 2-methylimidazole (2-MI) at room temperature for 8 minutes, and then sprayed onto the surface of a metal substrate at a speed of 5~10 cm / s to obtain a thermally enhanced photothermal anti-icing coating. The amount of dicyandiamide added is 10~20% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, curing agent, and curing accelerator, and the amount of 2-methylimidazole added is 3% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, curing agent, and curing accelerator.

[0045] like Figure 1 The figure shows a schematic diagram of the thermally enhanced photothermal anti-icing coating structure prepared according to the present invention. As can be seen from the figure, a thermally enhanced photothermal anti-icing coating is formed on the substrate 1. Boron nitride nanosheets 2 are attached to the wall of carbon nanotubes 4 and grafted with azobenzene 3 containing photothermal groups, which are filled into the epoxy resin coating matrix 5 and interconnected to form a thermally conductive network.

[0046] This invention utilizes a specific ratio of boric acid and urea to precisely control the reaction and generate BN powder. Benzyl benzoate is then used to assist ball milling, efficiently preparing high-quality BNNSs. NaOH and acidification treatments modify the BNNSs and CNTs respectively, enhancing dispersion and compatibility. After mixing and reacting, a high-performance BNNSs@CNTs composite material is formed, featuring a unique structure with boron nitride nanosheets on the outside and carbon nanotubes loaded onto the surface. Functional modification with silane coupling agents such as KH-550 improves dispersibility and introduces active sites. AOZ grafted onto the BNNSs@CNTs surface, with its reversible structural transformation properties, imparts photothermal effects to the composite material, making it suitable for photothermal conversion and anti-icing applications. The composite coating is formulated with functionalized AOZ-BNNSs@CNTs and epoxy resin, with optimized ratios and stirring conditions to improve performance. A dicyandiamide and 2-methylimidazole curing system achieves rapid curing at room temperature. Spraying technology ensures uniform and high-adhesion coating, and after curing, the surface filler particles protrude, forming a hydrophobic surface and enhancing low-temperature anti-icing capabilities.

[0047] Example 1

[0048] First, H3BO3 and CH4N2O were mixed at a molar ratio of 1:12, then deionized water was added, the mixture was heated to evaporate, and calcined at 1200℃ for 6 hours to produce BN powder. 2g of BN powder was ball-milled with 20ml of benzyl benzoate at 400rpm for 8 hours, washed with ethanol and deionized water, and dried to obtain BNNSs.

[0049] BNNSs were modified with 4 mol / L NaOH solution and then dispersed in 20 ml of ethanol to obtain solution A. CNTs were modified with an acidic solution (the acidic solution was prepared by sulfuric acid, hydrogen peroxide and nitric acid in a volume ratio of 3:2:1) and then dispersed in 20 ml of ethanol to obtain solution B. Solutions A and B, with a mass ratio of 3:7, were mixed and stirred at 80℃ for 12 h. After washing with deionized water and drying, BNNSs@CNTs were obtained.

[0050] After modifying BNNSs@CNTs with KH-550, 3g of the modified BNNSs@CNTs was ultrasonically dispersed in 10ml of dichloromethane to obtain a BNNSs@CNTs dispersion. 0.5ml of azobenzene was dissolved in 4ml of dichloromethane and then added dropwise to the BNNSs@CNTs dispersion at a rate of 0.5ml / min. The reaction was carried out under nitrogen protection for 72h. After washing and drying with ethanol and acetone, AOZ-BNNSs@CNTs were obtained.

[0051] AOZ-BNNSs@CNTs were modified with KH-550, and then 14% of the modified AOZ-BNNSs@CNTs, 1% of fluorocarbon surfactant and 1% of silicone defoamer were added to EP and mixed and stirred at 60℃ for 5 min to obtain AOZ-BNNSs@CNTs / EP composite coating.

[0052] The AOZ-BNNSs@CNTs / EP composite coating was stirred with 20% DICY and 3% 2-MI at room temperature for 8 minutes, and then sprayed onto the surface of a metal substrate at a speed of 5 cm / s to obtain a thermally enhanced photothermal anti-icing coating.

