Wave-absorbing conductive foam, preparation method and application thereof

Abstract

The application relates to a wave-absorbing conductive foam and a preparation method and application thereof, the wave-absorbing conductive foam comprising a wave-absorbing sponge and a conductive layer wrapping the wave-absorbing sponge, the wave-absorbing sponge comprising a sponge and a composite magnetic material distributed in the sponge; wherein the composite magnetic material comprises a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials and an organic insulating material coated on the surface of the composite material, wherein in the composite material, a plurality of the porous graphene ellipsoids are sequentially arranged to form a graphene group, and the zinc sulfide nanomaterials are fused in the graphene group. The composite magnetic material has excellent wave-absorbing performance, ductility and toughness, and when distributed in the sponge, does not affect the performance of the sponge itself, and makes the sponge have excellent wave-absorbing performance. Therefore, when the wave-absorbing conductive foam is applied to electronic equipment, the risk of electromagnetic leakage can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave absorbing materials technology, and in particular to wave absorbing conductive foam, its preparation method and application. Background Technology

[0002] Conductive foam refers to flame-retardant sponge wrapped with conductive cloth. After a series of treatments, it acquires good surface conductivity and can be easily fixed to devices requiring shielding with adhesive tape. Conductive foam has many uses, but its most widespread application is in electronic packaging, such as displays, components, electronic accessories, and various household appliances. However, traditional conductive foam, due to its internal foam structure and relatively large gaps, poses a significant risk of electromagnetic leakage. Summary of the Invention

[0003] Therefore, it is necessary to provide a wave-absorbing conductive foam, its preparation method and application, which has excellent electromagnetic shielding performance, in response to the above-mentioned technical problems.

[0004] The present invention provides a wave-absorbing conductive foam, comprising a wave-absorbing sponge and a conductive layer encapsulating the wave-absorbing sponge, wherein the wave-absorbing sponge comprises a sponge and a composite magnetic material distributed in the sponge;

[0005] The composite magnetic material includes a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials, and an organic insulating material coated on the surface of the composite material. In the composite material, multiple porous graphene ellipsoids are arranged in an orderly manner to form a graphene group, and the zinc sulfide nanomaterials are fused into the graphene group.

[0006] In one embodiment, the composite magnetic material has a mass fraction of 20%-40% in the microwave absorbing sponge.

[0007] In one embodiment, the porous graphene ellipsoids in the graphene group are arranged in a three-dimensional array.

[0008] In one embodiment, the porous graphene ellipsoid has an equatorial radius of 100nm-120nm and a polar radius of 200nm-250nm.

[0009] In one embodiment, the pore size of the porous graphene ellipsoid is 14nm-25nm.

[0010] In one embodiment, the ratio of the particle size of the zinc sulfide nanomaterial to the pore size of the porous carbon rod is 1:8 to 1:12.

[0011] In one embodiment, the mass ratio of the zinc sulfide nanomaterial to the graphene group in the composite magnetic material is 1:3-1:5.

[0012] In one embodiment, the conductive layer is selected from aluminum foil.

[0013] The present invention also provides a method for preparing the aforementioned wave-absorbing conductive foam, comprising the following steps:

[0014] The composite magnetic material is dispersed in water to form a slurry;

[0015] The slurry is placed in a sponge and dried to obtain a wave-absorbing sponge.

[0016] The microwave-absorbing sponge is combined with a conductive layer to form a microwave-absorbing and conductive foam.

[0017] The present invention also provides an application of the aforementioned wave-absorbing conductive foam in electronic devices.

[0018] This invention, through the selection of materials and the control of structure in the composite magnetic material, achieves an insertion loss of approximately 25 dB in the 20 MHz-1200 MHz frequency band, exhibiting excellent wave absorption performance. Furthermore, the composite magnetic material of this invention uses a graphene swarm composed of multiple porous graphene ellipsoids arranged in an orderly manner as the matrix, incorporating zinc sulfide nanomaterials. This results in a dense structure, good toughness, and resistance to breakage failure under load, exhibiting excellent ductility.

