Nanoporous composite photothermal coating and preparation method thereof

Abstract

The present invention discloses a nanoporous composite photothermal coating and a preparation method thereof. The preparation method comprises mixing triethanolamine with water and stirring, mixing the resulting oily solution with silica aerogel powder, ultrasonically treating, and stirring, mixing the resulting silica aerogel dispersion with polyvinyl alcohol, stirring, and vacuuming, mixing the resulting silica aerogel aqueous slurry with multi-walled carbon nanotubes, ultrasonically treating, and stirring, and spraying or brushing the resulting nanoporous composite photothermal coating onto a substrate to obtain the nanoporous composite photothermal coating. The preparation method of the present invention has a simple process, convenient steps, and can be industrially produced. The nanoporous composite photothermal coating has excellent photothermal performance, strong deicing ability, strong applicability, and stable chemical and mechanical properties. It can be widely used for deicing wind turbine blades, is of great significance for enhancing the performance of wind turbines and increasing power generation, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of photothermal coatings, and in particular to a nanoporous composite photothermal coating and a preparation method thereof. Background Art

[0002] my country's onshore wind power market is currently quite widespread, with large-scale wind farm construction underway in the resource-rich Northeast, Northwest, and North China regions, as well as in the central and southern regions, which are home to high-altitude mountainous areas. Wind turbines in these regions are exposed to cold, damp conditions, often accompanied by freezing rain, frost, fog, and snowfall, often leading to blade ice buildup. If ice buildup on wind turbine blades is not promptly removed, it can cause serious problems.

[0003] In order to ensure the performance of wind turbines and reduce the economic losses caused by blade icing, there are currently two main methods to reduce or eliminate ice on blades: (1) traditional deicing methods, such as mechanical, thermal and chemical deicing technologies; (2) new coating deicing methods, such as superhydrophobic, photothermal and composite deicing coating technologies. Although traditional deicing methods are widely used in engineering, they still have many disadvantages in terms of energy consumption, environmental impact and cost. In contrast, coating deicing technology is low-cost, environmentally friendly and can be used for a long time. Therefore, it is very important to develop deicing coatings for wind turbine blades.

[0004] Photothermal deicing coatings with high photothermal properties and high mechanical stability are an appropriate solution to the current problem of icing on wind turbine blades. The photothermal deicing coatings currently being studied at home and abroad can exhibit excellent photothermal performance under the irradiation of specific excitation light sources or direct sunlight, but at the same time, the high temperature on the coating surface will also transfer heat downward, causing the temperature of the covered parts to rise. Long-term high temperature will cause thermal oxidation aging of the wind turbine blade material, resulting in severe cracking of the blade material resin matrix. Therefore, how to prepare the photothermal coating required for wind turbine blades simply, at low cost, efficiently, and on a large scale without damaging the blade surface material is of great significance for enhancing the performance of wind turbines and increasing power generation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a nanoporous composite photothermal coating with excellent photothermal performance, strong deicing ability, strong applicability, stable chemical and mechanical properties, and can be widely used for deicing treatment of wind turbine blades, and a preparation method thereof.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0007] A method for preparing a nanoporous composite photothermal coating comprises the following steps:

[0008] S1. Mix triethanolamine and water and stir to obtain an oily solution;

[0009] S2, mixing the oily solution obtained in step S1 with silica aerogel powder, and subjecting the mixture to ultrasonic treatment and stirring to obtain a silica aerogel dispersion;

[0010] S3, mixing the silica aerogel dispersion obtained in step S2 with polyvinyl alcohol, stirring, and vacuuming to obtain a silica aerogel aqueous slurry;

[0011] S4, mixing the silica aerogel aqueous slurry obtained in step S3 with multi-walled carbon nanotubes, and subjecting the mixture to ultrasonic treatment and stirring to obtain a nanoporous composite photothermal coating;

[0012] S5. Spray or brush the nanoporous composite photothermal coating obtained in step S4 onto the substrate to obtain a nanoporous composite photothermal coating.

[0013] In the above-mentioned method for preparing the nanoporous composite photothermal coating, preferably, the mass ratio of triethanolamine, water, silica aerogel powder, polyvinyl alcohol, and multi-walled carbon nanotubes is 0.02-0.03:50-55:10-12:0.05-0.06:0.36-0.40.

