Preparation method of wave-absorbing and heat-dissipating film and wave-absorbing and heat-dissipating film

Abstract

The embodiment of the invention provides a preparation method of a wave-absorbing and heat-dissipating film and the wave-absorbing and heat-dissipating film. The preparation method comprises the following steps: carrying out amination modification on Ti < 3 > C < 2 > T < x > powder to obtain NH < 2 >-Ti < 3 > C < 2 > T < x > powder; the preparation method comprises the following steps: carrying out carboxylation modification on the Fe3O4 nano particles to obtain the Fe3O4-COOH particles. And mixing the NH2-Ti3C2Tx powder with the Fe3O4-COOH particles, and carrying out an amidation condensation reaction, so as to obtain the Ti3C2Tx-Fe3O4 complex. The preparation method comprises the following steps: dissolving polyvinyl butyral in ethanol, and stirring and mixing to obtain a precursor solution; adding the Ti3C2Tx-Fe3O4 complex and hexagonal boron nitride powder into the precursor solution, and stirring and dispersing to obtain a composite glue solution; and coating a substrate with the composite glue solution, drying, curing, and stripping from the substrate to obtain the wave-absorbing and heat-dissipating film. Multiple interfaces exist between Ti3C2Tx-Fe3O4 and h-BN, electromagnetic waves are reflected and scattered for multiple times between the interfaces with different dielectric constants, and the electromagnetic waves are fully lost. H-BN cooperates with Ti3C2Tx-Fe3O4 to jointly form a stable heat conduction channel, so that heat is rapidly conducted to the surface of the wave-absorbing heat dissipation film from a heat source and dissipated, and the situation of local overheating is reduced.

Description

Technical Field

[0001] This application relates to the field of electromagnetic wave shielding technology, and in particular to a method for preparing a wave-absorbing and heat-dissipating thin film and the wave-absorbing and heat-dissipating thin film itself. Background Technology

[0002] As modern electronic devices rapidly evolve towards higher frequencies, higher power, and lighter weights, the coordinated design of thermal management and electromagnetic wave absorption has become increasingly urgent. In fields such as 5G communications, electric vehicles, and aerospace, the heat accumulation and electromagnetic interference problems generated by highly integrated electronic devices during high-speed operation are intertwined, making it difficult for traditional single-function materials to simultaneously meet the dual requirements of efficient heat dissipation and broadband electromagnetic protection. For example, the millimeter-wave band of 5G base stations requires materials with excellent electromagnetic shielding performance while also addressing the significant temperature rise challenge caused by high-power operation. Electric vehicle battery packs, on the other hand, have combined requirements for thermal management and electromagnetic stealth.

[0003] Iron(III) oxide (Fe3O4), a typical magnetic dielectric material, is widely used in electromagnetic wave absorption due to its unique magnetic loss mechanism and good impedance matching characteristics. However, as a magnetic semiconductor, the thermal conductivity of Fe3O4 mainly depends on phonon conduction, and the presence of Fe in its crystal structure... 2+ / Fe 3+ The disordered arrangement of cations strongly scatters phonons, resulting in low thermal conductivity, which limits their performance in thermal management-electromagnetic absorption synergistic applications. Summary of the Invention

[0004] This application aims to provide a method for preparing a microwave absorbing and heat dissipating film and the microwave absorbing and heat dissipating film, with the goal of improving the thermal conductivity of the microwave absorbing and heat dissipating film.

[0005] Firstly, this application proposes a method for preparing a microwave absorbing and heat dissipation thin film, including providing Ti3C2T x Powder, containing the Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x Powder; providing Fe3O4 nanoparticles, and modifying the Fe3O4 nanoparticles by carboxylation to obtain Fe3O4-COOH particles; and the NH2-Ti3C2T x The powder was mixed with the Fe3O4-COOH particles and then subjected to an amidation condensation reaction to obtain Ti3C2T. x -Fe3O4 complex; polyvinyl butyral is dissolved in ethanol, and after stirring and mixing, a precursor solution is obtained; the Ti3C2T x-Fe3O4 composite and hexagonal boron nitride powder are added to the precursor solution and stirred and dispersed to obtain a composite adhesive. The composite adhesive is coated on a substrate, and after drying and curing, it is peeled off from the substrate to obtain a microwave absorbing and heat dissipation film.

