A flexible carbon fiber composite film and a preparation method and application thereof

Abstract

The application discloses a flexible carbon fiber composite film and a preparation method and application thereof, and the flexible carbon fiber composite film comprises a hydrophobic coating A, a hot melt polymer layer A, a metal-coated carbon fiber layer, a hot melt polymer layer B and a hydrophobic coating B which are sequentially stacked. The flexible carbon fiber composite film has excellent flexibility, toughness, self-repairing performance, wave absorbing performance and electromagnetic shielding performance; when the surface of the composite film is damaged, the hot melt polymer layer A and the hot melt polymer layer B melt under the condition of power-on, and the damaged position is filled and repaired within 30 seconds, so that the hydrophobic performance of the composite film is restored. In addition, the water contact angle of the composite film reaches 118-125 DEG, and the composite film has excellent hydrophobic performance; meanwhile, the metal coating on the carbon fiber layer enables the composite film to have excellent electromagnetic shielding performance, and the total shielding efficiency of the composite film in the frequency band of 8.2-12.4 GHz is 35-45 dB.

Description

Technical Field

[0001] This invention belongs to the field of materials, specifically relating to a flexible carbon fiber composite membrane, its preparation method, and its application. Background Technology

[0002] With the rapid development of technology, the demand for flexible composite membranes in various fields is gradually increasing. Traditional composite membranes have poor self-healing and electromagnetic shielding performance, which seriously limits their application. In addition, existing composite membrane preparation methods require a large amount of solvent, with complex and cumbersome processes, cumbersome operation, and high production costs, making them unsuitable for large-scale industrial production. The use of solvents also has adverse environmental impacts, failing to meet the requirements of energy-saving and environmentally friendly production, and causing significant production difficulties for enterprises. Therefore, there is an urgent need to develop a new composite membrane with a simple preparation method and low solvent consumption to meet the ever-growing market demand. Summary of the Invention

[0003] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a flexible carbon fiber composite membrane.

[0004] The second objective of this invention is to provide a method for preparing a flexible carbon fiber composite membrane.

[0005] The third objective of this invention is to provide a sensor.

[0006] The fourth objective of this invention is to provide an electromagnetic shielding material.

[0007] The fifth objective of this invention is to provide an application of flexible carbon fiber composite film in the fields of electronics, communications, or aerospace.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] The first aspect of the present invention provides a flexible carbon fiber composite membrane, comprising a hydrophobic coating A, a hot-melt polymer layer A, a metal-coated carbon fiber layer, a hot-melt polymer layer B, and a hydrophobic coating B stacked sequentially.

[0010] Preferably, the materials of the hot melt polymer layer A and / or the hot melt polymer layer B are thermoplastic flexible polymer materials.

[0011] Preferably, the material of the hot melt polymer layer A and / or the hot melt polymer layer B is selected from at least one of ethylene-vinyl acetate copolymer, styrene-ethylene-butene-styrene block copolymer, and thermoplastic polyurethane; more preferably, the material of the hot melt polymer layer A and / or the hot melt polymer layer B is ethylene-vinyl acetate copolymer hot melt mesh.

[0012] Preferably, the number of hot melt polymer layer A and / or hot melt polymer layer B is 1 to 6; more preferably, the number of hot melt polymer layer A and / or hot melt polymer layer B is 3 to 6.

[0013] Preferably, the material of the hydrophobic coating A and / or the hydrophobic coating B is selected from at least one of polytetrafluoroethylene, fluorinated polyethylene, and fluorocarbon wax. More preferably, the material of the hydrophobic coating A and / or the hydrophobic coating B is selected from polytetrafluoroethylene.

[0014] Preferably, the metal is selected from at least one of copper, silver, gold, aluminum, and iron.

[0015] Preferably, the thickness of the hot melt polymer layer A and the hot melt polymer layer B is 0.1 to 0.15 mm.

[0016] Preferably, the thickness of the hydrophobic coating A and the hydrophobic coating B is 0.005 to 0.01 mm.

