A ceramicizable electromagnetic shielding composite material with an inorganic filler network

Abstract

This invention relates to the field of electromagnetic shielding technology and discloses a ceramicizable electromagnetic shielding composite material with an inorganic filler network. This invention solves the problem of balancing electromagnetic shielding effectiveness and high-temperature structural stability in protective materials through an inorganic filler gradation strategy. The copolymer and elastomer matrix provide room-temperature bending compliance; low-melting-point glass powder and mica powder melt and bond at high temperatures, transforming into a ceramicized framework; nickel-plated carbon nanotubes are interspersed within, maintaining continuous shielding pathways. At room temperature, the material adheres to components to attenuate electromagnetic interference; at high temperatures, the polymer undergoes pyrolysis, melting the inorganic powder to form a dense ceramic body that blocks heat and oxygen and anchors the conductive network to prevent collapse and breakage, constructing a physical isolation and electromagnetic protection system that is flexible at room temperature and robust when exposed to fire.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding technology, and more specifically, to a ceramicizable electromagnetic shielding composite material with an inorganic filler network. Background Technology

[0002] With the rapid development of new energy vehicles, aerospace, and 5G communication base stations, the integration of high-power electronic components is becoming increasingly sophisticated, placing extremely stringent requirements on the protective materials for equipment casings and internal cables. Composite materials that combine high-temperature physical protection with electromagnetic interference resistance have become the most widely used protective basebands in this field. Especially in extreme conditions involving sudden fires and complex electromagnetic environments, electromagnetic shielding composite materials with ceramizable properties are particularly important. They can provide stable electromagnetic shielding performance at room temperature and form a robust protective layer when exposed to high-temperature flames, ensuring that internal core circuits and data transmission are not interfered with by external electromagnetic signals, thereby significantly improving the overall system's safety and reliability.

[0003] However, existing protective materials generally face a physical contradiction between high shielding effectiveness and high-temperature structural stability. To achieve high-strength electromagnetic shielding, it is often necessary to fill the matrix with large amounts of metal powder or carbon-based conductive media. This not only leads to a sharp increase in the weight of the composite material but also a significant decrease in its flexibility, making it highly susceptible to physical cracking under complex wiring bending or long-term vibration. When existing shielding composite materials are exposed to sustained high-temperature flame combustion, their polymer matrix inevitably undergoes pyrolysis and ashing, causing the originally dispersed conductive shielding network to collapse and break. This results in the irreversible loss of electromagnetic shielding capability in a fire, leading to high-frequency signal leakage inside the equipment or fatal penetration by external strong electromagnetic pulses, thus losing its safety isolation capability as an electronic protective component. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a ceramicizable electromagnetic shielding composite material with an inorganic filler network, which solves the problems existing in the field of existing ceramicizable electromagnetic shielding composite materials.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network, comprising the following steps: S1, by mass, takes 22-28 parts of zinc borosilicate glass powder, 50-70 parts of fluorophlogopite powder, and 3-7 parts of nickel-plated carbon nanotubes, puts them into a high-speed mixer, dries them, and then sprays the vinyltrimethoxysilane coupling agent solution onto the surface of the filler to obtain an activated filler mixture. S2 plasticizes 100 parts of ethylene-octene copolymer base through a two-roll mill. After the base is melted, antioxidants and crosslinking agents are added. The activated filler mixture is added in batches and then continuously mixed to obtain a composite compound. S3 preheats the upper and lower molds of the flat vulcanizing machine, places the composite compound into the mold of the flat vulcanizing machine, first closes the mold to vent the air, then holds the pressure at 14~18MPa for 10~14min, cools the mold after holding the pressure, and takes it out to obtain the ceramicizable electromagnetic shielding composite material.

[0007] In a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, in step S1, the zinc borosilicate glass powder is 25 parts, the fluorophlogopite powder is 60 parts, and the nickel-plated carbon nanotubes are 5 parts.

[0008] As a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, in step S3, the pressure of the pressure holding process is 16 MPa and the pressure holding time is 12 min.

[0009] As a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, in step S1, the parameters of the drying process are: stirring at 80℃~90℃ for 10~20min; after spraying, the temperature is raised to 110℃~120℃ and kept at the temperature for 15~25min to remove the organic solvent.