[0014] In the above-mentioned method for preparing the nanoporous composite photothermal coating, more preferably, the mass fraction of the multi-walled carbon nanotubes in the nanoporous composite photothermal coating is 0.6%.

[0015] In the above-mentioned method for preparing the nanoporous composite photothermal coating, preferably, the particle size of the silica aerogel powder is 20 μm to 70 μm.

[0016] In the above-mentioned method for preparing the nanoporous composite photothermal coating, preferably, the inner diameter of the multi-walled carbon nanotubes is 5 nm to 12 nm, the outer diameter is 30 nm to 50 nm, and the length is 10 μm to 20 μm.

[0017] In the above-mentioned method for preparing the nanoporous composite photothermal coating, preferably, in step S1, the stirring speed is 300 r / min to 400 r / min, and the stirring time is 10 min to 20 min.

[0018] In the above-mentioned method for preparing the nanoporous composite photothermal coating, preferably, in step S2, the ultrasonic treatment time is 0.5h to 0.6h, the stirring speed is 300r / min to 400r / min, and the stirring time is 25min to 35min.

[0019] In the above-mentioned method for preparing the nanoporous composite photothermal coating, preferably, in step S3, the stirring temperature is 85°C to 95°C, the stirring speed is 300r / min to 400r / min, and the stirring time is 20min to 60min.

[0020] In the above-mentioned method for preparing the nanoporous composite photothermal coating, preferably, in step S4, the ultrasonic treatment time is 1 hour to 1.2 hours, the stirring speed is 300 r / min to 400 r / min, and the stirring time is 30 minutes to 40 minutes.

[0021] As a general technical concept, the present invention also provides a nanoporous composite photothermal coating prepared by the above-mentioned preparation method.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] (1) The present invention provides a method for preparing a nanoporous composite photothermal coating, which uses silica aerogel (SiO2) with a unique three-dimensional nanoporous structure, multi-walled carbon nanotubes (CNTs) with high-efficiency photothermal conversion characteristics, and polyvinyl alcohol for synergistic enhancement. The present invention uses SiO2 aerogel particles to form a thermal insulation bottom layer to avoid damaging the matrix structure, and uses polyvinyl alcohol to reduce the autonomous aggregation of SiO2 aerogel particles, which on the one hand further enhances the thermal insulation, and on the other hand is conducive to the embedding of multi-walled carbon nanotubes in the next step. The filling of multi-walled carbon nanotubes can increase the limit temperature and the heating rate. Multiple characteristics work synergistically and are linked together to obtain a composite photothermal deicing coating suitable for solving the problem of ice on the surface of wind turbine blades. It solves the problem that the traditional photothermal coating causes thermal oxidation aging of the wind turbine blade material due to long-term high temperature, resulting in serious cracking of the resin matrix of the blade material. The nanoporous composite photothermal coating thus prepared has the characteristics of excellent photothermal performance, strong deicing ability, strong applicability, strong durability, stable chemical / mechanical properties, etc. The preparation method of the present invention also has the advantages of simple preparation process, convenient operation steps, and industrial production. It can prepare composite photothermal coatings on a large scale, which is conducive to industrial and industrial applications.

[0024] (2) In the preparation method of the present invention, the mass ratio of triethanolamine, water, silica aerogel powder, polyvinyl alcohol, and multi-walled carbon nanotubes is controlled to be 0.02-0.03:50-55:10-12:0.05-0.06:0.36-0.40. The present invention controls the amount and particle size of the silica aerogel powder, constructs the nanoporous structure of the coating's thermal insulation base layer, allows the SiO2 aerogel particles to more fully contact water, strengthens the peptization dispersion effect, and improves the dispersion of the SiO2 aerogel particles in the liquid phase.

[0025] The present invention optimizes the amount of polyvinyl alcohol used, thereby making the SiO2 aerogel particles more stable, reducing the spontaneous aggregation of the particles, making the mixed liquid more evenly dispersed, and enhancing the thermal insulation of the coating.