[0017] Preferably, the thickness of the metal-coated carbon fiber layer is 0.1 to 0.3 mm.

[0018] Preferably, the water contact angle of the flexible carbon fiber composite membrane is 118–125°.

[0019] Preferably, the total shielding effectiveness of the flexible carbon fiber composite film in the 8.2–12.4 GHz frequency band is 35–45 dB.

[0020] The second aspect of the present invention provides a method for preparing the flexible carbon fiber composite membrane provided in the first aspect of the present invention, comprising the following steps:

[0021] S1: Coat the carbon fiber layer with metal to obtain a carbon fiber layer coated with metal;

[0022] S2: Layer hot-melt polymer layer A, the metal-coated carbon fiber layer and hot-melt polymer layer B, and then hot-press to obtain a composite film precursor;

[0023] S3: Coating the upper and lower surfaces of the composite membrane precursor with hydrophobic coating A and hydrophobic coating B to obtain the flexible carbon fiber composite membrane.

[0024] Preferably, step S1 involves coating the upper and lower sides of the carbon fiber layer with metal powder.

[0025] Preferably, step S1 is: immersing the carbon fiber layer in a liquid containing metal powder, and then removing and drying it.

[0026] Preferably, the particle size of the metal powder is not higher than 100 μm.

[0027] Preferably, in step S2, the hot pressing temperature is 100–160°C.

[0028] Preferably, in step S2, the hot pressing pressure is 8 to 500 N.

[0029] Preferably, in step S2, the hot pressing time is 5 to 25 minutes.

[0030] Preferably, in step S2, the hot pressing step is performed in a vacuum environment.

[0031] A third aspect of the present invention provides a sensor comprising the flexible carbon fiber composite membrane provided in the first aspect of the present invention.

[0032] A fourth aspect of the present invention provides an electromagnetic shielding material, including the flexible carbon fiber composite membrane provided in the first aspect of the present invention.

[0033] The fifth aspect of the present invention provides the application of the flexible carbon fiber composite membrane provided in the first aspect of the present invention in the fields of electronics, communications or aerospace.

[0034] The beneficial effects of this invention are: the flexible carbon fiber composite membrane of this invention has excellent self-healing properties, wave absorption properties, and electromagnetic shielding properties. Specifically:

[0035] (1) When the surface of the composite membrane in this invention is damaged, the hot melt polymer layer A and the hot melt polymer layer B melt under the condition of electricity, and fill and repair the damaged part within 30 seconds, thereby restoring the hydrophobic properties of the composite membrane. The self-repair time is short, which reduces the risk of performance degradation or even failure caused by damage, improves the reliability of the composite membrane, extends its service life, reduces maintenance costs and replacement frequency, and improves the economic benefits of composite membrane.

[0036] (2) The composite membrane in this invention uses hydrophobic coating A and hydrophobic coating B to make the water contact angle of the composite membrane reach 118 to 125°, which has excellent hydrophobic properties; at the same time, by coating metal on the carbon fiber layer, the composite membrane has excellent electromagnetic shielding performance, and its total shielding effectiveness in the 8.2 to 12.4 GHz frequency band is 35 to 45 dB.

[0037] (3) The composite membrane of this invention has high applicability, excellent plasticity and flexibility, enabling it to adapt to complex curved surfaces and shapes, and providing a wider range of application possibilities. The composite membrane combines excellent flexibility and self-healing properties, maintaining stable performance under different environmental and stress conditions, and adapting to diverse application needs. The composite membrane of this invention can be applied to multiple fields. For example, in robotics, it can improve grasping accuracy and stability; in the medical field, it can be applied to physiological signal monitoring and wearable devices; in industrial automation, it can be used for deformation detection and mechanical measurement, etc.

[0038] The preparation method in this invention adopts a dry preparation method, which avoids the use of organic solvents, reduces production costs, and is safer and more environmentally friendly. Moreover, its preparation process is simple, the reaction raw materials are widely available and low cost, and it can be continuously industrialized in an assembly line, which is conducive to large-scale industrial production applications. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the flexible carbon fiber composite membrane in this invention.

