A high-power microwave shielding composite material and its preparation method

Abstract

This invention discloses a high-power microwave shielding composite material and its preparation method. The composite material includes a CNT composite layer and an MXene composite layer, which are stacked together. The CNT composite layer is composed of a mixture of modified MVQ and modified CNTs, with the modification of MVQ and CNTs used to achieve uniform dispersion of CNTs in MVQ. The MXene composite layer is composed of a mixture of modified MVQ and modified MXene, with the modification of MVQ and MXene used to achieve uniform dispersion of MXene in MVQ. The preparation method modifies CNTs, MVQ, and MXene to ensure good dispersion of both CNTs and MXene in MVQ, thereby preparing the stacked CNT and MXene composite layers. This results in superior HPM shielding performance, reduced overall filler loading, and decreased surface DC conductivity.

Description

Technical Field

[0001] This application relates to the technical field of electronic materials, and in particular to a high-power microwave shielding composite material and its preparation method. Background Technology

[0002] High-power microwave (HPM) refers to electromagnetic pulses with a frequency band of 0.3–300 GHz and a peak power greater than 100 MW or an average power greater than 1 MW.

[0003] Today, the peak power of strong electromagnetic pulses (HPMs) can reach the MW or even GW level, and can attack multiple targets simultaneously. Electronic components subjected to such high-intensity electromagnetic shocks will experience massive malfunctions and burnouts instantly, leading to equipment and system failures or even paralysis, causing enormous economic losses and serious consequences. Furthermore, HPMs also cause significant harm to the human body. The GB9175-88 "Environmental Electromagnetic Wave Hygiene Standard" formulated by the Ministry of Ecology and Environment of the People's Republic of China in 1989 states that exposure to power densities of 200 mW / cm² can cause serious damage. 2 Under electromagnetic waves, cells in organs such as the brain and liver of mice can be oxidized; if exposed to HPM radiation for a short period of time, it can directly burn or kill the organism, and in severe cases, it can cause the organism to lose its ability to move.

[0004] Currently, the main electromagnetic protection methods include filtering technology, ultrafast limiting technology, and the use of high-performance electromagnetic protection materials. Filtering is one of the most commonly used frequency domain protection technologies. By limiting the frequency band output of electromagnetic waves through filters, out-of-band signals that threaten the operation of electronic equipment are filtered out, effectively suppressing out-of-band electromagnetic signal coupling. It is widely used in electromagnetic protection for radar, communications, and airborne weapons. However, because filtering technology can only target a specific frequency band, it is difficult to cope with the multi-band coverage of HPM (High-Performance Mechanism) destructive weapons. Regarding ultrafast limiting technology, developed countries began research and development of related devices early on, significantly improving the response time of conventional limiters. However, the problem of peak energy leakage has not yet been well resolved. High-performance electromagnetic protection materials belong to airspace electromagnetic protection technology. They isolate electrically sensitive electronic equipment from electromagnetic radiation interference to ensure the safety of internal components and personnel. Furthermore, they do not require modification of the protected object during use, offering the advantage of not affecting the normal operation of the instrument. Therefore, high-performance HPM protection materials have become a current research hotspot.

[0005] Currently, mainstream electromagnetic shielding fillers (mainly including conductive polymers, carbon-based materials, metal nanomaterials, and two-dimensional transition metal carbides and / or nitrides) all possess high electrical conductivity. Regardless of their filler composition, their surfaces are generally covered with a continuous conductive layer. However, when faced with electromagnetic waves of different frequencies and powers, surface currents of varying densities are excited on the surface, causing localized overheating, short circuits, and even arcing. Especially when subjected to high-power electromagnetic pulses, the power density can reach 10 W / cm². 2 The above poses a serious threat to the safety of surrounding personnel and equipment. Therefore, developing HPM protective materials with low surface conductivity has become a current research hotspot and challenge in related fields. Summary of the Invention

[0006] This application addresses the aforementioned technical problems by providing a low-surface-conductivity HPM shielding composite material and its preparation method. The composite material comprises grouped carbon nanotubes (CNTs), MXene, and a methyl vinyl silicone rubber (MVQ) substrate. A "CNT-MXene" laminated composite material is prepared using hot pressing, chemical modification, and other techniques. The "CNT-MXene" laminated composite material utilizes the synergistic effect of the CNT and MXene layers to achieve superior HPM shielding performance without the introduction of magnetic metals, while reducing the overall filler load and decreasing the surface DC conductivity. The preparation of this low-surface-conductivity shielding material is of great significance for the development and application of high-power microwave composite materials. In particular, the low load of the conductive filler results in a low surface conductivity, avoiding hazards such as localized short circuits and overheating, thus providing support for HPM protection.

