MXene-carbon fiber composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of electromagnetic shielding materials, in particular to an MXene-carbon fiber composite material and a preparation method and application thereof. The MXene-carbon fiber composite material is prepared from carbon fibers, a high-molecular polymer and an MXene material, the mass ratio of the carbon fiber to the high-molecular polymer to the MXene material is (40-65): (20-40): (1-20); the carbon fibers are carbon fiber unidirectional cloth or carbon fiber gridding cloth; the carbon fiber gridding cloth is any one of plain weave, satin weave and twill weave; warps in the carbon fiber unidirectional cloth are carbon fiber yarns, and wefts are chemical fiber or natural fiber yarns. The shielding material has a good electromagnetic shielding effect and a good microwave absorption effect, and also has a good shielding effect at a low frequency band or ultrahigh frequency, and the introduction of the MXene material improves the overall mechanical property, wear resistance and weather resistance, and expands the application range of the shielding material.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding materials, and in particular to an MXene-carbon fiber composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Carbon fiber CF has the advantages of high strength, high modulus, corrosion resistance, fatigue resistance, etc., and is widely used in various fields such as aerospace, automobiles, wind power blades, construction industry, sports and leisure products, and pressure vessels. Carbon fiber CF is made by high-temperature treatment (such as carbonization, graphitization, etc.) and has good electrical conductivity, and can be used as an electromagnetic shielding material. The electrical conductivity of carbon fiber CF mainly stems from the special structure and arrangement of its carbon atoms. The carbon atoms in the carbon fiber are combined by covalent bonds to form long-chain molecules, which have a certain orientation and arrangement in the fiber axis. Its structure is similar to that of graphite and has a certain delocalized electron system. The delocalized electrons can carry and transport charges to a certain extent, thereby endowing the carbon fiber with electrical conductivity.

[0003] At present, the production method of carbon fiber composite materials is based on a carbon fiber prepreg tape formed by carbon fiber / epoxy resin, and is made by a hand lay-up molding process or a compression molding process. The electromagnetic shielding performance of the prepared carbon fiber composite material is limited, and the electromagnetic shielding performance is limited to the GHz frequency band, while the above carbon fiber composite material has a poor shielding effect on the low-frequency band or ultra-high frequency. Therefore, the present invention provides an MXene-carbon fiber composite material, a preparation method thereof, and an application thereof. Summary of the Invention

[0004] In order to solve the defect that the electromagnetic shielding performance of the existing carbon fiber composite material is limited, its electromagnetic shielding performance is limited to the GHz frequency band, and the shielding effect on the low-frequency band or ultra-high frequency is poor; the present invention provides an MXene-carbon fiber composite material, a preparation method thereof, and an application thereof.

[0005] An MXene-carbon fiber composite material provided by the present invention is achieved through the following scheme:

[0006] An MXene-carbon fiber composite material comprises carbon fiber, a polymer, and an MXene material. The content of the MXene material in the MXene-carbon fiber composite material is 0.5-15 wt%; the carbon fiber is a carbon fiber unidirectional fabric or a carbon fiber grid fabric; the carbon fiber grid fabric is any one of a plain weave, a satin weave, and a twill weave; the warp of the carbon fiber unidirectional fabric is a carbon fiber yarn, and the weft is a chemical fiber or natural fiber yarn.

[0007] The MXene-carbon fiber composite material in the present invention has good electromagnetic shielding effect and microwave absorption effect, and also has good shielding effect in the low-frequency band or ultra-high frequency. Moreover, the introduction of the MXene material improves the overall mechanical properties, wear resistance and weather resistance, and expands its application scope.

[0008] Preferably, the structural formula of the MXene material is M n+1 X n T x , where n = 1-4, M is a transition metal, and M includes at least one of Ti, Al, Mo, V, and Sn; X is C and / or N, and T is a surface group, and T is O or OH.

[0009] Preferably, the MXene material is a hydrophilic modified MXene nanosheet. The hydrophilic modified Ti3AlC2 nanosheet is prepared by the method of HF chemical etching and LiCl intercalation exfoliation of Ti3AlC2 powder. The time of HF chemical etching is 24-120 h, and the time of LiCl intercalation exfoliation is 4-48 h.

[0010] More preferably, the MXene material is a Fe3O4 grafted modified MXene nanosheet.

[0011] In the present invention, the hydrophilic property of the Fe3O4 grafted modified MXene nanosheet facilitates its dispersion in polar solutions, and further facilitates the uniform dispersion of the MXene material in the aqueous polymer emulsion, improving the processing performance and environmental protection performance of the carbon fiber composite material. It can ensure the mechanical properties, weather resistance, wear resistance, and electromagnetic shielding performance of the prepared carbon fiber composite material, and has a good electromagnetic shielding effect in the low-frequency band or ultra-high frequency.

[0012] Preferably, the preparation method of the Fe3O4 grafted modified MXene nanosheet is as follows:

[0013] First, Ti3AlC2 nanosheets are prepared by the method of HF chemical etching and LiCl intercalation exfoliation of Ti3AlC2 powder;

[0014] Then, 1-5 g of Ti3AlC2 nanosheets are dissolved in 50-100 mL of ethanol, 0.1-0.5 g of FeC2O4·2H2O is added, and ultrasonic dispersion is carried out at 40-80 °C for 1-3 h. After the iron source is completely dissolved, the ethanol is removed by heating;

[0015] Finally, the obtained material is dried and then transferred to a tubular furnace. Under nitrogen protection, it is heated to 500-550 °C at a rate of 10-20 °C / min and calcined for 3-4 h.

[0016] The preparation method of the Fe3O4 grafted modified Ti3AlC2 nanosheet in the present invention is simple and convenient for batch production.

[0017] Preferably, the carbon fiber is a carbon fiber mesh cloth with a grammage of 200-400 g / m 2 .

[0018] Preferably, the carbon fiber yarn woven in the carbon fiber mesh cloth is any one of 3K T300, 6K T300, 6K T400, and 12K T700.

[0019] Preferably, the MXene-carbon fiber composite further includes a synergist.

[0020] Preferably, the content of the synergist is 0.5-10 wt%.

[0021] Preferably, the synergist is at least one of carbon fiber, carbon nanotube, silicon carbide whisker, and graphene.

[0022] By adopting the above technical solution, the mechanical properties, weather resistance, wear resistance, electromagnetic shielding performance, and electromagnetic shielding range of the prepared carbon fiber composite can be improved.