[0010] In a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, the amount of the vinyltrimethoxysilane coupling agent is 1 to 3 parts, and the solution for dissolving the vinyltrimethoxysilane coupling agent is one of anhydrous ethanol, methanol, and toluene.

[0011] As a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, wherein: in step S2, the initial roll temperature of the two-roll mill is 130℃~140℃, and the roll gap needs to be adjusted to 2~3mm before adding the activated filler mixture; the antioxidant is one of antioxidant 1010, antioxidant 168, and antioxidant B215, and the addition amount is 1~2 parts; the crosslinking agent is one of dicumyl peroxide, di-tert-butyl peroxide, or bis(2,5-dimethyl-2,5-di-tert-butylhexane)peroxide, and the addition amount is 1~2 parts.

[0012] As a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, in step S2, the activated filler mixture is added in 3 to 5 batches. After adding, mechanical mixing is maintained until the powder is completely coated by the resin and there is no obvious dry powder on the surface of the mixture, and then the next batch is added. After mixing is completed, the roller temperature is raised to 150°C to 160°C and mixing is continued for 15 to 20 minutes.

[0013] As a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, in step S3, the preheating temperature of the upper and lower templates is 170℃~180℃; the mold venting process requires 2~4 cycles of rapid venting for 2~4 seconds at 5~10MPa.

[0014] As a preferred embodiment of the method for preparing the ceramicizable electromagnetic shielding composite material with an inorganic filler network according to the present invention, in step S3, the process of cooling the mold is to introduce cold water into the flat vulcanizing machine to cool the mold to room temperature.

[0015] This invention also provides a ceramizable electromagnetic shielding composite material with an inorganic filler network, prepared by the above method, wherein: the ceramizable electromagnetic shielding composite material exhibits a dense cross-linked multiphase structure with low porosity at room temperature, and its interior contains a thermosetting cross-linked continuous phase formed by ethylene-octene copolymer, an insulating rigid support phase composed of zinc borosilicate glass powder and fluorophlogopite powder; and surface-activated nickel-plated carbon nanotubes, which are interwoven and enriched in the microscopic interface between the insulating rigid support phase and the thermosetting cross-linked continuous phase, forming a three-dimensional continuous room temperature electromagnetic shielding network. During the high-temperature calcination phase transformation process, which is higher than the melting temperature of the zinc borosilicate glass powder, the thermosetting cross-linked continuous phase undergoes pyrolysis dissipation, and the zinc borosilicate glass powder softens and melts into a high-temperature liquid phase. It also wets and binds the fluorophlogopite powder and the nickel-plated carbon nanotubes in situ to form a solid skeleton. After the polymer substrate is burned off, the physical continuity of the electromagnetic shielding circuit is maintained. During the cooling and ceramicization stage, the high-temperature liquid phase solidifies into a dense inorganic ceramic phase, accompanied by micro-expansion of the lattice to buffer the internal thermal stress of cold contraction, restricting the initiation of microcracks and volume collapse of the ceramic skeleton, so that the nickel-plated carbon nanotubes are rigidly anchored and locked in the micro-gap of the inorganic ceramic phase.

[0016] The beneficial effects of this invention are as follows: by employing a multi-dimensional inorganic filler gradation and step-by-step network construction process strategy, the technical problem of simultaneously achieving electromagnetic shielding effectiveness and structural stability at high temperatures in protective materials is solved.

[0017] The flexible carrier can maintain the bending compliance of the material at room temperature. Low melting point glass powder and mica powder can undergo phase change melting and bond together in a high temperature environment, transforming into a ceramic physical framework. Nickel-plated carbon nanotubes provide a high-frequency electromagnetic wave reflection and absorption interface through the metallic nickel layer on their surface, and their one-dimensional tubular structure is interspersed in the inorganic framework, so that the material can maintain a continuous three-dimensional electromagnetic shielding path in both room temperature and high temperature ashing states.