[0019] Furthermore, distributing composite magnetic materials within the sponge does not affect the sponge's inherent properties, while simultaneously giving it excellent wave-absorbing capabilities. Therefore, when the wave-absorbing conductive foam of this invention is applied to electronic devices, the risk of electromagnetic leakage can be effectively reduced. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a high-magnification scanning electron microscope image of the graphene group obtained in Example 1;

[0022] Figure 2 This is a high-magnification scanning electron microscope image of the composite magnetic material prepared in Example 1;

[0023] Figure 3 Electromagnetic compatibility radiated interference diagrams for electronic devices using the absorbing foam of Example 1;

[0024] Figure 4Electromagnetic compatibility (EMC) radiation emissions diagram for electronic devices using the absorbing foam of Comparative Example 1. Detailed Implementation

[0025] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0027] The microwave absorbing and conductive foam provided by the present invention includes a microwave absorbing sponge and a conductive layer encapsulating the microwave absorbing sponge. The microwave absorbing sponge includes a sponge and a composite magnetic material distributed in the sponge.

[0028] Specifically, the composite magnetic material includes a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials, and an organic insulating material coated on the surface of the composite material. In the composite material, multiple porous graphene ellipsoids are arranged in an orderly manner to form a graphene group, and the zinc sulfide nanomaterials are fused into the graphene group.

[0029] Specifically, the zinc sulfide nanomaterials are integrated into the graphene group in the following ways: zinc sulfide nanomaterials are attached to the surface of at least a portion of the porous graphene ellipsoids, and zinc sulfide nanomaterials are filled in at least a portion of the gaps in the graphene group; furthermore, when the particle size of the zinc sulfide nanomaterials is smaller than the pore size of the porous graphene ellipsoids, the integration of the zinc sulfide nanomaterials into the graphene group also includes the presence of zinc sulfide nanomaterials within the channels of at least a portion of the porous graphene ellipsoids. Of course, the specific integration method will not have a substantial impact on the wave absorption performance.

[0030] Different structural types and materials exhibit varying electromagnetic wave conversion capabilities. In this invention, graphene and zinc sulfide are combined in terms of materials. Structurally, graphene particles are bonded together with binders such as phenolic resin to form porous graphene ellipsoids, which are then arranged in an orderly manner to form graphene clusters. Zinc sulfide nanomaterials are integrated into these graphene clusters in various ways. This allows for faster and more efficient conversion of electromagnetic waves into heat energy. Furthermore, graphene's excellent thermal conductivity enables rapid heat transfer, resulting in an insertion loss of approximately 25 dB for the composite magnetic material in the 20 MHz-1200 MHz frequency band, demonstrating excellent wave absorption performance.

[0031] Meanwhile, the composite magnetic material of this invention uses a graphene cluster composed of multiple porous graphene ellipsoids arranged in an orderly manner as the matrix, and integrates zinc sulfide nanomaterials. It exhibits a dense structure, good toughness, and is not prone to breakage failure under load. Furthermore, the composite material is coated with an organic insulating material, which not only imparts insulation to the composite magnetic material but also makes the bonding of the composite material more stable. Optionally, during the coating process, the organic insulating material can partially coat the surface of the composite material or completely coat the composite material; preferably, the organic insulating material completely coats the composite material. The organic insulating material is preferably a block polymer, such as ethylene oxide and propylene oxide block copolymer ether.

[0032] Therefore, the composite magnetic material of the present invention has excellent ductility, toughness and wave absorption properties. Distributing the composite magnetic material in a sponge will not affect the performance of the sponge itself, but will also give the sponge excellent wave absorption properties.

[0033] To further optimize the wave absorption performance, toughness, and ductility of the wave-absorbing conductive foam, composite magnetic materials can be further optimized.

[0034] For example, in composite magnetic materials, when multiple porous graphene ellipsoids are arranged in an orderly manner to form a graphene group, the porous graphene ellipsoids are arranged in a three-dimensional array; and / or, the equatorial radius of the porous graphene ellipsoids is 100nm-120nm, and the polar radius is 200nm-250nm; and / or, the pore size of the porous graphene ellipsoids is 14nm-25nm, and the ratio of the particle size of the zinc sulfide nanomaterial to the pore size of the porous graphene ellipsoids is 1:8-1:12.