[0023] Preferably, the polymer is formed by curing an aqueous polymer emulsion, and the aqueous polymer emulsion is at least one of an aqueous polyurethane resin, an aqueous acrylate, an aqueous acrylate-modified polyurethane resin, and an aqueous polyurethane-modified acrylate.

[0024] By adopting the above technical solution, the hydrophilic MXene material can be uniformly dispersed in the aqueous polymer emulsion, thereby ensuring the electromagnetic shielding performance of the prepared carbon fiber composite, and the preparation process can be optimized to improve the production environmental protection performance.

[0025] A preparation method of an MXene-carbon fiber composite provided by the present invention is realized through the following technical solutions:

[0026] A preparation method of an MXene-carbon fiber composite includes the following steps:

[0027] Step 1, preparation of MXene material: The MXene powder is prepared into an MXene material by a method of HF chemical etching and LiCl intercalation exfoliation:

[0028] Step 2, mixing the aqueous polymer emulsion, additives, and the MXene material in Step 1 evenly to obtain a prepreg. The additives include a leveling agent, an antifoaming agent, a thickening agent, an antioxidant, and an ultraviolet absorber;

[0029] Step 3, scraping the prepreg in Step 2 onto the surface of the carbon fiber, evaporating the water, and curing at 20-45 °C for 12-48 h to obtain an MXene-carbon fiber prepreg sheet;

[0030] Step 4: Stack the MXene-carbon fiber prepreg sheets into a MXene-carbon fiber preform according to the designed thickness, and then perform hot molding on the MXene-carbon fiber preform to obtain the MXene-carbon fiber molded special-shaped part.

[0031] The preparation method of the present invention is relatively simple, the preparation process is mature, and it is convenient to realize industrial production.

[0032] A MXene-carbon fiber composite material has good electromagnetic shielding performance. It not only has good electromagnetic interference performance in the intermediate frequency, but also has good shielding effect electromagnetic interference performance in the low frequency band or ultra-high frequency. It is applied to the fields of 6G communication, automobiles, radar detection, drones, stealth aircraft, microwave anechoic chambers, and military communication equipment.

[0033] In summary, the present invention has the following advantages:

[0034] 1. The MXene-carbon fiber composite material in the present invention has good electromagnetic shielding effect and microwave absorption effect. It not only has good electromagnetic interference performance in the intermediate frequency, but also has good shielding effect in the low frequency band or ultra-high frequency, solving the problem that the electromagnetic shielding performance of the existing carbon fiber composite material is limited, its electromagnetic shielding performance is limited to the GHz frequency band, and the shielding effect is poor in the low frequency band or ultra-high frequency.

[0035] 2. The introduction of the MXene material in the present invention not only improves the broadband electromagnetic interference performance, but also improves the overall mechanical properties, wear resistance and weather resistance of the carbon fiber composite, expanding its application range.

[0036] 3. The preparation method of the present invention is relatively simple, the preparation process is mature, and it is convenient to realize industrial production. Detailed Embodiments

[0037] In order to further understand the creativity and technological progress of the present invention, the preferred implementation schemes of the present invention will be discussed in detail below in combination with examples and comparative examples.

[0038] Example

[0039] A MXene-carbon fiber composite material is composed of carbon fiber, polymer and MXene material. The content of the MXene material in the MXene-carbon fiber composite material is 0.5-15 wt%. Among them, the content of the MXene material is adjusted according to the requirements of the application scenario. For application scenarios with high electromagnetic shielding requirements, the thickness of the MXene-carbon fiber composite material and the content of the MXene material can be adjusted to improve the electromagnetic shielding effect of the MXene-carbon fiber composite material, and thus the application requirements of customers can be customized.

[0040] Preferably, the MXene-carbon fiber composite material comprises carbon fiber, synergist, polymer, and MXene material. The content of the synergist in the MXene-carbon fiber composite material affects the overall electrical conductivity. The addition of the synergist improves the three-dimensional cross-linked conductive network structure in the MXene-carbon fiber composite material, thereby uniformly enhancing the electrical conductivity, electromagnetic shielding performance, and thermal conductivity of the MXene-carbon fiber composite material.

[0041] The content of the synergist is 0.5-10 wt%. Preferably, the content of the synergist is 4-8 wt%.

[0042] The synergist is at least one of carbon fiber, carbon nanotube, silicon carbide whisker, and graphene. Preferably, the synergist is graphene combined with at least one of carbon fiber, carbon nanotube, and silicon carbide whisker with a high aspect ratio, which can better build a three-dimensional cross-linked conductive network structure and improve the overall electrical and thermal conductivity and electromagnetic shielding performance.

[0043] The polymer in the MXene-carbon fiber composite material is formed by curing an aqueous polymer emulsion.

[0044] The aqueous polymer emulsion is at least one of aqueous polyurethane resin, aqueous acrylate, aqueous acrylate-modified polyurethane resin, and aqueous polyurethane-modified acrylate.

[0045] Preferably, the aqueous polymer emulsion is aqueous acrylate.

[0046] The MXene material is a hydrophilic modified MXene nanosheet. Specifically, the surface groups of the MXene nanosheet are -O or -OH, which can make it uniformly dispersed in the aqueous polymer emulsion and improve the mechanical properties, wear resistance, weather resistance, electromagnetic interference resistance, and microwave absorption performance of the prepared carbon fiber composite material.

[0047] The structural formula of the MXene material is as follows M n+1 X n T x , n = 1-4, where M is a transition metal, M includes at least one of Ti, Al, Mo, V, and Sn; X is C and / or N, and T is a surface group, T is O or OH.

[0048] Preferably, the MXene material is a hydrophilic modified MXene nanosheet.

[0049] The MXene material is hydrophilic modified MXene nanosheets, which are prepared by the method of HF chemical etching and LiCl intercalation exfoliation of Ti3AlC2 powder. Among them, the time of HF chemical etching is 24 - 120 h, and the time of LiCl intercalation exfoliation is 4 - 48 h. Prolonging the time of HF chemical etching and LiCl intercalation exfoliation can improve the exfoliation layer number of MXene nanosheets, which is beneficial to improving the overall electromagnetic shielding performance, but it will also increase the production cost.

[0050] Further preferably, the MXene material is Fe3O4 grafted modified MXene nanosheets.

[0051] The preparation method of Fe3O4 grafted modified MXene nanosheets is as follows: First, Ti3AlC2 nanosheets are prepared by the method of HF chemical etching and LiCl intercalation exfoliation of Ti3AlC2 powder. Then, 1 - 5 g of Ti3AlC2 nanosheets are dissolved in 50 - 100 mL of ethanol, 0.1 - 0.5 g of FeC2O4·2H2O is added, and ultrasonic dispersion is carried out at 40 - 80 °C for 1 - 3 h. After the iron source is completely dissolved, the ethanol is removed by heating. The obtained material is dried and then transferred to a tube furnace. Under nitrogen protection, it is heated to 500 - 550 °C at a rate of 10 - 20 °C / min and calcined for 3 - 4 h.