[0018] Under normal conditions, it can adhere to the surface of electronic components, providing electromagnetic interference attenuation. In high-temperature flame scenarios, as the polymer matrix pyrolyzes, the low-melting-point glass powder melts in situ and encapsulates mica powder and carbon nanotubes, shrinking to form a ceramic body. The ceramicized shell blocks the intrusion of external oxygen and heat, and anchors the internal nickel-plated carbon nanotube network in its original position, preventing the collapse and breakage of the conductive network after the polymer material burns. This constructs a physical isolation and electromagnetic protection system that provides flexible shielding at room temperature and structural support when exposed to fire. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Figure 1 shows the experimental results of optimizing the ceramic substrate ratio.

[0021] Figure 2 Figure 2 shows the experimental results of optimizing the ceramic substrate ratio.

[0022] Figure 3 The figure shows the experimental results of optimizing the proportions of electromagnetic shielding materials.

[0023] Figure 4 Figure 1 shows the experimental results of optimizing hot pressing process parameters.

[0024] Figure 5 Figure 2 shows the experimental results of optimizing hot pressing process parameters.

[0025] Figure 6 This is a flowchart of a method for preparing a ceramicizable electromagnetic shielding composite material with an inorganic filler network. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "example" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The appearance of an embodiment in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that mutually excludes other embodiments.

[0029] Example 1 This embodiment aims to develop a composite material that combines high electromagnetic shielding effectiveness with high-temperature ceramizability. It addresses the problems of traditional shielding materials, which, in pursuit of high-strength electromagnetic interference resistance, often suffer from abnormal stiffness and brittleness due to the addition of large amounts of fillers, making them difficult to adhere to complex irregular structures. Furthermore, in actual high-temperature fire conditions, these materials are prone to overall pulverization and collapse, thus completely losing their isolation and protective capabilities.

[0030] 1.1 Selection of substrate materials During the transformation of materials into dense ceramic bodies in a high-temperature fire, the thermal decomposition of the polymer matrix must not damage the newly formed inorganic framework. It is necessary to screen for a polymer matrix that undergoes mild pyrolysis at high temperatures to ensure stable shrinkage during thermal carbonization, without affecting the shaping of the ceramic framework and the maintenance of the electromagnetic shielding network.

[0031] Experimental materials: A1 Silicone rubber (SR), A2 Ethylene-vinyl acetate copolymer (EVA), A3 Polyurethane elastomer (TPU), A4 Ethylene propylene diene monomer (EPDM), A5 Polyvinyl chloride (PVC), A6 Polypropylene (PP), A7 Ethylene-octene copolymer (POE), A8 Styrene-butadiene-styrene block copolymer (SBS), A9 Chlorosulfonated polyethylene rubber (CSM), A10 Nitrile butadiene rubber (NBR).

[0032] Small amounts of pure substrate polymer samples were placed in the crucible of a thermogravimetric analyzer (TGA). Under air atmosphere, the samples were heated from room temperature to 800°C at a constant heating rate of 20°C / min. The thermogravimetric curves were processed using the instrument's software with a first-order derivative, and the maximum thermal decomposition rate (% / min) was extracted and recorded. A rate that is too high indicates that the matrix will vaporize significantly at a certain temperature, with the expanding gas breaking through the inorganic framework undergoing phase transition and cross-linking. A rate that is too low indicates that the matrix cannot decompose and volatilize in time during the initial stages, hindering the bonding between inorganic particles.

[0033] Each group of base polymers was mixed with an equal amount of calcium carbonate powder in a torque rheometer. Mixing was performed at a standardized initial temperature and rotor speed, and the torque changes during the mixing process were continuously recorded. Once the materials were uniformly melted and the torque curve stabilized, the mixing equilibrium torque (N·m) was read. This data is used to evaluate the polymer matrix's ability to accommodate high concentrations of inorganic powder and its processing rheology. Excessively high equilibrium torque data indicates that the material is dry and generates significant frictional heat during mixing, which will inevitably lead to equipment jamming or severe powder agglomeration in industrial scale-up production. Low equilibrium torque data indicates extremely poor melt strength and a lack of physical viscosity, making it unable to effectively encapsulate and hold the heavy inorganic filler.

[0034] The uniformly mixed high-filler materials were hot-pressed into shape using a flat vulcanizing machine and then punched into dumbbell-shaped standard specimens using a standard cutter. The specimens were clamped on a universal testing machine and subjected to uniaxial tensile testing at a constant tensile speed at room temperature (25°C) until fracture, and the elongation at break (%) was recorded. The flexibility and bending compliance of the composite material at room temperature were evaluated. An excessively high elongation at break indicates that the material is too soft and prone to irreversible tensile deformation during actual coating; an excessively low elongation indicates that the substrate has become extremely stiff and brittle after the addition of a large amount of powder, making it highly susceptible to fracture when facing the bending and laying of complex electrical circuits, failing to meet the physical coating requirements of the substrate.