[0026] The present invention improves the maximum temperature and heating rate of the coating during photothermal heating and reduces the heating time by optimizing the dosage of multi-walled carbon nanotubes (preferably, the mass percentage of multi-walled carbon nanotubes in the nanoporous composite photothermal coating is 0.6%). This is mainly because as the amount of multi-walled carbon nanotubes increases, the multi-walled carbon nanotube particles gradually fill the porous three-dimensional structure space of the aerogel and gradually cover the surface of the aerogel particles. However, after the mass percentage exceeds 0.6%, the saturated multi-walled carbon nanotube content causes agglomeration to form, and the increase in the mass percentage of multi-walled carbon nanotubes does not significantly improve the maximum temperature, heating rate, and heating time compared to the 0.6% content.

[0027] (3) The nanoporous composite photothermal coating of the present invention has the characteristics of excellent photothermal performance, strong deicing ability, strong applicability, strong durability, stable chemical / mechanical properties, etc. It can be widely used in the deicing treatment of wind turbine blades, which is of great significance for enhancing the performance of wind turbines and increasing power generation, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a physical schematic diagram of the nanoporous composite photothermal coating prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of the present invention is not limited thereby. The materials and instruments used in the following examples are all commercially available, and the raw materials are of analytical grade. In the following examples, unless otherwise specified, the data obtained are the average values ​​of more than three repeated tests.

[0030] Example 1

[0031] A method for preparing a nanoporous composite photothermal coating of the present invention comprises the following steps:

[0032] S1. Mix 0.02 g of triethanolamine and 50 g of deionized water, and stir at a speed of 300 r / min for 10 minutes to obtain an oily solution.

[0033] S2. The oily solution obtained in step S1 was mixed with 10 g of silica aerogel powder, subjected to ultrasonic treatment for 30 minutes, and stirred at a rotation speed of 300 r / min for 30 minutes to obtain a silica aerogel dispersion.

[0034] S3. The silica aerogel dispersion obtained in step S2 was mixed with 0.05 g of polyvinyl alcohol, and stirred at a temperature of 90° C. and a rotation speed of 300 r / min for 50 min. After stirring, the mixture was evacuated in a vacuum box and allowed to stand for degassing to obtain an aqueous slurry of silica aerogel.

[0035] S4. The silica aerogel aqueous slurry obtained in step S3 was mixed with 0.36 g of multi-walled carbon nanotubes, subjected to ultrasonic treatment for 1 h, and stirred at a speed of 300 r / min for 30 min to obtain a nanoporous composite photothermal coating.

[0036] S5. Spray the nanoporous composite photothermal coating obtained in step S4 onto a 25 mm×25 mm glass sheet and dry it at room temperature to obtain a nanoporous composite photothermal coating.

[0037] Figure 1 This is a schematic diagram of the nanoporous composite photothermal coating prepared in Example 1. Figure 1 It can be seen that CNTs particles can be well captured by the three-dimensional nanostructure of SiO2 aerogel and fixed in the coating structure, forming a stable and strong symbiotic skeleton, giving the coating excellent photothermal and mechanical properties.

[0038] The nanoporous composite photothermal coating (A1) prepared in Example 1 and an uncoated substrate (A2) were placed on an ice test bench, and a 5 mm thick ice layer was frozen on the coating surface. The test was carried out under near-infrared light source irradiation. The results showed that compared with the uncoated sample (A2), the ice on the sample (A1_) coated with the nanoporous composite photothermal coating of the present invention was easier to melt, and the deicing time was only 230 s.

[0039] The nanoporous composite photothermal coating (A1) prepared in Example 1 was placed at ambient temperatures of 0°C and 20°C to simulate an acid rain (SAR) environment (pH = 4). The coating was subjected to a 168-h scouring test. The sample was taken out, washed, and dried in a drying oven after 24 hours. The quality test and photothermal performance test were then carried out. The results showed that after a long period of scouring, the limit temperature of the nanoporous composite photothermal coating remained near the initial limit temperature of 153.4°C, with a fluctuation range of less than 0.5°C, and the coating had good acid resistance and stability.

[0040] The above-mentioned nanoporous composite photothermal coating (A1) prepared in Example 1 was placed on SiC sandpaper, and then a weight was placed on the coating sample for wear performance testing. The results showed that the wear rate of the nanoporous composite photothermal coating was only 2.11%, and the extreme temperature of the coating surface under the irradiation of the light source hardly changed, remaining above 150°C, and still had good photothermal performance.