[0007] In a first aspect, an HPM shielding composite material is provided, comprising a first CNT composite layer and a first MXene composite layer, wherein the first CNT composite layer and the first MXene composite layer are stacked; the CNT composite layer is composed of a mixture of modified MVQ and modified CNT, wherein the modification of MVQ and CNT is used to achieve uniform dispersion of CNT in MVQ; the MXene composite layer is composed of a mixture of modified MVQ and modified MXene, wherein the modification of MVQ and MXene is used to achieve uniform dispersion of MXene in MVQ.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, the HPM shielding composite material further includes a second CNT composite layer, and the first CNT composite layer, the first MXene composite layer, and the second CNT composite layer are sequentially stacked to form a sandwich layered structure.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the HPM shielding composite material further includes a second MXene composite layer, and the first MXene composite layer, the first CNT composite layer, and the second MXene composite layer are stacked sequentially to form a sandwich layered structure.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, modified CNT refers to hydroxylated CNT, modified MVQ refers to hydroxylated MVQ, and modified MXene refers to hydroxylated or carboxylated MXene.

[0011] Secondly, a method for preparing HPM shielding composite material is provided, comprising:

[0012] The product of the first MXene composite layer is cured on the first CNT composite layer, or the product of the first CNT composite layer is cured on the first MXene composite layer.

[0013] The first CNT composite layer's internal mixing product is prepared by the following method:

[0014] CNTs were modified to obtain modified CNT powder.

[0015] MVQ is modified to obtain modified MVQ;

[0016] The prepared modified CNTs were added to the modified MVQ premix and then mixed in an internal mixer.

[0017] The first MXene composite layer's internal mixing product is prepared by the following method:

[0018] MXene was modified to obtain modified MXene powder;

[0019] MVQ is modified to obtain modified MVQ;

[0020] The prepared modified MXene was added to the modified MVQ premix and then mixed in an internal mixer.

[0021] In conjunction with the second aspect, in some implementations of the second aspect, the modification of the CNT includes:

[0022] The CNT dispersion was placed in methanol, and sodium borohydride was slowly added while stirring slowly to allow the reaction to proceed.

[0023] The blend was filtered through a polytetrafluoroethylene membrane, then rinsed with deionized water until the pH of the filtrate was neutral, and dried to obtain modified CNTs.

[0024] In conjunction with the second aspect, in some implementations of the second aspect, the modification of MXene includes:

[0025] Ti3AlC2 was etched in a LiF / HCl solution to obtain Ti3C2T x (MXene) dispersion was neutralized, centrifuged and dried to obtain MXene powder;

[0026] MXene was treated with ClCH2COOH solution to complete its surface carboxylation.

[0027] In conjunction with the second aspect, in some implementations of the second aspect, the modification of MVQ includes:

[0028] KH550 solution was added to MVQ for modification to achieve hydroxylation of the rubber substrate.

[0029] In conjunction with the second aspect, in certain implementations of the second aspect, the fabrication process of the first CNT composite layer satisfies at least one of the following:

[0030] The mass ratio of CNT to sodium borohydride is 1:0.1 to 1:1000;

[0031] The mass ratio of MVQ to the added KH550 solution is 1:0.1 to 1:1000;

[0032] The mass ratio of modified CNT to modified MVQ premix is ​​1:0.1 to 1:10000;

[0033] The curing temperature of the premix containing modified CNT and modified MVQ is 100℃~300℃.