[0035] Furthermore, the mass ratio of porous graphene ellipsoids to zinc sulfide nanomaterials in the composite magnetic material can be further optimized, as can the mass fraction of the composite magnetic material in the microwave absorbing sponge. In one embodiment, the mass ratio of zinc sulfide nanomaterials to graphene groups in the composite magnetic material is 1:3-1:5; in another embodiment, the mass fraction of the composite magnetic material in the microwave absorbing sponge is 20%-40%.

[0036] This invention does not limit the preparation method of composite magnetic materials; any preparation method can be used to obtain them, as long as the structure and materials meet the above-mentioned conditions of this invention, the desired effect can be achieved.

[0037] In one embodiment, the preparation method of the composite magnetic material includes the following steps: preparing graphene groups using a colloidal crystal template method, then mixing the graphene groups with zinc sulfide nanomaterials, adding organic insulating materials, heating to a viscous state, and then cooling to obtain the composite magnetic material.

[0038] The specific steps for preparing graphene groups using the colloidal crystal template method include: preparing a first formulation by mixing graphene with water, then mixing the first formulation with a binder to form a second formulation, then adding the second formulation to a colloidal crystal template and heating it under an inert atmosphere, and then cooling it under a reducing atmosphere to obtain graphene groups.

[0039] The graphene to water mass ratio is 1:2-1:4, the graphene to binder mass ratio is 10:1-10:3, the binder is preferably a resin-based binder, such as phenolic resin, the graphene to colloidal crystal mass ratio is 6:1-12:1, the colloidal crystal template is selected from polymethyl methacrylate colloidal crystal template, the heating temperature is preferably 180℃-220℃, the heating time is preferably 20h-28h, the inert atmosphere is selected from nitrogen, argon, etc., and the reducing atmosphere is selected from carbon monoxide, hydrogen, etc.

[0040] To further improve the stability of graphene, a reducing catalyst, such as SnCl2 or FeCl2, can be added to the first formulation. The mass ratio of graphene to the reducing catalyst is 1:1 to 2:1. Then, the mixture is heated in an inert gas and cooled in a reducing atmosphere to obtain a more stable first formulation. The preferred heating temperature is 220℃ to 280℃, and the preferred heating time is 4h to 8h.

[0041] It is understood that the wave-absorbing conductive foam of the present invention is essentially a composite magnetic material distributed within the sponge of a traditional conductive foam. Therefore, the present invention does not limit the specific structure of the wave-absorbing conductive foam, and any traditional conductive foam can be used to make the wave-absorbing conductive foam of the present invention. Similarly, the selection of the conductive layer in the wave-absorbing conductive foam of the present invention is not limited in any way. Preferably, the conductive layer of the present invention is selected from aluminum foil.

[0042] Similarly, the preparation method of the wave-absorbing conductive foam of this invention is no different from the preparation method of traditional conductive foam, and can be carried out using any conductive foam preparation method. The difference lies in that composite magnetic materials are pre-distributed within the foam to prepare the wave-absorbing foam. Therefore, the wave-absorbing conductive foam of this invention can be adapted to all conductive foam production lines and can be industrially produced.

[0043] Preferably, the present invention provides a method for preparing wave-absorbing conductive foam, comprising the following steps:

[0044] S1, Disperse the composite magnetic material in water to make a slurry;

[0045] S2, the slurry is placed in a sponge and dried to obtain a microwave-absorbing sponge;

[0046] S3, the microwave-absorbing sponge is combined with a conductive layer to form a microwave-absorbing and conductive foam.

[0047] There are many ways to place the slurry in the sponge. The sponge can be soaked in the slurry multiple times, or the slurry can be injected into the sponge using equipment. This invention does not limit the methods.

[0048] The wave-absorbing conductive foam of the present invention can also be provided with double-sided conductive tape and release film. In use, after removing the release film, the wave-absorbing conductive foam can be fixed to the required electronic device by the double-sided conductive tape.

[0049] Therefore, the present invention also provides an application of wave-absorbing conductive foam in electronic devices. Electronic devices using wave-absorbing conductive foam of the present invention can effectively reduce the risk of electromagnetic leakage.

[0050] The following specific examples will further illustrate the wave-absorbing conductive foam, its preparation method, and its application.

