Preparation method of flexible montmorillonite fiber fabric wave-absorbing superstructure as well as composite material and application of flexible montmorillonite fiber fabric wave-absorbing superstructure

Abstract

The invention discloses a preparation method of a flexible montmorillonite fiber fabric wave-absorbing superstructure as well as a composite material and application of the flexible montmorillonite fiber fabric wave-absorbing superstructure. The preparation of the flexible montmorillonite fiber fabric wave-absorbing superstructure is realized through a resin mask auxiliary etching method. The montmorillonite fiber fabric wave-absorbing composite material disclosed by the invention realizes a wave-absorbing function on the basis of maintaining the characteristics of light weight, excellent mechanical property and the like of a traditional fiber composite material. The montmorillonite fiber fabric and the montmorillonite fiber fabric wave-absorbing superstructure are homogeneous with traditional fibers, so that the montmorillonite fiber fabric and the montmorillonite fiber fabric wave-absorbing superstructure have good compatibility with a resin-based composite material process and system, and compared with other wave-absorbing materials, the montmorillonite fiber fabric and the montmorillonite fiber fabric wave-absorbing superstructure are more beneficial to realizing function integration based on a layering process. The introduction of a wave-transparent window is realized through selective etching while the continuity of a fiber substrate is not influenced, so that the mechanical property of the fiber reinforced resin composite material is maintained. The montmorillonite fiber has good flexibility and thus has good special-shaped structure adaptability, the wave absorbing performance is further improved through the partition design, and meanwhile, the mechanical property of the fiber reinforced composite material is not affected.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of wave-absorbing stealth materials, and particularly relates to a preparation method of a flexible montmorillonite fiber fabric wave-absorbing superstructure, a composite material thereof and application. BACKGROUND

[0002] Existing wave-absorbing materials include the following types, each of which has defects. (1) Magnetic wave-absorbing material The magnetic wave-absorbing material mainly refers to a wave-absorbing material containing Fe, Co, Ni and other magnetic metal elements. Commonly used magnetic metal micropowder, magnetic oxide, polycrystalline metal fiber, magnetic nanometer microspheres and ferrite ceramic materials are used. This kind of material generally has high magnetic permeability in the microwave frequency band, and has both magnetic loss and dielectric loss mechanisms for electromagnetic waves, and is therefore widely used in the preparation of wave-absorbing materials. The advantage of the magnetic wave-absorbing material is excellent wave-absorbing performance, but for high-speed aerospace vehicles, its disadvantage is that it is difficult to be used in high-temperature environments due to the existence of Curie temperature. In addition, in order to achieve the ideal wave-absorbing effect, the magnetic wave-absorbing material needs a large thickness, so it is difficult to achieve lightweight, which also restricts its application in the aerospace field.

[0003] (2) Ceramic-based wave-absorbing material The ceramic-based wave-absorbing material is mainly represented by SiC ceramic and its composite material, and ferrite ceramic is also one of them. Some parts of aircraft and weapons, such as the nose cone, engine inlet and nozzle, need to withstand high temperatures. In order to meet the stealth requirements of these special parts, high-temperature wave-absorbing materials such as ceramic balls, ceramic fibers and ceramic-based composite materials are being actively developed at home and abroad. The ceramic wave-absorbing materials reported at present mainly include SiC, SiC / SiBCN, Si3N4, Al2O3 and Ti3SiC2. Among them, the research on SiC nanomaterials and ceramic composite materials is the most extensive. The advantages of the ceramic-based wave-absorbing material are high strength, high hardness, good oxidation resistance and high thermal stability, but its shortcomings are also obvious, that is, its dielectric properties and microwave absorption performance are weak, and it is difficult to achieve lightweight.

