Wave absorbing / bearing integrated fiber reinforced resin-based composite material as well as preparation method and application thereof

Abstract

The invention discloses a wave-absorbing / bearing integrated fiber-reinforced resin-based composite material as well as a preparation method and application thereof, and particularly relates to the field of electromagnetic wave absorption. Comprising a fiber reinforcement body and a resin matrix, and the resin matrix fills gaps of the fiber reinforcement body and wraps the surface of the fiber reinforcement body; the fiber reinforcement body comprises a first fiber reinforcement body and a second fiber reinforcement body which are laminated; each of the first fiber reinforcement and the second fiber reinforcement comprises a fiber fabric, and the surface of the fiber fabric is coated with a metal sulfide; a fiber fabric with periodically arranged patterns is formed on the surface of the second fiber reinforcement body; wherein the periodically arranged patterns are formed by ultraviolet lithography. On the basis of the mode, the efficient wave absorbing capacity and the high bearing capacity of the fiber reinforced resin matrix composite can be guaranteed at the same time.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave absorption, and more particularly to a fiber-reinforced resin matrix composite material that integrates wave absorption and load bearing, its preparation method, and its application. Background Technology

[0002] In recent years, with the rapid development of electronic information technology, the demand for integrated structural and functional materials has become increasingly urgent, requiring materials to simultaneously provide excellent mechanical load-bearing performance and outstanding microwave absorption performance. Traditional material design often considers functions separately, resulting in large system weight and volume. High-strength, lightweight fiber-reinforced resin matrix composites are excellent load-bearing structural materials, but their electromagnetic properties are poor, and they lack microwave absorption performance. To endow composite materials with microwave absorption capabilities, researchers have tried adding microwave-absorbing fillers to the resin matrix; however, this physical mixing method often sacrifices the material's mechanical properties, and the microwave absorption performance is difficult to control and the effect is unsatisfactory. To overcome the bottleneck of excessive thickness caused by the "quarter-wavelength" limitation of traditional microwave-absorbing materials, researchers have introduced the design concept of metamaterials, especially ultrathin microwave absorbers based on electromagnetic metasurfaces. This design achieves ultrathin and efficient absorption of electromagnetic waves by constructing subwavelength periodic structures and utilizing local electromagnetic resonance.

[0003] However, integrating these sophisticated metamaterial structures into high-strength composite materials presents significant manufacturing challenges: using traditional machining methods, such as milling or scribing, to create periodic patterns on the cured structure inevitably introduces stress concentration points and microcracks on the surface, severely compromising the original load-bearing capacity, fatigue life, and reliability of the composite material. Therefore, overall, fiber-reinforced resin matrix composites still face the challenge of achieving efficient wave absorption while maintaining high load-bearing capacity. Summary of the Invention

[0004] The main objective of this application is to provide a fiber-reinforced resin matrix composite material that integrates wave absorption and load bearing, as well as its preparation method and application, in order to solve the problem that existing materials cannot simultaneously guarantee high wave absorption capacity and strong load bearing capacity.

[0005] To achieve the above objectives, this application provides a fiber-reinforced resin matrix composite material integrating microwave absorption and load bearing, comprising a fiber reinforcement and a resin matrix. The resin matrix fills the voids in the fiber reinforcement and covers the surface of the fiber reinforcement. The fiber reinforcement includes a first fiber reinforcement and a second fiber reinforcement stacked together. Both the first fiber reinforcement and the second fiber reinforcement have a core-shell structure, wherein the core structure is a fiber fabric and the shell structure is a metal sulfide. The surface of the second fiber reinforcement has a fiber fabric with a periodically arranged pattern, wherein the periodically arranged pattern is formed by ultraviolet lithography.

[0006] Optionally, the metal sulfide is copper, nickel, or silver; the fibrous fabric includes oxide fibers or chemical fibers; and the resin matrix includes thermosetting resins or thermoplastic resins.

[0007] Optionally, the upper and / or lower surfaces of the second fiber reinforcement are formed into a fiber fabric with a periodically arranged pattern.

[0008] Optionally, the fiber reinforcement has a constant cross-section structure or a variable cross-section structure in the thickness direction.