[0052] For the Fe3O4 grafted modified Ti3AlC2 nanosheets prepared by the above method, the requirements for the time of HF chemical etching and LiCl intercalation exfoliation of Ti3AlC2 nanosheets are relatively low. Fe3O4 produced by the sol - gel method has relatively more active residues - OH, which can improve the hydrophilicity of Fe3O4 grafted modified Ti3AlC2 nanosheets. It not only optimizes the preparation process of Ti3AlC2 nanosheets, but also the carbon fiber composite material prepared by it has a better electromagnetic shielding effect, and has a relatively good shielding effect in the low - frequency band or ultra - high - frequency band.

[0053] The carbon fiber is carbon fiber unidirectional cloth or carbon fiber grid cloth, and different specifications of carbon fiber unidirectional cloth or carbon fiber grid cloth are selected according to the use scenario.

[0054] When the carbon fiber is carbon fiber grid cloth, the carbon fiber grid cloth is any one of plain weave, satin weave, and twill weave. The carbon fiber grid cloth has a gram weight of 200 - 400 g / m 2 , and the specification of the carbon fiber yarn woven in the carbon fiber grid cloth is any one of 3KT300, 6K T300, 6K T400, and 12K T700.

[0055] When the carbon fiber is a unidirectional carbon fiber cloth, the warp in the unidirectional carbon fiber cloth is a carbon fiber yarn, and the weft is a chemical fiber or natural fiber yarn. The specification of the carbon fiber yarn as the warp in the unidirectional carbon fiber cloth is any one of 3K T300, 6K T300, 6K T400, and 12K T700. The chemical fiber in the weft of the unidirectional carbon fiber cloth can be selected from polyester, spandex, aramid, polypropylene, ultra-high molecular weight polyethylene fiber, etc. The natural fiber yarn can be selected from cotton thread, linen thread, silk fiber, binder fiber, soybean protein fiber, etc.

[0056] A preparation method of an MXene-carbon fiber composite material includes the following steps:

[0057] Step 1, preparation of MXene material: The MXene powder is prepared into MXene material by the method of HF chemical etching and LiCl intercalation peeling:

[0058] Step 2, mixing an aqueous polymer emulsion, an auxiliary agent and the MXene material in Step 1 evenly to obtain a prepreg, and the auxiliary agent includes a leveling agent, an antifoaming agent, a thickening agent, an antioxidant, and an ultraviolet absorber;

[0059] Step 3, scraping the prepreg in Step 2 on the surface of the carbon fiber, evaporating to remove moisture, and curing at 20-45 °C for 12-48 h to obtain an MXene-carbon fiber prepreg sheet;

[0060] Step 4, stacking the MXene-carbon fiber prepreg sheets into an MXene-carbon fiber prefabricated board according to the designed thickness, and performing hot molding treatment on the MXene-carbon fiber prefabricated board to obtain an MXene-carbon fiber molded special-shaped part. The prepared MXene-carbon fiber molded special-shaped part is used in the fields of 6G communication, automobiles, radar detection, unmanned aerial vehicles, stealth aircraft, microwave anechoic chambers, and military communication equipment, and can achieve excellent electromagnetic shielding effects, have excellent electromagnetic interference performance in the intermediate frequency (GHz), and also have good shielding effect electromagnetic interference performance in the low frequency band (kHz, MHz) or ultra-high frequency (THz).

[0061] Example 1: A preparation method of an MXene-carbon fiber composite material includes the following steps:

[0062] Step 1, preparation of MXene material:

[0063] S1.1. HF Chemical Etching: Under magnetic stirring at 120 rpm, add 24 mL of hydrochloric acid aqueous solution with a concentration of 9 M and 5 mL of HF solution with a concentration of 40 wt% to 12 mL of deionized water, maintain the temperature at 35 °C and mix evenly to obtain the chemical etching solution. Under magnetic stirring, divide 2 g of Ti3AlC2 powder (Chihhe New Materials Technology Nanjing Co., Ltd., 600 mesh) into 5 portions of MXene unit powder. Add one portion of 0.4 g of MXene unit powder to the chemical etching solution every 15 minutes. After adding all the MXene powder, maintain the temperature at 35 °C and etch for 24 h under magnetic stirring. Centrifuge and wash the obtained mixture with deionized water until the liquid and solid are neutral. Discard the supernatant and retain the precipitate. The obtained precipitate is HF chemically etched and modified MXene;

[0064] S1.2. LiCl Intercalation and Exfoliation: Add the HF chemically etched and modified MXene in S1 and 2 g of LiCl to 125 mL of deionized water, maintain the temperature at 35 °C, and perform intercalation and exfoliation for 4.0 h under magnetic stirring at 120 rpm. Then, perform multiple centrifugation + washing treatments on the intercalated and exfoliated suspension. The specific operations are as follows: First, centrifuge at a speed of 5000 rpm for 120 s, pour out the upper clear liquid and retain the precipitate, manually shake well with deionized water, add deionized water with a mass equal to 25 times the mass of the retained precipitate, continue to centrifuge at a speed of 5000 rpm for 120 s, pour out the upper clear liquid and retain the precipitate, repeat the washing and centrifugation operations twice. Then, manually shake well the obtained retained precipitate with deionized water to obtain a suspension, centrifuge at a speed of 8000 rpm for 180 s, pour out the upper clear liquid and retain the precipitate, add deionized water with a mass equal to 25 times the mass of the retained precipitate, shake well and centrifuge at a speed of 3500 rpm for 120 s, pour out the upper clear liquid and retain the precipitate. Dry the obtained solid to obtain MXene nanosheets:

[0065] Step 2: Mix 184 g of a finished waterborne acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether-modified silicone leveling agent SSL-320, and 5 g of the MXene nanosheets in Step 1 to obtain a prepreg;

[0066] Mix the waterborne acrylate resin (BASF JONCRYL 678, effective ingredient content 98.7%) with deionized water to obtain a finished waterborne acrylate resin with a solid content of 50 wt%;

[0067] Step 3: Knife-coat the prepreg in Step 2 on the upper and lower surfaces of a carbon fiber grid cloth (gram weight 300 g / m 2 , a carbon fiber mesh cloth woven from Toray 6K T300 carbon fiber yarn, plain weave structure, thickness 0.167 mm). The single-sided coating amount of the prepreg is 85 g / m 2After evaporating the water, the MXene-carbon fiber prepreg was obtained by aging at 40°C for 24 hours;

[0068] Step 4: Take four MXene-carbon fiber prepreg sheets and stack them into a MXene-carbon fiber prefabricated board, and perform hot molding treatment on the MXene-carbon fiber prefabricated board. The hot molding treatment parameters are: pressure 10MPa, temperature 85°C, and hot pressing time 30min. A MXene-carbon fiber molded plate with a thickness of 1.0mm can be obtained, and the content of MXene nanosheets in the MXene-carbon fiber molded plate is 1.3w%.