[0035] The high-filler compound was cut into standard cuboid specimens, and their initial volume was measured. The specimens were then placed in a muffle furnace preheated to 800°C and calcined in air for 30 minutes. After the specimens cooled naturally to room temperature, their volume was measured again, and the volume change rate (%) after combustion was calculated and recorded. This was used to evaluate the macroscopic dimensional stability of the material during the critical period of transformation to a dense ceramic body. A large negative value indicates that the material expanded and foamed during combustion, tearing the internal conductive shielding mesh; a large positive value indicates that the material underwent severe shrinkage and collapse, leading to cracking of the protective layer and loss of its insulating function.

[0036] The test results are as follows: Among them, the substrate needs to meet the basic threshold conditions for industrial mass production and high-temperature physical molding. The high-filling mixing balance torque of the substrate material should be in the moderate range of 45~85 N·m to ensure that it has sufficient powder adhesion without causing overload of the extrusion equipment. Its volume change rate after combustion needs to be maintained in a slightly positive range of +1.00% to +8.00% to ensure that the inorganic powders move closer together and are shaped during pyrolysis without causing destructive deformation.

[0037] Polyurethane elastomers exhibit good elongation at break, and their microphase separation structure of soft and hard segments within the macromolecular chain endows the material with normal flexibility, toughness, and tear resistance. However, their volume change rate after combustion is relatively high, and in actual fire conditions, the violently expanding internal gas can damage the inorganic framework.

[0038] Silicone rubber exhibits good pyrolysis stability due to the extremely high intrinsic thermal stability of its main chain Si-O bonds, resulting in very mild and slow combustion degradation at high temperatures. However, due to the extremely low surface energy of silicone rubber, the system becomes extremely dry after incorporating a high proportion of inorganic fillers (up to 60%). This leads to a high equilibrium torque, which can cause open mill roll slippage or twin-screw extruders to seize up and stop, making it impossible to complete the premixing process of the high-concentration inorganic network.

[0039] While maintaining a usable range in terms of POE balance torque and post-combustion volume change rate, it also exhibits high room-temperature elongation at break and maximum thermal decomposition rate. Considering both the application compliance of high-dose powder absorption without brittle fracture at room temperature and the structural maintenance capability under mild and stable pyrolysis at high fire temperatures, ethylene-octene copolymer was ultimately selected as the composite material matrix.

[0040] 1.2 Screening of ceramicized frameworks Both aggregate powder sintering and the eutectic reaction with silicon-based fillers require high temperatures to trigger the process. However, the polymer matrix begins to pyrolyze in the initial fire environment, causing the material to lose its physical support within this temperature range. Special polymer matrices with high-temperature self-ceramic properties (such as silicon-containing precursors) are extremely expensive and cannot meet the needs of large-scale industrial production. Therefore, a combination of low-melting-point binder and high-melting-point aggregate is chosen. The binder preferentially undergoes phase transformation and melts at a lower temperature, wetting and binding the aggregate, filling the physical strength gap after the matrix pyrolysis gives way and before complete sintering, thus ensuring the structural integrity during the ceramization process.

[0041] 1.2.1 Screening of high-temperature skeleton binders Based on relevant data and industrial application data, blind tests were conducted on the optimal theoretical dosage of each adhesive material in its conventional system to ensure that it fully demonstrates its theoretical optimal performance. All groupings below use 100 parts by weight of ethylene-octene copolymer (base) and 100 parts by weight of calcium carbonate (base filler) as absolute references.

