Preparation method of CNTs-MXene-CF modified PDMS-based composite material

Abstract

The invention discloses a preparation method of a CNTs (carbon nanotubes)-MXene-CF (carbon nanotubes) modified PDMS (polydimethylsiloxane)-based composite material. CF is soaked in deionized water and subjected to first heat drying treatment, and pretreated CF is obtained; the preparation method comprises the following steps: adding MXene into deionized water, and carrying out ultrasonic dispersion for 1-3 hours to form an MXene dispersion liquid with the concentration of 0.002-0.2 g / L; immersing the pretreated CF into an MXene dispersion liquid, taking out the pretreated CF, and carrying out second thermal drying treatment to obtain an MXene-CF preform; the MXene-CF prefabricated body is put into a heat treatment furnace, the temperature is increased to 700-900 DEG C, and heat preservation is started; a mixed solution composed of absolute ethyl alcohol, ethanediamine and ferrocene is injected into the heat treatment furnace, carbon nanotubes grow in situ under the heat preservation condition, the temperature is reduced to the room temperature after the reaction is finished, and a multi-scale reinforcement is formed; dipping the multi-scale reinforcement in a mixed solution of a PDMS polymer and a curing agent to obtain a composite material preform; and carrying out degassing and curing treatment on the composite material preform. By introducing the multi-scale reinforcement of MXene and CNTs, the electromagnetic shielding effectiveness of the composite material is improved, and the key point is to optimize the combination of a three-dimensional network structure and an interface.

Description

Technical Field

[0001] The present application relates to the field of material technology, and in particular to a method for preparing a CNTs-MXene-CF modified PDMS-based composite material. Background Art

[0002] With the rapid development of technologies like 5G and the Internet of Things (IoT), the surge in the number of electronic devices has led to increasingly severe electromagnetic interference (EMI) issues. This has placed higher demands on electromagnetic shielding materials in terms of full-band coverage, performance stability, flexibility, adaptability, and environmental tolerance. However, traditional electromagnetic shielding materials (such as metal foils and conductive coatings) generally suffer from technical bottlenecks such as poor frequency band selectivity, insufficient mechanical flexibility, weak corrosion resistance, and high processing costs, making them difficult to meet the demands of complex electromagnetic environments and lightweight devices. Carbon nanotubes, with their one-dimensional nanostructure, high conductivity, and large aspect ratio, can effectively scatter and absorb electromagnetic waves by forming conductive networks. However, their dispersion and interfacial compatibility require further optimization. MXene materials, with their two-dimensional layered structure, high conductivity, and chemical / thermal stability, provide multiple reflection and absorption pathways for electromagnetic waves. However, they face challenges with mechanical strength. Their lamellar structure is prone to slippage and fracture when subjected to external forces, resulting in a decrease in mechanical properties and limiting their application in applications requiring high strength. Summary of the Invention

[0003] The embodiments of the present application solve the problems raised in the background technology by providing a method for preparing a CNTs-MXene-CF modified PDMS-based composite material.

[0004] The present embodiment provides a method for preparing a CNTs-MXene-CF modified PDMS-based composite material, comprising: S1: immersing CF in deionized water and performing a first thermal drying treatment to obtain pretreated CF; S2: Add MXene to deionized water and ultrasonically disperse it for 1-3 hours to form a MXene dispersion with a concentration of 0.005-0.2 g / L; S3: immersing the pretreated CF into the MXene dispersion, taking it out and subjecting it to a second thermal drying treatment to obtain a MXene-CF preform; S4: placing the MXene-CF preform into a heat treatment furnace under an argon protective atmosphere, heating it to 700-900° C. and starting to keep it warm; S5: injecting a mixed solution of anhydrous ethanol, ethylenediamine and ferrocene into the heat treatment furnace, in-situ growing carbon nanotubes under heat preservation conditions, and cooling to room temperature after the reaction to form a multi-scale reinforcement; S6: Immersing the multi-scale reinforcement in a mixture of a PDMS polymer and a curing agent at room temperature to obtain a composite material preform; degassing and curing the composite material preform to obtain a CNTs-MXene-CF modified PDMS-based composite material.

[0005] In a possible implementation, in S1, the first thermal drying treatment temperature is 50-200° C., and the time is 20-60 minutes.

