A graphene broadband wave absorbing component and preparation method thereof

Abstract

The present application discloses a graphene broadband absorbing component and a preparation method thereof, which relates to the field of absorbing material technology and at least solves the technical problem that the performance of existing graphene absorbing components is difficult to meet application requirements. The graphene broadband absorbing component is composed of a wave-transmitting layer and a wave-absorbing layer; the modified graphene in the wave-transmitting layer is oriented along the Z-0° direction, and the graphene in the wave-absorbing layer is oriented along the X-Y direction; the graphene broadband absorbing component basically achieves full absorption in the 8GHz to 18GHz band.

Description

Technical Field

[0001] The present application relates to the technical field of absorbing materials, and in particular to a graphene broadband absorbing component and a preparation method thereof. Background Art

[0002] Graphene is considered to be an efficient microwave absorber due to its high electrical conductivity, specific surface area, thermal conductivity and low density. However, the electromagnetic incompatibility of the single component and structure of original graphene makes its impedance performance poor, and the electromagnetic waves are almost reflected instead of dissipated, resulting in extremely limited absorption performance. Common improvement strategies are to modify the graphene surface, such as loading magnetic particles and surface oxidation; or to construct special microstructures, such as porous structures and honeycomb structures, to improve interface properties and introduce multiple reflections, thereby enhancing the absorption performance of the overall structure. However, all of the above rely on complex preparation processes and high graphene addition amounts. The mechanical properties of the prepared components are poor and it is difficult to meet actual application requirements. Summary of the invention

[0003] The present application provides a graphene broadband absorbing component and a preparation method thereof, which at least solves the technical problem that the performance of existing graphene absorbing components is difficult to meet application requirements.

[0004] To solve the above technical problems, the embodiments of the present application provide: a graphene broadband wave absorbing component, the component consisting of a wave-transmitting layer and a wave-absorbing layer; the modified graphene in the wave-transmitting layer is oriented along the Z-0° direction, and the graphene in the wave-absorbing layer is oriented along the XY direction;

[0005] The graphene broadband wave-absorbing component achieves full absorption less than -10 dB in the 8 GHz to 18 GHz band, and the wave-absorbing bandwidth can reach 8.5 GHz.

[0006] As some optional embodiments of the present application, the content of modified graphene used in the wave-transmitting layer is 1wt% to 10wt%; the content of graphene in the wave-absorbing layer is 1wt% to 10wt%.

[0007] As some optional embodiments of the present application, the content of modified graphene used in the wave-transmitting layer is 2wt%~3wt%; the content of graphene in the wave-absorbing layer is 1wt%~2wt%.

[0008] As some optional embodiments of the present application, the content of modified graphene used in the wave-transmitting layer is 2.1 wt %; the content of graphene in the wave-absorbing layer is 1.2 wt %.

[0009] As some optional embodiments of the present application, the graphene in the absorbing layer includes original graphene and modified graphene; the mixing ratio of the original graphene and the modified graphene is 1~5:5~9.

[0010] As some optional embodiments of the present application, the mixing ratio of the original graphene and the modified graphene is 5:5, 4:6, 3:7, 2:8 or 1:9.

[0011] On the other hand, the embodiment of the present application provides a method for preparing the graphene broadband wave absorbing component as described above, comprising the following steps:

[0012] Performing modification treatment on original graphene to obtain modified graphene;

[0013] The modified graphene, the photocurable resin monomer and the photocuring agent are uniformly mixed to obtain a photocurable slurry;

[0014] Based on the photocurable slurry, printing layer by layer along the XY direction according to the digital model, after printing to the target thickness, cutting perpendicularly to the XY direction to obtain a first flat plate with a first target thickness; wherein the modified graphene in the first flat plate is oriented along the Z-0° direction;

[0015] Using the first flat plate as a substrate and based on the photocurable slurry, printing layer by layer along the XY direction according to the digital model to obtain a printed cube with a second target thickness;

[0016] The printed cube is taken out and the substrate is placed upward, and after ultraviolet light post-curing treatment, a broadband absorbing component is obtained; wherein the broadband absorbing component consists of a wave-transmitting layer and a wave-absorbing layer; the modified graphene in the wave-transmitting layer is oriented along the Z-0° direction, and the graphene in the wave-absorbing layer is oriented along the XY direction.

