Super-black carbon powder with infrared / visible dual-band absorption performance and controllable preparation method and application thereof

Abstract

An ultra-black carbon powder with infrared / visible dual-band absorption performance, a morphology-controllable preparation method and application thereof belong to the field of ultra-black carbon powder preparation.The purpose of the present application is to solve the technical problems of existing ultra-black carbon powder preparation, such as complexity, high production cost and performance to be improved.The method comprises the following steps: firstly, melamine and cyanuric acid are respectively dissolved in dimethyl sulfoxide or ethylene glycol; then, the melamine solution is added dropwise into the cyanuric acid solution, and stirring reaction or stirring reaction under heating condition is carried out to obtain a hydrogen-bonded organic framework; then, the hydrogen-bonded organic framework is added into a phenolic resin anhydrous ethanol solution, stirring reaction is carried out, and the solid product is dried after centrifugation and calcined under a protective atmosphere to obtain the ultra-black carbon powder.The method is simple in process and low in cost.The obtained ultra-black carbon powder is stable in structure, good in dispersibility in a polymer organic rubber and high in processability, and can be used for absorbing visible light and infrared waves.

Description

Technical Field

[0001] The present invention belongs to the field of ultra-black carbon powder preparation, and in particular relates to an ultra-black carbon powder with infrared / visible light dual-band absorption performance and a morphology-controllable preparation method and application thereof. Background Art

[0002] In the aerospace field, the use of high-precision optical equipment is often affected by stray light, which can reduce the detection signal-to-noise ratio, sensitivity, and inversion accuracy. Ultra-black coating is an effective stray light-eliminating coating that absorbs and attenuates non-imaging-sensitive light within a specific wavelength range in the space environment, effectively eliminating stray light.

[0003] Carbon materials generally have a large conjugated system and a moderate free electron density, making them a popular ultra-black material. Ultra-black carbon powder is added to a high molecular weight polymer to prepare a composite coating, which can achieve a light-absorbing coating with high efficiency, high chemical stability, light resistance, weather resistance, and light weight. However, the preparation processes of traditional carbon-based ultra-black materials such as carbon nanotube arrays and carbon aerogels are very complicated, and it is not easy to prepare them into processable ultra-black coatings. In addition, there are some ultra-black carbon powders. Although their processability has been improved, in order to obtain hollow light-trapping structures, these schemes usually use a hard template method to prepare samples, which inevitably uses high-risk chemical reagents such as strong acids and strong bases. This not only greatly increases production costs, but also causes environmental pollution problems. At the same time, due to their simple structure, these ultra-black carbon powders are usually difficult to achieve broadband absorption covering both infrared and visible light bands. The above problems limit their practical application potential. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems of the existing ultra-black carbon powder, such as complex preparation, high production cost and performance to be improved, and to provide an ultra-black carbon powder with infrared / visible light dual-band absorption performance and its morphology controllable preparation method and application.

[0005] One of the objectives of the present invention is to provide a method for preparing ultra-black carbon powder with controllable morphology having infrared / visible light dual-band absorption properties, the method being carried out in the following steps:

[0006] S1: Melamine and cyanuric acid are dissolved in dimethyl sulfoxide or ethylene glycol, respectively, and then the melamine solution is added dropwise to the cyanuric acid solution, and the mixture is stirred for reaction. When the melamine solution is dissolved in ethylene glycol, the mixture is stirred for reaction under heating conditions. After the reaction, the mixture is washed with hot water by suction filtration and freeze-dried to obtain a hydrogen-bonded organic framework;

[0007] S2: adding the hydrogen-bonded organic framework to an anhydrous ethanol solution of phenolic resin, stirring the reaction, drying the solid product after centrifugation, and calcining it under a protective atmosphere to obtain ultra-black carbon powder.

[0008] Further, the mass ratio of melamine and cyanuric acid in S1 is 1.5:(1-2).

[0009] Further, the concentration of melamine solution in S1 is 0.04-0.06 g / mL, and the concentration of cyanuric acid solution is 0.05-0.07 g / mL when dissolved in dimethyl sulfoxide.

[0010] Further, the concentration of melamine solution in S1 is 0.02-0.03 g / mL, and the concentration of cyanuric acid solution is 0.005-0.015 g / mL when dissolved in ethylene glycol.

[0011] Further, the stirring reaction time in S1 is 5-10 min at 70-90℃.

[0012] Further, the hot water cleaning in S1 is at 70-90℃.

[0013] Further, the mass ratio of hydrogen-bonded organic framework and phenolic resin in S2 is 0.5:(0.3-0.5).