[0051] Example 1

[0052] Fabrication of composite magnetic materials:

[0053] (1) Graphene powder was added to water at a mass ratio of 1:3 and mixed. Then, SnCl2 was added, with a mass ratio of SnCl2 to graphene powder of 1:1. The mixture was placed in an argon atmosphere and heated at 250°C for 6 hours, followed by cooling in a CO atmosphere to obtain the first formulation. The first formulation was mixed with phenolic resin to obtain the second formulation, wherein the mass ratio of graphene powder to phenolic resin was 10:2.

[0054] (2) The second formulation was added to polymethyl methacrylate colloidal crystals, with a graphene to polymethyl methacrylate colloidal crystal mass ratio of 8:1. The mixture was then placed in an argon atmosphere and heated at 200°C for 24 hours, followed by cooling in a carbon monoxide environment to obtain the following... Figure 1 The graphene group shown is composed of porous graphene ellipsoids arranged in a three-dimensional array. The equatorial radius of the porous graphene ellipsoids is 100 nm, the polar radius is 210 nm, and the pore size is 18 nm.

[0055] (3) Graphene groups and zinc sulfide nanomaterials with a particle size of 1.8 nm were added to water, wherein the mass ratio of graphene groups to zinc sulfide nanomaterials was 4:1. The mixture was stirred and mixed, and then ethylene oxide and propylene oxide block copolymer ether were added. The mixture was placed in an argon atmosphere and heated to 150°C until it reached a viscous state. After cooling, the following product was obtained: Figure 2 The composite magnetic material shown.

[0056] Wave-absorbing conductive foam manufacturing:

[0057] (1) According to the final specifications of the wave-absorbing conductive foam, the sponge is cut into sections, and the thickness of the sponge should be 0.25mm±0.05mm thicker than the final wave-absorbing conductive foam to ensure the elasticity of the final wave-absorbing conductive foam.

[0058] (2) Mix the composite magnetic material with water to make a slurry.

[0059] (3) Soak the cut sponge in the slurry and apply pressure to the sponge with a heavy object, repeating the process 100 times. Then cool and dry at room temperature to obtain the wave-absorbing sponge, wherein the mass fraction of the composite magnetic material in the wave-absorbing sponge is 30%.

[0060] (4) Cut aluminum foil and double-sided conductive tape according to the final specifications of the wave-absorbing conductive foam, and then use a molding machine to form it. Wrap the aluminum foil around the wave-absorbing foam and apply double-sided conductive tape to obtain wave-absorbing conductive foam.

[0061] Example 2

[0062] Fabrication of composite magnetic materials:

[0063] (1) Graphene powder was added to water at a mass ratio of 1:3 and mixed. Then, SnCl2 was added, with a mass ratio of SnCl2 to graphene powder of 1:1. The mixture was placed in an argon atmosphere and heated at 250°C for 6 hours, followed by cooling in a CO atmosphere to obtain the first formulation. The first formulation was mixed with phenolic resin to obtain the second formulation, wherein the mass ratio of graphene powder to phenolic resin was 10:2.

[0064] (2) The second formulation was added to polymethyl methacrylate colloidal crystals, with a mass ratio of graphene to polymethyl methacrylate colloidal crystals of 8:1. The mixture was then placed in an argon atmosphere and heated at 200°C for 24 hours. After cooling in a carbon monoxide environment, a graphene group was obtained. The graphene group consisted of porous graphene ellipsoids arranged in a three-dimensional array. The equatorial radius of the porous graphene ellipsoids was 100 nm, the polar radius was 210 nm, and the pore size was 18 nm.

[0065] (3) Add graphene groups and zinc sulfide nanomaterials with a particle size of 1.8 nm to water, wherein the mass ratio of graphene groups to zinc sulfide nanomaterials is 5:1. Stir and mix, then add ethylene oxide and propylene oxide block copolymer ether, and place in an argon atmosphere. Heat at 150°C until viscous, then cool to obtain composite magnetic material.

[0066] The fabrication of wave-absorbing conductive foam is described in Example 1.