[0004] (3) Structural wave-absorbing metamaterial Magnetic and ceramic-based wave-absorbing materials gradually fade out of the historical stage due to the defects of large density, high weight, narrow absorption peak and weak wave-absorbing capacity, while structural wave-absorbing superstructures are gradually replacing traditional coating-type wave-absorbing materials and becoming the focus of researchers in this field at home and abroad because of their light weight, wide frequency band and strong wave-absorbing capacity. The structural supermaterials widely reported in recent years include frequency selective surface (FSS), electromagnetic band-gap (EBG), high impedance surface (HIS), artificial magnetic conductor (AMC) and phase gradient metasurface (PGM), which can realize precise manipulation of electromagnetic waves through special structure design. The wave-absorbing materials based on supermaterials are easy to realize the characteristics of thinness, lightness, wide frequency band and strong wave-absorbing capacity, and have wide application prospects in the military field. However, the wave-absorbing supermaterials widely studied at present usually use metal patches as the resistive layer, and most of them lack flexibility, making it difficult to adapt to special-shaped structures.

[0005] Although traditional fiber-reinforced composites perform excellently in mechanical properties, lightweight and corrosion resistance, they still have significant shortcomings in high-temperature resistance, interface stability and electromagnetic stealth function, making it difficult to meet the use requirements of future advanced equipment.

[0006] Therefore, the preparation of fiber-reinforced resin-based composites with wave-absorbing stealth performance that can adapt to special-shaped structures is an urgent problem to be solved. SUMMARY

[0007] To solve the problems of the prior art: (1) the existing wave-absorbing structure increases the weight and thickness of the overall structure, and cannot adapt to the long-term stable service requirements of aerospace equipment; (2) lack of flexibility, cannot adapt to special-shaped structural parts. Based on the advantages of lightweight of fiber-reinforced resin-based composites, a flexible graphene fiber fabric superstructure preparation strategy compatible with resin-based composite process and system is developed. The graphene fiber fabric superstructure is prepared by etching the surface of CVD grown graphene fiber fabric, and further combined with resin to endow traditional fiber-reinforced resin-based composites with wave-absorbing function. In addition, the graphene fiber fabric wave-absorbing superstructure layer and graphene fiber fabric heating layer can be integrated to realize the integration of wave-absorbing and electric heating functions. Further, based on the flexibility of graphene fabric, the surface designability and continuity are utilized to develop a partition design wave-absorbing structure suitable for special-shaped curved surface structures.

[0008] The application provides a method for preparing a flexible graphene fiber fabric wave-absorbing superstructure by using a resin mask-assisted etching method compatible with a composite system.

[0009] The method for preparing the flexible graphene fiber fabric wave-absorbing superstructure comprises the following steps: 1. A pattern mold is manufactured according to the pattern design and structure parameters of the graphene fiber fabric superstructure, and the obtained pattern mold is covered on the graphene fiber fabric. 2. A resin adhesive film is attached to the graphene fiber fabric covered with the pattern mold, and impregnation is performed, so that the resin is vertically penetrated into the graphene fiber fabric, and the graphene fiber in the covered area of the resin adhesive film is conformally coated. 3. The pattern mold and the resin adhesive film thereon are removed, the resin adhesive film in the pattern area is left on the graphene fiber fabric in a patterned manner, and a graphene fiber fabric attached with a patterned resin adhesive film is obtained. Or, the resin adhesive film set according to the pattern design and structure parameters of the graphene fiber fabric superstructure is directly attached to the graphene fiber fabric without performing steps 1) to 3), impregnation is performed, and a graphene fiber fabric attached with a patterned resin adhesive film is obtained. 4. A reactive ion etching treatment is performed to etch the graphene on the surface layer of the graphene fiber fabric in the area not covered by the patterned resin adhesive film, and a patterned graphene fiber fabric wave-absorbing superstructure is obtained.