[0006] In combination with the first aspect, in a possible implementation, in S2, the concentration of the MXene dispersion is 0.05 g / L.

[0007] In combination with the first aspect, in a possible implementation, in S3, the pretreated carbon fiber cloth is immersed in the MXene dispersion for 10-60 minutes, and the second thermal drying treatment temperature is 50-100° C. and the time is 5-30 minutes.

[0008] In a possible implementation, in S6, the mass ratio of the PDMS polymer to the curing agent is 10:1.

[0009] In a possible implementation, the curing agent is a silicon-based cross-linking agent.

[0010] In a possible implementation, in S5, the mixed solution is injected into the heat treatment furnace and reacted for 20-60 minutes under insulation conditions to in-situ grow carbon nanotubes, and then cooled to room temperature to form a multi-scale reinforcement.

[0011] In one possible implementation, in S4, under an argon protective atmosphere, the MXene-CF preform is placed in a heat treatment furnace, and the temperature is increased to 700-900° C. at a rate of 5° C. / min and maintained at this temperature.

[0012] In a possible implementation, in S6, the composite material preform is degassed in a vacuum drying oven and then cured in an air drying oven.

[0013] In one possible implementation, the MXene is .

[0014] One or more technical solutions provided in the embodiments of this application have at least the following technical effects: The CNTs-MXene-CF modified PDMS-based composite material prepared by the preparation method of the present application uses MXene sheets to uniformly coat carbon fiber cloth (CF) to form a dense conductive substrate. Its two-dimensional layered structure and high conductivity provide multiple reflection paths for electromagnetic waves, effectively enhancing the scattering and absorption capabilities of electromagnetic waves. On this basis, a three-dimensional network structure is constructed by in-situ growth of one-dimensional tubular carbon nanotubes (CNTs) using chemical vapor deposition. This three-dimensional network structure not only further extends the transmission path of electromagnetic waves and promotes multiple reflections and absorption of electromagnetic waves within the material, but also avoids the dispersion and agglomeration of CNTs through the in-situ growth process, improving the interfacial bonding strength and the continuity of the conductive network.

[0015] The synergistic effect of MXene and CNTs is the key to achieving full-band electromagnetic shielding in this composite material: the MXene flakes provide electromagnetic wave reflection and absorption within the two-dimensional plane, while the one-dimensional tubular shape of the CNTs enhances the dissipation of electromagnetic waves in the vertical direction through the spatial waveguide effect. The three-dimensional network structure formed by the two together constructs an electromagnetic wave attenuation mechanism covering the entire frequency band. At the same time, the carbon fiber cloth acts as a skeletal support structure, giving the composite material high strength and bending resistance; and the flexibility of the PDMS polymer further enhances the material's mechanical reliability and environmental adaptability, enabling it to meet the requirements of use in complex working conditions. By combining the multi-scale reinforcement (CNTs-MXene-CF) with the PDMS polymer, this application successfully solves the technical bottlenecks of traditional electromagnetic shielding materials, such as narrow frequency band coverage, poor flexibility, and weak interface bonding, providing a lightweight solution for high-frequency and high-speed electronic equipment that combines efficient shielding performance with mechanical reliability.

[0016] In terms of preparation process, this application has carried out strict degassing and curing treatment on the composite material preform. The internal pores of the material are eliminated by vacuum degassing, which improves the density and structural uniformity of the PDMS polymer; and the curing treatment further enhances the interfacial bonding strength, ensuring the environmental stability of the composite material during long-term use. This process optimization not only improves the electromagnetic shielding effectiveness and mechanical properties of the composite material, but also extends its service life, providing reliable guarantees for practical applications. Therefore, the CNTs-MXene-CF modified PDMS-based composite material prepared in the embodiment of the present application shows significant advantages in electromagnetic shielding, mechanical properties and environmental adaptability, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 This is an SEM image of the second pretreated CF prepared in Example 1; Figure 2 This is the SEM image of MXene-CF prepared in Example 2; Figure 3 This is a low-magnification SEM image of the CNTs-MXene-CF prepared in Example 3; Figure 4 This is the SEM high-magnification image of CNTs-MXene-CF prepared in Example 3. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0020] In the description of the embodiments of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present application. The terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0021] The present embodiment provides a method for preparing a CNTs-MXene-CF modified PDMS-based composite material, comprising steps S1-S6: S1: immersing CF (carbon fiber cloth) in deionized water and performing a first thermal drying treatment to obtain pretreated CF.