[0069] The anti-electromagnetic interference performance of the MXene-carbon fiber molded plate with a thickness of 1.0 mm in Example 1: EMI shielding efficiency (8-12 GHz frequency) is >80 dB, EMI shielding efficiency (10 kHz-1.0 GHz frequency) is >40 dB, and EMI shielding efficiency (100 GHz-1.0 THz frequency) is >40 dB.

[0070] The difference between Example 2 and Example 1 is: S1.1. HF chemical etching in step 1 of the preparation method of MXene-carbon fiber composite material: under 120rpm magnetic stirring, add 24mL of 9M hydrochloric acid aqueous solution and 5mL of 40wt% HF solution to 12mL deionized water, maintain the mixture at 35°C and mix evenly to obtain a chemical etching solution, under magnetic stirring, divide 2g of Mo2Ti2C3 powder (Xi'an Qiyue Biotechnology Co., Ltd.) into 5 portions of MXene unit powder, add 0.4g of MXene unit powder to the chemical etching solution every 15min, after the MXene powder is added, maintain the temperature at 35°C, etch for 24h under magnetic stirring, centrifuge the obtained mixed solution, wash until the liquid is neutral, remove the supernatant and retain the precipitate, the obtained precipitate is HF chemical etching modified MXene, and the remaining steps are the same.

[0071] The anti-electromagnetic interference performance of the MXene-carbon fiber molded plate with a thickness of 1.0 mm in Example 2: EMI shielding efficiency (8-12 GHz frequency) is >70 dB; EMI shielding efficiency (10 kHz-1.0 GHz frequency) is >40 dB, and EMI shielding efficiency (100 GHz-1.0 THz frequency) is >40 dB.

[0072] The difference between Example 3 and Example 1 is: S1.1. HF chemical etching in step 1 of the preparation method of MXene-carbon fiber composite material: under 120rpm magnetic stirring, add 24mL of 9M hydrochloric acid aqueous solution and 5mL of 40wt% HF solution to 12mL deionized water, maintain the mixture at 35°C and mix evenly to obtain a chemical etching solution, under magnetic stirring, divide 2g of Ti2SnC powder (Xi'an Qiyue Biotechnology Co., Ltd.) into 5 portions of MXene unit powder, add 0.4g of MXene unit powder to the chemical etching solution every 15min, after the MXene powder is added, maintain the temperature at 35°C, etch for 24h under magnetic stirring, centrifuge the obtained mixed solution, wash until the liquid is neutral, remove the supernatant and retain the precipitate, the obtained precipitate is HF chemical etching modified MXene, and the remaining steps are the same.

[0073] The anti-electromagnetic interference performance of the MXene-carbon fiber molded plate with a thickness of 1.0 mm in Example 3: EMI shielding efficiency (8-12 GHz frequency) is >70 dB, EMI shielding efficiency (10 kHz-1.0 GHz frequency) is >40 dB, and EMI shielding efficiency (100 GHz-1.0 THz frequency) is >40 dB.

[0074] The difference between Example 4 and Example 1 is that in step 2 of the preparation method of MXene-carbon fiber composite material, 190g of finished water-based acrylic resin with a solid content of 50wt%, 2g of silicone defoamer FoamStar SI 2292, 1g of polyether modified siloxane leveling agent SSL-320, and 2g of MXene nanosheets in step 1 are mixed uniformly to obtain a prepreg. The content of MXene nanosheets in the obtained MXene-carbon fiber molded plate is 0.52w%.

[0075] The anti-electromagnetic interference performance of the MXene-carbon fiber molded plate with a thickness of 1.0 mm in Example 4: EMI shielding efficiency (8-12 GHz frequency) is >60 dB, EMI shielding efficiency (10 kHz-1.0 GHz frequency) is >30 dB, and EMI shielding efficiency (100 GHz-1.0 THz frequency) is >30 dB.

[0076] The difference between Example 5 and Example 1 is that in step 2 of the preparation method of MXene-carbon fiber composite material, 178g of finished water-based acrylic resin with a solid content of 50wt%, 2g of silicone defoamer FoamStar SI 2292, 1g of polyether modified siloxane leveling agent SSL-320, and 8g of MXene nanosheets in step 1 are mixed uniformly to obtain a prepreg. The content of MXene nanosheets in the obtained MXene-carbon fiber molded plate is 2.08w%.

[0077] Electromagnetic interference shielding performance of the MXene-carbon fiber compression-molded sheet with a thickness of 1.0 mm in Example 5: EMI shielding efficiency (8 - 12 GHz frequency) > 70 dB, EMI shielding efficiency (10 kHz - 1.0 GHz frequency) > 40 dB, EMI shielding efficiency (100 GHz - 1.0 THz frequency) > 40 dB.

[0078] The difference between Example 6 and Example 1 lies in Step 2 of the preparation method of the MXene-carbon fiber composite material. 168 g of a finished aqueous acrylate resin with a solid content of 50 wt%, 2.5 g of an organosilicon defoamer FoamStar SI 2292, 1.5 g of a polyether-modified silicone leveling agent SSL-320, and 12 g of the MXene nanosheets in Step 1 are mixed evenly to obtain a prepreg. The content of MXene nanosheets in the obtained MXene-carbon fiber compression-molded sheet is 3.12 w%.

[0079] Electromagnetic interference shielding performance of the MXene-carbon fiber compression-molded sheet with a thickness of 1.0 mm in Example 6: EMI shielding efficiency (8 - 12 GHz frequency) > 75 dB, EMI shielding efficiency (10 kHz - 1.0 GHz frequency) > 45 dB, EMI shielding efficiency (100 GHz - 1.0 THz frequency) > 40 dB.