[0017] As some optional embodiments of the present application, the step of modifying the original graphene to obtain the modified graphene includes:

[0018] The original graphene is oxidized by Hummers method to obtain graphene oxide with oxygen-containing functional groups on the surface and a partially destroyed conjugated structure;

[0019] Through the reaction of active oxygen-containing functional groups and silane coupling agents, reactive vinyl groups are introduced to obtain graphene oxide grafted with double bonds;

[0020] Adding the graphene oxide grafted with double bonds into a solution containing ionic polymer monomers to perform free radical copolymerization, so that a large amount of ionic polymers are introduced onto the surface of the graphene oxide;

[0021] The graphene oxide is then placed in an acidic / alkaline solution to dissociate and form a polyelectrolyte with a positive charge or a negative charge, thereby obtaining modified graphene.

[0022] As some optional embodiments of the present application, the temperature of the oxidation treatment is 45° C. to 55° C., and the treatment time is 8 hours to 72 hours.

[0023] As some optional embodiments of the present application, the ionic polymer monomer includes at least one of polyacrylic acid, polyethyleneimine, polylysine, polyvinylamine and polyphosphazene.

[0024] As some optional embodiments of the present application, the photocurable resin monomer includes at least one of 1,6-hexanediol diacrylate, 1,1,1-trimethylolpropane triacrylate, 606B resin and NH-S200.

[0025] As some optional embodiments of the present application, the photocurable resin monomer is a mixture of 1,6-hexanediol diacrylate and 1,1,1-trimethylolpropane triacrylate.

[0026] As some optional embodiments of the present application, the mixing ratio of the 1,6-hexanediol diacrylate and the 1,1,1-trimethylolpropane triacrylate is 4:1.

[0027] As some optional embodiments of the present application, the photocuring agent is 2,4,6-trimethylbenzoylphosphine oxide, and the amount used is 1wt% of the amount of the photocurable resin monomer used.

[0028] As some optional implementations of the present application, the first target thickness is 0.5 mm to 4 mm, and the second target thickness is 0.5 mm to 4 mm.

[0029] As some optional embodiments of the present application, the first target thickness is 2.1 mm, and the second target thickness is 1.8 mm.

[0030] Compared with the prior art, the present application provides a graphene broadband wave absorbing component, which is composed of a wave-transmitting layer and a wave-absorbing layer; the modified graphene in the wave-transmitting layer is oriented along the Z-0° direction, and the graphene in the wave-absorbing layer is oriented along the XY direction; the graphene broadband wave-absorbing component achieves full absorption in the 8GHz to 18GHz band, and the wave-absorbing bandwidth less than -10dB can reach 8.5GHz. It can be seen that the present application constructs a honeycomb-like "wave-transmitting" structure with vertically oriented graphene in the upper layer with excellent impedance and conducive to the incidence of electromagnetic waves, and a "wave-absorbing" structure with vertical and horizontal orientation of graphene in the lower layer with excellent wave-absorbing performance, which exhibits excellent broadband wave-absorbing capabilities at low graphene content and low thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation of the present application or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0032] Figure 1 A process flow chart for preparing the "wave-transmitting-wave-absorbing" heterostructure described in this application;

[0033] Figure 2 This is a schematic diagram of the modified graphene described in this application;

[0034] Figure 3 Schematic diagram of preparing a "wave-transmitting-wave-absorbing" heterostructure by photocuring 3D printing as described in this application;

[0035] Figure 4 Schematic diagram of the "wave-transmitting-wave-absorbing" structure described in this application for absorbing electromagnetic waves.

[0036] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] In recent years, the emerging additive manufacturing (3D printing) technology is based on the principle of discrete stacking, using automatic control to stack materials layer by layer to achieve rapid manufacturing of complex parts. It has the advantages of flexible structural design, integrated processing and molding, high preparation accuracy, and short preparation cycle, providing a new way to prepare absorbing parts with complex structures. Among them, light-curing 3D printing technology is a method in which a photoinitiator induces the polymerization of photosensitive resin monomers to form a polymer cross-linked network under the irradiation of light of a specific wavelength, fixes the absorber, and solidifies and molds layer by layer on the machine printing table to finally obtain a three-dimensional absorbing structure.