[0010] In step 1) of the above method, the pattern mold can be a metal mold, a paper mold or the like; the pattern mold has the functions of covering the area not attached with the adhesive film and positioning. The graphene fiber fabric comprises a graphene glass fiber fabric, a graphene quartz fiber fabric and a graphene aluminum oxide fiber fabric, and the weaving mode can be plain weave, twill weave or satin weave. The graphene fiber fabric can be prepared by the following method: graphene is grown on the surface of the fiber fabric by using a chemical vapor deposition method, and a graphene fiber fabric is obtained. Before the growth of graphene, the fiber fabric is subjected to a de-wetting agent treatment, i.e., a de-gluing treatment. The de-wetting agent treatment is realized by a heat treatment method, i.e., the fiber fabric is heated in an air or oxygen atmosphere, the heating temperature can be 800-900 ℃, and the heating time can be 3-5 h. The chemical vapor deposition uses ethylene, acetylene, methane or the like as a carbon source, the growth temperature can be 900-1100 ℃, and the growth time can be 0.5-48 h. The fiber fabric comprises a glass fiber fabric, a quartz fiber fabric and an aluminum oxide fiber fabric (aluminum oxide content: 72%-99%), and the weaving mode can be plain weave, twill weave or satin weave; the thickness of the fiber fabric can be 0.1-0.3 mm.

[0011] The material of the resin film is epoxy resin; The impregnation operation is to send the attached resin film of the Molyene fiber fabric into a vacuum bag, vacuumize to (-850) to (-1000) mbar, and keep the temperature at 50-85℃ for 20-60 min; In the step 4) of the above method, the reaction ion etching treatment is to use oxygen plasma to bombard graphene, break the carbon-carbon bond in graphene, and make carbon atoms react with oxygen atoms to generate carbon monoxide (CO) and carbon dioxide (CO2) gas, so as to etch graphene; The oxygen-containing gas source used in the reaction ion etching treatment is one or both of air and oxygen, the oxygen-containing active reaction species (oxygen plasma) can be adjusted by the ratio of the oxygen-containing gas source to the inert gas source (helium or argon), the power is 30-100% of the instrument setting value, and the processing time can be 10 min-120 min.

[0012] The patterned Molyene fiber fabric wave-absorbing superstructure prepared by the above method also belongs to the protection scope of the present application.

[0013] The patterned Molyene fiber fabric wave-absorbing superstructure comprises: a fiber fabric, at least one array pattern graphene unit (wave-absorbing area) conformally coated on the surface of the fiber fabric, and resin conformally coated on the surface of the array pattern graphene unit.

[0014] The present application also provides a wave-absorbing composite material or wave-absorbing composite structure containing the above patterned Molyene fiber fabric wave-absorbing superstructure.

[0015] The wave-absorbing composite material or wave-absorbing composite structure containing the patterned Molyene fiber fabric wave-absorbing superstructure is prepared by a method comprising the following steps: 1) directly laminating the patterned Molyene fiber fabric wave-absorbing superstructure with one or more of glass fiber reinforced resin prepreg, copper electrode Molyene fiber fabric reinforced resin prepreg, and carbon fiber reinforced resin prepreg to obtain a wave-absorbing composite preform, or laminating resin film on the patterned Molyene fiber fabric wave-absorbing superstructure again, impregnating enough resin to fully contact the fibers to coat the etched area, and then laminating one or more of glass fiber reinforced resin prepreg, copper electrode Molyene fiber fabric reinforced resin prepreg, and carbon fiber reinforced resin prepreg to obtain a wave-absorbing composite preform; 2) curing the obtained wave-absorbing composite preform to obtain a wave-absorbing composite material or wave-absorbing composite structure; In the step 1) of the above method, the patterned Molyene fiber fabric wave-absorbing superstructure is alternately laminated with one or more of glass fiber reinforced resin prepreg, copper electrode Molyene fiber fabric reinforced resin prepreg, and carbon fiber reinforced resin prepreg. The patterned molybdenum fabric wave-absorbing superstructure in the wave-absorbing composite preform is at least one layer; One or more of the glass fiber reinforced resin prepreg, the molybdenum fabric wave-absorbing superstructure reinforced resin prepreg containing copper electrode and the carbon fiber reinforced resin prepreg is at least one layer. The resin in the patterned molybdenum fabric wave-absorbing superstructure is consistent with the resin in the glass fiber reinforced resin prepreg, the molybdenum fabric wave-absorbing superstructure reinforced resin prepreg containing copper electrode and the carbon fiber reinforced resin prepreg. When the molybdenum fabric wave-absorbing superstructure reinforced resin prepreg containing copper electrode is laminated with the patterned molybdenum fabric wave-absorbing superstructure, the obtained wave-absorbing composite material or wave-absorbing composite structure is a wave-absorbing-heating integrated functional material.