[0080] The difference between Example 7 and Example 1 lies in Step 2 of the preparation method of the MXene-carbon fiber composite material. 151 g of a finished aqueous acrylate resin with a solid content of 50 wt%, 3 g of an organosilicon defoamer FoamStar SI 2292, 2 g of a polyether-modified silicone leveling agent SSL-320, and 19.5 g of the MXene nanosheets in Step 1 are mixed evenly to obtain a prepreg. The content of MXene nanosheets in the obtained MXene-carbon fiber compression-molded sheet is 5.06 w%.

[0081] Electromagnetic interference shielding performance of the MXene-carbon fiber compression-molded sheet with a thickness of 1.0 mm in Example 7: EMI shielding efficiency (8 - 12 GHz frequency) > 75 dB, EMI shielding efficiency (10 kHz - 1.0 GHz frequency) > 50 dB, EMI shielding efficiency (100 GHz - 1.0 THz frequency) > 40 dB.

[0082] The difference between Example 8 and Example 1 lies in Step 2 of the preparation method of the MXene-carbon fiber composite material. 182 g of a finished aqueous acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether-modified silicone leveling agent SSL-320, and 1 g of graphene (hydroxylated graphene TimesGraph TM, Purity: >98 wt%, Thickness: 0.55 - 3.74 nm, Diameter: 0.5 - 3 microns, Number of layers: <10 layers, Oxygen content: >10 wt%, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences). 5 g of the MXene nanosheets in Step 1 were mixed evenly to obtain a prepreg.

[0083] The electromagnetic interference shielding performance of the MXene - carbon fiber molded sheet with a thickness of 1.0 mm in Example 8: The EMI shielding efficiency (8 - 12 GHz frequency) is >70 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is >45 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is >40 dB.

[0084] The difference between Example 9 and Example 1 lies in Step 2 of the preparation method of the MXene - carbon fiber composite material. 182 g of a finished aqueous acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether - modified silicone leveling agent SSL - 320, 1 g of carbon nanotubes (high - purity multi - walled carbon nanotubes MWCNTs, model TNMH0, outer diameter: 4 - 8 nm, length 10 - 20 microns, oxygen content 5.57 wt%, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences), and 5 g of the MXene nanosheets in Step 1 were mixed evenly to obtain a prepreg.

[0085] The electromagnetic interference shielding performance of the MXene - carbon fiber molded sheet with a thickness of 1.0 mm in Example 9: The EMI shielding efficiency (8 - 12 GHz frequency) is >70 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is >45 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is >40 dB.

[0086] The difference between Example 10 and Example 1 lies in Step 2 of the preparation method of the MXene - carbon fiber composite material. 182 g of a finished aqueous acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether - modified silicone leveling agent SSL - 320, 1 g of silicon carbide whiskers (diameter 0.1 - 2.5 microns, length 10 - 50 microns, silicon carbide whiskers D500A, brand Hongwu Nano), and 5 g of the MXene nanosheets in Step 1 were mixed evenly to obtain a prepreg.

[0087] The electromagnetic interference shielding performance of the MXene - carbon fiber molded sheet with a thickness of 1.0 mm in Example 10: The EMI shielding efficiency (8 - 12 GHz frequency) is >70 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is >45 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is >40 dB.

[0088] The difference between Example 11 and Example 1 lies in Step 2 of the preparation method of the MXene-carbon fiber composite material. 182 g of a finished aqueous acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether-modified silicone leveling agent SSL-320, 0.5 g of carbon nanotubes (high-purity multi-walled carbon nanotubes MWCNTs, model TNMH0, outer diameter: 4 - 8 nm, length 10 - 20 microns, oxygen content 5.57 wt%, Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences), 0.5 g of graphene (hydroxylated graphene TimesGraph TM , purity: >98 wt%, thickness: 0.55 - 3.74 nm, diameter: 0.5 - 3 microns, number of layers: <10 layers, oxygen content: >10 wt%, Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences), and 5 g of the MXene nanosheets in Step 1 are mixed evenly to obtain a prepreg.

[0089] The electromagnetic interference shielding performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Example 11: The EMI shielding efficiency (8 - 12 GHz frequency) is >70 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is >45 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is >40 dB.

[0090] The difference between Example 12 and Example 1 lies in Step 2 of the preparation method of the MXene-carbon fiber composite material. 182 g of a finished aqueous acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether-modified silicone leveling agent SSL-320, 0.5 g of silicon carbide whiskers, 0.5 g of graphene (hydroxylated graphene TimesGraph TM , purity: >98 wt%, thickness: 0.55 - 3.74 nm, diameter: 0.5 - 3 microns, number of layers: <10 layers, oxygen content: >10 wt%, Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences), and 5 g of the MXene nanosheets in Step 1 are mixed evenly to obtain a prepreg.

[0091] The electromagnetic interference shielding performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Example 12: The EMI shielding efficiency (8 - 12 GHz frequency) is >70 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is >45 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is >40 dB.

[0092] Example 13 is different from Example 1 in that: in Step 4, eight MXene-carbon fiber prepreg sheets are stacked to form an MXene-carbon fiber preform, and the MXene-carbon fiber preform is subjected to hot die pressing. The parameters for the hot die pressing are: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min, and an MXene-carbon fiber molded sheet with a thickness of 2.0 mm can be obtained. The remaining steps are the same.

[0093] The electromagnetic interference resistance performance of the MXene-carbon fiber molded sheet with a thickness of 2.0 mm in Example 13: The EMI shielding efficiency (8 - 12 GHz frequency band) is > 80 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency band) is > 50 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency band) is > 40 dB.

[0094] Example 14 is different from Example 1 in that: in Step 4, twelve MXene-carbon fiber prepreg sheets are stacked to form an MXene-carbon fiber preform, and the MXene-carbon fiber preform is subjected to hot die pressing. The parameters for the hot die pressing are: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min, and an MXene-carbon fiber molded sheet with a thickness of 3.0 mm can be obtained. The remaining steps are the same.

[0095] The electromagnetic interference resistance performance of the MXene-carbon fiber molded sheet with a thickness of 3.0 mm in Example 14: The EMI shielding efficiency (8 - 12 GHz frequency band) is > 90 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency band) is > 50 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency band) is > 40 dB.

[0096] Example 15 is different from Example 1 in that: in Step 4, sixteen MXene-carbon fiber prepreg sheets are stacked to form an MXene-carbon fiber preform, and the MXene-carbon fiber preform is subjected to hot die pressing. The parameters for the hot die pressing are: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min, and an MXene-carbon fiber molded sheet with a thickness of 4.0 mm can be obtained. The remaining steps are the same.