[0067] Example 3

[0068] Fabrication of composite magnetic materials:

[0069] (1) Graphene powder was added to water at a mass ratio of 1:3 and mixed. Then, SnCl2 was added, with a mass ratio of SnCl2 to graphene powder of 1:1. The mixture was placed in an argon atmosphere and heated at 250°C for 6 hours, followed by cooling in a CO atmosphere to obtain the first formulation. The first formulation was mixed with phenolic resin to obtain the second formulation, wherein the mass ratio of graphene powder to phenolic resin was 10:2.

[0070] (2) The second formulation was added to polymethyl methacrylate colloidal crystals, with a mass ratio of graphene to polymethyl methacrylate colloidal crystals of 8:1. The mixture was then placed in an argon atmosphere and heated at 200°C for 24 hours. After cooling in a carbon monoxide environment, a graphene group was obtained. The graphene group consisted of porous graphene ellipsoids arranged in a three-dimensional array. The equatorial radius of the porous graphene ellipsoids was 100 nm, the polar radius was 210 nm, and the pore size was 18 nm.

[0071] (3) Add graphene groups and zinc sulfide nanomaterials with a particle size of 1.8 nm to water, wherein the mass ratio of graphene groups to zinc sulfide nanomaterials is 3:1. Stir and mix, then add ethylene oxide and propylene oxide block copolymer ether, and place in an argon atmosphere. Heat at 150°C until viscous, then cool to obtain composite magnetic material.

[0072] The fabrication of wave-absorbing conductive foam is described in Example 1.

[0073] Example 4

[0074] Fabrication of composite magnetic materials:

[0075] (1) Graphene powder was added to water at a mass ratio of 1:3 and mixed. Then, SnCl2 was added, with a mass ratio of SnCl2 to graphene powder of 1:1. The mixture was placed in an argon atmosphere and heated at 250°C for 6 hours, followed by cooling in a CO atmosphere to obtain the first formulation. The first formulation was mixed with phenolic resin to obtain the second formulation, wherein the mass ratio of graphene powder to phenolic resin was 10:2.

[0076] (2) The second formulation was added to polymethyl methacrylate colloidal crystals, with a mass ratio of graphene to polymethyl methacrylate colloidal crystals of 8:1. The mixture was then placed in an argon atmosphere and heated at 180°C for 24 hours. After cooling in a carbon monoxide environment, a graphene group was obtained. The graphene group consisted of porous graphene ellipsoids arranged in a three-dimensional array. The equatorial radius of the porous graphene ellipsoids was 100 nm, the polar radius was 200 nm, and the pore size was 14 nm.

[0077] (3) Add graphene groups and zinc sulfide nanomaterials with a particle size of 1.7 nm to water, wherein the mass ratio of graphene groups to zinc sulfide nanomaterials is 4:1. Stir and mix, then add ethylene oxide and propylene oxide block copolymer ether, and place in an argon atmosphere. Heat at 150°C until viscous, then cool to obtain composite magnetic material.

[0078] The fabrication of wave-absorbing conductive foam is described in Example 1.

[0079] Example 5

[0080] Fabrication of composite magnetic materials:

[0081] (1) Graphene powder was added to water at a mass ratio of 1:3 and mixed. Then, SnCl2 was added, with a mass ratio of SnCl2 to graphene powder of 1:1. The mixture was placed in an argon atmosphere and heated at 250°C for 6 hours, followed by cooling in a CO atmosphere to obtain the first formulation. The first formulation was mixed with phenolic resin to obtain the second formulation, wherein the mass ratio of graphene powder to phenolic resin was 10:2.

[0082] (2) The second formulation was added to polymethyl methacrylate colloidal crystals, with a mass ratio of graphene to polymethyl methacrylate colloidal crystals of 8:1. The mixture was then placed in an argon atmosphere and heated at 220°C for 22 hours. After cooling in a carbon monoxide atmosphere, a graphene group was obtained. The graphene group consisted of porous graphene ellipsoids arranged in a three-dimensional array. The equatorial radius of the porous graphene ellipsoids was 110 nm, the polar radius was 210 nm, and the pore size was 17 nm.

[0083] (3) Add graphene groups and zinc sulfide nanomaterials with a particle size of 1.7 nm to water, wherein the mass ratio of graphene groups to zinc sulfide nanomaterials is 4:1. Stir and mix, then add ethylene oxide and propylene oxide block copolymer ether, and place in an argon atmosphere. Heat at 150°C until viscous, then cool to obtain composite magnetic material.