[0016] The application further provides a circular arc curved surface composite wave-absorbing special-shaped part containing the patterned molybdenum fabric wave-absorbing superstructure.

[0017] The circular arc curved surface composite wave-absorbing special-shaped part contains at least two patterned molybdenum fabric wave-absorbing superstructures arranged in different regions. The patterned molybdenum fabric wave-absorbing superstructures in the two regions are both composed of a fiber fabric and an array pattern graphene unit (a wave-absorbing region) conformally coated on the surface of the fiber fabric, and the shapes and / or sizes of the array pattern graphene units in the wave-absorbing superstructures arranged in the two regions are different.

[0018] The application further provides a molybdenum fabric wave-absorbing superstructure composite material containing a wave-transparent window.

[0019] The molybdenum fabric wave-absorbing superstructure composite material containing a wave-transparent window contains the patterned molybdenum fabric wave-absorbing superstructure, the wave-transparent window is a region not covered by graphene, and the remaining regions are wave-absorbing regions containing array pattern graphene units conformally coated on the surface of the fiber fabric.

[0020] Compared with traditional fiber reinforced composite materials, the molybdenum fabric wave-absorbing composite material of the application has the functions of wave absorption while retaining the characteristics of traditional fiber composite materials, such as light weight and excellent mechanical properties. The molybdenum fabric and the molybdenum fabric wave-absorbing superstructure have the same structure as traditional fibers, and thus have good compatibility with resin-based composite material processes and systems. Based on the lamination process, compared with other wave-absorbing materials, the molybdenum fabric wave-absorbing composite material is more conducive to functional integration, such as giving glass fiber composite materials, carbon fiber composite materials, and molybdenum fiber composite materials with stealth function and wave-absorbing-heating integrated function.

[0021] The designability of the surface graphene functional layer of the shell-core structure molybdenum fiber enables functional partition design, and the introduction of a wave-transparent window can be easily realized through selective etching without affecting the continuity of the fiber substrate and thus maintaining the mechanical properties of the fiber reinforced resin composite material.

[0022] The montmorillonite fiber has good flexibility, and thus has good special-shaped structure adaptability. For a special-shaped structure, the partition design is beneficial to further improve the wave absorption performance, and meanwhile does not affect the mechanical properties of the fiber reinforced composite material. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The process flow chart of the montmorillonite fiber fabric wave absorption superstructure and the montmorillonite fabric wave absorption superstructure composite material prepared by the resin mask assisted etching method in the application is shown in the figure.

[0024] Figure 2 The schematic diagram of the montmorillonite fiber covered by the resin adhesive film in the vertical penetration immersion of the resin adhesive film in the application is shown in the figure.

[0025] Figure 3 In the figure, a is the geometric parameter of the superstructure fractal pattern prepared in Example 1 of the application; and b is the actual picture of the fractal montmorillonite fabric superstructure prepared in Example 1 of the application.

[0026] Figure 4 The wave absorption performance of the montmorillonite fiber fabric wave absorption superstructure resin matrix composite material sample prepared in Example 1 of the application is shown in the figure.

[0027] Figure 5 The heating infrared imaging figure of the wave absorption-heating integrated montmorillonite fabric superstructure composite material prepared in Example 1 of the application is shown in the figure.

[0028] Figure 6 The wave absorption performance comparison of the carbon fiber and the montmorillonite superstructure with the carbon fiber and the aluminum plate as the reflection layer in Example 2 of the application is shown in the figure.

[0029] In the figure 7, a is the photograph of the montmorillonite fiber fabric superstructure containing a wave transmission window prepared in Example 3 of the application; and b is the electromagnetic performance of the wave transmission window and the wave absorption area.