[0053] Example 2

[0054] First, H3BO3 and CH4N2O were mixed at a molar ratio of 1:10, then deionized water was added, the mixture was heated to evaporate, and calcined at 1100℃ for 5 hours to produce BN powder. 2g of BN powder was ball-milled with 20ml of benzyl benzoate at 400rpm for 8 hours, and after washing with ethanol and deionized water and drying, BNNSs was obtained.

[0055] BNNSs were modified with 4 mol / L NaOH solution and then dispersed in 20 ml of ethanol to obtain solution A. CNTs were modified with an acidic solution (the acidic solution was prepared by sulfuric acid, hydrogen peroxide and nitric acid in a volume ratio of 3:2:1) and then dispersed in 20 ml of ethanol to obtain solution B. Solutions A and B, with a mass ratio of 4:6, were mixed and stirred at 80℃ for 12 h to obtain BNNSs@CNTs.

[0056] After modifying BNNSs@CNTs with KH-550, 3g of the modified BNNSs@CNTs was ultrasonically dispersed in 10ml of dichloromethane to obtain a BNNSs@CNTs dispersion. 0.5ml of azobenzene was dissolved in 4ml of dichloromethane and then added dropwise to the BNNSs@CNTs dispersion at a rate of 0.5ml / min. The reaction was carried out under nitrogen protection for 72h. After washing and drying with ethanol and acetone, AOZ-BNNSs@CNTs were obtained.

[0057] AOZ-BNNSs@CNTs were modified with KH-550. Then, 12% of the modified AOZ-BNNSs@CNTs, 1% of fluorocarbon surfactant and 1% of silicone defoamer were added to EP and mixed and stirred at 60℃ for 5 min to obtain AOZ-BNNSs@CNTs / EP composite coating.

[0058] The AOZ-BNNSs@CNTs / EP composite coating was stirred with 20% DICY and 3% 2-MI at room temperature for 8 minutes, and then sprayed onto the surface of a metal substrate at a speed of 5 cm / s to obtain a thermally enhanced photothermal anti-icing coating.

[0059] Example 3

[0060] First, H3BO3 and CH4N2O were mixed at a molar ratio of 1:8, then deionized water was added, the mixture was heated to evaporate, and calcined at 1000℃ for 4 hours to produce BN powder. 2g of BN powder was then ball-milled with 20ml of benzyl benzoate at 200rpm for 8 hours. After separation, BNNSs was obtained.

[0061] BNNSs were modified with 4 mol / L NaOH solution and then dispersed in 20 ml of ethanol to obtain solution A. CNTs were modified with an acidic solution (the acidic solution was prepared by sulfuric acid, hydrogen peroxide and nitric acid in a volume ratio of 3:2:1) and then dispersed in 20 ml of ethanol to obtain solution B. Solutions A and B in a mass ratio of 5:5 were mixed and stirred at 80℃ for 12 h. After washing with deionized water and drying, BNNSs@CNTs were obtained.

[0062] After modifying BNNSs@CNTs with KH-560, 3g of the modified BNNSs@CNTs were ultrasonically dispersed in 10ml of dichloromethane to obtain a BNNSs@CNTs dispersion. 0.5ml of azobenzene was dissolved in 4ml of dichloromethane and then added dropwise to the BNNSs@CNTs dispersion at a rate of 0.5ml / min. The reaction was carried out under nitrogen protection for 72h. After washing and drying with ethanol and acetone, AOZ-BNNSs@CNTs were obtained.

[0063] AOZ-BNNSs@CNTs were modified with KH-550. Then, 10% of the modified AOZ-BNNSs@CNTs, 1% of the fluorocarbon surfactant and 1% of the silicone defoamer were added to EP and mixed and stirred at 60℃ for 5 min to obtain the AOZ-BNNSs@CNTs / EP composite coating.

[0064] The AOZ-BNNSs@CNTs / EP composite coating was stirred with 10% DICY and 3% 2-MI at room temperature for 8 minutes, and then sprayed onto the surface of a metal substrate at a speed of 10 cm / s to obtain a thermally enhanced photothermal anti-icing coating.