[0040] Figure 2 The images are scanning electron microscope images of the composite membrane precursors in Comparative Example 1 and Example 3.

[0041] Figure 3 This is the elemental analysis diagram of the composite membrane in Example 3.

[0042] Figure 4 The graphs show the mechanical properties of the composite membranes in Example 3 and Comparative Example 1.

[0043] Figure 5 The image shows the infrared test pattern of the composite film in Example 3.

[0044] Figure 6 The graphs show the thermodynamic performance test results of the composite membranes in Example 3 and Comparative Example 1.

[0045] Figure 7 The images show the surface morphology and water contact angle test results of the composite membrane in Example 3.

[0046] Figure 8 The images show the surface morphology and water contact angle test results of the composite membrane in Example 3.

[0047] Figure 9 The images show the surface morphology and water contact angle test results of the composite membrane in Example 3.

[0048] Figure 10 The electromagnetic shielding performance test diagrams are for the composite film and EVA film in Example 3 and Comparative Example 1. Detailed Implementation

[0049] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0050] The raw material information used in the embodiments of this invention is as follows:

[0051] EVA hot melt fabric is an ethylene-vinyl acetate copolymer hot melt fabric nonwoven fabric.

[0052] CF stands for carbon fiber fabric;

[0053] Cu is metallic copper powder;

[0054] PTFE is polytetrafluoroethylene.

[0055] Reference Figure 1 The structural diagram shows that the self-healing electromagnetic shielding flexible carbon fiber composite membrane in Embodiments 1-3 of this invention consists of, from the inside out, carbon fiber fabric (CF) coated with metal powder, an EVA hot-melt mesh, and a PTFE coating. The CF is encased within an equal number of layers of EVA hot-melt mesh. Under the heating and pressurization of a press, the CF layer and its surface metal powder are effectively protected and will not detach. The outer PTFE coating provides a hydrophobic effect. The thickness of the EVA hot-melt mesh is 0.1–0.15 mm; the thickness of the PTFE coating is 0.005–0.01 mm; and the thickness of the carbon fiber fabric coated with metal powder is 0.1–0.3 mm.

[0056] Example 1

[0057] This example provides a self-healing, electromagnetic shielding flexible carbon fiber composite membrane. The composite membrane is prepared by brushing a metal powder slurry onto the surface of a carbon fiber fabric, wherein the mass ratio of copper to silver is 2:1, stacking three layers of EVA hot melt mesh film on the top and bottom, and then heating and pressurizing in a vacuum environment to form a precursor. Then, a PTFE hydrophobic coating is sprayed onto the top and bottom surfaces of the precursor.

[0058] The self-healing electromagnetic shielding flexible carbon fiber composite film in this example was prepared using the following method, with the specific steps as follows:

[0059] S1. Cut the carbon fiber fabric to the designed size, which is 10×10cm. 2 Its density is 2.0 g / m³ 2 ;

[0060] S2. Apply a metal powder slurry to both sides of the coating. The metal powder has a particle size of less than 100 μm, a solid content of 28-30±1%, a viscosity of 120±3 cP (measured at 25℃), a specific gravity of 1.45 g / mL, a surface resistivity of ≤0.5 Ohm / 10cm, an adhesion rating of 4B, and the adhesion test standard is GB / T9286-1998. The theoretical hiding power is 8-10 μm. 2 / kg (coating thickness = 15μm);

[0061] S3. Lay three layers of the above-mentioned EVA hot-melt mesh film on each side of the carbon fiber fabric coated with metal powder. The size of the EVA hot-melt mesh film is 10×10cm. 2 Its density is 38 g / m³ 2 ;

[0062] S4. Cu@CF / EVA flexible composite membrane precursor was prepared by heating and pressurizing in a vacuum environment. The press was set to a temperature of 100℃, a pressure of 20N, and a heating and pressurizing time of 5min.