[0097] The electromagnetic interference resistance performance of the MXene-carbon fiber molded sheet with a thickness of 4.0 mm in Example 15: The EMI shielding efficiency (8 - 12 GHz frequency band) is > 100 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency band) is > 50 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency band) is > 40 dB.

[0098] Example 16 is different from Example 1 in that: in Step 4, twenty MXene-carbon fiber prepreg sheets are stacked to form an MXene-carbon fiber preform, and the MXene-carbon fiber preform is subjected to hot die pressing. The parameters of the hot die pressing are: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min, and then an MXene-carbon fiber molded sheet with a thickness of 5.0 mm can be obtained. The remaining steps are the same.

[0099] The electromagnetic interference resistance performance of the MXene-carbon fiber molded sheet with a thickness of 5.0 mm in Example 16: the EMI shielding efficiency (8 - 12 GHz frequency) is > 100 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is > 60 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is > 40 dB.

[0100] Example 17 is different from Example 1 in that: in Step 1 of the preparation method of the MXene-carbon fiber composite material, the preparation of the MXene material: 1 g of the MXene nanosheets obtained in S1.2 in Example 1 is dissolved in 50 mL of ethanol, 0.24 g of FeC2O4·2H2O is added, and ultrasonic dispersion is carried out at 60 °C for 3 h. After the iron source is completely dissolved, the ethanol is removed by heating. The obtained material is dried and then transferred to a tube furnace. Under nitrogen protection, it is heated to 550 °C at a rate of 20 °C / min and calcined for 3 h to obtain the finished MXene nanosheets, that is, Fe3O4 grafted and modified Ti3AlC2 nanosheets.

[0101] The electromagnetic interference resistance performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Example 17: the EMI shielding efficiency (8 - 12 GHz frequency) is > 70 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is > 45 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is > 40 dB.

[0102] Example 18 is different from Example 2 in that: in Step 1 of the preparation method of the MXene-carbon fiber composite material, the preparation of the MXene material: 1 g of the MXene nanosheets obtained in S1.2 in Example 2 is dissolved in 50 mL of ethanol, 0.24 g of FeC2O4·2H2O is added, and ultrasonic dispersion is carried out at 60 °C for 3 h. After the iron source is completely dissolved, the ethanol is removed by heating. The obtained material is dried and then transferred to a tube furnace. Under nitrogen protection, it is heated to 550 °C at a rate of 20 °C / min and calcined for 3 h to obtain the finished MXene nanosheets, that is, Fe3O4 grafted and modified Mo2Ti2C3 nanosheets.

[0103] Electromagnetic interference shielding performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Example 18: EMI shielding efficiency (8 - 12 GHz frequency) > 70 dB, EMI shielding efficiency (10 kHz - 1.0 GHz frequency) > 45 dB, EMI shielding efficiency (100 GHz - 1.0 THz frequency) > 40 dB.

[0104] The difference between Example 19 and Example 3 lies in Step 1 of the preparation method of the MXene-carbon fiber composite material, the preparation of the MXene material: Dissolve 1 g of the MXene nanosheets obtained in S1.2 of Example 3 in 50 mL of ethanol, add 0.24 g of FeC2O4·2H2O, ultrasonically disperse at 60 °C for 3 h. After the iron source is completely dissolved, heat up to remove ethanol. The obtained material is dried and then transferred to a tube furnace. Under nitrogen protection, heat up to 550 °C at a rate of 20 °C / min and calcine for 3 h to obtain the finished MXene nanosheets, which are Fe3O4-grafted modified Ti2SnC nanosheets.

[0105] Electromagnetic interference shielding performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Example 19: EMI shielding efficiency (8 - 12 GHz frequency) > 70 dB, EMI shielding efficiency (10 kHz - 1.0 GHz frequency) > 45 dB, EMI shielding efficiency (100 GHz - 1.0 THz frequency) > 40 dB.

[0106] The difference between Example 20 and Example 17 lies in Step 2 of the preparation method of the MXene-carbon fiber composite material. Mix 182 g of the finished waterborne acrylate resin with a solid content of 50 wt%, 2 g of the silicone defoamer FoamStar SI 2292, 1 g of the polyether-modified silicone leveling agent SSL-320, 0.5 g of carbon nanotubes, 0.5 g of graphene, and 5 g of the MXene nanosheets in Step 1 to obtain a prepreg. Step 3, scrape and coat the prepreg in Step 2 on the upper and lower surfaces of a carbon fiber grid cloth (gram weight 300 g / m 2 , a carbon fiber mesh cloth woven from Toray 6K T300 carbon fiber yarn, plain weave, with a thickness of 0.167 mm). The single-sided coating amount of the prepreg is 185 g / m 2 , after evaporating the moisture, cure at 40 °C for 24 h to obtain the MXene-carbon fiber prepreg sheet. Step 4, stack six MXene-carbon fiber prepreg sheets to form a MXene-carbon fiber preform, and perform hot molding treatment on the MXene-carbon fiber preform. The hot molding treatment parameters are: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min, to obtain a MXene-carbon fiber molded sheet with a thickness of 2.10 mm.

[0107] Electromagnetic interference shielding performance of the MXene-carbon fiber compression-molded sheet with a thickness of 2.10 mm in Example 20: The EMI shielding efficiency (8 - 12 GHz frequency) is > 80 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is > 50 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is > 40 dB.

[0108] Comparative Example 1: A method for preparing an MXene-carbon fiber composite material, comprising the following steps:

[0109] Step 1, preparation of MXene material: Under magnetic stirring at 120 rpm, add 24 mL of hydrochloric acid aqueous solution with a concentration of 9 M and 5 mL of HF solution with a concentration of 40 wt% to 12 mL of deionized water, maintain the mixture at 35 °C and mix evenly to obtain a chemical etching solution. Under magnetic stirring, divide 2 g of Ti3AlC2 powder (Zhihuo New Materials Technology Nanjing Co., Ltd., 600 mesh) into 5 portions of MXene unit powder, and add 0.4 g of one portion of MXene unit powder to the chemical etching solution every 15 minutes. After adding all the MXene powder, maintain the temperature at 35 °C and etch for 24 h under magnetic stirring. Centrifuge and wash the obtained mixture with deionized water until the liquid material is neutral, remove the supernatant and retain the precipitate. The obtained precipitate is HF chemically etched and modified MXene;

[0110] Step 2, mix 184 g of a finished waterborne acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether-modified silicone leveling agent SSL-320, and 5 g of the HF chemically etched and modified MXene in Step 1 evenly to obtain a prepreg;

[0111] Mix the waterborne acrylate resin (BASF JONCRYL 678, effective ingredient content 98.7%) with deionized water evenly to obtain a finished waterborne acrylate resin with a solid content of 50 wt%;

[0112] Step 3, scrape and coat the prepreg in Step 2 on the upper and lower surfaces of a carbon fiber grid cloth (gram weight 300 g / m 2 , a carbon fiber mesh cloth woven from Toray 6K T300 carbon fiber yarn, plain weave structure, thickness 0.167 mm). The single-sided coating amount of the prepreg is 85 g / m 2 , evaporate the moisture, and cure at 40 °C for 24 h to obtain an MXene-carbon fiber prepreg sheet;

[0113] Step 4: Take four MXene-carbon fiber prepregs and stack them into an MXene-carbon fiber preform. Perform hot die pressing on the MXene-carbon fiber preform. The parameters for hot die pressing are: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min. Then, an MXene-carbon fiber molded sheet with a thickness of 1.0 mm can be obtained.