[0065] Example 4

[0066] First, H3BO3 and CH4N2O were mixed in a molar ratio of 1:6, then deionized water was added, the mixture was heated to evaporate, and calcined at 900℃ for 3 hours to produce BN powder. 2g of BN powder was ball-milled with 20ml of benzyl benzoate at 200rpm for 8 hours, washed with ethanol and deionized water, and dried to obtain BNNSs.

[0067] BNNSs were modified with 4 mol / L NaOH solution and then dispersed in 20 ml of ethanol to obtain solution A. CNTs were modified with an acidic solution (the acidic solution was prepared by sulfuric acid, hydrogen peroxide and nitric acid in a volume ratio of 3:2:1) and also dispersed in 20 ml of ethanol to obtain solution B. Solutions A and B, with a mass ratio of 6:4, were mixed and stirred at 80℃ for 12 h. After washing with deionized water and drying, BNNSs@CNTs were obtained.

[0068] After modifying BNNSs@CNTs with KH-570, 3g of the modified BNNSs@CNTs was ultrasonically dispersed in 10ml of dichloromethane to obtain a BNNSs@CNTs dispersion. 0.5ml of azobenzene was dissolved in 4ml of dichloromethane and then added dropwise to the BNNSs@CNTs dispersion at a rate of 0.5ml / min. The reaction was carried out under nitrogen protection for 72h. After washing and drying with ethanol and acetone, AOZ-BNNSs@CNTs were obtained.

[0069] AOZ-BNNSs@CNTs were modified with KH-570, and then 8% of the modified AOZ-BNNSs@CNTs, 1% of fluorocarbon surfactant and 1% of silicone defoamer were added to EP and mixed and stirred at 60℃ for 5 min to obtain AOZ-BNNSs@CNTs / EP composite coating.

[0070] The AOZ-BNNSs@CNTs / EP composite coating was stirred with 10% DICY and 3% 2-MI at room temperature for 8 minutes, and then sprayed onto the surface of a metal substrate at a speed of 10 cm / s to obtain a thermally enhanced photothermal anti-icing coating.

[0071] Table 1 shows the comparison results of the contact angle, roll-off angle, temperature rise after 5 minutes of near-infrared irradiation, and solar absorption rate of the thermally conductive enhanced photothermal anti-icing coating prepared in Example 1, the anti-icing coating for wind turbine blades, and the TiO2 / PAE polyurea superhydrophobic coating.

[0072] Table 1

[0073] Category Contact angle (°) Rolling angle (°) Temperature rise (°C) under near-infrared light irradiation for 5 min Solar absorption rate The heat-conducting enhanced photothermal anti-icing coating prepared in Example 1 165.2 2.3 52.3 99.1% Anti-icing coating for fan blades 159 5 / 97.7% TiO2 / PAE polyurea superhydrophobic coating 162.4 3.8 / /

[0074] As can be seen from Table 1, although the contact angle and roll-off angle of the TiO2 / PAE polyurea superhydrophobic coating are already very good, it cannot prevent icing until the water droplets freeze because it does not have a photothermal effect. The heat transfer efficiency of the anti-icing coating for wind turbine blades is not high due to the particulate nature of the thermally conductive material, and the temperature rise may not be significant in a short time. In contrast, the thermally enhanced photothermal anti-icing coating prepared in Example 1 can form an uneven surface after curing to achieve a hydrophobic effect. Furthermore, azobenzene has photothermal groups, which absorb and release photon energy during its cis-trans isomerization process, resulting in a photothermal effect. At the same time, the interconnected carbon nanotubes / boron nitride nanosheets are excellent thermally conductive materials, which significantly accelerates the heat transfer efficiency during the photothermal conversion process.

[0075] The above description of the present invention represents only some embodiments, but the present invention is not limited to the above embodiments. The above embodiments are illustrative and not restrictive. All specific extensions using the materials and methods of the present invention, without departing from the spirit and scope of the claims, are within the protection scope of the present invention.