[0034] In conjunction with the second aspect, in certain implementations of the second aspect, the fabrication process of the first MXene composite layer satisfies at least one of the following:

[0035] The concentration of LiF / HCl solution ranges from 0.01M to 20M;

[0036] The mass ratio of Ti3AlC2 powder to LiF / HCl solution is 1:0.1 to 1:100;

[0037] The concentration of ClCH2COOH solution ranges from 0.01M to 20M;

[0038] The mass ratio of Ti3AlC2 powder to ClCH2COOH solution is 1:0.1 to 1:100;

[0039] The mass ratio of modified MXene to modified MVQ premix is ​​1:0.1 to 1:10000;

[0040] The curing temperature of the premix containing modified MXene and modified MVQ is 100℃~300℃.

[0041] Thirdly, an HPM shielding composite material is provided, which is prepared by the preparation method described in any of the implementations of the second aspect above.

[0042] Compared with the prior art, the solution provided in this application has at least the following beneficial technical effects:

[0043] The composite material prepared by the above method includes grouped carbon nanotubes (CNTs) and MXene, as well as a methyl vinyl silicone rubber (MVQ) substrate. Due to the low loading of the conductive filler (CNT / MXene), it has a low surface conductivity, avoiding hazards such as local short circuits and overheating. Due to the synergistic effect of the CNT layer and the MXene layer, it has better HPM shielding performance without the introduction of magnetic metal, and the overall filler loading is reduced, resulting in a decrease in surface DC conductivity.

[0044] Preferably, the "CNT-MXene-CNT" composite material with a sandwich structure has an HPM shielding efficiency of 31.8dB at a thickness of 3mm, an overall filler loading of 1.5%, and a surface DC conductivity of only 2.3μS / m.

[0045] The high-power microwave shielding material with low surface conductivity of the present invention has universality and is applicable to most vulcanizing curing agents.

[0046] The present invention discloses a high-power microwave shielding material with low surface conductivity. Due to the use of sodium borohydride graft modification, the number of exposed hydroxyl groups is greatly increased, which makes CNTs highly dispersible in silicone rubber and avoids their agglomeration, thus preventing the material performance from deteriorating.

[0047] The present invention discloses a high-power microwave shielding material with low surface conductivity. Due to the use of ClCH2COOH graft modification, the number of exposed carboxyl groups is greatly increased, which makes MXene highly dispersible in silicone rubber and avoids its agglomeration, thus preventing the material performance from deteriorating.

[0048] The present invention discloses a high-power microwave shielding material with low surface conductivity. Due to the synergistic effect of CNT and MXene layer, the prepared composite material still has high high-power microwave shielding effectiveness with a low filler loading.

[0049] The present invention discloses a high-power microwave shielding material with low surface conductivity, which has excellent surface insulation properties due to the low loading of CNTs and MXene per unit volume.

[0050] The present invention discloses a high-power microwave shielding material with low surface conductivity. Since it does not use magnetic metal, it does not exhibit magnetism and will not interfere with the electromagnetic field distribution within the system.

[0051] The present invention provides a high-power microwave shielding material with low surface conductivity, which has the advantages of rapid large-scale preparation, low cost, good product performance, simple operation, and environmental friendliness. Attached Figure Description

[0052] Figure 1 This is a flowchart illustrating the fabrication process of a high-power microwave shielding material with low surface electrical conductivity. Detailed Implementation

[0053] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0054] The present invention provides an HPM shielding composite material with low surface conductivity, comprising a CNT composite layer and an MXene composite layer, wherein the CNT composite layer and the MXene composite layer are stacked.

[0055] Furthermore, the present invention also provides a sandwich-structured HPM shielding composite material with low surface conductivity, such as... Figure 1 As shown, it includes a first CNT composite layer, an MXene composite layer, and a second CNT composite layer stacked together. This sandwich-structured HPM shielding composite material with low surface conductivity is particularly suitable for HPM shielding applications with a density of 31.8 dB. At a thickness of 3 mm, the overall filler loading is 1.5%, and the surface DC conductivity is only 2.3 μS / m.

[0056] In other embodiments, depending on the HPM shielding requirements, the CNT composite layer and the MXene composite layer can be stacked in other ways.