[0014] Further, the concentration of phenolic resin in the solution of anhydrous ethanol in S2 is 6-10 mg / mL.

[0015] Further, the stirring reaction time in S2 is 10-12 h.

[0016] Further, the drying temperature in S2 is 50-70℃.

[0017] Further, the calcination procedure in S2 is: first, increase the temperature to 350-450℃ at a rate of 1-3℃ / min, and keep the temperature for 1-2.5 h; then increase the temperature to 500-550℃, and keep the temperature for 2-4 h; continue to increase the temperature to 700-800℃, and keep the temperature for 1.5-4 h; and finally, cool down to room temperature.

[0018] The second object of the present application is to provide a bowl-shaped ultra-black carbon powder prepared by the above method, which is obtained by dissolving in dimethyl sulfoxide, and has an irregular porous hollow spherical shape with an opening on the sphere.

[0019] Further, the diameter of the bowl-shaped ultra-black carbon powder is 700-950 nm, and the diameter of the opening is 200-300 nm.

[0020] The third object of the present application is to provide a cage-shaped ultra-black carbon powder prepared by the above method, which is obtained by dissolving in ethylene glycol, and has an irregular porous hollow spherical shape.

[0021] Further, the diameter of the cage-shaped ultra-black carbon powder is 1-2.5 μm.

[0022] A fourth object of the present invention is to provide an ultra-black composite coating based on the above-mentioned bowl-shaped ultra-black carbon powder and cage-shaped ultra-black carbon powder.

[0023] A fifth object of the present invention is to provide a method for preparing an ultra-black composite coating based on the bowl-shaped ultra-black carbon powder and the cage-shaped ultra-black carbon powder, the method comprising the following steps:

[0024] The ultra-black carbon powder is mixed with PDMS, acetone and a curing agent, and then allowed to stand in a vacuum oven, and then heated and cured to obtain an ultra-black composite coating.

[0025] A sixth object of the present invention is to provide an application of the above-mentioned ultra-black composite coating in absorbing visible light and infrared waves.

[0026] Compared with the prior art, the present invention has the following significant effects:

[0027] The present invention provides two structurally adjustable ultra-black carbon powders with high light absorption properties and a preparation method thereof. The method first utilizes the self-assembly between melamine and cyanuric acid to obtain a hydrogen-bonded organic framework powder. At the same time, by adjusting the polarity of the reaction solvent, the hydrogen bond length and angle in the hydrogen-bonded organic framework can be effectively regulated, thereby achieving control over its structure. Further, the phenolic resin molecules are coated with secondary hydrogen bonds as a carbon source for subsequent calcination. During calcination, the melamine-cyanuric acid supramolecules undergo a dehydration polycondensation reaction, first forming a carbon nitride (C3N4) phase composed of triazine rings. When the calcination temperature rises, the triazine rings, due to their unstable sp 2 The hybrid C-N bonds are destroyed and begin to degrade until they are completely decomposed into gaseous carbon. At the same time, the carbon atoms in the outer phenolic resin molecules continue to rearrange, and the degree of carbonization continues to increase, ultimately forming a complex porous hollow structure. Its innovations are as follows:

[0028] (1) This invention utilizes a hydrogen-bonded organic framework precursor conversion strategy to produce ultra-black carbon powder after calcination. By simply controlling the reaction solvent, the material structure can be controlled and adjusted, resulting in two stable ultra-black carbon powders: bowl-shaped MB and cage-shaped MC. This process is simple and cost-effective.

[0029] (2) The bowl-shaped MB and cage-shaped MC super black carbon powders prepared in the present invention have a complex light-trapping structure. The micron / submicron-level inner cavity matches the wavelength of infrared / visible light. The porous irregular morphology is conducive to reducing the reflection of incident light and enhancing multiple scattering, thereby achieving strong light absorption. At the same time, the powder has good dispersibility in polymer organic rubber and has high processability.