[0063] S5. Spray a PTFE hydrophobic coating on both sides of the precursor for 5 seconds to obtain the self-healing electromagnetic shielding flexible carbon fiber composite film in this example.

[0064] Example 2

[0065] This example provides a self-healing, electromagnetic shielding flexible carbon fiber composite membrane. The composite membrane is prepared by brushing copper powder onto the surface of carbon fiber fabric, then stacking four layers of EVA hot melt mesh film on both the top and bottom of the carbon fiber fabric, and then heating and pressurizing in a vacuum environment to form a precursor. Finally, a PTFE hydrophobic coating is sprayed onto both the top and bottom of the precursor.

[0066] The self-healing electromagnetic shielding flexible carbon fiber composite film in this example was prepared using the following method, with the specific steps as follows:

[0067] S1. Cut the carbon fiber fabric to the designed size, which is 10×10cm. 2 Its density is 2.0 g / m³ 2 ;

[0068] S2. Apply a copper powder slurry to both sides of the coating. The copper powder has a particle size of less than 100 μm, a solid content of 28-30±1%, a viscosity of 120±3 cP (measured at 25℃), a specific gravity of 1.45 g / mL, a surface resistivity of ≤0.5 Ohm / 10cm, an adhesion grade of 4B, and an adhesion test standard of GB / T9286-1998. The theoretical hiding power is 8-10 m2 / kg (film thickness = 15 μm).

[0069] S3. Lay the above 4 layers of EVA hot-melt mesh film on both sides of the carbon fiber fabric coated with copper powder. The size of the EVA hot-melt mesh film is 10×10cm. 2 Its density is 38 g / m³ 2 ;

[0070] S4. Cu@CF / EVA flexible composite membrane precursor was prepared by heating and pressurizing in a vacuum environment. The press was set to a temperature of 160℃, a pressure of 500N, and a heating and pressurizing time of 25min.

[0071] S5. Spray a PTFE hydrophobic coating on both sides of the precursor for 10 seconds to obtain the self-healing electromagnetic shielding flexible carbon fiber composite film in this example.

[0072] Example 3

[0073] This example provides a self-healing, electromagnetic shielding flexible carbon fiber composite membrane. The composite membrane is prepared by brushing copper powder onto the surface of carbon fiber fabric, then stacking three layers of EVA hot melt mesh film on both the top and bottom of the carbon fiber fabric, and then heating and pressurizing it in a vacuum environment to form a precursor. Finally, a PTFE hydrophobic coating is sprayed onto both the top and bottom of the precursor.

[0074] The self-healing electromagnetic shielding flexible carbon fiber composite film in this example was prepared using the following method, with the specific steps as follows:

[0075] S1. Cut the carbon fiber fabric to the designed size, which is 10×10cm. 2 Its density is 2.0 g / m³ 2 ;

[0076] S2. Spray a copper powder slurry onto both sides. The copper powder has a particle size of less than 100 μm, a solid content of 28-30±1%, a viscosity of 120±3 cP (measured at 25℃), a specific gravity of 1.45 g / mL, a surface resistivity of ≤0.5 Ohm / 10cm, an adhesion rating of 4B, and the adhesion test standard is GB / T9286-1998. The theoretical hiding power is 8-10 μm. 2 / kg (coating thickness = 15μm);

[0077] S3. Lay the above three layers of EVA hot-melt mesh film on both sides of the carbon fiber fabric coated with copper powder. The size of the EVA hot-melt mesh film is 10×10cm. 2 Its density is 38 g / m³ 2 ;

[0078] S4. Cu@CF / EVA flexible composite membrane precursor was prepared by heating and pressurizing in a vacuum environment. The press was set to a temperature of 160℃, a pressure of 500N, and a heating and pressurizing time of 25min.

[0079] S5. Spray a PTFE hydrophobic coating on both sides of the precursor for 10 seconds to obtain the self-healing electromagnetic shielding flexible carbon fiber composite film in this example, denoted as Cu@FCFRP.