[0057] For example, the present invention also provides an HPM shielding composite material with low surface conductivity, comprising a first MXene composite layer, a CNT composite layer and a second MXene composite layer stacked sequentially.

[0058] For example, the present invention also provides an HPM shielding composite material with low surface conductivity, comprising a first CNT composite layer, a first MXene composite layer, a second MXene composite layer and a second CNT composite layer stacked sequentially.

[0059] For example, the present invention also provides an HPM shielding composite material with low surface conductivity, comprising a first MXene composite layer, a first CNT composite layer, a second CNT composite layer, a second MXene composite layer, and a second CNT composite layer stacked sequentially.

[0060] For example, the present invention also provides an HPM shielding composite material with low surface conductivity, comprising a first CNT composite layer, a first MXene composite layer, a second CNT composite layer and a second MXene composite layer stacked sequentially.

[0061] For example, the present invention also provides an HPM shielding composite material with low surface conductivity, comprising a target CNT composite layer and a target MXene composite layer, wherein at least one CNT composite layer and / or at least one MXene composite layer are disposed between the target CNT composite layer and the target MXene composite layer.

[0062] The aforementioned CNT composite layer is composed of modified methyl vinyl silicone rubber (MVQ) and modified CNTs. Modified CNTs can refer to hydroxylated CNTs, and modified MVQ can refer to hydroxylated MVQ. CNTs and MVQs can also undergo other functionalization treatments, provided that the functional groups used can improve the dispersibility of CNTs within the MVQ.

[0063] One possible method for preparing the CNT composite layer is as follows.

[0064] Step (1a): The CNT dispersion is placed in methanol, and sodium borohydride is slowly added while stirring slowly to ensure a complete reaction. The use of sodium borohydride in this step results in a relatively high number of hydroxyl groups on the CNT surface. This step can also be achieved by plasma cleaning or ozone treatment to further increase the number of hydroxyl groups on the CNT surface.

[0065] Step (2a): The blend is filtered through a polytetrafluoroethylene membrane, then rinsed with deionized water until the pH of the filtrate is neutral, and dried to obtain modified CNTs.

[0066] Step (3a): Modify MVQ by adding KH550 solution to achieve hydroxylation of the rubber substrate. MVQ can also be hydroxylated by ozone treatment to achieve hydroxylation of the rubber substrate.

[0067] Step (4a): Add the prepared modified CNTs to the modified MVQ premix, mix them in an internal mixer, and then place them in a flat vulcanizing machine for curing. This allows the exposed hydroxyl groups of the CNTs to connect with the hydroxyl groups of the rubber matrix, enhancing the dispersibility of the CNTs in the MVQ.

[0068] In a preferred embodiment, in step (1a), the mass ratio of CNT to sodium borohydride is 1:0.1 to 1:1000.

[0069] In a preferred embodiment, in step (3a), the mass ratio of the methyl vinyl silicone rubber substrate to the added KH550 solution is 1:0.1 to 1:1000.

[0070] In a preferred embodiment, in step (3a), the mass fraction of KH550 solution added to the methyl vinyl silicone rubber substrate is 1:0.1 to 1:100.

[0071] In a preferred embodiment, in step (4a), the mass ratio of modified CNT to modified MVQ premix is ​​1:0.1 to 1:10000.

[0072] In a preferred embodiment, in step (4a), the curing temperature of the premix containing modified CNT and modified MVQ is 100°C to 300°C.

[0073] The aforementioned MXene composite layer is composed of a mixture of modified methyl vinyl silicone rubber (MVQ) and modified MXene. Modified MXene can refer to hydroxylated or carboxylated MXene, and modified MVQ can refer to hydroxylated MVQ. MXene and MVQ can also undergo other functionalization treatments, provided that the functional groups used can improve the dispersibility of MXene in MVQ.

[0074] One possible method for preparing the MXene composite layer is as follows.

[0075] Step (1b): Ti3AlC2 is etched in LiF / HCl solution to obtain Ti3C2T x (MXene) dispersion is neutralized, centrifuged and dried to obtain MXene powder.