[0030] (3) The ultra-black carbon powder produced by the present invention exhibits excellent dual-band infrared and visible light absorption properties. Thanks to its unique hierarchical structure, the maximum absorption rates in the short-wave, medium-wave, and long-wave infrared ranges reach 99.7%, 97.6%, and 98.7%, respectively. The maximum absorption rate for visible light is approximately 99.72%, achieving efficient dual-band absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Scanning electron microscope (SEM) images and transmission electron microscope (TEM) images of the bowl-shaped MB and cage-shaped MC super black carbon powders prepared in Examples 1-2; (a)-MB-SEM, (c)-MB-TEM, (b)-MC-SEM, (d)-MC-TEM;

[0032] Figure 2 (a) is an optical photograph of the bowl-shaped MB and cage-shaped MC ultra-black carbon powders prepared in Example 1-2 at a brightness of -10,000 lumens under high dynamic range camera shooting mode; Figure 2 (b) is a photo of the ultra-black composite coating obtained in Example 1;

[0033] Figure 3 X-ray diffraction (XRD) patterns of the bowl-shaped MB and cage-shaped MC ultra-black carbon powders prepared in Examples 1-2;

[0034] Figure 4 Visible light excitation Raman spectra of the bowl-shaped MB and cage-shaped MC ultra-black carbon powders prepared in Example 1-2;

[0035] Figure 5 The reflectivity of the bowl-shaped MB and cage-shaped MC super black carbon powders prepared in Examples 1-2 in the long-wave infrared and mid-wave infrared bands;

[0036] Figure 6 The reflectivity of the bowl-shaped MB and cage-shaped MC super black carbon powders prepared in Examples 1-2 in the ultraviolet-shortwave infrared wavelength range;

[0037] Figure 7 The reflectivity of the bowl-shaped MB and cage-shaped MC super black carbon powders prepared in Examples 1-2 within the visible light wavelength range. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used are conventional in the art and can be obtained commercially by those skilled in the art unless otherwise specified.

[0040] As used in the following examples, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0041] The endpoints of the ranges and any values ​​disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0042] Example 1:

[0043] The method for preparing the ultra-black composite coating based on bowl-shaped ultra-black carbon powder in this embodiment is carried out as follows:

[0044] (1) 1.50 g of melamine was added to 30 mL of dimethyl sulfoxide and stirred until completely dissolved to obtain a melamine solution. 1.52 g of cyanuric acid was added to 25 mL of dimethyl sulfoxide and stirred until completely dissolved to obtain a cyanuric acid solution. The obtained melamine solution was added dropwise to the obtained cyanuric acid solution and stirred for 10 minutes. The product was transferred to a vacuum filtration bottle, washed with 80°C hot water, and freeze-dried for 48 hours to obtain a hydrogen-bonded organic framework material.

[0045] (2) 0.5 g of the hydrogen-bonded organic framework product was added to 50 mL of anhydrous ethanol solution of phenolic resin (molecular weight 1000) with a concentration of 0.008 g / mL. After stirring for 12 h, the solid product was centrifuged and dried at 60 °C. It was then placed in a sealed porcelain boat and calcined in an argon atmosphere using a tubular furnace. It was first heated to 400 °C at a rate of 2 °C / min and kept warm for 2 h, then heated to 530 °C at a rate of 1 °C / min and kept warm for 3 h. Finally, it was continued to be heated to 750 °C at a rate of 1 °C / min and kept warm for 3 h. It was then cooled to room temperature with the furnace and a bowl-shaped ultra-black powder was collected and recorded as MB.

[0046] (3) 150 mg of ultra-black MB powder was mixed with 3 g of PDMS, 0.3 g of acetone, and 0.3 g of curing agent. The mixture was placed in a vacuum oven at 0.1 MPa and allowed to stand for 30 min. The mixture was then added to a mold and placed in a vacuum oven again and cured at 100°C for 1 h to obtain an ultra-black composite coating.

[0047] Example 2:

[0048] The preparation method of the ultra-black composite coating based on the cage-shaped ultra-black carbon powder in this embodiment is carried out by the following steps:

[0049] (1) 1.50 g of melamine was added to 60 mL of ethylene glycol and stirred at 80°C until completely dissolved to obtain a melamine solution. 1.52 g of cyanuric acid was added to 125 mL of ethylene glycol and stirred at 80°C until completely dissolved to obtain a cyanuric acid solution. The obtained melamine solution was added dropwise to the obtained cyanuric acid solution, and the mixture was stirred at 80°C for 10 min. The product was transferred to a vacuum filtration bottle, washed with 80°C hot water, and freeze-dried for 48 h to obtain a hydrogen-bonded organic framework material.

[0050] (2) Take 0.5g of hydrogen bond organic framework product and add it to 50mL of anhydrous ethanol solution of phenolic resin (molecular weight 1000) with a concentration of 0.008g / mL. After stirring for 12h, centrifuge to obtain a solid product, dry it at 60℃, then place it in a sealed porcelain boat, and calcine it in an argon atmosphere using a tubular furnace. First, heat it to 400℃ at a rate of 2℃ / min and keep it warm for 2h, then heat it to 530℃ at a rate of 1℃ / min and keep it warm for 3h, finally, continue to heat it to 750℃ at a rate of 1℃ / min and keep it warm for 3h, then cool it to room temperature with the furnace, collect the cage-shaped ultra-black powder, and record it as MC.