[0030] Figure 8 In the figure, a is the curved surface partition design scheme of the curved surface special-shaped part prepared in Example 4 of the application; and b is the actual picture of the partition superstructure and the curved surface structure.

[0031] Figure 9 The wave absorption performance comparison of the non-uniform curved surface superstructure wave absorption composite material and the uniform curved surface superstructure wave absorption composite material prepared in Example 4 of the application is shown in the figure. DETAILED DESCRIPTION

[0032] The application will be further described in detail below in combination with specific embodiments. The embodiments provided below are only for illustrating the application, and are not intended to limit the scope of the application. The embodiments provided below can be used as a guide for further improvement by those skilled in the art, and do not constitute any limitation on the application.

[0033] The experimental methods in the following examples are conventional methods, and are performed according to the techniques or conditions described in the literature in the art or according to the product instructions, unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained commercially, unless otherwise specified.

[0034] Example 1, Preparation of wave-absorbing and heating integrated composite material This example is prepared according to the flow chart shown in Figure 1 The specific steps are as follows: Step 1, degumming of continuous glass fiber fabric: in air atmosphere, set the temperature to 850 ℃, and treat for 3 h; grow graphene on the degummed continuous glass fiber fabric using ethylene as the carbon source to obtain continuous graphene glass fiber fabric (sheet resistance is 35 Ω / sq), wherein the growth temperature of graphene is 900 ℃, and the growth time is 9 h; Step 2, manufacture pattern paper mold by laser processing technology; Step 3, cover the paper mold plate on the graphene glass fiber fabric, and attach the epoxy resin adhesive film; Step 4, send the graphene fiber fabric with the attached resin adhesive film into a vacuum bag, and vacuumize to -930 mbar, and immerse at a temperature of 70 ℃ for 45 min to make the epoxy resin adhesive film fully wrap the pattern area graphene glass fiber (schematic diagram as shown in Figure 2 ); Step 5, remove the paper mold, and only the resin adhesive film in the pattern area penetrates into the interior of the graphene glass fiber fabric and wraps it, and the resin adhesive film in the non-pattern area remains on the paper mold and is removed with the mold plate; Step 6, perform reactive ion etching treatment on the graphene glass fiber fabric wrapped with part of the resin, and the reactive ion etching treatment uses oxygen as the gas source, adopts a medium frequency power supply, the power is 100% (300 W), and the treatment time is 120 min, to obtain a graphene glass fiber fabric wave-absorbing superstructure preform (actual object diagram is shown in Figure 3 b); Step 7, add copper electrodes to the graphene glass fiber fabric by electroplating, use CuSO4 acid solution as the electroplating solution, use copper plate as the anode, and use the graphene fiber fabric as the cathode. Apply a voltage (about 4 V), and pass electricity for 5 min, so that the orange copper electrodes are deposited on the graphene fiber, which is beneficial to realize uniform flow. At the breakpoint of the two electroplated copper electrodes, weld a copper foil electrode with a length of 6 cm, which is convenient for connection with the power supply; ​Step 8, lay-up of composite preform, from top to bottom lay-up scheme: 20 layers of glass fiber reinforced epoxy resin prepreg, 1 layer of Moven glass fiber fabric wave absorbing superstructure preform with fractal pattern (prepared in step 6), 30 layers of glass fiber reinforced epoxy resin prepreg, 1 layer of Moven glass fiber fabric with copper electrode (prepared in step 7); Step 9, coat the release agent on the glass plate, place the composite preform on the glass plate, and vacuum bag; Step 10, vacuum bag is placed in the oven for heating and curing, and Moven fiber fabric wave absorbing superstructure resin matrix composite is obtained after curing.

[0035] In step 3, the epoxy resin film is attached to make the resin mass ratio of the pattern area 39.02%; In step 6, the template cuts the square fractal pattern of the periodic array, and the fractal pattern structure parameters are described as follows: the center square has a side length of 6 mm, and the center square is connected to four squares with a side length of 3 mm through four corners; the unit period is 20 mm (as shown in Figure 3 ).