[0039] It is worth noting that the photocurable slurry will undergo a slurry flattening process during the photocuring 3D process. During this process, the slurry is subjected to shear force, which may cause the absorber in the slurry (especially the two-dimensional sheet structure raw material) to be oriented in the horizontal direction.

[0040] Based on this, the present application proposes to utilize the characteristics of photocuring 3D printing to first prepare a cube with a certain thickness of graphene oriented in the horizontal direction (XY plane), and then obtain a flat plate with a certain thickness by cutting perpendicular to the XY direction. The graphene in the flat plate is oriented in the Z-0° direction to form a three-dimensional structure similar to a "honeycomb". After that, a certain thickness of graphene-containing material is continued to be printed with the flat plate as the substrate. After printing, the workpiece is taken out and the substrate is placed upward to obtain a "wave-transmitting-wave-absorbing" heterostructure in which the upper graphene is oriented in the Z-0° direction and the lower graphene is oriented in the XY direction. In addition, in order to further improve the wave transmission performance of the upper layer, it is necessary to solve the problems of agglomeration and high conductivity of the original graphene to improve the impedance matching and orientation degree of the graphene, so as to finally achieve broadband and efficient absorption of electromagnetic waves under low graphene loading and maintain good mechanical properties of the structure.

[0041] Specifically, Figure 1 As shown, the embodiment of the present application provides a design and preparation method for constructing a broadband wave absorbing structure with low graphene loading based on photocuring 3D printing, and the specific process steps and conditions are as follows:

[0042] Step S10: modifying the original graphene to obtain modified graphene.

[0043] Specifically, the step of modifying the original graphene to obtain the modified graphene comprises:

[0044] The original graphene is oxidized by the Hummers method to obtain graphene oxide with oxygen-containing functional groups on the surface of which the conjugated structure is partially destroyed; reactive vinyl groups are introduced by reaction with silane coupling agents to obtain graphene oxide grafted with double bonds; the graphene oxide grafted with double bonds is added to a solution containing ionic polymer monomers for free radical copolymerization, so that a large amount of ionic polymers are introduced on the surface of the graphene oxide; the graphene oxide is then placed in an acidic / alkaline solution to dissociate, forming a polyelectrolyte with positive or negative charge, and obtaining modified graphene. The oxidation treatment temperature is 45°C to 55°C, and the treatment time is 8 hours to 72 hours. The ionic polymer monomer includes at least one of polyacrylic acid, polyethyleneimine, polylysine, polyethyleneamine and polyphosphazene.

[0045] Step S20: uniformly mix the modified graphene, the photocurable resin monomer and the photocuring agent to obtain a photocurable slurry.

[0046] Specifically, the photocurable resin monomer includes at least one of 1,6-hexanediol diacrylate, 1,1,1-trimethylolpropane triacrylate, 606B resin and NH-S200. The photocurable resin monomer is a mixture of 1,6-hexanediol diacrylate and 1,1,1-trimethylolpropane triacrylate. The mixing ratio of the 1,6-hexanediol diacrylate and the 1,1,1-trimethylolpropane triacrylate is 4:1. The photocuring agent is 2,4,6-trimethylbenzoylphosphine oxide, and the amount used is 1wt% of the amount of the photocurable resin monomer.

[0047] Step S30: Based on the photocurable slurry, print layer by layer along the XY direction according to the digital model, and after printing to the target thickness, cut it perpendicular to the XY direction to obtain a first flat plate with a first target thickness; wherein the modified graphene in the first flat plate is oriented along the Z-0° direction.

[0048] Specifically, the first target thickness is 0.5 mm to 4 mm, preferably 2.1 mm.

[0049] Step S40: Using the first flat plate as a substrate and based on the photocurable slurry, printing layer by layer along the XY direction according to the digital model to obtain a printed cube with a second target thickness.

[0050] Specifically, the second target thickness is 0.5 mm to 4 mm, preferably 1.8 mm.