[0080] When the self-healing electromagnetic shielding flexible carbon fiber composite membrane in Embodiments 1-3 of this invention is damaged and its use is affected, it can be energized with an energizing voltage of approximately 9V. This can repair a 10mm wide self-healing electromagnetic shielding flexible carbon fiber composite membrane. Under energizing conditions, the EVA hot-melt mesh melts, filling and repairing the damaged areas, thereby restoring the hydrophobic properties of the composite membrane and achieving self-healing. Moreover, the self-healing process is short, requiring less than 30 seconds to achieve self-healing.

[0081] Comparative Example 1

[0082] The flexible carbon fiber composite membrane in this example is prepared by stacking three layers of EVA hot-melt mesh film on both the top and bottom of a carbon fiber fabric, then heating and pressurizing it under vacuum to form a precursor, and finally spraying a PTFE hydrophobic coating on both the top and bottom of the precursor. The difference from Example 3 is that copper particles were not used in Comparative Example 1.

[0083] The flexible carbon fiber composite membrane in this example was prepared using the following method, with the specific steps as follows:

[0084] S1. Cut the carbon fiber fabric to the designed size, which is 10×10cm. 2 Its density is 2.0 g / m³ 2 ;

[0085] S2. Lay three layers of the above-mentioned EVA hot-melt mesh film on each side of the carbon fiber fabric. The size of the EVA hot-melt mesh film is 10×10cm. 2 Its density is 38 g / m³ 2 ;

[0086] S3. CF / EVA flexible composite membrane precursor was prepared by heating and pressurizing in a vacuum environment. The press was set to a temperature of 160℃, a pressure of 500N, and a heating and pressurizing time of 25min.

[0087] S4. Spray a PTFE hydrophobic coating on both sides of the precursor for 10 seconds to obtain the flexible carbon fiber composite membrane in this example, denoted as Pure FCFRP.

[0088] Performance testing

[0089] (1) Surface morphology test

[0090] The surface morphology of the composite film precursors in Example 3 and Comparative Example 1 was tested using scanning electron microscopy. The specific test results are as follows: Figure 2 As shown, where, Figure 2 (a) Figure 2 (b) and Figure 2 (c) SEM images of the composite membrane precursors in Comparative Example 3 at scale bars of 10 μm, 2 μm, and 5 μm, respectively. Figure 2(d) and Figure 2 (e) SEM images of the composite membrane precursors in Example 3, with scale bars of 5 μm and 2 μm, respectively. Figure 2 As shown in (a) to (c), the carbon fiber interfaces in Comparative Example 1 are clearly demarcated, with no fiber entanglement or mixing. At the interface junctions, EVA resin tightly wraps the fibers, and each carbon fiber is separated by a layer of EVA resin matrix. This indicates that the carbon fibers are fully impregnated with EVA resin, ensuring that the stress on the composite material can be fully and uniformly transferred to the carbon fibers through the EVA resin matrix, thus allowing the advantages of the composite film to be fully realized. Figure 2 As can be seen from (d) to (e), the Cu@CF / EVA flexible composite membrane precursor in Example 3 has an internal structure that is basically the same as that of the flexible carbon fiber composite membrane in Comparative Example 1.

[0091] (2) Elemental analysis test

[0092] Elemental analysis was performed on the composite membrane in Example 3, and the specific test results are as follows: Figure 3 As shown in Table 1 below.

[0093] Table 1. Elemental analysis results of the composite membrane in Example 3

[0094]

[0095]

[0096] As shown in Table 1, the composite membrane in Example 3 contains elements such as carbon, oxygen, fluorine, silicon, and copper. The role of metallic copper is to further enhance the electrical conductivity of the composite material, thereby achieving its self-healing effect; the elemental fluorine comes from the PTFE coating on the surface, achieving the hydrophobic effect.