[0036] At 16.4 GHz, the Moven fiber fabric superstructure composite absorption peak (a) RL min ) reaches -20.1 dB; in the range of 2-18 GHz, the effective absorption bandwidth (EAB) reaches 9.76 GHz, the effective absorption coverage rate of X band (8-12 GHz) is 100%, and the effective absorption coverage rate of Ku band (12-18 GHz) reaches 70% (when testing the wave absorbing performance, 3 mm aluminum plate is used as the reflecting plate) (as shown in Figure 4 ).

[0037] The voltage applied to the Moven fiber fabric heating layer is 33V, the current is 4A, and the temperature of the Moven fabric composite is about 80℃.

[0038] Figure 5 The heating infrared imaging diagram of the prepared wave absorbing-heating integrated Moven fabric superstructure composite.

[0039] Example 2 This example is the same as example 1, except that: Lay-up of composite preform, from top to bottom lay-up scheme: 20 layers of glass fiber reinforced epoxy resin prepreg, 1 layer of Moven glass fiber fabric superstructure with fractal pattern, 30 layers of glass fiber reinforced epoxy resin prepreg, 1 layer of Moven glass fiber fabric with copper electrode, and 1 layer of carbon fiber reinforced prepreg.

[0040] Figure 6To compare the wave-absorbing performance of carbon fiber and molybdenum fabric superstructure with carbon fiber and aluminum plate as reflecting layer.

[0041] Compared with Example 1, the wave-absorbing performance of the molybdenum fabric superstructure composite placed on the carbon fiber is basically not affected. The molybdenum fabric superstructure composite and the corresponding carbon fiber composite system and process have good compatibility, which can give the strong reflection carbon fiber composite a wave-absorbing stealth function.

[0042] Example 3, preparation of molybdenum fabric superstructure composite with wave-transparent window In this example, the molybdenum glass fabric wave-absorbing superstructure preform was prepared according to the operation of steps 1-6 in Example 1, wherein the superstructure preform was divided into a wave-absorbing region and a wave-transparent window, and the total size of the flat plate was 300 mm x 300 mm, wherein a square region of 180 mm x 180 mm at the center of the flat plate was designed as a wave-transparent window without graphene, and the remaining region was a wave-absorbing region containing an array of molybdenum fabric units (fractal pattern structure parameters are described as follows: the center square has a side length of 6 mm, and the center square is connected to four squares with a side length of 3 mm through four top corners; the unit period is 20 mm) (as shown in FIG. 1a). Figure 7

[0043] The composite preform was laid up from top to bottom according to the following scheme: 30 layers of glass fiber reinforced epoxy resin prepreg, 1 layer of molybdenum glass fabric wave-absorbing superstructure preform, and 20 layers of glass fiber reinforced epoxy resin prepreg.

[0044] Figure 7 FIG. 1b shows the electromagnetic properties of the wave-transparent window and the wave-absorbing region. The results show that the wave-transparent window has a transmittance to electromagnetic signals in the frequency range of 8-18 GHz.

[0045] Example 4, preparation of molybdenum fabric superstructure composite with wave-transparent window and wave-absorbing region The arc surface composite wave-absorbing special-shaped part includes: a molybdenum alumina fabric preform with different period superstructures in the equivalent incident angle partition, glass fiber reinforced epoxy resin prepreg before and after the molybdenum alumina fabric superstructure, and a carbon fiber reflecting layer at the bottom.

[0046] The molybdenum alumina fabric preform with different period superstructures was prepared according to steps 1-6 in Example 1: after removing the glue from the γ-alumina fabric, graphene was grown on the γ-alumina fabric with a thickness of 0.16 mm using ethylene as the carbon source, at a temperature of 900 ℃ for 14 h, to obtain a molybdenum alumina fabric with a sheet resistance of 50 Ω / sq; a resin-assisted mask method was used to prepare a molybdenum alumina fabric preform with different period superstructures in the partition. ​The curved surface sub-area of the molybdenum aluminide fiber fabric preform with different period superstructure is shown in FIG. 1 Figure 8 The superstructure unit period of the A area (equivalent incident angle 0°-20°) is 15 mm, and the superstructure unit period of the B area (equivalent incident angle 20°-40°) is 13 mm. The pattern is a square fractal pattern of a period array, and the fractal pattern structure parameters are described as follows: the center square has a side length of 6 mm, and the center square is connected to four squares with a side length of 3 mm through four top corners.