[0009] Optionally, the cross-sectional structure of the fiber reinforcement in the thickness direction is a variation or combination of one or more of the following: pyramidal, rectangular, hourglass, and spindle-shaped.

[0010] To achieve the above objectives, this application also provides a method for preparing a fiber-reinforced resin matrix composite material that integrates wave absorption and load bearing, comprising: preparing a first fiber reinforcement and a second fiber reinforcement respectively; stacking the second fiber reinforcement on top of the first fiber reinforcement to obtain a fiber reinforcement; and introducing a resin matrix into the fiber reinforcement through a liquid molding process or a solid molding process to obtain a fiber-reinforced resin matrix composite material.

[0011] Optionally, the preparation method of the first fiber reinforcement includes: coating a metal layer on the surface of the fiber fabric; converting the metal layer into a metal sulfide layer by in-situ liquid phase vulcanization to obtain the first fiber reinforcement.

[0012] Optionally, the preparation method of the second fiber reinforcement includes: coating a metal layer on the surface of a fiber fabric; performing ultraviolet photolithography on the surface of the fiber fabric coated with the metal layer through a mask to form a periodically arranged pattern; and converting the metal layer of the fiber fabric with the periodically arranged pattern into a metal sulfide layer through in-situ liquid phase vulcanization to obtain the second fiber reinforcement.

[0013] Optionally, ammonium sulfide or sodium sulfide solution may be used in the in-situ liquid phase sulfidation process; Liquid molding processes include hand lay-up molding, resin transfer molding, or vacuum infusion molding, while solid molding processes include autoclave molding, compression molding, or vacuum bag molding.

[0014] To achieve the above objectives, this application also provides an application of a fiber-reinforced resin matrix composite material with integrated wave absorption and load bearing in the field of electromagnetic wave absorption.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: This invention relates to a fiber-reinforced resin matrix composite material integrating microwave absorption and load bearing. The fiber reinforcement comprises a first fiber reinforcement with a planar structure and a second fiber reinforcement with a periodically arranged pattern on its surface. The introduction of the second fiber reinforcement endows the composite material system with metamaterial characteristics, greatly enhancing the microwave absorption performance of the composite material. Due to the lightweight nature of the resin matrix, the composite material retains its lightweight characteristics after being combined with the fiber reinforcement. In the preparation method, the periodic pattern is formed by ultraviolet lithography, which avoids macroscopic mechanical damage to the fiber skeleton and load bearing structure, thereby ensuring the excellent load bearing capacity of the composite material. The first and second fiber reinforcements have a core-shell structure, and Cu2S nanosheets grown on the surface of SiO2 fibers form a large number of heterogeneous interfaces with SiO2. Under the action of an electromagnetic field, charges accumulate at the interface between the two heterogeneous materials, forming a capacitor-like structure. These capacitor-like structures store and consume the energy of the external electromagnetic field, enhancing the interfacial polarization loss of the material and facilitating the absorption of electromagnetic waves. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the cross-sectional shape of a fiber-reinforced resin matrix composite material that integrates wave absorption and load bearing according to this application; Figure 2 Optical photographs of the fiber reinforcements prepared at different stages in Example 1; Figure 3 These are scanning electron microscope images of the fiber reinforcements prepared at different stages in Example 1; Figure 4 The periodic pattern mask is customized as described in Example 1; Figure 5 These are optical photographs of the SiO2-Cu fiber fabric before and after double-sided ultraviolet lithography in Example 1; Figure 6 This is a schematic diagram of the square periodic pattern used in Example 1; Figure 7 This is the result of optimizing the periodic pattern structure parameters h1 and a2 in Example 1; Figure 8 This is the result of further optimization of the periodic pattern structure parameters h1 and a2 in Example 1; Figure 9 This represents further optimization results of the structural parameters for the periodic patterns h1=1.3 mm and h1=1.4 mm in Example 1; Figure 10 The final reflection loss diagram of the optimized model of the periodic pattern a2 from 7 mm to 7.5 mm in Example 1; Figure 11 The simulation results are for the case without a periodic pattern in Example 1; Figure 12 This is a schematic diagram of a circular periodic pattern used in Example 1; Figure 13 This is the final reflection loss diagram of the periodic circular optimization model in Example 1; Figure 14 Optical photographs of the periodically patterned SiO2-Cu fiber fabric in Example 1 before and after vulcanization; Figure 15 An optical photograph of the fiber-reinforced resin matrix composite material that integrates wave absorption and load bearing in Example 1; Figure 16 The reflectivity of the fiber-reinforced resin matrix composite material with integrated wave / load bearing in Example 1; Figure 17 The tensile strength of the fiber-reinforced resin matrix composite material that integrates wave absorption and load bearing in Example 1.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The first embodiment of the present invention provides a fiber-reinforced resin matrix composite material integrating microwave absorption and load bearing, comprising a fiber reinforcement and a resin matrix, wherein the resin matrix fills the voids of the fiber reinforcement and covers the surface of the fiber reinforcement; the fiber reinforcement comprises a first fiber reinforcement and a second fiber reinforcement stacked together; both the first fiber reinforcement and the second fiber reinforcement are core-shell structures, wherein the core structure is a fiber fabric and the shell structure is a metal sulfide; the surface of the second fiber reinforcement is formed with a fiber fabric of a periodically arranged pattern; wherein the periodically arranged pattern is formed by ultraviolet lithography.