[0097] (3) Mechanical property testing

[0098] The mechanical properties of Cu@FCFRP obtained in Example 3 and Pure FCFRP in Comparative Example 1 were tested according to the existing national standard GB / T228.1-2010 "Metallic Materials - Tensile Testing Method". The specific test results are as follows: Figure 4 As shown. By Figure 4 It can be seen that the mechanical properties of Example 3 are basically the same as those of Comparative Example 1. The fracture strength of both is around 1600 MPa, the elongation at break is around 6%, and the Young's modulus is around 3.8 GPa. That is, the introduction of copper particles did not reduce the mechanical properties of the original flexible carbon fiber composite material, and the mechanical properties are basically consistent with those of the original carbon fiber.

[0099] (4) Infrared testing

[0100] The infrared spectrum obtained in Test Example 3 is shown in the following figures. Figure 5 As shown, by Figure 5 It can be seen that the functional group absorption peaks of the components such as metallic copper, EVA, PTFE, and carbon fiber in Example 3 are distinctive.

[0101] (5) Thermodynamic performance testing

[0102] The Cu@FCFRP obtained in Example 3 and the Pure FCFRP composite film in Comparative Example 1 were subjected to TGA and DTG tests, respectively. The specific test results are as follows: Figure 6 As shown, by Figure 6 It can be seen that the residual weight percentage of the samples in Example 3 and Comparative Example 1 both showed a two-stage decrease during the heating process. The final residual weight percentage of both mainly exists in the use of copper particles in Example 3. The initial decrease occurred at around 320 degrees Celsius, proving that the initial degradation of the samples occurred at around 320 degrees Celsius. That is, the actual safe operating temperature range of the samples in Example 3 and Comparative Example 1 is at least 200 degrees Celsius.

[0103] (6) Surface morphology and water contact angle test of composite membrane

[0104] The surface morphology of the Cu@FCFRP composite film in Example 3 was tested using scanning electron microscopy. Water droplets were placed on the surface of the composite film in Example 3, and its water contact angle was measured. The test results of the surface morphology and water contact angle of the composite film in Example 3 are as follows: Figure 7 (a) and Figure 7 As shown in (b), by Figure 7 It can be seen that the water contact angle of the composite membrane in Example 3 is 120° to 130°, exhibiting excellent hydrophobic effect.

[0105] The surface of the composite membrane in Example 3 was damaged using a blade. The blade cut through the PTFE coating and the internal EVA hot-melt mesh, exposing the internal carbon fiber fabric and obtaining a damaged surface test sample. This sample was tested using a scanning electron microscope. Water droplets were then placed on the surface of the damaged surface test sample, and its water contact angle was measured. The surface morphology and water contact angle test results of the damaged surface of the composite membrane in Example 3 are as follows: Figure 8 (a) and Figure 8 As shown in (b), by Figure 8 It can be seen that the water contact angle of the damaged surface of the composite membrane in Example 3 is 95.5-98.1°, and the water droplets only stay at the crack for a few seconds before penetrating into the interior due to capillary effect. This shows that if the surface of the composite membrane is scratched, its moisture absorption effect will be significantly enhanced, thereby greatly reducing the service life of the composite membrane.

[0106] The damaged surface test sample of the composite membrane in Example 3 was energized with a voltage of 9V. The sample length was 10mm, and the energizing time was 30s, resulting in a repaired test sample of the composite membrane in Example 3. The repaired test sample was tested using a scanning electron microscope. Water droplets were placed on the surface of the repaired test sample, and the water contact angle was measured. The surface morphology and water contact angle test results of the repaired test sample of the composite membrane in Example 3 are as follows: Figure 9 (a) and Figure 9 As shown in (b), by Figure 9 It can be seen that after the EVA mesh layer in the composite membrane melts, it adheres to each other, which in turn causes the PTFE on the surface to close up as well, thereby enabling the surface of the composite membrane to self-repair. In Example 3, the water contact angle of the test sample after the composite membrane was repaired reached 118-120.9°, which is basically consistent with the water contact angle of the original undamaged composite membrane, further demonstrating that the composite membrane in Example 3 of the present invention has excellent self-repair performance.