[0047] The arc curved surface special-shaped mold is manufactured by using five-axis machining technology and poly (methyl methacrylimide) (PMI) foam as a raw material, and the arc curved surface special-shaped male mold is obtained by attaching release cloth. The composite preform is manufactured by layering, the PMI curved surface foam is used as a mold, and the pre-impregnated material is sequentially layered and attached from top to bottom: 25 layers of glass fiber reinforced epoxy pre-impregnated material, 1 layer of molybdenum aluminide fiber fabric preform with different period superstructure in sub-areas, 20 layers of glass fiber reinforced epoxy pre-impregnated material, and 1 layer of carbon fiber reinforced pre-impregnated material. After the layering and attachment are completed, a vacuum bag is punched, the vacuum degree is greater than 950 mbar, and the oven vacuum bag pressure curing process is used to cure the obtained wave-absorbing composite preform, and the molybdenum fabric superstructure wave-absorbing composite curved surface special-shaped part is obtained after the curing is completed. Figure 8 The sub-area superstructure and the curved surface structure are shown in FIG. 1b), and the reflectivity peak and bandwidth in the range of 2-18 GHz are tested. Figure 9 The wave-absorbing performance of the uniform and non-uniform curved surface superstructure wave-absorbing composite material (the non-uniform curved surface superstructure is prepared by the method of Example 4, and the uniform curved surface superstructure is prepared by the method of Example 1 steps 1-6, wherein the center square has a side length of 6 mm, the center square is connected to four squares with a side length of 3 mm through four top corners, the unit period is 15 mm, and the layering scheme is the same as that of the molybdenum fabric superstructure wave-absorbing composite curved surface special-shaped part in Example 4). The results show that by setting the sub-area superstructure of the arc curved surface composite wave-absorbing special-shaped part, more balanced wave-absorbing performance can be obtained, and the mechanical performance of the composite part is not affected.

[0048] The present application has been described in detail. For those skilled in the art, without departing from the purpose and scope of the present application, and without unnecessary experiments, the present application can be implemented in a wide range under the same parameters, concentrations and conditions. Although the present application gives a special example, it should be understood that further improvements can be made to the present application. In summary, according to the principle of the present application, the present application intends to include any change, use or improvement of the present application, including changes made by conventional techniques known in the art, which deviates from the scope disclosed in the present application.

Claims

1. A method for preparing a flexible styrene fiber fabric microwave absorbing superstructure, comprising the following steps: 1) Based on the pattern design and structural parameters of the montmorillonite fiber fabric superstructure, a pattern mold is manufactured, and the obtained pattern mold is applied to the montmorillonite fiber fabric; 2) Apply the resin film to the montmorillonite fiber fabric covered with the pattern mold, impregnate it, so that the resin penetrates vertically into the montmorillonite fiber fabric and conformally covers the montmorillonite fibers in the area covered by the resin film. 3) Remove the pattern mold and the resin film on it. The resin film in the patterned area remains on the montmorillonite fiber fabric in a patterned manner to obtain a montmorillonite fiber fabric with a patterned resin film attached. Alternatively, skipping steps 1)-3), directly attach the resin film based on the pattern design and structural parameters of the montmorillon fiber fabric superstructure to the montmorillon fiber fabric, impregnate it, and obtain the montmorillon fiber fabric with the patterned resin film attached. 4) Reactive ion etching process: Etching the graphene on the surface of the montmorillonite fiber fabric in the area not covered by the patterned resin film to obtain the patterned montmorillonite fiber fabric microwave absorbing superstructure.