[0020] For example, the metal sulfide may be copper, nickel, or silver. The fibrous fabric may include oxide fibers or chemical fibers. Oxide fibers may include silica fibers, alumina fibers, or zirconium oxide fibers, while chemical fibers may include Kevlar fibers or PBO fibers. The resin matrix may include thermosetting resins or thermoplastic resins. Thermosetting resins may include epoxy resins, polyimide resins, or phenolic resins, while thermoplastic resins may include polypropylene, polyamide, or polyetheretherketone.

[0021] Furthermore, the upper and / or lower surfaces of the second fiber reinforcement form a fiber fabric with a periodically arranged pattern. The fiber reinforcement has a constant or variable cross-section structure in the thickness direction, meaning its cross-sectional dimensions or shape are variable or fixed. Cross-sectional structures include variations or combinations of one or more of the following: pyramidal, rectangular, hourglass, and spindle-shaped. See [link to documentation]. Figure 1 From left to right, the cross-sections correspond to rectangular, pyramidal, hourglass, and spindle-shaped structures, respectively. The main advantages of the rectangular structure are its simple manufacturing and high material utilization. In terms of load-bearing capacity, it provides a uniform stress distribution, making it an ideal choice for basic laminated slabs and simple structural components. In terms of wave absorption, its uniform thickness allows for precise control of absorption performance at specific frequencies. The pyramidal structure's advantages lie in its efficient bending and shear resistance, maximizing stiffness by concentrating material on the load-bearing side. In terms of wave absorption, the gradient change in its cross-sectional thickness facilitates a gradual change in electromagnetic impedance, thereby reducing surface reflection and achieving a wider frequency band absorption effect. The core advantage of the hourglass structure is its excellent resistance to delamination and impact. Adjacent units achieve mechanical interlocking through a central contraction (neck), significantly improving interlaminar shear strength. Electromagnetically, the geometric abrupt change can create a local notch effect, enhancing the dissipation and loss of electromagnetic waves. The main advantage of the spindle-shaped structure is that it maximizes bending stiffness and buckling stability by concentrating the material at the center to maximize the moment of inertia of the section. At the same time, the smooth transition helps to disperse stress and extend fatigue life. In terms of wave absorption, its curved surface design achieves optimal impedance matching and can achieve efficient broadband wave absorption through the focusing effect.