[0076] Step (2b): Treat MXene with ClCH2COOH solution to complete its surface carboxylation. Alternatively, to complete the surface hydroxylation of MXene, any of the following methods can be used: sodium borohydride, plasma, or ozone. Carboxylation of MXene improves its dispersion in MVQ.

[0077] Step (3b): Add KH550 solution to MVQ for modification to achieve hydroxylation of the rubber substrate. The specific implementation method can be referred to step (3a) above.

[0078] Step (4b): Add the prepared modified MXene to the modified MVQ premix, place it in an internal mixer for internal mixing, and then place it in a flat vulcanizing machine for curing. This allows the exposed carboxyl or hydroxyl groups of MXene to connect with the hydroxyl groups of the rubber substrate, enhancing the dispersibility of MXene in MVQ.

[0079] In a preferred embodiment, in step (1b), the concentration of the LiF / HCl solution is 0.01M to 20M.

[0080] In a preferred embodiment, in step (1b), the mass ratio of Ti3AlC2 powder to LiF / HCl solution is 1:0.1 to 1:100.

[0081] In a preferred embodiment, in step (2b), the concentration of the ClCH2COOH solution is 0.01M to 20M.

[0082] In a preferred embodiment, in step (2b), the mass ratio of Ti3AlC2 powder to ClCH2COOH solution is 1:0.1 to 1:100.

[0083] In a preferred embodiment, in step (4b), the mass ratio of modified MXene to modified MVQ premix is ​​1:0.1 to 1:10000.

[0084] In a preferred embodiment, in step (4b), the curing temperature of the premix containing modified MXene and modified MVQ is 100°C to 300°C.

[0085] For the stacked CNT composite layer and MXene composite layer, another composite layer can be prepared on the surface of one composite layer after hot pressing. The following explanation uses the preparation method of the aforementioned sandwich-structured HPM shielding composite material with low surface conductivity as an example.

[0086] Step (1c): Place the CNT dispersion in methanol and slowly add sodium borohydride, stirring slowly to ensure a complete reaction; the specific execution method can be referred to step (1a) above.

[0087] Step (2c): Filter the blend through a polytetrafluoroethylene membrane, then rinse with deionized water until the pH of the filtrate is neutral, and dry to obtain surface-grouped CNTs; the specific execution method can be referred to step (2a) above.

[0088] Step (3c): Immerse Ti3AlC2 in LiF / HCl solution for etching to obtain Ti3C2T x The (MXene) dispersion is neutralized, centrifuged and dried to obtain MXene powder; the specific implementation method can be referred to step (1b) above.

[0089] Step (4c): Treat MXene with ClCH2COOH solution to complete its surface carboxylation; the specific execution method can be referred to step (2b) above.

[0090] Step (5c): Add KH550 solution to MVQ for modification to achieve hydroxylation of the rubber substrate; the specific implementation method can be referred to step (3a) above.

[0091] Step (6): Add the prepared surface-grouped CNTs to the modified MVQ premix, put it into an internal mixer for internal mixing, and then put it into a flat vulcanizing machine for heating and curing; the specific execution method can be referred to step (4a) above.

[0092] Step (7c): Add the prepared surface-grouped MXene to the modified MVQ premix, and mix it three times in the same way. Then put it into a flat vulcanizing machine for heating and curing. The specific execution method can be referred to step (4b) above.

[0093] Step (8c): Mix CNTs in the same way as in step (6), and add the resulting MVQ / CNT blend to the mold of the sample cured in step (7), and use a flat vulcanizing machine to heat and cure it; the specific execution method can be referred to step (4a) above.

[0094] Step (9c): Finally, the sample is cooled and demolded to obtain the CNT-MXene-CNT layered structure.

[0095] In a preferred embodiment, in step (9), the demolding temperature of the CNT-MXene-CNT layered structure is -100℃ to 300℃.

[0096] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The amounts of CNT and MXene fillers can be easily controlled by their addition, and the sample size is determined according to experimental requirements. In the embodiments described below, the thickness of the CNT-MXene-CNT samples is 3 mm.

[0097] Example 1

[0098] A low-conductivity, non-magnetic terahertz shielding composite thin film was prepared according to the following steps:

[0099] (1) Place the CNT dispersion in methanol and slowly add sodium borohydride. The mass ratio of CNT to sodium borohydride is 1:5. Stir slowly to allow the reaction to proceed.