[0022] In the embodiment of the present application, in S1, the first thermal drying treatment temperature is 50-200° C. and the time is 20-60 minutes.

[0023] It should be noted that step S1 uses a first heat drying treatment at 50-200°C to pretreat the carbon fiber cloth (CF) soaked in deionized water. By precisely controlling the temperature and time parameters, it effectively removes moisture and residual impurities on the fiber surface to improve the interface cleanliness, while avoiding fiber structure damage and performance degradation caused by high temperature. At the same time, it optimizes the wettability of the fiber surface, creating ideal conditions for the uniform loading of subsequent functional coatings, while retaining the inherent high strength and high modulus properties of carbon fiber, so that it can fully play its reinforcing role in the final composite material.

[0024] S2: Add MXene to deionized water and ultrasonically disperse it for 1-3 hours to form a MXene dispersion with a concentration of 0.005-0.2 g / L.

[0025] Specifically, in the present embodiment, 0.001-0.01 g MXene is added to 50-200 ml of deionized water to form a MXene dispersion with a concentration of 0.005-0.2 g / L. .

[0026] This application achieves nanoscale dispersion of MXene flakes in solution, which not only avoids the attenuation of electromagnetic shielding performance caused by flake stacking at high concentrations, but also ensures sufficient MXene loading at low concentrations to form a continuous conductive network, thereby improving the electromagnetic wave reflection loss and interface conductivity of the composite material.

[0027] In the embodiment of the present application, in S2, the concentration of the MXene dispersion is 0.05 g / L.

[0028] S3: Immerse the pretreated CF in MXene dispersion, take it out and then perform a second thermal drying treatment to obtain a MXene-CF preform.

[0029] In the embodiment of the present application, in S3, the pretreated carbon fiber cloth is immersed in the MXene dispersion for 10-60 minutes, and the second thermal drying treatment temperature is 50-100°C for 5-30 minutes, achieving uniform loading and efficient curing of MXene on the fiber surface. Specifically, this combination of process parameters not only ensures the full penetration and adsorption of MXene sheets in the fiber gaps, forming a dense and continuous conductive coating, but also avoids oxidative degradation of MXene and damage to the fiber structure through low-temperature, short-term drying. At the same time, deionized water is quickly removed to maintain a strong interface bond between the coating and the fiber, ultimately improving the electromagnetic shielding effectiveness and mechanical properties of the MXene-CF preform, laying the structural foundation for the subsequent construction of a multi-scale reinforcement (CNTs-MXene-CF).

[0030] S4: Under an argon protective atmosphere, the MXene-CF preform is placed in a heat treatment furnace, heated to 700-900°C and started to be kept warm.

[0031] In the embodiment of the present application, in S4, the MXene-CF preform is placed in a heat treatment furnace under an argon protective atmosphere, and the temperature is raised to 700-900°C at a rate of 5°C / min and kept warm, thereby achieving multiple technical effects: first, the inert argon environment effectively isolates oxygen, preventing MXene from oxidative decomposition at high temperatures, ensuring that its two-dimensional lamellar structure and high conductivity are retained; second, the precise temperature control of 700-900°C not only promotes the chemical bonding between MXene and CF surface functional groups, strengthens the interfacial bonding force, but also avoids the degradation of the fiber mechanical properties caused by excessively high temperatures; finally, this process significantly improves the conductive stability and electromagnetic shielding effectiveness of the MXene-CF preform, while retaining the high strength characteristics of CF, providing a highly active and high-bonding-strength substrate for the subsequent in-situ growth of carbon nanotubes (CNTs), and synergistically optimizing the electromagnetic and mechanical properties of the composite material.

[0032] S5: A mixed solution of anhydrous ethanol, ethylenediamine and ferrocene is injected into the heat treatment furnace to in situ grow carbon nanotubes (CNTs) under heat preservation conditions. After the reaction is completed, the temperature is lowered to room temperature to form a multi-scale reinforcement (CNTs-MXene-CF).