[0051] Step S50, taking out the printed cube and placing the substrate upward, performing ultraviolet light post-curing treatment to obtain a broadband absorbing component; wherein the broadband absorbing component consists of a wave-transmitting layer and a wave-absorbing layer; the modified graphene in the wave-transmitting layer is oriented along the Z-0° direction, and the graphene in the wave-absorbing layer is oriented along the XY direction.

[0052] In some specific embodiments, the above steps may include:

[0053] 1) Modification of pristine graphene (e.g. Figure 2 shown)

[0054] ① The original graphene (G) is oxidized by the Hummers method to obtain graphene oxide (GO) with a partially destroyed conjugated structure and a large number of oxygen-containing functional groups on the surface; the temperature of the Hummers method modified graphene is controlled at 50°C, and the reaction time is 8-72 hours, preferably 12 hours.

[0055] ②Introducing reactive vinyl groups through the reaction of active oxygen-containing functional groups (carboxyl or hydroxyl) with silane coupling agent (KH570);

[0056] ③ Adding the double bond-grafted GO into a solution containing an ionic polymer monomer for free radical copolymerization, thereby introducing a large amount of ionic polymers on the surface of GO; the ionic polymer is polyacrylic acid, polyethyleneimine, polylysine, polyvinylamine, polyphosphazene, etc., preferably polyacrylic acid.

[0057] ④ Use acidic / alkaline to dissociate and form positively or negatively charged polyelectrolytes, and finally obtain modified graphene (GO-PA - ).

[0058] 2) Preparation of light-curing slurry

[0059] The modified graphene, photocuring agent and photocuring resin are fully and evenly mixed to obtain a slurry that can be used for photocuring 3D printing. The photocuring resins are 1,6-hexanediol diacrylate (HDDA), 1,1,1-trimethylolpropane triacrylate (TMPTA), 606B resin and NH-S200, etc., which can be selected according to actual use requirements. For the sake of idea verification only, 1,6-hexanediol diacrylate (HDDA) and 1,1,1-trimethylolpropane triacrylate (TMPTA) can be preferred, and the preferred molar ratio is 4:1. The photocuring agent is biphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), and the content is preferably 1wt% of the monomer mass.

[0060] The content of the modified graphene used is 1wt% to 10wt%, preferably 2.1wt%. The graphene used is original graphene and modified graphene, the ratio is 5:5, 4:6, 3:7, 2:8, 1:9, preferably 1:9; the content is 1wt% to 10wt%, preferably 1.2wt%.

[0061] 3) Photocuring 3D printing of the upper wave-transmitting structure (such as Figure 3 shown)

[0062] The slurry containing modified graphene obtained in step 2) is placed in a material pool, and is printed layer by layer along the XY direction according to the digital model to prepare a cube of modified graphene with a certain thickness, and then a plate with a certain thickness is obtained by cutting the printed cube perpendicular to the XY direction, and the modified graphene in the plate is oriented along the Z-0° direction. The thickness of the cut plate is 0.5 mm to 4 mm, preferably 2.1 mm.

[0063] 4) Photocuring 3D printing of the lower absorbing structure (such as Figure 3 shown)

[0064] The slurry containing original graphene and modified graphene obtained in step 2) is placed in a material pool, and the flat plate obtained in step 3) is used as a substrate, and is printed layer by layer along the XY direction according to the digital model to prepare a cube with a certain thickness of graphene oriented along the XY direction. The printing thickness is 0.5 mm to 4 mm, preferably 1.8 mm.

[0065] 5) Post-curing treatment

[0066] After printing is completed, the product is taken out and the substrate is placed upward. After UV post-curing treatment, a "wave-transmitting-wave-absorbing" heterostructure can be obtained in which the upper modified graphene is oriented along the Z-0° direction and the lower graphene is oriented along the XY direction.

[0067] It can be seen that the double-layer heterostructure absorbing plate prepared by the above method provided in the embodiment of the present application has a very significant improvement (3.9mm) compared with the graphene absorbing structure prepared by the traditional method, and achieves full absorption in the 8-18GHz band, and the absorption bandwidth less than -10dB can reach 8.5GHz. In addition, the tensile strength of the double-layer heterostructure absorbing plate with 1,6-hexanediol diacrylate (HDDA) and 1,1,1-trimethylolpropane triacrylate (TMPTA) as monomers reaches 54MPa, and the bending strength reaches 62MPa, which is better than the conventional porous structure.