[0006] In some embodiments, the Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x Powder, comprising: Ti3C2T x The powder was dispersed in dimethylformamide, a silane coupling agent was added, and the mixture was refluxed at 60°C to 100°C for 4 to 8 hours. After washing and drying, NH2-Ti3C2T was obtained. x ; wherein, the Ti3C2T x The mass ratio of the powder to the silane coupling agent is 1:(5~15).

[0007] In some embodiments, the carboxylation modification of the Fe3O4 nanoparticles to obtain Fe3O4-COOH particles includes: dispersing the Fe3O4 nanoparticles in a sodium citrate solution, stirring at a temperature of 50°C to 70°C for 10 h to 14 h, and obtaining Fe3O4-COOH particles after standing, washing, and drying; wherein the concentration of the sodium citrate solution is 0.05 mol / L to 0.2 mol / L.

[0008] In some embodiments, the NH2-Ti3C2T x The powder was mixed with the Fe3O4-COOH particles, and Ti3C2T was obtained through an amidation condensation reaction. x -Fe3O4 complex, comprising: dispersing Fe3O4-COOH particles in a buffer solution, activating with a carbodiimide compound and N-hydroxysuccinimide, and then reacting with NH2-Ti3C2T x The powders were mixed and reacted under an inert atmosphere for 10 to 14 hours to obtain a precipitate. The precipitate was then washed and dried to obtain Ti3C2T. x -Fe3O4 complex; wherein the molar ratio of the Fe3O4-COOH particles, the carbodiimide compound and the N-hydroxysuccinimide is 1: (1.5~2.5): (0.8~1.2).

[0009] In some embodiments, the buffer solution includes an MES buffer solution.

[0010] In some embodiments, the mass-to-volume ratio of polyvinyl butyral to ethanol is 1:(8~10).

[0011] In some embodiments, the Ti3C2T x The mass ratio of the Fe3O4 composite to the hexagonal boron nitride powder is (0.5~2):1.

[0012] In some embodiments, the drying conditions include: drying for 0.5 h to 1.5 h in a vacuum environment at a temperature of 40°C to 60°C; the stirring and dispersion conditions include: a rotation speed of 2500 rpm to 3500 rpm for 20 min to 40 min.

[0013] In some embodiments, the provision of Ti3C2T x The powder includes: Ti3C2T x The wafer was added to the etching solution and stirred at 35°C to 40°C for 24 to 48 hours to obtain a mixture. The mixture was washed with deionized water until neutral, then sonicated and centrifuged to obtain the precipitate. The precipitate was then vacuum dried to obtain Ti3C2T. x powder.

[0014] Secondly, embodiments of this application also provide a microwave absorbing and heat dissipation film, which is prepared using the microwave absorbing and heat dissipation film preparation method as described in any one of the first aspects.

[0015] Unlike existing technologies, this application provides a method for preparing a microwave absorbing and heat dissipation thin film. This preparation method includes providing Ti3C2T... x Powder, Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x Powder. Fe3O4 nanoparticles are provided, and carboxylation modification is performed on the Fe3O4 nanoparticles to obtain Fe3O4-COOH particles. NH2-Ti3C2T x The powder was mixed with Fe3O4-COOH particles and then subjected to an amidation condensation reaction to obtain Ti3C2T. x -Fe3O4 complex. Polyvinyl butyral was dissolved in ethanol, and after stirring and mixing, a precursor solution was obtained. Ti3C2T x Fe3O4 composite and hexagonal boron nitride powder were added to a precursor solution and stirred to disperse, obtaining a composite adhesive. The composite adhesive was coated onto a substrate, dried, cured, and then peeled off from the substrate to obtain a microwave absorbing and heat dissipating film. (Ti3C2T) x The -Fe3O4 complex achieves chemical bonding through amide bonds, forming a stable electromagnetic heterostructure. Simultaneously, Ti3C2T xMultiple interfaces exist between Fe3O4 and h-BN, allowing electromagnetic waves to undergo multiple reflections and scatterings between interfaces with different dielectric constants, ultimately resulting in significant loss. h-BN exhibits high thermal conductivity and excellent insulation properties, similar to Ti3C2T. x Fe3O4 is co-dispersed in the precursor solution. After coating and drying, the precursor solution solidifies to form a continuous microwave absorbing and heat dissipating film. h-BN synergistically reacts with Ti3C2T x -Fe3O4 particles together form a stable heat-conducting channel, allowing heat to be rapidly conducted from the heat source to the surface of the microwave-absorbing heat dissipation film and dissipated, reducing localized overheating. The microwave-absorbing heat dissipation film integrates microwave absorption and heat dissipation, improving the integration and reliability of the microwave-absorbing product.