[0022] In this embodiment, the fiber reinforcement comprises a first fiber reinforcement with a planar structure and a second fiber reinforcement with a periodically arranged pattern on its surface. The introduction of the second fiber reinforcement endows the composite material system with metamaterial characteristics, greatly enhancing the wave absorption performance of the composite material. The periodic pattern formed by ultraviolet lithography avoids macroscopic mechanical damage to the fiber skeleton and load-bearing structure, thereby ensuring the excellent load-bearing capacity of the composite material. Since the resin matrix is ​​lightweight, the composite material retains its lightweight characteristics after being combined with the fiber reinforcement. With the first and second fiber reinforcements having a core-shell structure, a large number of heterogeneous interfaces are formed between the Cu2S nanosheets grown on the surface of SiO2 fibers and SiO2. Under the action of an electromagnetic field, charges accumulate at the interface between the two heterogeneous materials, forming a capacitor-like structure. These capacitor-like structures store and consume the energy of the external electromagnetic field, enhancing the interfacial polarization loss of the material and facilitating the absorption of electromagnetic waves by the material.

[0023] The second embodiment of the present invention provides a method for preparing a fiber-reinforced resin matrix composite material that integrates wave absorption and load bearing, specifically including the following steps: Step S1: Prepare the first fiber reinforcement and the second fiber reinforcement respectively; Step S11: A metal layer is coated onto the surface of the fiber fabric using the PAMD (polymer-assisted metal deposition) method; Specifically, the fiber fabric is silanized, and the silanized fiber fabric is immersed in a polymer solution for free radical polymerization to obtain a fiber fabric with polymer grafted on its surface; the fiber fabric with polymer grafted on its surface is immersed in a catalyst solution to load catalyst ions on the surface of the fiber fabric; the fiber fabric loaded with catalyst ions is immersed in a deposition solution to obtain a fiber fabric with a metal coating on its surface.

[0024] Step S12: The metal layer is converted into a metal sulfide layer by in-situ liquid phase sulfidation to obtain the first fiber reinforcement.

[0025] Specifically, the fiber fabric obtained in step S11 is immersed in a sulfurizing solution and allowed to react at 25-30°C for 5-15 minutes to obtain a core-shell structured fiber fabric, i.e., the first fiber reinforcement. The sulfurizing solution is an ammonium sulfide or sodium sulfide solution.

[0026] Step S13: Coating the surface of the fiber fabric with a metal layer; it is worth noting that the first step in preparing the first fiber reinforcement and the second fiber reinforcement is to coat the surface of the fiber fabric with a metal layer. Therefore, in order to clearly illustrate the preparation method, the methods for the two are described separately in this embodiment. Thus, steps S11 and S13 are the same.

[0027] Step S14: Ultraviolet lithography is performed on the surface of the fiber fabric covered with the metal layer using a mask to form a periodically arranged pattern. Specifically, photoresist is dipped into the surface of a fiber fabric coated with a metal layer and heated in an oven at 105-115 °C for 5-15 min to cure the photoresist layer covering the fabric; a photomask is then placed over the surface of the photoresist-coated fiber fabric and subjected to ultraviolet irradiation for 2-4 min, followed by heating in an oven at 90-110 °C for 2-4 min to promote the photoresist reaction; the photoresist in the unpatterned areas is removed with a developer, and the metal under the unpatterned areas is etched with an etchant, and the photoresist on the metal pattern is washed away, forming a periodically arranged pattern on the surface of the fiber fabric.

[0028] Step S15: Through in-situ liquid phase vulcanization, the metal layer of the fiber fabric with a periodically arranged pattern is transformed into a metal sulfide layer to obtain the second fiber reinforcement.

[0029] Step S2: Place the second fiber reinforcement stack on top of the first fiber reinforcement to obtain the fiber reinforcement; Step S3 involves introducing the resin matrix into the fiber reinforcement using either a liquid molding process or a solid molding process to obtain a fiber-reinforced resin matrix composite material. The liquid molding process includes hand lay-up molding, resin transfer molding, or vacuum induction molding, while the solid molding process includes autoclave molding, compression molding, or vacuum bag molding.