[0107] (7) Electromagnetic shielding performance test

[0108] Test Procedure: Testing and inspection were conducted according to ASTM D4935-10, a standard that uses the insertion attenuation method to determine the electromagnetic shielding effect of the sample. The sample was cut into 22.9*10.2mm pieces, clamped between fixtures, and the signal was output through the output port of a vector array analyzer. After being filtered by the electromagnetic shielding material, the signal was received through the receiving port of the vector array analyzer. The electromagnetic shielding effects of the Cu@FCFRP sample obtained in Example 3 and the composite film samples Pure FCFRP and pure EVA hot-melt web material (EVA) in Comparative Example 1 in the 8.2-12.4GHz frequency band are as follows: Figure 10 As shown. Where T is the total shielding effectiveness; A is the absorption shielding effectiveness; and R is the reflection shielding effectiveness. From... Figure 10 It is known that the pure EVA film has the lowest shielding effect, with a total shielding effect of around 0. The Cu@FCFRP sample in Example 3 achieved a total shielding effectiveness of 40-45 dB, indicating that the attenuation of electromagnetic waves through the composite film of this invention reached 99%. Furthermore, the total shielding effectiveness T, absorption effectiveness A, and reflection effectiveness R did not change significantly with increasing frequency, indicating that this material maintains excellent performance even in high-frequency environments, making it an excellent electromagnetic shielding material. The sample in Example 3, due to the presence of metallic copper particles, possesses better absorption shielding effectiveness A, efficiently absorbing and reflecting electromagnetic radiation, effectively reducing the impact of interference and noise on the performance of the flexible composite film. This further demonstrates the superior electromagnetic compatibility performance of the flexible composite film in this invention, providing reliable support for its widespread application in fields such as electronic communication and wireless technology.

[0109] The performance of the composite membranes in Examples 1 and 2 was tested and found to be basically the same as that in Example 3.

[0110] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A flexible carbon fiber composite membrane, characterized in that: It includes a hydrophobic coating A, a hot-melt polymer layer A, a metal-coated carbon fiber layer, a hot-melt polymer layer B, and a hydrophobic coating B, which are stacked in sequence. The metal is selected from at least one of copper, silver, gold, aluminum, and iron; The materials of the hot melt polymer layer A and the hot melt polymer layer B are ethylene. A vinyl acetate copolymer hot melt web film; the number of hot melt polymer layer A and hot melt polymer layer B is 3 to 6; the thickness of hot melt polymer layer A and hot melt polymer layer B is 0.1 to 0.15 mm; The materials of the hydrophobic coating A and the hydrophobic coating B are polytetrafluoroethylene; The flexible carbon fiber composite film has a total shielding effectiveness of 35–45 dB in the 8.2–12.4 GHz frequency band.

2. The flexible carbon fiber composite membrane according to claim 1, characterized in that: The thickness of the hydrophobic coating A and the hydrophobic coating B is 0.005~0.01mm; And / or, the thickness of the metal-coated carbon fiber layer is 0.1~0.3 mm.

3. The flexible carbon fiber composite membrane according to claim 1, characterized in that: The water contact angle of the flexible carbon fiber composite membrane is 118~125°.

4. The method for preparing the flexible carbon fiber composite membrane according to any one of claims 1 to 3, characterized in that: Includes the following steps: S1: Coat the carbon fiber layer with metal to obtain a carbon fiber layer coated with metal; S2: Layer hot melt polymer layer A, the metal-coated carbon fiber layer and hot melt polymer layer B, and then hot press to obtain a composite film precursor; S3: Coating the upper and lower surfaces of the composite membrane precursor with hydrophobic coating A and hydrophobic coating B to obtain the flexible carbon fiber composite membrane.

5. A sensor, characterized in that: Includes the flexible carbon fiber composite membrane according to any one of claims 1 to 3.

6. An electromagnetic shielding material, characterized in that: Includes the flexible carbon fiber composite membrane according to any one of claims 1 to 3.

7. The application of the flexible carbon fiber composite film according to any one of claims 1 to 3 in the fields of electronics, communications or aerospace.

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