[0033] In the embodiment of the present application, a mixed solution containing anhydrous ethanol, ethylenediamine and ferrocene is injected into a heat treatment furnace and reacted for 20-60 minutes under insulation conditions.

[0034] The 20-60 min reaction time ensures that the catalyst precursor (ferrocene) and carbon source (anhydrous ethanol) are fully decomposed and diffused to the fiber surface at high temperature, forming uniform CNT growth sites and avoiding insufficient growth due to too short a reaction time or CNT agglomeration caused by too long a reaction time. Ethylenediamine, as a growth aid, promotes the nucleation and directional growth of CNTs. Furthermore, CNTs grow in situ on the MXene-CF surface, constructing a three-dimensional network structure, improving the electromagnetic shielding effectiveness and electrical conductivity of the composite material. At the same time, the high aspect ratio and high strength characteristics of CNTs further enhance the tensile strength and toughness of the composite material.

[0035] S6: Immersing the multiscale reinforcement in a mixture of PDMS (polydimethylsiloxane) polymer and a curing agent at room temperature to obtain a composite preform. Degassing and curing the composite preform yields a CNTs-MXene-CF modified PDMS-based composite.

[0036] In the embodiment of the present application, in S6, the mass ratio of PDMS polymer to curing agent is 10:1.

[0037] In the embodiment of the present application, the curing agent is a silicon-based cross-linking agent.

[0038] In the embodiment of the present application, in S6, the composite material preform is degassed in a vacuum drying oven and then cured in an air drying oven.

[0039] It should be noted that by mixing PDMS polymer and curing agent in a mass ratio of 10:1 to prepare a solution, and selecting a silicon cross-linking agent as the curing agent, after impregnating the multi-scale reinforcement at room temperature to obtain a composite material preform, degassing treatment in a vacuum drying oven can effectively remove bubbles in the preform, thereby avoiding the adverse effects of bubbles on the performance of the composite material. After curing treatment in a blast drying oven, the composite material preform can be fully cured, and finally a CNTs-MXene-CF modified PDMS-based composite material with excellent performance is obtained.

[0040] It should be noted that the CNTs-MXene-CF-modified PDMS-based composite prepared by this method utilizes MXene sheets uniformly coated on carbon fiber (CF) to form a dense conductive substrate. Its two-dimensional lamellar structure and high conductivity provide multiple reflection paths for electromagnetic waves, effectively enhancing their scattering and absorption capabilities. Furthermore, a three-dimensional network structure is constructed by in situ growth of one-dimensional tubular carbon nanotubes (CNTs) using chemical vapor deposition. This 3D network not only further extends the transmission path of electromagnetic waves and promotes multiple reflections and absorption within the material, but also avoids the dispersion and agglomeration of CNTs through the in situ growth process, improving interfacial bonding strength and the continuity of the conductive network.

[0041] The synergistic effect of MXene and CNTs is the key to achieving full-band electromagnetic shielding in this composite material: the MXene flakes provide electromagnetic wave reflection and absorption within the two-dimensional plane, while the one-dimensional tubular shape of the CNTs enhances the dissipation of electromagnetic waves in the vertical direction through the spatial waveguide effect. The three-dimensional network structure formed by the two together constructs an electromagnetic wave attenuation mechanism covering the entire frequency band. At the same time, the carbon fiber cloth acts as a skeletal support structure, giving the composite material high strength and bending resistance; and the flexibility of the PDMS polymer further enhances the material's mechanical reliability and environmental adaptability, enabling it to meet the requirements of use in complex working conditions. By combining the multi-scale reinforcement (CNTs-MXene-CF) with the PDMS polymer, this application successfully solves the technical bottlenecks of traditional electromagnetic shielding materials, such as narrow frequency band coverage, poor flexibility, and weak interface bonding, providing a lightweight solution for high-frequency and high-speed electronic equipment that combines efficient shielding performance with mechanical reliability.