[0016] Additional aspects and advantages of the embodiments of this application will be described, shown, or illustrated in part by way of implementation of the embodiments of this application in the following description. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0018] Figure 1 A flowchart of some methods for preparing microwave absorbing and heat dissipation thin films provided in this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0020] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0022] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0023] The technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0024] Firstly, this application proposes a method for preparing a microwave absorbing and heat dissipation thin film, please refer to... Figure 1 The preparation method includes the following steps: Step S1: Provide Ti3C2T x Powder, Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x powder.

[0025] Ti3C2T x MXene is a two-dimensional layered transition metal carbide with unique electrical, optical, and mechanical properties, including high electrical conductivity and a large specific surface area. In this designation, "Ti" represents titanium, "C" represents carbon, and "T" represents titanium. x "" indicates functional groups on the surface of the material, which are typically -OH (hydroxyl), -F (fluorine), or -O (oxygen), etc. As an electromagnetic wave absorbing material, Ti3C2T x Electromagnetic waves can be attenuated through methods such as conductive loss, multiple reflections, or polarization loss.

[0026] In some embodiments, Ti3C2T is provided x The powder includes: Ti3C2T x The wafer was added to the etching solution and stirred at 35°C to 40°C for 24 to 48 hours to obtain a mixture. The mixture was washed with deionized water until neutral, then sonicated and centrifuged to obtain the precipitate. The precipitate was then vacuum dried to obtain Ti3C2T. x Powder. The etching solution consists of lithium fluoride and hydrochloric acid.

[0027] If Ti3C2T x When powder and Fe3O4 nanoparticles are directly mixed, only a weak physical adsorption force exists between them, making them easy to separate. Through amination modification, the Ti3C2T... x The type of functional groups on the powder surface makes Ti3C2T x The powder is stably bonded to Fe3O4 nanoparticles.

[0028] Amination modification refers to the introduction of amino (-NH2) functional groups into Ti3C2T through chemical methods. x The surface of Ti3C2T is modified by amino functional groups. x The properties of Ti3C2T x The powder and Fe3O4 nanoparticles are bonded together by covalent bonds, which improves the stability of the material.

[0029] In some embodiments, Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x Powder, including Ti3C2T x The powder was dispersed in dimethylformamide (DMF), a silane coupling agent was added, and the mixture was refluxed at 60°C to 100°C for 4 to 8 hours. After washing and drying, NH2-Ti3C2T was obtained. x Among them, Ti3C2T x The mass ratio of powder to silane coupling agent is 1:(5~15).

[0030] In some embodiments, the silane coupling agent is 3-aminopropyltriethoxysilane (APTES).

[0031] Step S2: Provide Fe3O4 nanoparticles and modify them with carboxylation to obtain Fe3O4-COOH particles.

[0032] Iron(III) oxide is a magnetic black crystal that is often used as a magnetic dielectric material. It efficiently dissipates electromagnetic wave energy through various magnetic loss mechanisms such as magnetic loss, natural resonance, and exchange resonance.

[0033] Carboxylation modification refers to the introduction of carboxyl (-COOH) functional groups into the surface of Fe3O4 nanoparticles through chemical methods. This alters the properties of the Fe3O4 nanoparticles by changing the carboxyl functional groups, thus enabling the modification of Ti3C2T... x The powder and Fe3O4 nanoparticles are bonded together by covalent bonds, which improves the stability of the material.

[0034] In some embodiments, Fe3O4 nanoparticles are carboxylated to obtain Fe3O4-COOH particles. This includes dispersing Fe3O4 nanoparticles in a sodium citrate solution, stirring at 50°C to 70°C for 10 to 14 hours, and then allowing them to stand, washing, and drying to obtain Fe3O4-COOH particles. The concentration of the sodium citrate solution is 0.05 mol / L to 0.2 mol / L.