2. The method according to claim 1, characterized in that, The montmorillonite fiber fabric includes montmorillonite glass fiber fabric, montmorillonite quartz fiber fabric, and montmorillonite alumina fiber fabric. The resin film is made of epoxy resin; The impregnation process involves placing the resin-coated montmorillonite fiber fabric into a vacuum bag, evacuating it to -850 to (-1000) mbar, and maintaining it at a temperature of 50-85°C for 20-60 minutes.

3. The method according to claim 1, characterized in that, In step 4), the oxygen source used in the reactive ion etching process is one or both of air and oxygen, and the processing time is 10 min-120 min.

4. A patterned montmorillonite fiber fabric microwave absorbing superstructure prepared by the method of any one of claims 1-3, wherein the patterned montmorillonite fiber fabric microwave absorbing superstructure comprises: The fiber fabric, at least one array patterned graphene unit conformally coated on the surface of the fiber fabric, and a resin conformally coated on the surface of the array patterned graphene unit.

5. A microwave absorbing composite material or microwave absorbing composite structure containing the patterned montmorillonite fiber fabric microwave absorbing superstructure as described in claim 4.

6. A method for preparing the microwave absorbing composite material or microwave absorbing composite structure containing the patterned montmorillonite fiber fabric microwave absorbing superstructure as described in claim 5, comprising the following steps: 1) directly laminating the patterned montmorillonite fiber fabric microwave absorbing superstructure with one or more of glass fiber reinforced resin prepreg, copper electrode montmorillonite fiber fabric reinforced resin prepreg, and carbon fiber reinforced resin prepreg to obtain a microwave absorbing composite preform; or, again laminating a resin film on the patterned montmorillonite fiber fabric microwave absorbing superstructure, impregnating it to ensure sufficient resin contact with the fibers to cover the etched area fibers, and then laminating it with one or more of glass fiber reinforced resin prepreg, copper electrode montmorillonite fiber fabric reinforced resin prepreg, and carbon fiber reinforced resin prepreg to obtain a microwave absorbing composite preform; 2) The obtained microwave absorbing composite preform is cured to obtain microwave absorbing composite material or microwave absorbing composite structural component.

7. The method according to claim 6, characterized in that, In step 1), the patterned montmorillonite fiber fabric microwave absorbing superstructure is alternately laid with one or more of the following: glass fiber reinforced resin prepreg, copper electrode montmorillonite fiber fabric reinforced resin prepreg, and carbon fiber reinforced resin prepreg. In the microwave absorbing composite preform, the patterned montmorillonite fiber fabric microwave absorbing superstructure has at least one layer; At least one or more of the glass fiber reinforced resin prepreg, copper electrode montmorillon fiber fabric reinforced resin prepreg, and carbon fiber reinforced resin prepreg are laid in one layer. The resin in the patterned montmorillonite fiber fabric microwave absorbing superstructure is the same as the resin in the glass fiber reinforced resin prepreg, the copper electrode montmorillonite fiber fabric reinforced resin prepreg, and the carbon fiber reinforced resin prepreg.

8. A curved surface composite microwave absorbing component comprising the patterned montmorillonite fiber fabric microwave absorbing superstructure as described in claim 4, characterized in that, The arc-shaped composite material absorbing component contains at least two partitioned patterned montmorillon fiber fabric absorbing superstructures. The patterned graphene fiber fabric microwave absorbing superstructures contained in the two partitions both include fiber fabric and arrayed patterned graphene units conformally covering the surface of the fiber fabric, and the arrayed patterned graphene units in the microwave absorbing superstructures set in the two partitions have different shapes and / or sizes.

9. A microwave-absorbing superstructure composite material containing a wave-transparent window made of montmorillonite fiber fabric, characterized in that, The composite material contains the patterned graphene fiber fabric microwave absorbing superstructure as described in claim 4, including a microwave absorbing region and a microwave transmission window; the microwave transmission window is a region that is not covered with graphene; the remaining region is a microwave absorbing region containing an array of patterned graphene units conformally covering the surface of the fiber fabric.

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