[0114] The electromagnetic interference resistance performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Comparative Example 1: The EMI shielding efficiency (8 - 12 GHz frequency) is > 60 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency) is > 30 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency) is > 30 dB.

[0115] Comparative Example 2: A preparation method of an MXene-carbon fiber composite material, including the following steps:

[0116] Step 1: Preparation of MXene material: Under magnetic stirring at 120 rpm, add 24 mL of hydrochloric acid aqueous solution with a concentration of 9 M and 5 mL of HF solution with a concentration of 40 wt% to 12 mL of deionized water, and maintain the mixture at 35 °C to obtain a chemical etching solution. Under magnetic stirring, divide 2 g of Mo2Ti2C3 powder into 5 portions of MXene unit powder, and add 0.4 g of one portion of MXene unit powder to the chemical etching solution every 15 min. After adding all the MXene powder, maintain the temperature at 35 °C and etch for 24 h under magnetic stirring. Perform centrifugation and deionized water washing on the obtained mixed solution, wash until the liquid material is neutral, remove the supernatant, and retain the precipitate. The obtained precipitate is HF chemically etched and modified MXene;

[0117] Step 2: Mix 184 g of a finished waterborne acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether-modified silicone leveling agent SSL-320, and 5 g of the HF chemically etched and modified MXene in Step 1 to obtain a prepreg;

[0118] Mix the waterborne acrylate resin (BASF JONCRYL 678, effective ingredient content 98.7%) with deionized water to obtain a finished waterborne acrylate resin with a solid content of 50 wt%;

[0119] Step 3: Coat the prepreg in Step 2 on the upper and lower surfaces of a carbon fiber mesh cloth (gram weight 300 g / m 2 , a carbon fiber mesh cloth woven from Toray 6K T300 carbon fiber yarn, plain weave structure, thickness 0.167 mm). The single-sided coating amount of the prepreg is 85 g / m 2 , evaporate the moisture, and cure at 40 °C for 24 h to obtain an MXene-carbon fiber prepreg;

[0120] Step 4: Take four MXene-carbon fiber prepreg sheets and stack them into an MXene-carbon fiber preform. Conduct hot die pressing on the MXene-carbon fiber preform. The parameters for the hot die pressing process are as follows: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min. Then, an MXene-carbon fiber molded sheet with a thickness of 1.0 mm can be obtained.

[0121] The electromagnetic interference resistance performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Comparative Example 2: The EMI shielding efficiency (8 - 12 GHz frequency band) is > 60 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency band) is > 30 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency band) is > 30 dB.

[0122] Comparative Example 3: A preparation method of an MXene-carbon fiber composite material, comprising the following steps:

[0123] Step 1: Preparation of MXene material: Under magnetic stirring at 120 rpm, add 24 mL of hydrochloric acid aqueous solution with a concentration of 9 M and 5 mL of HF solution with a concentration of 40 wt% to 12 mL of deionized water, and maintain the mixture at 35 °C to obtain a chemical etching solution. Under magnetic stirring, divide 2 g of Ti2SnC into 5 portions of MXene unit powder, and add 0.4 g of one portion of MXene unit powder to the chemical etching solution every 15 min. After adding all the MXene powder, maintain the temperature at 35 °C and etch for 24 h under magnetic stirring. Centrifuge and wash the obtained mixed solution with deionized water until the liquid material is neutral, remove the supernatant, and retain the precipitate. The obtained precipitate is HF chemically etched and modified MXene.

[0124] Step 2: Mix 184 g of a finished waterborne acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, 1 g of a polyether-modified silicone leveling agent SSL-320, and 5 g of the HF chemically etched and modified MXene in Step 1 to obtain a prepreg.

[0125] Mix the waterborne acrylate resin (BASF JONCRYL 678, effective ingredient content 98.7%) with deionized water to obtain a finished waterborne acrylate resin with a solid content of 50 wt%.

[0126] Step 3: Coat the prepreg in Step 2 on the upper and lower surfaces of a carbon fiber grid cloth (gram weight 300 g / m 2 , a carbon fiber mesh cloth woven from Toray 6K T300 carbon fiber yarn, plain weave structure, thickness 0.167 mm). The single-sided coating amount of the prepreg is 85 g / m 2, after evaporating and removing the moisture, it was cured at 40 °C for 24 h to obtain a MXene-carbon fiber prepreg sheet;

[0127] Step 4, take four MXene-carbon fiber prepreg sheets and stack them into a MXene-carbon fiber preform, and perform hot die pressing on the MXene-carbon fiber preform. The parameters of the hot die pressing are: pressure 10 MPa, temperature 85 °C, and hot pressing time 30 min, then a MXene-carbon fiber molded sheet with a thickness of 1.0 mm can be obtained.

[0128] The electromagnetic interference shielding performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Comparative Example 3: the EMI shielding efficiency (8 - 12 GHz frequency band) is > 60 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency band) is > 30 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency band) is > 30 dB.

[0129] The difference between Comparative Example 4 and Example 1 lies in: in Step 2 of the preparation method of the MXene-carbon fiber composite material, 194 g of a finished water-based acrylate resin with a solid content of 50 wt%, 2 g of an organosilicon defoamer FoamStar SI 2292, and 1 g of a polyether-modified silicone leveling agent SSL-320 were mixed evenly to obtain a prepreg.

[0130] The electromagnetic interference shielding performance of the MXene-carbon fiber molded sheet with a thickness of 1.0 mm in Comparative Example 4: the EMI shielding efficiency (8 - 12 GHz frequency band) is < 60 dB, the EMI shielding efficiency (10 kHz - 1.0 GHz frequency band) is < 30 dB, and the EMI shielding efficiency (100 GHz - 1.0 THz frequency band) is < 30 dB.