[0035] In some embodiments, the particle size of Fe3O4 nanoparticles is 20 nm to 50 nm. The natural resonance frequency of magnetic particles is closely related to their size. A particle size range of 20 nm to 50 nm allows the resonance peak of Fe3O4 nanoparticles to be modulated into the main frequency bands of radar waves and microwave communications, thereby achieving a high magnetic loss frequency within these bands. Nanoscale Fe3O4 has a relatively large specific surface area, which can increase its interaction with electromagnetic waves, enhance dielectric loss, and facilitate the interaction between Fe3O4-COOH particles and NH2-Ti3C2T. x Numerous interfaces are formed on the contact surfaces of powders. These interfaces trap charge carriers, causing interfacial polarization and increasing electromagnetic wave loss.

[0036] If the particle size of Fe3O4 nanoparticles is too large, and Fe3O4 itself is magnetic, a large number of Fe3O4 nanoparticles will attract each other and clump together, causing the Fe3O4 nanoparticles to interact with Ti3C2T. x The powder cannot bind well. When the particle size of Fe3O4 nanoparticles is 20nm to 50nm, Fe3O4 nanoparticles are more easily intercalated into Ti3C2T. x The layered structure and surface form a denser and more uniform electro-magnetic synergistic network.

[0037] Step S3: Add NH2-Ti3C2T x The powder was mixed with Fe3O4-COOH particles and then subjected to an amidation condensation reaction to obtain Ti3C2T. x -Fe3O4 complex.

[0038] Amide condensation is a chemical process in which a carboxyl group (-COOH) and an amino group (-NH2) react to remove a water molecule (H2O) and form an amide bond (-CO-NH-).

[0039] In some embodiments, NH2-Ti3C2T x The powder was mixed with Fe3O4-COOH particles, and Ti3C2T was obtained through an amidation condensation reaction. x -Fe3O4 complex, comprising dispersing Fe3O4-COOH particles in a buffer solution, activating with a carbodiimide compound and N-hydroxysuccinimide, and then reacting with NH2-Ti3C2T x The powders are mixed and reacted under an inert atmosphere for 10 to 14 hours to obtain a precipitate. The precipitate is then washed and dried to obtain Ti3C2T. x -Fe3O4 complex. The molar ratio of Fe3O4-COOH particles, carbodiimide compounds and N-hydroxysuccinimide is 1: (1.5~2.5): (0.8~1.2).

[0040] Buffer solutions can maintain the reaction system at a pH range of 5.5 to 6.5, maximizing the activation efficiency of Fe3O4-COOH. For example, a MES buffer solution can be used. 2-Morpholinoethanesulfonic acid (MES) buffer solution is a commonly used biochemical buffer, typically with a pH buffering range between 5.5 and 7.0. MES buffer solutions are characterized by high stability and low cytotoxicity, and are widely used in molecular biology and biochemistry.

[0041] It is understandable that if NH2-Ti3C2T is directly used... x When mixed with Fe3O4-COOH, the reaction is extremely slow and inefficient. The carboxyl group itself has low reactivity and is difficult to react rapidly with amino groups. Carbodiimides are a commonly used class of dehydrating agents, and N-hydroxysuccinimide (NHS) is a co-activator. Carbodiimides and N-hydroxysuccinimide can synergistically react with NH2-Ti3C2T x The amidation condensation reaction with Fe3O4-COOH.

[0042] Specifically, the carboxyl group on the surface of the carbodiimide compound Fe3O4-COOH reacts to generate a highly reactive O-acylisourea intermediate. NHS immediately reacts with the O-acylisourea intermediate to generate a very stable and even more reactive NHS ester, NH2-Ti3C2T. x The amino groups on the surface are nucleophilic and attack the carbonyl carbon atom on the activated NHS ester to form an amide bond (-CO-NH-), releasing NHS molecules. Ultimately, the Fe3O4 nanoparticles are covalently bonded to Ti3C2T. x superior.

[0043] In some embodiments, carbodiimide compounds include 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC).

[0044] Step S4: Dissolve polyvinyl butyral in ethanol, stir and mix to obtain a precursor solution.

[0045] Polyvinyl butyral (PVB) is a resin with excellent transparency, good solubility, and good film-forming properties. PVB can form films with high transparency, flexibility, and excellent mechanical properties. The precursor solution can effectively wet and encapsulate subsequently added powdered materials and reduce their sedimentation.

[0046] In some embodiments, the mass-to-volume ratio of polyvinyl butyral to ethanol is 1:(8~10) to form a solution with moderate viscosity, uniformity, and transparency.