[0030] Example 1 Preparation of SiO2-Cu2S / PI Step S10: Rinse the SiO2 fiber fabric with deionized water (see...) Figure 2 (a) The SiO2 fiber fabric was dried at 80 °C for 10 min; the SiO2 fiber fabric was immersed in a mixture of 4% (v / v) [3-(methacryloyloxy)propyl]trimethoxysilane, 95% ethanol (EtOH), 1% acetic acid (HAc) and 4% deionized water, and silanized at 25 °C for 1 h, and then rinsed; the silanized SiO2 fiber fabric was immersed in a mixture of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC) (20 wt.%) and potassium persulfate (2 g / L) in water, and free radical polymerization was carried out at 80 °C for 1 h to grow the polymer in situ, thus obtaining P-METAC-coated SiO2 fiber fabric; it was rinsed with deionized water and dried at 80 °C for 10 min; the P-METAC-coated SiO2 fiber fabric was immersed in 5×10 -3 The mixture was placed in an aqueous solution of M(NH4)2PdCl4 and reacted in the dark for 20 min to load [PdCl4]. 2 Load [PdCl4] 2 SiO2 fiber fabric was immersed in Cu electrodeposition solution for 30 min, [PdCl4] 2 As a catalyst, Cu is deposited on the surface of SiO2 fiber fabric, resulting in SiO2 fiber fabric with a Cu layer on the surface. (See...) Figure 2 (b) The electrodeposition solution consists of a 1:1 (v / v) mixture of solutions A and B. Solution A is a mixture of NaOH (12 g / L), CuSO4·5H2O (13 g / L), and KNaC4H4O6·4H2O (29 g / L). Solution B is an aqueous solution of formaldehyde (HCHO, 9.5 mL / L).

[0031] Step S20: The SiO2 fiber fabric with a Cu layer on its surface is cleaned with a mixed solution of acetone, alcohol, and distilled water. The cleaned SiO2 fiber fabric with a Cu layer on its surface is then immersed in ammonium sulfide and allowed to react at 25°C for 10 minutes. It is then washed several times with distilled water and dried to obtain the first fiber reinforcement, namely the SiO2-Cu2S fiber fabric. (See...) Figure 2 (c) in the middle. Figure 2 SiO2 fiber fabric in (a), see Figure 2 (b) is a SiO2 fiber fabric with a Cu layer on its surface. Figure 2 The SEM image of (c) SiO2-Cu2S fiber fabric is shown in [reference]. Figure 3 As shown in the figure (ac), after the growth of metallic Cu and its conversion to Cu₂S, the diameter of the monofilament fibers significantly increases. The magnified image reveals that the fiber diameter increases from approximately 7.3 μm to 9.6 μm and then to 11.1 μm. Furthermore, the porosity between the fibers gradually decreases. After the growth of metallic Cu, some dot-like protrusions appear on the surface of the fiber bundle. These dot-like protrusions can be identified as the grown metallic copper in the magnified SEM image. The Cu₂S obtained by in-situ liquid-phase sulfidation exhibits a distinct lamellar structure.