[0068] In order to facilitate the understanding of the technical solution of the present application by those skilled in the art, the technical solution of the present application is described in detail below in combination with specific implementation methods:

[0069] Example 1

[0070] 1) Modification of pristine graphene

[0071] ① The original graphene (G) was oxidized according to the improved Hummers method. The oxidation process mainly has two stages: Pre-oxidation stage: 3g of graphene, concentrated sulfuric acid, potassium persulfate, and phosphorus pentoxide were added to a beaker and stirred, heated to 80°C in an oil bath and kept for 5 hours, cooled naturally to room temperature, and slowly added 500mL of ice water to dilute, and finally filtered and washed to pH 7, dried at room temperature for 48 hours to obtain pre-oxidized graphene. Oxidation stage: Add the above pre-oxidized graphene to 120 mL of concentrated sulfuric acid, slowly add 9g of potassium permanganate, and stir in an ice bath for 1 hour. Adjust the temperature to 50°C and react for 12 hours. Put the product currently obtained into ice water, add appropriate hydrogen peroxide and stir continuously. When the solution color begins to show bright yellow, it can be left to stand for 48 hours to pour off the supernatant, and the lower precipitate is washed with deionized water and hydrochloric acid to make the pH about 7, and dried at room temperature for 48 hours to obtain the desired graphene oxide (GO).

[0072] ② Grafting KH570: Add 3g GO to 500mL anhydrous ethanol, disperse it by ultrasonic for 30min, then add 500mg of vinyl alkane coupling agent (KH570) and stir it magnetically, heat it to 70℃ in a water bath and keep it for 10 hours, cool it naturally to room temperature, filter and wash to remove the ungrafted coupling agent, and dry it at room temperature for 48 hours to obtain modified graphene (GO-KH570).

[0073] ③ Grafted ionic polymer: Add 3g GO-KH70 into 500mL dimethylacetamide (DMAc), disperse by ultrasonic for 30min, then add 100g acrylic acid and 0.5g azobisisobutyronitrile and stir magnetically, heat to 80℃ in a water bath and keep for 8 hours, cool naturally to room temperature, and finally filter and wash to remove the ungrafted monomer to obtain modified graphene (GO-PA).

[0074] ④ Ionization: 5 g of GO-PA was added to a sodium hydroxide aqueous solution with a pH of 1, dispersed by ultrasound for 30 min, and magnetically stirred for 10 h. Finally, the modified graphene (GO-PA) was obtained by filtration and drying. - ).

[0075] 2) Preparation of light-curing slurry

[0076] 5.14 g of biphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) and 10.8 g of GO-PA - Add to 400mL of 1,6-hexanediol diacrylate (HDDA) and 100mL of 1,1,1-trimethylolpropane triacrylate (TMPTA), first mechanically stir for 2h, then ultrasonically disperse for 2h, and finally ball mill for 6h. The grinding beads are selected with diameters of 5mm / 10mm / 15mm, respectively, and the mass ratios are 5 / 3 / 2, with small beads being the majority. Finally, large impurities are removed by filter pressing to obtain the target photocurable slurry.

[0077] 3) Photocuring 3D printing of the upper wave-transmitting structure

[0078] The model to be printed was obtained by drawing with Materialise Magics software, and then sliced ​​with Cura software. Before printing, the slurry needs to be tested for printability to determine the appropriate exposure time and slice thickness. When laying the material, the horizontal orientation of graphene is further increased by increasing the vibration field. -The printable slurry is placed in a material pool, and printing is started along the XY direction according to the digital model to prepare a cube with a certain thickness in which the modified graphene is oriented along the XY direction. Then, a flat plate with a thickness of 1.8 mm is obtained by cutting the printed cube perpendicular to the X direction, in which the modified graphene is oriented along the Z-0° direction.

[0079] 4) Photocuring 3D printing of the lower absorbing structure

[0080] The 0.12wt% original graphene and 1.08wt% GO-PA - The printable slurry is placed in a material pool, and the flat plate obtained in step 3) is used as a substrate. Printing is started according to the digital model to prepare a cube with a thickness of 2.1 mm and graphene oriented along the XY direction.