[0051] (3) 150 mg of ultra-black MC powder was mixed with 3 g of PDMS, 0.3 g of acetone, and 0.3 g of curing agent. The mixture was placed in a vacuum oven at 0.1 MPa and allowed to stand for 30 min. The mixture was then added to a mold and placed in a vacuum oven again and cured at 100°C for 1 h to obtain an ultra-black composite coating.

[0052] Figure 1 a, c are the SEM images and TEM images of the bowl-shaped MB microparticles prepared in Example 1. It can be seen from the figures that the bowl-shaped MB microparticles are irregular porous hollow spheres as a whole with a diameter of about 700-950 nm and an obvious opening with an opening diameter of about 200-300 nm.

[0053] Figure 1b and d are the SEM images and TEM images of the cage-like MC microparticles prepared in Example 2. It can be seen from the figures that the cage-like MC microparticles are also irregular porous hollow spheres as a whole, but the structure is complete and has no open structure. The diameter is about 2 μm.

[0054] Figure 2 Figure a shows a high dynamic range optical photograph of the bowl-shaped MB and cage-shaped MC super-black carbon powder samples prepared in Examples 1 and 2 at 10,000 lumens brightness. Compared to phthalocyanine-based black inks, as well as commercial super-black materials such as Musou Black 2.0 (99.4%) and Nacate Black 4.0 (99.0%), the MB and MC super-black carbon powders prepared in this invention exhibit higher black contrast to the naked eye.

[0055] Figure 2 b is a photo of the coating after the bowl-shaped MB super black carbon powder sample prepared in Example 1 was compounded with PDMS. It can be seen that the obtained coating still exhibits extremely high blackness.

[0056] Figure 3 Figure 2 shows the XRD spectra of the bowl-shaped MB and cage-shaped MC ultra-black carbon powders obtained in Example 1 and Example 2. The results show that both have typical amorphous characteristics. The diffraction peak near 2θ=25° comes from the (002) crystal plane of carbon, and the broad peak shape indicates that the order of carbon atoms is low.

[0057] Figure 4 The Raman spectra of the bowl-shaped MB and cage-shaped MC super black carbon powders obtained in Example 1 and Example 2 show that the peak positions and peak shapes of the D and G peaks of the two materials are almost identical, and the half-peak widths are also almost identical, which indicates that their microstructures are very consistent, with only differences in shape. The integrated intensities of the D and G peaks are calculated to obtain I D / I G The ratios of the two materials are 3.50 and 3.53, respectively, which again proves that their microstructures are highly similar. D / I G The value indicates that the degree of graphitization is very low.

[0058] Figure 5The reflectivity of the bowl-shaped MB and cage-shaped MC ultra-black carbon powder samples obtained in Example 1 and Example 2 in the long-wave (8-14μm) infrared and medium-wave (3-5μm) infrared bands. According to Kirchhoff's law, the absorptivity and emissivity are equal under thermal equilibrium. Therefore, it can be seen that the maximum absorptivity of the bowl-shaped MB and cage-shaped MC ultra-black carbon powder in the long-wave infrared band can reach 98.7%, and the average absorptivity in the entire long-wave infrared band can reach 98%. In the medium-wave infrared band, the absorptivity of both decreases to 97.6%. The absorptivity of the bowl-shaped MB in the entire medium-wave infrared band can reach 97.5%. Since the constructed bowl-shaped MB and cage-shaped MC particles have an irregular shape and a porous hollow structure, it is conducive to the entry of light waves into the interior of the material without emission. Subsequently, the strong light absorption in the long / medium-wave infrared band may come from the multiple scattering effect of light between particles.

[0059] Figure 6 The reflectivity of the bowl-shaped MB and cage-shaped MC ultra-black carbon powders obtained in Examples 1 and 2 within the UV-shortwave infrared wavelength range is shown. In the shortwave infrared band (850-2500 nm), both exhibit absorptivity exceeding 99%, with a maximum absorptivity reaching 99.7%. The cage-shaped MC exhibits stronger shortwave infrared absorption overall, likely due to the wavelength-matched diameter of the cage-shaped MC (approximately 2 μm), resulting in strong multiple reflections within the particles and achieving efficient shortwave infrared absorption.