[0032] Step S30: Photoresist is dipped into the surface of the SiO2 fiber fabric coated with a Cu layer, and heated in an oven at 110 °C for 10 min to cure the photoresist layer covering the fabric. A photomask is then placed over both surfaces of the photoresist-coated fiber fabric, subjected to ultraviolet irradiation for 3 min, and heated in an oven at 100 °C for 3 min to promote the photoresist reaction. The photoresist in the unpatterned areas is removed with a developer, and the Cu under the unpatterned areas is etched with FeCl3 solution. The photoresist on the pattern is then washed away, forming a periodically arranged pattern on the surface of the fiber fabric. The size of the photomask is determined based on the structural parameters of the pattern. (See photomask description). Figure 4 Optical photographs of the SiO2 fiber fabric before and after photolithography are shown below. Figure 5 , Figure 5 In the image, 'a' represents a SiO2 fiber fabric coated with a Cu layer before photolithography. Figure 5 As can be seen in b, the surface of the SiO2-Cu fiber fabric is covered with lustrous metallic Cu, while after double-sided ultraviolet lithography, a square periodic structure pattern appears on the surface of the SiO2-Cu fiber fabric. Figure 5 (c and d), and the pattern preparation is very clear and accurate, the boundary between SiO2 and Cu under high magnification optical imaging ( Figure 5 (e) is also very clear. The periodically arranged pattern in this embodiment is a square cross-section, see [reference needed]. Figure 6 In (a), the pattern and the plane below it are shown. Figure 6In section (b), the geometric parameters of the structural unit include: the side lengths of the lower and upper layers of the structural unit are a1 and a2, respectively, and the heights of the lower and upper layers are h1 and h2, respectively. The model structural parameters in this embodiment are: a1 = 10 mm, a2 = 7.2 mm, h1 = 1.3 mm, h2 = 3.7 mm, which is the optimal size with a maximum effective absorption bandwidth of 11.2 GHz. The optimal size in this embodiment is obtained by optimizing to the final h1 + h2 = 5 mm. The optimization process is as follows: The geometric parameters h1 and a2 of the structural unit in this embodiment are optimized to optimize the RL (reflectivity) of the SiO2-Cu2S composite material in the frequency range of 4~18 GHz. With the geometric parameter a1 = 10 mm fixed, the thicknesses of the upper and lower layers (h1 and h2) and the side length of the upper step (a2) are optimized. Since h1 + h2 = 5 mm, only h1 needs to be optimized; h2 is set to 5 - h1, and parameter scanning is performed. Specifically, the optimization range is: optimizing h1 (from 0.5 mm to 5 mm) and a2 (from 0.5 mm to 10 mm), with a step size of 0.5 mm for both. Figure 7 As shown, when h1 is optimized in the range of 0.5 mm to 3 mm (step size of 0.5 mm), for each h1 value, the effective absorption bandwidth first increases and then decreases with the increase of a2. Furthermore, as h1 gradually increases from 0.5 mm to 3 mm, the effective absorption bandwidth for all optimized a2 values ​​(from 0.5 mm to 10 mm) also shows a trend of first increasing and then decreasing. However, when h1 is optimized from 3 mm to 4.5 mm, the effective absorption bandwidth is very narrow, all between 1 and 2 GHz, resulting in poor absorption performance.

[0033] Specifically, when h1 = 0.5 mm, the effective absorption bandwidth first increases and then decreases with the gradual increase of a2, reaching a maximum of 8.8 GHz when a2 = 7.5 mm; when h1 = 1 mm, the effective absorption bandwidth first increases and then decreases with the gradual increase of a2, reaching a maximum of 10.56 GHz when a2 = 7 mm; when h1 = 1.5 mm, the effective absorption bandwidth first increases and then decreases with the gradual increase of a2, reaching a maximum of 10.56 GHz when a2 = 6.5 mm; when h1 = 2 mm, the effective absorption bandwidth generally first increases and then decreases with the gradual increase of a2, reaching a maximum of 7.2 GHz when a2 = 5 mm and a2 = 6 mm; when h1 = 2.5 mm, the effective absorption bandwidth first increases and then decreases with the gradual increase of a2, reaching a maximum of 7.2 GHz when a2 = 7.5 mm. When h1=3 mm, the effective absorption bandwidth reaches a maximum of 5.2 GHz; when h1=3 mm, as a2 gradually increases, the effective absorption bandwidth first increases and then decreases, and when a2=8.5 mm, the effective absorption bandwidth reaches a maximum of 4.08 GHz.

[0034] according to Figure 7 The optimization results show that when a1=10 mm, a2=7 mm, h1=1 mm, h2=4 mm, EAB max =10.56 GHz, when a1=10 mm, a2=6.5 mm, h1=1.5 mm, h2=3.5 mm, EAB max =10.56 GHz.

[0035] Figure 8 The optimization results for h1 with a step size of 0.1 mm are shown. When a1=10 mm, a2=7 mm, h1=1.3 mm, and h2=3.7 mm, EAB max =10.96 GHz; when a1=10 mm, a 2= When h1 = 1.4 mm and h2 = 3.6 mm, EAB max =10.96GHz.

[0036] Figure 9 The optimization results for a2 with a step size of 0.1 mm are shown. When a1=10 mm, a2=7.2 mm, h1=1.3 mm, and h2=3.7 mm, the maximum effective absorption bandwidth of the square periodic structure model is 11.2 GHz.