[0081] 5) Post-curing treatment

[0082] After printing is completed, the product is taken out and the substrate is placed upward. The sample is irradiated with 2KW ultraviolet light with a wavelength of 405nm from the upper and lower directions for post-curing treatment for 1 hour to obtain a "wave-transmitting-wave-absorbing" heterostructure in which the upper modified graphene is oriented along the Z-0° direction and the lower graphene is oriented along the XY direction.

[0083] The wave absorbing performance of the double-layer heterogeneous structure (4) described in Example 1 is compared with that of the conventional disordered structure (1), and the single upper wave-transmitting structure (2) or the single lower wave-absorbing structure (3), wherein the conventional disordered structure (1) refers to a disordered state in which graphene is randomly distributed in a matrix by melt blending or solvent blending. The test standard is GJB 2038A-2011, the bow method test system is used, the test frequency range is 2-18 GHz, and the sample size is 1801803.9 mm. The results are shown in Table 1, and the wave absorbing performance of the double-layer heterogeneous structure described in the present application is better than that of the conventional structure, and the single upper wave-transmitting structure or the single lower wave-absorbing structure.

[0084] Table 1:

[0085]

[0086] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0087] ① The embodiment of the present application innovatively constructs a "honeycomb wave-transmitting" structure with graphene vertical orientation having excellent impedance on the upper layer and being conducive to the incidence of electromagnetic waves, and a "wave-absorbing" structure with graphene vertically and horizontally oriented in the lower layer having excellent wave-absorbing performance (such as Figure 4As shown in the figure, the double-layer heterostructure composed of the two exhibits excellent broadband absorption capability (8.5GHz, RL<-10dB) at low graphene content (upper layer 2.1wt% + lower layer 1.2wt%) and low thickness (upper layer 2.1mm + lower layer 1.8mm).

[0088] ② Graphene usually has a high absorbance due to its large conjugation effect, and it is difficult to initiate the curing of graphene-containing slurry by conventional ultraviolet light. The embodiment of the present application not only breaks the large conjugation effect of graphene and reduces the absorbance of graphene through oxidation and ion polymer modification, but also improves the dispersibility of graphene, so that low-content graphene can exert excellent wave absorption performance.

[0089] ③ The embodiment of the present application utilizes graphene arranged in a vertical plane as a "wave-transmitting" channel. Thanks to the excellent mechanical properties and dense composite structure of graphene, it has excellent mechanical properties compared to the traditional method of introducing gaps or cavities, and can meet the usage requirements of most scenarios.

[0090] ④ Since the method of the embodiment of the present application is based on photocuring 3D printing, the typical "wave absorbing" and "wave transparent" structure design and optimization are flexible, the material utilization is high, and the post-processing process is less, which can shorten the design and manufacturing cycle and reduce production costs, providing a fast way for the development and flexible mass production of wave absorbing components.

[0091] ⑤ Based on this method, in addition to being applicable to a variety of low-dielectric plastics, it is also applicable to low-dielectric ceramic-based composite materials formed by precursor transformation, such as absorbing silicon oxide, silicon nitride and aluminum oxide.

[0092] ⑥The idea of ​​this method is also applicable to a variety of additive manufacturing processes, such as ink direct writing of absorbing polyvinyl alcohol.

[0093] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A graphene broadband wave absorbing component, characterized in that: The component is composed of a wave-transmitting layer and a wave-absorbing layer; the modified graphene in the wave-transmitting layer is oriented along the Z-0° direction, and the graphene in the wave-absorbing layer is oriented along the XY direction; the graphene in the wave-absorbing layer includes original graphene and modified graphene; the mixing ratio of the original graphene and the modified graphene is 1-5:5-9; The graphene broadband wave-absorbing component achieves full absorption in the 8 GHz to 18 GHz band, and the wave-absorbing bandwidth less than -10 dB can reach 8.5 GHz.

2. The graphene broadband wave absorbing component according to claim 1, characterized in that: The content of modified graphene used in the wave-transmitting layer is 1wt% to 10wt%; the content of graphene in the wave-absorbing layer is 1wt% to 10wt%.