[0084] The fabrication of wave-absorbing conductive foam is described in Example 1.

[0085] Example 6

[0086] Fabrication of composite magnetic materials:

[0087] (1) Graphene powder was added to water at a mass ratio of 1:3 and mixed. Then, SnCl2 was added, with a mass ratio of SnCl2 to graphene powder of 1:1. The mixture was placed in an argon atmosphere and heated at 250°C for 6 hours, followed by cooling in a CO atmosphere to obtain the first formulation. The first formulation was mixed with phenolic resin to obtain the second formulation, wherein the mass ratio of graphene powder to phenolic resin was 10:2.

[0088] (2) The second formulation was added to polymethyl methacrylate colloidal crystals, with a mass ratio of graphene to polymethyl methacrylate colloidal crystals of 8:1. The mixture was then placed in an argon atmosphere and heated at 220°C for 24 hours. After cooling in a carbon monoxide environment, a graphene group was obtained. The graphene group consisted of porous graphene ellipsoids arranged in a three-dimensional array. The equatorial radius of the porous graphene ellipsoids was 120 nm, the polar radius was 220 nm, and the pore size was 22 nm.

[0089] (3) Add graphene groups and zinc sulfide nanomaterials with a particle size of 2nm to water, wherein the mass ratio of graphene groups to zinc sulfide nanomaterials is 4:1. Stir and mix, then add ethylene oxide and propylene oxide block copolymer ether, and place in an argon atmosphere. Heat at 150°C until viscous, then cool to obtain composite magnetic material.

[0090] The fabrication of wave-absorbing conductive foam is described in Example 1.

[0091] Example 7

[0092] The fabrication of the composite magnetic material is described in Example 1.

[0093] Wave-absorbing conductive foam manufacturing:

[0094] (1) According to the final specifications of the wave-absorbing conductive foam, the sponge is cut into sections, and the thickness of the sponge should be 0.25mm±0.05mm thicker than the final wave-absorbing conductive foam to ensure the elasticity of the final wave-absorbing conductive foam.

[0095] (2) Mix the composite magnetic material with water to make a slurry.

[0096] (3) Soak the cut sponge in the slurry and apply pressure to the sponge with a heavy object, repeating the process 100 times. Then cool and dry at room temperature to obtain the wave-absorbing sponge, wherein the mass fraction of the composite magnetic material in the wave-absorbing sponge is 20%.

[0097] (4) Cut aluminum foil and double-sided conductive tape according to the final specifications of the wave-absorbing conductive foam, and then use a molding machine to form it. Wrap the aluminum foil around the wave-absorbing foam and apply double-sided conductive tape to obtain wave-absorbing conductive foam.

[0098] Example 8

[0099] The fabrication of the composite magnetic material is described in Example 1.

[0100] Wave-absorbing conductive foam manufacturing:

[0101] (1) According to the final specifications of the wave-absorbing conductive foam, the sponge is cut into sections, and the thickness of the sponge should be 0.25mm±0.05mm thicker than the final wave-absorbing conductive foam to ensure the elasticity of the final wave-absorbing conductive foam.

[0102] (2) Mix the composite magnetic material with water to make a slurry.

[0103] (3) Soak the cut sponge in the slurry and apply pressure to the sponge with a heavy object, repeating the process 100 times. Then cool and dry at room temperature to obtain the wave-absorbing sponge, wherein the mass fraction of the composite magnetic material in the wave-absorbing sponge is 40%.

[0104] (4) Cut aluminum foil and double-sided conductive tape according to the final specifications of the wave-absorbing conductive foam, and then use a molding machine to form it. Wrap the aluminum foil around the wave-absorbing foam and apply double-sided conductive tape to obtain wave-absorbing conductive foam.

[0105] Comparative Example 1:

[0106] Comparative Example 1 was carried out in accordance with Example 1, except that the sponge was not soaked in the slurry, but was directly formed with aluminum foil and double-sided conductive tape to obtain conductive foam.

[0107] Comparative Example 2

[0108] Comparative Example 2 was carried out in accordance with Example 1, except that the second formulation was added to polymethyl methacrylate colloidal crystals and heated at 150°C for 24 hours to obtain a three-dimensional arrangement of spherical graphene groups.