[0037] Figure 10The reflection loss diagram is shown for the optimized model with a1=10 mm, h1=1.3 mm, h2=3.7 mm, and a2 from 7.0 mm to 7.5 mm. As a2 increases from 7 mm to 7.5 mm, the peak near 8 GHz gradually shifts to the lower left, and the peak near 11 GHz gradually shifts downward. When a2=7.2 mm, the maximum effective absorption bandwidth of 11.2 GHz is achieved.

[0038] Comparative Example: The second fiber reinforcement in this embodiment was replaced with the first fiber reinforcement, resulting in a fiber-reinforced resin matrix composite material, i.e., h1 = 5 mm, without h2. Its microwave absorption performance was tested, see [reference needed]. Figure 11 The effective absorption bandwidth is only 1.04 GHz, and the absorption performance is very poor, which proves that the periodic structure layer in this embodiment has a great effect on improving the absorption performance.

[0039] In addition, this embodiment changes the pattern to a circle, see Figure 12 The optimal model structure parameters for its absorption bandwidth are: a1 = 10 mm, a2 = 8.1 mm, h1 = 1.3 mm, and h2 = 3.7 mm. The reflection loss diagram is shown below. Figure 13 The maximum effective absorption bandwidth is 11.12 GHz.

[0040] Step S40: Clean the SiO2 fiber fabric with a Cu layer on its surface using a mixed solution of acetone, alcohol, and distilled water, as described in step S30. Figure 14 In step a), the cleaned SiO2 fiber fabric with a Cu layer on its surface was immersed in ammonium sulfide, allowed to react at 25°C for 10 min, washed several times with distilled water, and dried to obtain the second fiber reinforcement. Optical photographs are shown below. Figure 14 As shown in image b, after in-situ sulfurization with ammonium sulfide, the yellow SiO2-Cu fiber fabric was transformed into a black SiO2-Cu2S fiber fabric, and the boundary between the black Cu2S and SiO2 fibers is very clear under high-magnification optical imaging. This further highlights the advantages of ultraviolet lithography in fabricating periodic structures.

[0041] Step S50: Stack multiple layers of first fiber reinforcement sequentially, and stack multiple layers of second fiber reinforcement on top of the first fiber reinforcement to obtain a fiber reinforcement. Step S60: A polyimide resin solution is introduced into the fiber reinforcement via vacuum bag impregnation, followed by warm pressing to obtain a fiber-reinforced resin matrix composite material (SiO2-Cu2S / PI) integrating microwave absorption and load bearing. See [link to relevant documentation]. Figure 15 The composite material has a thickness of 4.95 mm and a density of 1.4 g / cm3, indicating that it still retains its lightweight properties.

[0042] The reflectivity of the SiO2-Cu2S / PI composite material in this embodiment was tested in the ranges of 4–8 GHz and 8–18 GHz. Figure 16 As can be seen, within the 4–8 GHz frequency band, the reflectivity decreases with increasing frequency. Specifically, the minimum reflectivity is -18.1 dB, the maximum reflectivity is -7.1 dB, and the average reflectivity is -10.1 dB. Within the 8–18 GHz frequency band, the reflectivity first increases slowly and then decreases with increasing frequency. Specifically, the minimum reflectivity is -18.7 dB, and the average reflectivity is -12.9 dB. Therefore, the SiO2-Cu2S / PI composite material exhibits excellent broadband absorption performance within the 4–18 GHz range.

[0043] The tensile strength of the SiO2-Cu2S / PI composite material in this embodiment was tested. The stress-strain curve of the SiO2-Cu2S / PI composite material was measured using an electronic universal testing machine, as shown in the figure. Figure 17 As shown in the figure, the tensile strength reached 452 MPa, indicating that the composite material possesses excellent load-bearing capacity. This further highlights the importance of ultraviolet lithography technology for constructing fiber-reinforced resin matrix composites with integrated microwave absorption and load-bearing structures possessing metamaterial structures.

[0044] Example 2 The difference from Example 1 is that the fiber fabric is a Kevlar fiber fabric, wherein step S10 yields a KEVLAR-Cu fiber fabric, see... Figure 1 In step S20, KEVLAR-Cu2S fiber fabric is obtained (see section d). Figure 1 In the middle (e), fiber-reinforced resin matrix composite KEVLAR-Cu2S / PI.