Claims

1. A method for preparing a thermally enhanced photothermal anti-icing coating, characterized in that, The specific steps are as follows: Step 1: Preparation of boron nitride nanosheets by ball milling: Boric acid and urea were mixed, deionized water was added, and the mixture was heated to evaporate and calcined to generate BN powder. The BN powder was ball-milled with benzyl benzoate, and after washing and drying, boron nitride nanosheets (BNNSs) were obtained. Step 2, Preparation of carbon nanotubes loaded with boron nitride nanosheets: The BNNSs obtained in step 1 were modified with NaOH solution and dispersed in ethanol to obtain solution A. The carbon nanotubes were modified with acidic solution and dispersed in ethanol to obtain solution B. Solution A and solution B were mixed and stirred. After washing and drying, carbon nanotubes BNNSs@CNTs loaded with boron nitride nanosheets were obtained. Step 3, Preparation of azobenzene-grafted BNNSs@CNTs: The BNNSs@CNTs obtained in step 2 were modified with a silane coupling agent and dispersed in dichloromethane to obtain a BNNSs@CNTs dispersion. Azobenzene AOZ was dissolved in dichloromethane and added dropwise to the BNNSs@CNTs dispersion. The reaction was carried out under nitrogen protection. After washing and drying, azobenzene-grafted BNNSs@CNTs, namely AOZ-BNNSs@CNTs, were obtained. Step 4, prepare AOZ-BNNSs@CNTs / EP composite coating: The AOZ-BNNSs@CNTs obtained in step 3 were modified with a silane coupling agent. Then, the modified AOZ-BNNSs@CNTs, leveling agent and defoamer were added to epoxy resin EP and mixed and stirred to obtain AOZ-BNNSs@CNTs / EP composite coating. Step 5: Prepare a thermally enhanced photothermal anti-icing coating using a spraying method. The AOZ-BNNSs@CNTs / EP composite coating obtained in step 4 is mixed with a curing agent and a curing accelerator, stirred, and then sprayed onto the surface of a metal substrate to obtain a thermally enhanced photothermal anti-icing coating.

2. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, In step 1, the molar ratio of boric acid to urea is 1:6~12.

3. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, In step 1, the calcination atmosphere is nitrogen, the calcination temperature is 900~1200℃, and the calcination time is 3~6h; the ball milling speed is 200~400rpm, the ball milling time is 8h, and the washing uses ethanol and deionized water.

4. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, In step 2, the concentration of the NaOH solution is 4 mol / L, and the acidic solution is prepared by mixing sulfuric acid, hydrogen peroxide and nitric acid in a volume ratio of 3:2:

1.

5. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, In step 2, the mass ratio of solution A to solution B is 3:7 to 6:

4. Solution A and solution B are stirred at 80℃ for 12 hours, and deionized water is used for washing.

6. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, In step 3, the silane coupling agent is KH-550.

7. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 6, characterized in that, The specific steps for step 3 are as follows: 3g of KH-550 modified BNNSs@CNTs were dispersed in 10ml of dichloromethane to obtain a BNNSs@CNTs dispersion. 0.5ml of azobenzene AOZ was dissolved in 4ml of dichloromethane and added dropwise to the BNNSs@CNTs dispersion at a dropping rate of 0.5ml / min. The reaction was carried out under nitrogen protection for 72h. After washing and drying with ethanol and acetone, azobenzene-grafted BNNSs@CNTs, namely AOZ-BNNSs@CNTs, were obtained.

8. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, In step 4, the silane coupling agent is any one of KH-550, KH-560, and KH-570, the leveling agent is a fluorocarbon surfactant, and the defoamer is an organosilicon defoamer. The modified AOZ-BNNSs@CNTs accounts for 8-14% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, the leveling agent accounts for 1% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating, and the defoamer accounts for 1% of the total mass of the AOZ-BNNSs@CNTs / EP composite coating. The stirring time is 5 minutes, and the stirring temperature is 60℃.

9. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, The curing agent in step 5 is dicyandiamide, and the amount added is 10-20% of the total mass of AOZ-BNNSs@CNTs / EP composite coating, curing agent, and curing accelerator. The curing accelerator is 2-methylimidazole, and the amount added is 3% of the total mass of AOZ-BNNSs@CNTs / EP composite coating, curing agent, and curing accelerator.

10. The method for preparing a thermally enhanced photothermal anti-icing coating according to claim 1, characterized in that, In step 5, the AOZ-BNNSs@CNTs / EP composite coating, curing agent, and curing accelerator are stirred at room temperature for 8 minutes, and the spraying rate is 5~10cm / s.

Images