[0131] Table 1: Electromagnetic interference shielding performance parameters of MXene-carbon fiber molded sheets

[0132]

[0133]

[0134] Combined with Example 1 and Examples 4 - 7, it can be seen that controlling the MXene nanosheet content in the carbon fiber composite material to 5 - 50 wt% can ensure the overall electromagnetic shielding effect. The higher the MXene nanosheet content, the better the electromagnetic shielding effect of the carbon fiber composite material. When the MXene nanosheet content is greater than 20 wt%, the improvement effect of the electromagnetic shielding effect of the carbon fiber composite material slows down, and the appropriate MXene nanosheet content is 10 - 20 wt%.

[0135] Combined with Examples 1-3 and Comparative Examples 1-3, it can be seen that the electromagnetic shielding effect of the carbon fiber composite prepared from MXene nanosheets obtained by HF chemical etching and LiCl intercalation exfoliation is relatively good.

[0136] Combined with Example 1 and Examples 8-12, it can be seen that the synergist can improve the electromagnetic shielding effect of the carbon fiber composite, and the synergist is a compound of carbon nanotubes and graphene, which is more conducive to improving the electromagnetic shielding effect.

[0137] Combined with Example 1 and Examples 13-16, it can be seen that the thickness of the carbon fiber composite will affect the overall electromagnetic shielding effect. The thicker the carbon fiber composite, the better its electromagnetic shielding effect.

[0138] Combined with Examples 1-3 and Examples 17-19, it can be seen that the carbon fiber composite prepared by grafting and modifying MXene nanosheets with Fe3O4 has a better electromagnetic shielding effect, which is more conducive to the production of carbon fiber composites with broadband electromagnetic shielding, meeting the requirements of the shielding efficiency of the shielding body in the aerospace and military fields.

[0139] In summary, the MXene-carbon fiber composite in the present invention has good electromagnetic shielding effect and microwave absorption effect, and also has good shielding effect in the low-frequency band or ultra-high frequency band. Moreover, the introduction of the MXene material improves the overall mechanical properties, wear resistance and weather resistance, expanding its application range.

[0140] It should be noted that: this specific embodiment is only an explanatory illustration of the technical solution of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A MXene-carbon fiber composite material, characterized in that: The MXene-carbon fiber composite material comprises carbon fiber, a polymer, and an MXene material. The content of the MXene material in the MXene-carbon fiber composite material is 0.5-15 wt%. The carbon fiber is a unidirectional carbon fiber cloth or a carbon fiber grid cloth. The carbon fiber grid cloth is any one of a plain weave, a satin weave, and a twill weave. In the unidirectional carbon fiber cloth, the warp is a carbon fiber yarn, and the weft is a chemical fiber or natural fiber yarn.

2. The MXene-carbon fiber composite material according to claim 1, wherein: The structural formula of the MXene material is M n+1 X n T x , where n = 1 to 4, M is a transition metal, and M includes at least one of Ti, Al, Mo, V, and Sn; X is C and / or N, and T is a surface group, and T is O or OH.

3. The MXene-carbon fiber composite material according to claim 2, characterized in that: The MXene material is a hydrophilic modified MXene nanosheet, which is prepared by the method of HF chemical etching and LiCl intercalation exfoliation of Ti3AlC2 powder. The time of HF chemical etching is 24-120 h, and the time of LiCl intercalation exfoliation is 4-48 h.

4. The MXene-carbon fiber composite according to claim 2, wherein: The MXene material is an Fe3O4 grafted modified MXene nanosheet.

5. The MXene-carbon fiber composite material according to claim 4, characterized in that: The preparation method of the Fe3O4 grafted modified MXene nanosheet is as follows: First, Ti3AlC2 nanosheets are prepared by the method of HF chemical etching and LiCl intercalation exfoliation of Ti3AlC2 powder. Then, 1-5 g of Ti3AlC2 nanosheets are dissolved in 50-100 mL of ethanol, 0.1-0.5 g of FeC2O4·2H2O is added, and ultrasonic dispersion is carried out at 40-80 °C for 1-3 h. After the iron source is completely dissolved, ethanol is removed by heating. The obtained material is dried and then transferred to a tubular furnace. Under nitrogen protection, it is heated to 500-550 °C at a rate of 10-20 °C / min and calcined for 3-4 h.

6. The MXene-carbon fiber composite material according to claim 1, characterized in that: The carbon fiber is a carbon fiber mesh cloth with a weight of 200-400 g / m 2 , and the carbon fiber yarn woven in the carbon fiber mesh cloth is any one of 3K T300, 6K T300, 6K T400, and 12K T700.

7. The MXene-carbon fiber composite material according to claim 1, characterized in that: The MXene-carbon fiber composite material further includes a synergist, and the content of the synergist is 0.5-10 wt%. The synergist is at least one of carbon fiber, carbon nanotube, silicon carbide whisker, and graphene.

8. A MXene-carbon fiber composite material according to claim 1, characterized in that: The polymer is formed by curing an aqueous polymer emulsion, and the aqueous polymer emulsion is at least one of an aqueous polyurethane resin, an aqueous acrylate, an aqueous acrylate modified polyurethane resin, and an aqueous polyurethane modified acrylate.

9. The preparation method of the MXene-carbon fiber composite material according to any one of claims 1-8, characterized in that: It includes the following steps: Step 1, preparation of MXene material: MXene powder is prepared into MXene material by the method of HF chemical etching and LiCl intercalation exfoliation. Step 2, an aqueous polymer emulsion, an auxiliary agent, and the MXene material in Step 1 are mixed evenly to obtain a prepreg. The auxiliary agent includes a leveling agent, an antifoaming agent, a thickening agent, an antioxidant, and an ultraviolet absorber. Step 3, the prepreg in Step 2 is scraped on the surface of the carbon fiber. After the moisture is evaporated, it is cured at 20-45 °C for 12-48 h to obtain an MXene-carbon fiber prepreg sheet. Step 4, the MXene-carbon fiber prepreg sheets are stacked into an MXene-carbon fiber prefabricated board according to the designed thickness, and the MXene-carbon fiber prefabricated board is subjected to hot molding treatment to obtain an MXene-carbon fiber molded special-shaped part.

10. The MXene-carbon fiber composite material according to any one of claims 1-8 is applied to 6G communication, automobiles, radar detection, unmanned aerial vehicles, stealth aircraft, microwave anechoic chambers, and military communication equipment.

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