[0047] Step S5: Ti3C2T x -Fe3O4 composite and hexagonal boron nitride powder are added to the precursor solution and stirred to disperse, thus obtaining a composite adhesive.

[0048] Hexagonal boron nitride is a two-dimensional layered material composed of boron and nitrogen atoms. It is both an insulator and a good thermal conductor, exhibiting high heat resistance and maintaining lubricity and chemical stability at high temperatures. It does not react with most molten metals, acids, or alkalis. The hexagonal boron nitride powder obtained in this application can also be replaced with cubic boron nitride (c-BN), which has similar functions to hexagonal boron nitride.

[0049] High-speed stirring can provide strong shear force, effectively breaking down Ti3C2T. x The agglomeration of -Fe3O4 complex and hexagonal boron nitride (h-BN) powder makes Ti3C2T x -Fe3O4 complex and hexagonal boron nitride powder are uniformly distributed in the precursor solution at nano or micron sizes.

[0050] In some embodiments, the stirring and dispersion conditions include: a rotation speed of 2500 rpm to 3500 rpm and a time of 20 min to 40 min.

[0051] In some embodiments, Ti3C2T x The mass ratio of Fe3O4 composite to hexagonal boron nitride powder is (0.5~2):1.

[0052] The Ti3C2T in the embodiments of this application x The primary function of the Fe3O4 complex is to absorb electromagnetic waves and provide dielectric and magnetic losses. Hexagonal boron nitride powder mainly provides thermal conductivity pathways to achieve rapid heat transfer. When Ti3C2T... x When the content of the Fe3O4 composite is high, the prepared microwave absorbing and heat dissipation film has stronger electromagnetic wave absorption performance and can more effectively attenuate electromagnetic wave energy. However, the thermal conductivity of the microwave absorbing and heat dissipation film is relatively weak, and the continuity of the thermal conduction path is poor. When the content of hexagonal boron nitride powder is high, the thermal conductivity of the microwave absorbing and heat dissipation film is better, and the formed thermal conduction path is more efficient and more continuous. However, the electromagnetic wave absorption performance is poor. Therefore, when the content of Ti3C2T x When the mass ratio of Fe3O4 complex to hexagonal boron nitride powder is (0.5~2):1, especially for Ti3C2T... x When the ratio of Fe3O4 composite to hexagonal boron nitride powder is 1:1, the microwave absorbing and heat dissipation film simultaneously possesses excellent microwave absorption and heat dissipation properties.

[0053] Step S6: Apply the composite adhesive to the substrate, and after drying and curing, peel it off from the substrate to obtain a microwave absorbing and heat dissipation film.

[0054] The composite adhesive can be evenly spread on the substrate by coating, allowing Ti3C2T to achieve its desired consistency. x The Fe3O4 complex and hexagonal boron nitride powder maintain a uniform dispersion in the precursor solution, reducing the Ti3C2T content. x - The phenomenon of Fe3O4 complex agglomeration with hexagonal boron nitride powder.

[0055] In some embodiments, the substrate may be made of glass, aluminum plate, stainless steel plate, etc.

[0056] In some embodiments, the drying conditions include: drying in a vacuum environment at a temperature of 40°C to 60°C for a duration of 0.5 h to 1.5 h; This application provides a method for preparing a microwave absorbing and heat dissipating thin film. The preparation method includes providing Ti3C2T... x Powder, Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x Powder. Fe3O4 nanoparticles are provided, and carboxylation modification is performed on the Fe3O4 nanoparticles to obtain Fe3O4-COOH particles. NH2-Ti3C2T x The powder was mixed with Fe3O4-COOH particles and then subjected to an amidation condensation reaction to obtain Ti3C2T. x -Fe3O4 complex. Polyvinyl butyral was dissolved in ethanol, and after stirring and mixing, a precursor solution was obtained. Ti3C2T x Fe3O4 composite and hexagonal boron nitride powder were added to a precursor solution and stirred to disperse, obtaining a composite adhesive. The composite adhesive was coated onto a substrate, dried, cured, and then peeled off from the substrate to obtain a microwave absorbing and heat dissipating film. (Ti3C2T) x The -Fe3O4 complex achieves chemical bonding through amide bonds, forming a stable electromagnetic heterostructure. Simultaneously, Ti3C2T x Multiple interfaces exist between Fe3O4 and h-BN, allowing electromagnetic waves to undergo multiple reflections and scatterings between interfaces with different dielectric constants, ultimately resulting in significant loss. h-BN exhibits high thermal conductivity and excellent insulation properties, similar to Ti3C2T. x Fe3O4 is co-dispersed in the precursor solution. After coating and drying, the precursor solution solidifies to form a continuous microwave absorbing and heat dissipating film. h-BN synergistically reacts with Ti3C2T x-Fe3O4 particles together form a stable heat-conducting channel, allowing heat to be rapidly conducted from the heat source to the surface of the microwave-absorbing heat dissipation film and dissipated, reducing localized overheating. The microwave-absorbing heat dissipation film integrates microwave absorption and heat dissipation, improving the integration and reliability of the microwave-absorbing product.