[0042] In terms of preparation process, this application has carried out strict degassing and curing treatment on the composite material preform. The internal pores of the material are eliminated by vacuum degassing, which improves the density and structural uniformity of the PDMS polymer; and the curing treatment further enhances the interfacial bonding strength, ensuring the environmental stability of the composite material during long-term use. This process optimization not only improves the electromagnetic shielding effectiveness and mechanical properties of the composite material, but also extends its service life, providing reliable guarantees for practical applications. Therefore, the CNTs-MXene-CF modified PDMS-based composite material prepared in the embodiment of the present application shows significant advantages in electromagnetic shielding, mechanical properties and environmental adaptability, and has broad application prospects.

[0043] Example 1: CF modified PDMS-based composite material The carbon fiber cloth (CF) was washed in deionized water and then dried in a forced air drying oven at 80°C for 30 minutes to obtain a first pretreated CF; The first pretreated CF was heat treated at 800°C for 40 min under an argon protective atmosphere and then cooled to room temperature to obtain a second pretreated CF. The second pretreated CF was immersed in a mixed solution of 5 g of PDMS polymer and 0.5 g of curing agent to form a composite preform; The CF-modified PDMS-based composite material was obtained by degassing in a vacuum drying oven and curing in a forced air drying oven.

[0044] A vector network analyzer was used to test the S parameters of the material, and the electromagnetic interference shielding effectiveness (EMI SE) was calculated based on this. The results showed that the EMI SE value of the CF-modified PDMS-based composite material in the X-band (8.2-12.4 GHz) was approximately 18.4 dB, and the electromagnetic shielding effectiveness was the weakest, proving the key role of MXene sheets in interfacial conductivity.

[0045] Example 2: MXene-CF modified PDMS-based composite material The carbon fiber cloth (CF) was immersed in deionized water for cleaning, and then dried in a forced air drying oven at 80°C for 30 min to obtain the pretreated CF; 0.005 g of MXene was added to 100 ml of deionized water and subjected to ultrasonic dispersion treatment for 2 h to obtain a MXene dispersion; After the pretreated CF was immersed in the MXene dispersion for 30 min, it was taken out and dried in a forced air drying oven at 80 °C for 20 min to obtain a MXene-CF preform; The MXene-CF preform was heat-treated under an argon protective atmosphere by heating the heat treatment furnace to 800°C and then performing a heat preservation treatment; After the heat treatment for 40 minutes, the temperature of the heat treatment furnace was lowered to room temperature to obtain MXene-modified carbon fiber (MXene-CF). At room temperature, MXene-CF was immersed in 10 g of PDMS polymer and 1 g of curing agent to form a composite preform; The composite material preform was degassed and cured using a vacuum drying oven and a forced air drying oven to obtain a MXene-CF modified PDMS-based composite material.

[0046] A vector network analyzer was used to test the material's S parameters, and the electromagnetic interference shielding effectiveness (EMI SE) was calculated based on the results. The results showed that the EMISE value of the MXene-CF modified PDMS-based composite material in the X-band (8.2-12.4 GHz) was approximately 21.2 dB. The electromagnetic shielding effectiveness was improved compared to Example 1, but still at a medium level.

[0047] Example 3: CNTs-MXene-CF modified PDMS-based composite material The carbon fiber cloth (CF) was immersed in deionized water for cleaning and then dried in a forced air drying oven at 80 °C for 30 min; 0.005 g of MXene was added to 100 ml of deionized water and subjected to ultrasonic dispersion treatment for 2 h to obtain a MXene dispersion; After the pretreated CF was immersed in the MXene dispersion for 30 min, it was taken out and dried in a forced air drying oven at 80 °C for 20 min to obtain a MXene-CF preform; Under an argon protective atmosphere, the MXene-CF preform was placed in a heat treatment furnace, heated to 800°C and kept warm; A mixed solution of anhydrous ethanol, ethylenediamine, and ferrocene was injected into a heat treatment furnace for 40 minutes to in situ grow carbon nanotubes. After the injection, the temperature of the heat treatment furnace was lowered to room temperature to obtain a multi-scale reinforcement of MXene and CNTs-modified carbon fibers (CNTs-MXene-CF). At room temperature, CNTs-MXene-CF was immersed in a solution containing 10 g of PDMS polymer and 1 g of curing agent to form a composite preform; The composite material preform was degassed and cured using a vacuum drying oven and a forced air drying oven to obtain a CNTs-MXene-CF modified PDMS-based composite material.