[0060] Figure 7 The reflectivity of the bowl-shaped MB and cage-shaped MC ultra-black carbon powders obtained in Examples 1 and 2 across the visible light wavelength range is shown in Table 1. Both exhibit a reflectivity of less than 0.35% across the entire visible light band. For opaque objects, this means that the bowl-shaped MB and cage-shaped MC ultra-black carbon powders exhibit visible light absorptivity exceeding 99.65%. The bowl-shaped MB achieves a maximum absorptivity of 99.72%, exceeding the 99.70% for the cage-shaped MC. This is likely due to the bowl-shaped MB's size (700-800 nm) being more compatible with the wavelength, resulting in multiple light reflections.

[0061] Based on the above graphs and data analysis, this invention constructs structurally tunable ultra-black carbon powders, namely bowl-shaped MB and cage-shaped MC, through a hydrogen-bonded organic framework precursor conversion strategy. The complex, irregular, porous hollow structure promotes multiple reflections and scattering of light entering the material, achieving efficient visible and infrared dual-band absorption. The excellent absorption performance, simple preparation process, and low cost make this material promising for future applications and provide valuable insights and reference for the structural design of carbon-based ultra-black materials.

[0062] The foregoing are merely preferred embodiments of the present invention. These embodiments are all different implementations based on the overall concept of the present invention. The scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing ultra-black carbon powder with controllable morphology having infrared / visible light dual-band absorption properties, characterized in that: The method: S1: Melamine and cyanuric acid are dissolved in dimethyl sulfoxide or ethylene glycol, respectively, and then the melamine solution is dropwise added to the cyanuric acid solution, and the mixture is stirred for reaction. When dissolved in ethylene glycol, the mixture is stirred for reaction under heating conditions. After the reaction, the mixture is washed with hot water by suction filtration and freeze-dried to obtain a hydrogen-bonded organic framework. The mass ratio of melamine to cyanuric acid is 1.5:(1-2). When dissolved in dimethyl sulfoxide, the concentration of the melamine solution is 0.04-0.06 g / mL, and when dissolved in ethylene glycol, the concentration of the melamine solution is 0.02-0.03 g / mL. S2: adding the hydrogen-bonded organic framework to an anhydrous ethanol solution of phenolic resin, stirring the reaction, drying the solid product after centrifugation, and calcining it under a protective atmosphere to obtain ultra-black carbon powder. The mass ratio of the hydrogen-bonded organic framework to the phenolic resin is 0.5:(0.3-0.5).

2. The method according to claim 1, characterized in that When S1 is dissolved in dimethyl sulfoxide, the concentration of the cyanuric acid solution is 0.05-0.07 g / mL; when it is dissolved in ethylene glycol, the concentration of the cyanuric acid solution is 0.005-0.015 g / mL. The reaction is stirred at 70-90° C. and the stirring reaction time is 5-10 minutes.

3. The method according to claim 1, characterized in that The concentration of phenolic resin in the anhydrous ethanol solution of phenolic resin in S2 is 6-10 mg / mL, and the reaction is stirred for 10-12 hours. The calcination procedure is: first heat to 350-450℃ at a rate of 1-3℃ / min, keep warm for 1-2.5 hours, then heat to 500-550℃, keep warm for 2-4 hours, continue to heat to 700-800℃, keep warm for 1.5-4 hours, and cool to room temperature with the furnace after the insulation is completed.

4. Bowl-shaped super black carbon powder prepared by the method according to any one of claims 1 to 3, characterized in that: When dissolved in dimethyl sulfoxide, the bowl-shaped ultra-black carbon powder is obtained, which is in the shape of an irregular porous hollow sphere with openings on the sphere.

5. The bowl-shaped super black carbon powder according to claim 4, characterized in that: The bowl-shaped super black carbon powder has a diameter of 700-950nm and an opening diameter of 200-300nm.

6. The cage-shaped super black carbon powder prepared by the method according to any one of claims 1 to 3, characterized in that: When dissolved in ethylene glycol, the cage-like ultra-black carbon powder is obtained, which is in the shape of irregular porous hollow spheres.

7. The caged super black carbon powder according to claim 6, characterized in that: The diameter of cage-shaped super black carbon powder is 1-2.5μm.

8. An ultra-black composite coating made from ultra-black carbon powder prepared by the method according to any one of claims 1 to 3.

9. The method for preparing the ultra-black composite coating according to claim 8, characterized in that: The method: The ultra-black carbon powder is mixed with PDMS, acetone and a curing agent, and then allowed to stand in a vacuum oven, and then heated and cured to obtain an ultra-black composite coating.

10. Use of the ultra-black composite coating according to claim 8 in absorbing visible light and infrared waves.

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