[0041] Comparative Example 1

[0042] A preparation method of a composite photothermal coating is basically the same as that of Example 1, except that the mass of the multi-walled carbon nanotubes is 0.12 g (ie, the mass percentage of the multi-walled carbon nanotubes in the nanoporous composite photothermal coating is 0.2%).

[0043] After testing, the surface temperature of the composite photothermal coating remained constant at 72.7°C and no longer rose, indicating lower photothermal performance.

[0044] Comparative Example 2

[0045] A preparation method of a composite photothermal coating is basically the same as that of Example 1, except that the mass of the multi-walled carbon nanotubes is 0.48 g (ie, the mass percentage of the multi-walled carbon nanotubes in the nanoporous composite photothermal coating is 0.8%).

[0046] After testing, the surface temperature of the composite photothermal coating remained constant at 158.0°C and did not rise any more. Compared with the composite photothermal coating prepared in Example 1, the photothermal performance was not significantly improved.

[0047] Comparative Example 3

[0048] A preparation method of a composite photothermal coating is basically the same as that of Example 1, with the only difference being that polyvinyl alcohol is not added to the composite photothermal coating in Comparative Example 3.

[0049] After testing, it was found that the surface temperature of the composite photothermal coating rose unevenly, and the photothermal effect was poor in some areas of the coating sample.

[0050] The above description is only a preferred embodiment of the present invention and does not constitute any formal limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the spirit and technical solution of the present invention, use the methods and technical contents disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a nanoporous composite photothermal coating, characterized in that: The following steps are involved: S1. Mix triethanolamine and water and stir to obtain an oily solution; S2, mixing the oily solution obtained in step S1 with silica aerogel powder, and subjecting the mixture to ultrasonic treatment and stirring to obtain a silica aerogel dispersion; S3, mixing the silica aerogel dispersion obtained in step S2 with polyvinyl alcohol, stirring, and vacuuming to obtain a silica aerogel aqueous slurry; S4, mixing the silica aerogel aqueous slurry obtained in step S3 with multi-walled carbon nanotubes, and subjecting the mixture to ultrasonic treatment and stirring to obtain a nanoporous composite photothermal coating; S5, spraying or brushing the nanoporous composite photothermal coating obtained in step S4 on the substrate to obtain a nanoporous composite photothermal coating; The mass ratio of triethanolamine, water, silica aerogel powder, polyvinyl alcohol, and multi-walled carbon nanotubes is 0.02-0.03:50-55:10-12:0.05-0.06:0.36-0.40; The mass fraction of multi-walled carbon nanotubes in the nanoporous composite photothermal coating is 0.6%; The particle size of the silica aerogel powder is 20 μm to 70 μm.

2. The method for preparing the nanoporous composite photothermal coating according to claim 1, characterized in that: The multi-walled carbon nanotubes have an inner diameter of 5 nm to 12 nm, an outer diameter of 30 nm to 50 nm, and a length of 10 μm to 20 μm.

3. The method for preparing the nanoporous composite photothermal coating according to claim 1 or 2, characterized in that: In step S1, the stirring speed is 300 r / min to 400 r / min, and the stirring time is 10 min to 20 min.

4. The method for preparing the nanoporous composite photothermal coating according to claim 1 or 2, characterized in that: In step S2, the ultrasonic treatment time is 0.5h to 0.6h, the stirring speed is 300r / min to 400r / min, and the stirring time is 25min to 35min.

5. The method for preparing the nanoporous composite photothermal coating according to claim 1 or 2, characterized in that: In step S3, the stirring temperature is 85° C. to 95° C., the stirring speed is 300 r / min to 400 r / min, and the stirring time is 20 min to 60 min.

6. The method for preparing the nanoporous composite photothermal coating according to claim 1 or 2, characterized in that: In step S4, the ultrasonic treatment time is 1 hour to 1.2 hours, the stirring speed is 300 r / min to 400 r / min, and the stirring time is 30 minutes to 40 minutes.

7. A nanoporous composite photothermal coating prepared by the preparation method according to any one of claims 1 to 6.

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