[0048] The S parameters of the material were tested using a vector network analyzer, and the electromagnetic interference shielding effectiveness (EMI SE) was calculated based on the results. The results showed that the EMI SE value of the CNTs-MXene-CF modified PDMS-based composite material in the X-band (8.2-12.4 GHz) was approximately 32.1 dB, and the electromagnetic shielding effectiveness was significantly better than that of Examples 1 and 2.

[0049] Since PDMS polymer itself is colorless and transparent, the appearance differences between different samples are difficult to clearly show when imaging, and the contrast effect of taking pictures is poor, so this application adopts Figures 1-4 The microscopic morphologies of the prepared carbon fibers (CF), MXene-CF, and CNTs-MXene-CF after the second pretreatment were compared.

[0050] Example 1 ( Figure 1 ): The surface of carbon fiber cloth is smooth and flat, with tiny grooves along the axial direction of the fiber.

[0051] Example 2 ( Figure 2 ): The introduction of MXene makes the surface of carbon fiber cloth rough. MXene nanosheets are stacked and covered on the carbon fiber surface at different angles and directions. The edges of some sheets are curled or raised, forming an uneven microstructure.

[0052] Example 3 ( Figure 3 and Figure 4One-dimensional tubular carbon nanotubes (CNTs) are evenly distributed on the surface of the carbon fiber cloth. The CNTs exhibit a typical tubular morphology, intertwining with each other to form an irregular network structure. The CNTs are randomly distributed on the carbon fiber surface and attached to the MXene-modified carbon fiber surface, further increasing the surface roughness and structural complexity of the composite. The introduction of this multi-scale reinforcement significantly improves the electromagnetic shielding effectiveness of the composite, with the optimization of the three-dimensional network structure and interface bonding being key factors.

[0053] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0054] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A method for preparing a CNTs-MXene-CF modified PDMS-based composite material, characterized in that: include: S1: immersing CF in deionized water and performing a first thermal drying treatment to obtain pretreated CF; S2: Add MXene to deionized water and ultrasonically disperse it for 1-3 hours to form a MXene dispersion with a concentration of 0.005-0.2 g / L; S3: immersing the pretreated CF into the MXene dispersion, taking it out and subjecting it to a second thermal drying treatment to obtain a MXene-CF preform; S4: placing the MXene-CF preform into a heat treatment furnace under an argon protective atmosphere, heating it to 700-900° C. and starting to keep it warm; S5: injecting a mixed solution of anhydrous ethanol, ethylenediamine and ferrocene into the heat treatment furnace, in-situ growing carbon nanotubes under heat preservation conditions, and cooling to room temperature after the reaction to form a multi-scale reinforcement; S6: Immersing the multi-scale reinforcement in a mixture of a PDMS polymer and a curing agent at room temperature to obtain a composite material preform; degassing and curing the composite material preform to obtain a CNTs-MXene-CF modified PDMS-based composite material.

2. The method for preparing the CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: In S1, the first thermal drying treatment temperature is 50-200° C. and the time is 20-60 minutes.

3. The method for preparing the CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: In S2, the concentration of the MXene dispersion is 0.05 g / L.

4. The method for preparing the CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: In S3, the pretreated carbon fiber cloth is immersed in the MXene dispersion for 10-60 minutes, and the second thermal drying treatment temperature is 50-100° C. and the time is 5-30 minutes.

5. The method for preparing the CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: In S6, the mass ratio of the PDMS polymer to the curing agent is 10:

1.

6. The method for preparing the CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: The curing agent is a silicon-based cross-linking agent.

7. The method for preparing a CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: In S5, the mixed solution is injected into the heat treatment furnace and reacted for 20-60 minutes under insulation conditions to in-situ grow carbon nanotubes, and then cooled to room temperature to form a multi-scale reinforcement.

8. The method for preparing a CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: In S4, under an argon protective atmosphere, the MXene-CF preform is placed in a heat treatment furnace, and the temperature is increased to 700-900° C. at a rate of 5° C. / min and kept warm.

9. The method for preparing a CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: In S6, the composite material preform is degassed in a vacuum drying oven and then cured in an air drying oven.

10. The method for preparing a CNTs-MXene-CF modified PDMS-based composite material according to claim 1, characterized in that: The MXene is .

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