[0100] (2) The blend was filtered through a polytetrafluoroethylene membrane, then rinsed with deionized water until the pH of the filtrate was neutral, and dried to obtain surface-grouped CNTs.

[0101] (3) Ti3AlC2 was etched in a LiF / HCl solution with a concentration of 0.5 M. The mass ratio of Ti3AlC2 powder to LiF / HCl solution was 1:1 to obtain Ti3C2T x (MXene) dispersion was neutralized, centrifuged and dried to obtain MXene powder;

[0102] (4) MXene was treated with ClCH2COOH solution to complete its surface carboxylation. The concentration of ClCH2COOH solution was 0.5M, and the mass ratio of Ti3AlC2 powder to ClCH2COOH solution was 1:5.

[0103] (5) Add KH550 solution to methyl vinyl silicone rubber substrate for modification. The mass ratio of rubber substrate to added KH550 solution is 1:10 to achieve hydroxylation of rubber substrate.

[0104] (6) Add different amounts of prepared surface-grouped CNTs to the modified MVQ premix in batches, put them into an internal mixer for internal mixing, and put them into a flat vulcanizing machine for curing. The mass ratio of surface-grouped CNTs to modified MVQ premix is ​​1:100, and the curing temperature is 180℃.

[0105] (7) Add the prepared surface-grouped MXene to the modified MVQ premix, and knead it three times. Then put it into a flat vulcanizing machine to heat and cure it. The mass ratio of surface-grouped MXene to modified MVQ premix is ​​1:100, and the curing temperature is 160℃.

[0106] (8) The CNTs were mixed in the same way as in step (6), and the resulting MVQ / CNT blend was added to the mold of the sample after the second curing in step (7), and cured by heating with a flat vulcanizing machine.

[0107] (9) Finally, the sample was cooled and demolded to obtain a CNT-MXene-CNT layered structure at a cooling temperature of 25℃.

[0108] The prepared CNT-MXene-CNT composite material has an HPM shielding effectiveness of 31.8dB at a thickness of 3mm, with an overall filler loading of 1.5% and a surface DC conductivity of only 2.3μS / m.

[0109] Example 2

[0110] A low-conductivity, non-magnetic terahertz shielding composite thin film was prepared according to the following steps:

[0111] In this embodiment, except that the mass ratio of surface-grouped CNTs to modified MVQ premix in step (6) is 1:50, the other steps are the same as in Example 1. The prepared CNT-MXene-CNT composite material has an HPM shielding efficiency of 22.5dB at a thickness of 3mm, an overall filler loading of 0.9%, and a surface DC conductivity of 1.7μS / m.

[0112] Example 3

[0113] A low-conductivity, non-magnetic terahertz shielding composite thin film was prepared according to the following steps:

[0114] In this embodiment, except that the mass ratio of surface-grouped MXene to modified MVQ premix in step (7) is 1:50, the other steps are the same as in Example 1. The prepared CNT-MXene-CNT composite material has an HPM shielding efficiency of 28.9dB at a thickness of 3mm, an overall filler loading of 1.1%, and a surface DC conductivity of 1.9μS / m.

[0115] Comparative Example 1

[0116] A low-conductivity, non-magnetic terahertz shielding composite thin film was prepared according to the following steps:

[0117] In this embodiment, except that the curing temperature of the flat vulcanizing machine in step (7) is set to 400°C, the other steps are the same as in Example 1, and the prepared CNT-MXene-CNT composite material cannot be cured.

[0118] Comparative Example 2

[0119] A low-conductivity, non-magnetic terahertz shielding composite thin film was prepared according to the following steps:

[0120] In this embodiment, steps (1) and (2) are removed, and the remaining steps are the same as in Example 1. The CNT-MXene-CNT composite material prepared has poor CNT dispersion and agglomeration. At a thickness of 3 mm, it has an HPM shielding efficiency of 21.8 dB. The overall filler loading is 1.5%, and the surface DC conductivity is uneven.