[0109] Comparative Example 3

[0110] Comparative Example 3 was carried out in accordance with Example 1, except that the second formulation was added to polymethyl methacrylate colloidal crystals and heated at 190°C for 18 hours to obtain a three-dimensional arrangement of rod-shaped graphene groups.

[0111] Comparative Example 4

[0112] Comparative Example 4 was carried out in accordance with Example 1, except that carbon nanotubes were used instead of graphene to obtain a group of carbon nanotubes arranged in three dimensions of porous carbon nanotube ellipsoids.

[0113] Test Example 1

[0114] The microwave absorption performance of the microwave-absorbing conductive foams obtained in Examples 1-8 and Comparative Examples 1-4 was tested. The test methods are shown below, and the test results are shown in Table 1.

[0115] Absorption performance: Refer to GB / T32596 to test absorption bandwidth and insertion loss.

[0116] Table 1

[0117]

[0118] Application Experiment

[0119] The absorbing conductive foam of Example 1 and the conductive foam of Comparative Example 1 were applied to a security camera, and electromagnetic compatibility radiated interference tests were conducted. The results are as follows: Figure 3 He Ru Figure 4 As shown, from Figure 3 and Figure 4 It can be seen that the conductive foam of Comparative Example 1 still has a small amount of electromagnetic wave leakage, which will generate external electromagnetic wave interference. However, the wave-absorbing conductive foam of Example 1 can better prevent electromagnetic waves from radiating outward, especially for electromagnetic radiation interference above 300MHz, which has a more efficient shielding effect.

[0120] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A wave-absorbing and conductive foam, characterized in that, It includes a wave-absorbing sponge and a conductive layer encapsulating the wave-absorbing sponge, wherein the wave-absorbing sponge includes a sponge and a composite magnetic material distributed in the sponge; The composite magnetic material comprises a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials, and an organic insulating material coating the surface of the composite material. In the composite material, multiple porous graphene ellipsoids are arranged in an orderly manner to form a graphene group, and the zinc sulfide nanomaterials are fused into the graphene group. The equatorial radius of the porous graphene ellipsoids is 100nm-120nm, the polar radius is 200nm-250nm, and the pore size is 14nm-25nm. The mass ratio of the zinc sulfide nanomaterials to the graphene group is 1:3-1:

5.

2. The wave-absorbing conductive foam according to claim 1, characterized in that, The composite magnetic material has a mass fraction of 20%-40% in the microwave absorbing sponge.

3. The wave-absorbing conductive foam according to claim 1 or 2, characterized in that, In the graphene group, the porous graphene ellipsoids are arranged in a three-dimensional array.

4. The wave-absorbing conductive foam according to claim 1 or 2, characterized in that, The ratio of the particle size of the zinc sulfide nanomaterial to the pore size of the porous graphene ellipsoid is 1:8 to 1:

12.

5. The wave-absorbing conductive foam according to claim 1 or 2, characterized in that, The conductive layer is selected from aluminum foil.

6. A method for preparing the wave-absorbing conductive foam according to any one of claims 1-5, characterized in that, Includes the following steps: The composite magnetic material is dispersed in water to form a slurry; The slurry is placed in a sponge and dried to obtain a wave-absorbing sponge. The microwave-absorbing sponge is combined with a conductive layer to form a microwave-absorbing and conductive foam.

7. The method for preparing the wave-absorbing conductive foam according to claim 6, characterized in that, The preparation method of the composite magnetic material includes the following steps: preparing graphene groups using a colloidal crystal template method, then mixing the graphene groups with zinc sulfide nanomaterials, adding organic insulating materials, heating to a viscous state, and then cooling to obtain the composite magnetic material; The specific steps for preparing graphene groups using the colloidal crystal template method include: preparing a first formulation by mixing graphene with water, then mixing the first formulation with a binder to form a second formulation, then adding the second formulation to a colloidal crystal template and heating it under an inert atmosphere, and then cooling it under a reducing atmosphere to obtain graphene groups.

8. The application of the wave-absorbing conductive foam as described in any one of claims 1-5 in electronic devices.

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