[0045] Example 3 The difference from Example 1 is that ammonium sulfide is replaced with sodium sulfide in step S20, and the static reaction is allowed to proceed for 1 day.

[0046] Example 4 The difference from Example 1 is that in step S10, liquid A is NiSO4·6H2O (30 g / L) and Na3C6H5O7 (20 g / L), and liquid B is NaH2PO2·H2O (25 g / L), thus obtaining the fiber-reinforced resin matrix composite material SiO2-NiS / PI.

[0047] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A fiber-reinforced resin matrix composite material integrating wave absorption and load bearing, characterized in that, It includes a fiber reinforcement and a resin matrix, wherein the resin matrix fills the voids in the fiber reinforcement and covers the surface of the fiber reinforcement; The fiber reinforcement includes a first fiber reinforcement and a second fiber reinforcement stacked together; Both the first fiber reinforcement and the second fiber reinforcement are core-shell structures, wherein the core structure is a fiber fabric and the shell structure is a metal sulfide; The surface of the second fiber reinforcement is formed with a periodically arranged pattern of fiber fabric; wherein the periodically arranged pattern is formed by ultraviolet lithography.

2. The fiber-reinforced resin matrix composite material integrating wave absorption and load bearing according to claim 1, characterized in that, The metal sulfide is copper, nickel, or silver; The fiber fabric includes oxide fibers or chemical fibers; The resin matrix includes thermosetting resin or thermoplastic resin.

3. The fiber-reinforced resin matrix composite material integrating wave absorption and load bearing according to claim 1, characterized in that, The upper and / or lower surfaces of the second fiber reinforcement form a fiber fabric with a periodically arranged pattern.

4. The fiber-reinforced resin matrix composite material integrating wave absorption and load bearing according to claim 1, characterized in that, The fiber reinforcement has a constant cross-section structure or a variable cross-section structure in the thickness direction.

5. The fiber-reinforced resin matrix composite material integrating wave absorption and load bearing according to claim 1, characterized in that, The cross-sectional structure of the fiber reinforcement in the thickness direction is a variation or combination of one or more of the following: pyramidal, rectangular, hourglass, and spindle-shaped.

6. A method for preparing the integrated microwave absorption / load-bearing fiber-reinforced resin matrix composite material as described in claim 1, characterized in that, include: The first fiber reinforcement and the second fiber reinforcement were prepared separately. The second fiber reinforcement stack is placed on top of the first fiber reinforcement to obtain a fiber reinforcement; The resin matrix is ​​introduced into the fiber reinforcement through liquid molding or solid molding processes to obtain fiber-reinforced resin matrix composites.

7. The method for preparing the integrated microwave absorption / load-bearing fiber-reinforced resin matrix composite material according to claim 6, characterized in that, The method for preparing the first fiber reinforcement includes: Coating the surface of the fiber fabric with a metal layer; The metal layer is converted into a metal sulfide layer by in-situ liquid phase sulfidation to obtain the first fiber reinforcement.

8. The method for preparing the integrated microwave absorption / load-bearing fiber-reinforced resin matrix composite material according to claim 6, characterized in that, The method for preparing the second fiber reinforcement includes: Coating the surface of the fiber fabric with a metal layer; Ultraviolet lithography is performed on the surface of the fiber fabric coated with a metal layer using a photomask to form a periodically arranged pattern; By in-situ liquid-phase vulcanization, the metal layer of a fiber fabric with a periodically arranged pattern is transformed into a metal sulfide layer, resulting in a second fiber reinforcement.

9. The method for preparing the integrated microwave absorption / load-bearing fiber-reinforced resin matrix composite material according to claim 6, characterized in that, The in-situ liquid phase sulfidation process uses ammonium sulfide or sodium sulfide solution; The liquid molding process includes hand lay-up molding, resin transfer molding, or vacuum induction molding, and the solid molding process includes autoclave molding, compression molding, or vacuum bag molding.

10. The application of the fiber-reinforced resin matrix composite material with integrated wave absorption / load bearing as described in claim 1 in the field of electromagnetic wave absorption.

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