3. The graphene broadband wave absorbing component according to claim 2, characterized in that: The content of modified graphene used in the wave-transmitting layer is 2wt%-3wt%; the content of graphene in the wave-absorbing layer is 1wt%-2wt%.

4. The graphene broadband wave absorbing component according to claim 2, characterized in that: The content of modified graphene used in the wave-transmitting layer is 2.1 wt %; the content of graphene in the wave-absorbing layer is 1.2 wt %.

5. The graphene broadband wave absorbing component according to claim 1, characterized in that: The mixing ratio of the original graphene and the modified graphene is 5:5, 4:6, 3:7, 2:8 or 1:

9.

6. A method for preparing the graphene broadband wave absorbing component according to any one of claims 1 to 5, characterized in that: The following steps are involved: Performing modification treatment on original graphene to obtain modified graphene; The modified graphene, the photocurable resin monomer and the photocuring agent are uniformly mixed to obtain a photocurable slurry; Based on the photocurable slurry, printing layer by layer along the XY direction according to the digital model, after printing to the target thickness, cutting perpendicularly to the XY direction to obtain a first flat plate with a first target thickness; wherein the modified graphene in the first flat plate is oriented along the Z-0° direction; Using the first flat plate as a substrate and based on the photocurable slurry, printing layer by layer along the XY direction according to the digital model to obtain a printed cube with a second target thickness; The printed cube is taken out and the substrate is placed upward, and after ultraviolet light post-curing treatment, a broadband absorbing component is obtained; wherein the broadband absorbing component consists of a wave-transmitting layer and a wave-absorbing layer; the modified graphene in the wave-transmitting layer is oriented along the Z-0° direction, and the graphene in the wave-absorbing layer is oriented along the XY direction.

7. The method for preparing the graphene broadband wave absorbing component according to claim 6, characterized in that: The step of modifying the original graphene to obtain modified graphene comprises: The original graphene is oxidized by Hummers method to obtain graphene oxide with oxygen-containing functional groups on the surface and a partially destroyed conjugated structure; Through the reaction of active oxygen-containing functional groups and silane coupling agents, reactive vinyl groups are introduced to obtain graphene oxide grafted with double bonds; Adding the graphene oxide grafted with double bonds into a solution containing ionic polymer monomers to perform free radical copolymerization, so that a large amount of ionic polymers are introduced onto the surface of the graphene oxide; The graphene oxide is then placed in an acidic / alkaline solution to dissociate and form a polyelectrolyte with a positive charge or a negative charge, thereby obtaining modified graphene.

8. The method for preparing the graphene broadband wave absorbing component according to claim 7, characterized in that: The oxidation treatment temperature is 45° C. to 55° C., and the treatment time is 8 hours to 72 hours.

9. The method for preparing the graphene broadband wave absorbing component according to claim 7, characterized in that: The ionic polymer monomer includes at least one of polyacrylic acid, polyethyleneimine, polylysine, polyvinylamine and polyphosphazene.

10. The method for preparing the graphene broadband wave absorbing component according to claim 6, characterized in that: The photocurable resin monomer includes at least one of 1,6-hexanediol diacrylate, 1,1,1-trimethylolpropane triacrylate, 606B resin and NH-S200.

11. The method for preparing the graphene broadband wave absorbing component according to claim 10, characterized in that: The photocurable resin monomer is a mixture of 1,6-hexanediol diacrylate and 1,1,1-trimethylolpropane triacrylate.

12. The method for preparing the graphene broadband wave absorbing component according to claim 11, characterized in that: The mixing ratio of the 1,6-hexanediol diacrylate and the 1,1,1-trimethylolpropane triacrylate is 4:

1.

13. The method for preparing the graphene broadband wave absorbing component according to claim 6, characterized in that: The photocuring agent is 2,4,6-trimethylbenzoylphosphine oxide, and the amount used is 1wt% of the amount of the photocuring resin monomer used.

14. The method for preparing the graphene broadband wave absorbing component according to claim 6, characterized in that: The first target thickness is 0.5 mm to 4 mm, and the second target thickness is 0.5 mm to 4 mm.

15. The method for preparing the graphene broadband wave absorbing component according to claim 14, characterized in that: The first target thickness is 2.1 mm, and the second target thickness is 1.8 mm.

Images