[0057] Secondly, embodiments of this application also provide a microwave absorbing and heat dissipation film, which is prepared using the microwave absorbing and heat dissipation film preparation method as described in any embodiment of the first aspect.

[0058] The preparation method of the microwave absorbing and heat dissipation thin film is described below with reference to specific embodiments: Example 1 (1) Take 1 g of Ti3C2T x The powder was dispersed in 30 mL of DMF, and then 10 g of APTES and Ti3C2T were added. x The mixture was refluxed at 80 °C for 6 h with APTES at a mass ratio of 1:10, then washed three times with anhydrous ethanol to remove unreacted APTES. After centrifugation, the first powder at the bottom was collected and baked in a vacuum oven at 80 °C for 3 h to obtain NH2-Ti3C2T. x powder.

[0059] (2) 1g of Fe3O4 particles with a particle size of 50 nm were placed in 30 mL of sodium citrate solution with a concentration of 0.1 M. After stirring at 60 °C for 12 h, the mixture was allowed to stand for 2 h. The first solid layer was taken out and washed three times with anhydrous ethanol. Then, it was placed in a vacuum oven at 80 °C and baked for 3 h to obtain Fe3O4-COOH particles.

[0060] (3) Disperse 1 g of Fe3O4-COOH in MES buffer, add EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) and NHS (N-hydroxysuccinimide), activate at room temperature for 30 minutes, and then react with 1 g of NH2-Ti3C2T x The powders were mixed and reacted under nitrogen protection for 12 h. The precipitate at the bottom was removed, and the mixture was washed three times by centrifugation with anhydrous ethanol to remove unreacted reagents, yielding Ti3C2T. x -Fe3O4 composite. The molar ratio of Fe3O4-COOH particles, EDC, and NHS is Fe3O4-COOH particles:EDC:NHS = 1:2:1.

[0061] (4) Add 2 g of PVB particles to 18 mL of ethanol and stir for 4 h until a clear precursor solution is formed. Add 1 g of Ti3C2T x-Fe3O4 powder and 1 g of h-BN powder were added to the precursor solution and stirred at 3000 rpm for 30 min to obtain a composite adhesive. The adhesive was uniformly coated on glass and baked in a vacuum oven at 45 ℃ for 1 h. The film on the glass was then peeled off to obtain a microwave absorbing and heat dissipating film.

[0062] Example 2 (1) Take 1 g of Ti3C2T x The powder was dispersed in 30 mL of DMF, and then 15 g of APTES and Ti3C2T were added. x The mixture was refluxed with APTES at a mass ratio of 1:15 at 80 °C for 6 h, then washed three times with anhydrous ethanol to remove unreacted APTES. After centrifugation, the first powder at the bottom was collected and baked in a vacuum oven at 80 °C for 3 h to obtain NH2-Ti3C2T. x powder.

[0063] (2) 1g of Fe3O4 particles with a particle size of 20 nm were placed in 30 mL of sodium citrate solution with a concentration of 0.15 M. After stirring at 60 °C for 12 h, the mixture was allowed to stand for 2 h. The first solid layer was taken out and washed three times with anhydrous ethanol. Then, it was placed in a vacuum oven at 80 °C and baked for 3 h to obtain Fe3O4-COOH particles.