[0121] Comparative Example 3

[0122] A low-conductivity, non-magnetic terahertz shielding composite thin film was prepared according to the following steps:

[0123] In this embodiment, step (4) is removed, and the remaining steps are the same as in Example 1. The prepared CNT-MXene-CNT composite material has poor MXene dispersion and agglomeration. At a thickness of 3 mm, it has an HPM shielding efficiency of 20.1 dB. The overall filler loading is 1.5%, and the surface DC conductivity is uneven.

[0124] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A method for preparing HPM shielding composite material, characterized in that, include: The product of the first MXene composite layer is cured on the first CNT composite layer, or the product of the first CNT composite layer is cured on the first MXene composite layer. The first CNT composite layer's internal mixing product is prepared by the following method: CNTs were modified to obtain modified CNT powder. MVQ is modified to obtain modified MVQ; The prepared modified CNTs were added to the modified MVQ premix and then mixed in an internal mixer. The first MXene composite layer's internal mixing product is prepared by the following method: MXene was modified to obtain modified MXene powder; MVQ is modified to obtain modified MVQ; The prepared modified MXene was added to the modified MVQ premix, and then the mixture was subjected to intensive mixing in a mixer. The modification treatment of CNTs includes: The CNT dispersion was placed in methanol, and sodium borohydride was slowly added while stirring slowly to allow the reaction to proceed. The blend was filtered through a polytetrafluoroethylene membrane, then rinsed with deionized water until the pH of the filtrate was neutral, and dried to obtain modified CNTs. The modification treatment of MXene includes: Ti3AlC2 was etched in a LiF / HCl solution to obtain Ti3C2T x (MXene) dispersion, through neutralization, centrifugation and drying processes, yields MXene powder; MXene was treated with ClCH2COOH solution to complete its surface carboxylation; The modification of MVQ includes: Modification of the rubber substrate was achieved by adding KH550 solution to MVQ; The fabrication process of the first CNT composite layer satisfies at least one of the following: The mass ratio of CNT to sodium borohydride is 1:0.1 to 1:1000; The mass ratio of MVQ to the added KH550 solution is 1:0.1~1:1000; The mass ratio of modified CNT to modified MVQ premix is ​​1:0.1 to 1:10000; The curing temperature of the premix containing modified CNTs and modified MVQ is 100℃~300℃; The fabrication process of the first MXene composite layer satisfies at least one of the following: The concentration of LiF / HCl solution is 0.01M~20M; The mass ratio of Ti3AlC2 powder to LiF / HCl solution is 1:0.1~1:100; The concentration of ClCH2COOH solution is 0.01M~20M; The mass ratio of Ti3AlC2 powder to ClCH2COOH solution is 1:0.1~1:100; The mass ratio of modified MXene to modified MVQ premix is ​​1:0.1 to 1:10000; The curing temperature of the premix containing modified MXene and modified MVQ is 100℃~300℃.

2. A high-power microwave HPM shielding composite material, characterized in that, The method for preparing an HPM shielding composite material as described in claim 1 includes a first CNT composite layer and a first MXene composite layer, which are stacked together. The CNT composite layer is composed of a mixture of modified MVQ and modified CNTs, wherein the modification of MVQ and CNTs is used to achieve uniform dispersion of CNTs in MVQ. The MXene composite layer is composed of a mixture of modified MVQ and modified MXene, wherein the modification of MVQ and MXene is used to achieve uniform dispersion of MXene in MVQ.

3. The HPM shielding composite material according to claim 2, characterized in that, The HPM shielding composite material also includes a second CNT composite layer, and the first CNT composite layer, the first MXene composite layer and the second CNT composite layer are stacked in sequence to form a sandwich layered structure.

4. The HPM shielding composite material according to claim 2, characterized in that, The HPM shielding composite material also includes a second MXene composite layer. The first MXene composite layer, the first CNT composite layer, and the second MXene composite layer are stacked sequentially to form a sandwich layered structure.

5. The HPM shielding composite material according to any one of claims 2 to 4, characterized in that, Modified CNT refers to hydroxylated CNT, modified MVQ refers to hydroxylated MVQ, and modified MXene refers to hydroxylated or carboxylated MXene.

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