[0064] (3) Disperse 1 g of Fe3O4-COOH in MES buffer, add EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) and NHS (N-hydroxysuccinimide), activate at room temperature for 30 minutes, and then react with 1 g of NH2-Ti3C2T x The powders were mixed and reacted under nitrogen protection for 12 h. The precipitate at the bottom was removed, and the mixture was washed three times by centrifugation with anhydrous ethanol to remove unreacted reagents, yielding Ti3C2T. x -Fe3O4 composite. The molar ratio of Fe3O4-COOH particles, EDC, and NHS is Fe3O4-COOH particles:EDC:NHS = 1:2:1.

[0065] (4) Add 3 g of PVB particles to 17 mL of ethanol and stir for 4 h until a clear precursor solution is formed. Add 1 g of Ti3C2T x -Fe3O4 powder and 1 g of h-BN powder were added to the precursor solution and stirred at 3000 rpm for 30 min to obtain a composite adhesive. The adhesive was uniformly coated on glass and baked in a vacuum oven at 45 ℃ for 1 h. The film on the glass was then peeled off to obtain a microwave absorbing and heat dissipating film.

[0066] Comparative Example 1 (1) Take 1 g of Ti3C2T x The powder was dispersed in 30 mL of DMF, and then 10 g of APTES and Ti3C2T were added. x The mixture was refluxed at 80 °C for 6 h with APTES at a mass ratio of 1:10, then washed three times with anhydrous ethanol to remove unreacted APTES. After centrifugation, the first powder at the bottom was collected and baked in a vacuum oven at 80 °C for 3 h to obtain NH2-Ti3C2T. x powder.

[0067] (2) 1g of Fe3O4 particles with a particle size of 50 nm were placed in 30 mL of sodium citrate solution with a concentration of 0.1 M. After stirring at 60 °C for 12 h, the mixture was allowed to stand for 2 h. The first solid layer was taken out and washed three times with anhydrous ethanol. Then, it was placed in a vacuum oven at 80 °C and baked for 3 h to obtain Fe3O4-COOH particles.

[0068] (3) Disperse 1 g of Fe3O4-COOH in MES buffer, add EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) and NHS (N-hydroxysuccinimide), activate at room temperature for 30 minutes, and then react with 1 g of NH2-Ti3C2T x The powders were mixed and reacted under nitrogen protection for 12 h. The precipitate at the bottom was removed, and the mixture was washed three times by centrifugation with anhydrous ethanol to remove unreacted reagents, yielding Ti3C2T. x -Fe3O4 composite. The molar ratio of Fe3O4-COOH particles, EDC, and NHS is Fe3O4-COOH particles:EDC:NHS = 1:2:1.

[0069] (4) Add 2 g of PVB particles to 18 mL of ethanol and stir for 4 h until a clear precursor solution is formed. Add 1 g of Ti3C2T x Fe3O4 powder was added to the precursor solution and stirred at 3000 rpm for 30 min to obtain a composite adhesive. The adhesive was then uniformly coated onto glass and baked in a vacuum oven at 45 ℃ for 1 h. The film on the glass was then peeled off to obtain a microwave absorbing and heat dissipating film.

[0070] The microwave absorption and heat dissipation films prepared in Examples 1, 2, and 1 (Comparative Example 1) were tested for microwave absorption performance and thermal conductivity, respectively. The microwave absorption performance results and thermal conductivity of the different examples and comparative examples are shown in Table 1.

[0071] Table 1

[0072] Based on the absorption performance test results, by comparing the above embodiments and comparative examples, the minimum reflection loss value RLmin of the absorbing heat dissipation film in Embodiment 1 is -42.5dB. The minimum reflection loss value RLmin of the absorbing heat dissipation film in Embodiment 2 is -38.6dB. The minimum reflection loss value RLmin of the absorbing heat dissipation film in Comparative Example 1 is -33.5dB. It can be seen that the absorbing heat dissipation films in Embodiments 1 and 2 have strong absorption capabilities for electromagnetic waves, effectively reducing the radiation effect of electromagnetic waves.

[0073] Based on the thermal conductivity test results, and by comparing the above embodiments and comparative examples, the thermal conductivity of the microwave absorbing heat dissipation film in Embodiment 1 is 5.38 W / (m·K). The thermal conductivity of the microwave absorbing heat dissipation film in Embodiment 2 is 5.25 W / (m·K). The thermal conductivity of the microwave absorbing heat dissipation film in Comparative Example 1 is 1.55 W / (m·K). It can be seen that the microwave absorbing heat dissipation films in Embodiments 1 and 2 have good thermal conductivity and strong thermal conductivity.

[0074] By comparing the thermal conductivity of Example 1 and Comparative Example 1, Example 1, by introducing h-BN powder, demonstrates that h-BN exhibits high thermal conductivity and can react with Ti3C2T. x -Fe3O4 forms a continuous thermally conductive network, accelerating heat transfer. Therefore, the thermal conductivity in Example 1 is significantly better than that in Comparative Example 1 without the introduction of h-BN.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a microwave absorbing and heat dissipation thin film, characterized in that, include: Provide Ti3C2T x Powder, containing the Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x powder; Fe3O4 nanoparticles are provided, and the Fe3O4 nanoparticles are modified by carboxylation to obtain Fe3O4-COOH particles; The NH2-Ti3C2T x The powder was mixed with the Fe3O4-COOH particles and then subjected to an amidation condensation reaction to obtain Ti3C2T. x -Fe3O4 complex; Polyvinyl butyral was dissolved in ethanol and stirred to obtain a precursor solution. The Ti3C2T x -Fe3O4 composite and hexagonal boron nitride powder are added to the precursor solution and stirred and dispersed to obtain composite colloid; The composite adhesive is applied to a substrate, and after drying and curing, it is peeled off from the substrate to obtain a microwave absorbing and heat dissipation film.

2. The preparation method according to claim 1, characterized in that, The Ti3C2T x The powder was aminated to obtain NH2-Ti3C2T x Powder, including: The Ti3C2T x The powder was dispersed in dimethylformamide, a silane coupling agent was added, and the mixture was refluxed at 60°C to 100°C for 4 to 8 hours. After washing and drying, NH2-Ti3C2T was obtained. x ; Among them, the Ti3C2T x The mass ratio of the powder to the silane coupling agent is 1:(5~15).

3. The preparation method according to claim 1, characterized in that, The process of carboxylating the Fe3O4 nanoparticles to obtain Fe3O4-COOH particles includes: The Fe3O4 nanoparticles were dispersed in a sodium citrate solution and stirred at 50°C to 70°C for 10 to 14 hours. After standing, washing, and drying, Fe3O4-COOH particles were obtained. The concentration of the sodium citrate solution is from 0.05 mol / L to 0.2 mol / L.

4. The preparation method according to claim 1, characterized in that, The NH2-Ti3C2T x The powder was mixed with the Fe3O4-COOH particles, and Ti3C2T was obtained through an amidation condensation reaction. x -Fe3O4 complex, including: The Fe3O4-COOH particles were dispersed in a buffer solution, activated by adding a carbodiimide compound and N-hydroxysuccinimide, and then reacted with the NH2-Ti3C2T x The powders were mixed and reacted under an inert atmosphere for 10 to 14 hours to obtain a precipitate. The precipitate was then washed and dried to obtain Ti3C2T. x -Fe3O4 complex; The molar ratio of the Fe3O4-COOH particles, the carbodiimide compound, and the N-hydroxysuccinimide is 1: (1.5~2.5): (0.8~1.2).

5. The preparation method according to claim 4, characterized in that, The buffer solution includes MES buffer.

6. The preparation method according to claim 1, characterized in that, The mass-to-volume ratio of the polyvinyl butyral to the ethanol is 1:(8~10).

7. The preparation method according to claim 1, characterized in that, The Ti3C2T x The mass ratio of the Fe3O4 composite to the hexagonal boron nitride powder is (0.5~2):

1.

8. The preparation method according to claim 1, characterized in that, The drying conditions include: drying in a vacuum environment at a temperature of 40°C to 60°C for a duration of 0.5 h to 1.5 h; The stirring and dispersion conditions include: a rotation speed of 2500 rpm to 3500 rpm and a time of 20 min to 40 min.

9. The preparation method according to claim 1, characterized in that, The provided Ti3C2T x The powder includes: Ti3C2T x The wafer is added to the etching solution and stirred at 35°C to 40°C for 24 to 48 hours to obtain a mixture. The mixture was washed with deionized water until neutral, then sonicated and centrifuged to obtain the precipitate. The precipitate was then vacuum dried to obtain Ti3C2T. x powder.

10. A microwave absorbing and heat dissipation thin film, characterized in that, It is prepared by the method for preparing the microwave absorbing and heat dissipation thin film as described in any one of claims 1 to 9.

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