[0042] Experimental materials: B1 with 15 parts by weight of lead oxide-boron oxide low melting point glass powder ( B2 with 20 parts by weight of bismuth oxide-boron oxide low melting point glass powder B3 contains 18 parts by weight of phosphorus oxide-zinc oxide low melting point glass powder. B4 contains 22 parts by weight of vanadium oxide-barium oxide low-melting-point glass powder. B5 contains 25 parts by weight of zinc borosilicate low-melting-point glass powder. B6 with 24 parts by weight of barium borosilicate low-melting-point glass powder B7 contains 30 parts by weight of calcium aluminosilicate low-melting-point glass powder. B8 with 12 parts by weight of sodium silicate low-melting-point glass powder B9 contains 16 parts by weight of stannous fluoride-phosphorus oxide low-melting-point glass powder. ).

[0043] Each group of binder powders was pressed into standard-sized cylinders and placed on a ceramic substrate at a 45° angle. The substrate was then placed in a muffle furnace and calcined at 800°C for 15 minutes. After cooling, the downward flow distance of the melt on the substrate was measured. This was used to evaluate the fluid behavior of the binder under the high temperature of the initial fire. An excessively long flow distance indicates that the melt viscosity is too low, and it will flow and drip under gravity, losing its bond support from the material interior. An excessively short flow distance indicates that the melt is too dry and hard, unable to flow between the base filler particles and fill the pores, making it difficult to form a continuous physical bond network.

[0044] The polymer substrate, calcium carbonate, and each group of binders to be tested were mixed in a fixed ratio and hot-pressed into standard elongated test blocks. The test blocks were then calcined in a muffle furnace at 800℃ for 30 minutes. After natural cooling to room temperature, a three-point bending test was performed, and the flexural strength at fracture was recorded. This determines the physical support capacity of the ceramic body formed by the bonding of the binder and base filler after the pyrolysis of the substrate resin.

[0045] The test results are as follows: Calcium aluminosilicate low-melting-point glass powder exhibits high flexural strength in its ceramic-forming framework, but its short downward flow distance indicates that the melt is relatively dry and hard, making it unable to flow between the base filler particles and fill microscopic pores. This hinders the formation of a continuous bonding network in real, complex fire scenarios. Zinc borosilicate low-melting-point glass powder, on the other hand, demonstrates good flexural strength in its ceramic-forming framework and a moderate downward flow distance, indicating that its high-temperature melt possesses adequate flow and encapsulation properties. Therefore, it is selected as a ceramicizing binder for composite materials.

[0046] 1.2.2 Screening of High-Temperature Skeleton Support Phase Experimental groups (based on the final proportions in 1.2.1): C0 calcium carbonate powder, C1 32 parts by mass of muscovite powder, C2 36 parts by mass of phlogopite powder, C3 33 parts by mass of fluorophlogopite powder, C4 27 parts by mass of sericite powder, C5 41 parts by mass of talc powder, C6 38 parts by mass of wollastonite powder, C7 29 parts by mass of calcined kaolin, C8 43 parts by mass of flake alumina, and C9 21 parts by mass of hexagonal boron nitride powder.

[0047] In addition to determining the mixing equilibrium torque of each component under high-filling conditions using the aforementioned method, it is also necessary to expose one side of the composite material sample to a 1000℃ flame and record the absolute temperature of the unexposed side of the sample after 30 minutes of heating. This is used to evaluate the physical barrier effect formed by the two-dimensional lamellar structure of the framework phase after high-temperature densification. An excessively high unexposed side temperature indicates that the aspect ratio of the framework powder is insufficient or that crystal collapse has occurred at high temperatures, failing to form a dense, interlocking barrier, leading to direct heat penetration.

[0048] Then, the front surface was continuously sprayed with a standard cold water column at a set pressure to rapidly cool it to room temperature. The specimen was then placed on a universal testing machine for compression testing, and its residual compressive strength was recorded. This was used to evaluate the macroscopic mechanical stability of the ceramic skeleton under real extreme heat-cooling and mechanical impact conditions. A low residual compressive strength indicates severe thermal stress microcrack propagation within the skeleton phase itself, or a significant mismatch in the expansion coefficients with the binder phase leading to large-area tearing of the internal interfaces, which will result in collapse when exposed to fire-fighting water jets and building vibrations during fire rescue.

[0049] The test results are as follows: Among them, calcium carbonate powder undergoes a violent thermal decomposition reaction at a high temperature of 1000℃. The scouring of a large amount of gas destroys the internal ceramic network, resulting in high temperature on its unexposed surface and extremely low residual strength, thus losing its protective ability.

[0050] Hexagonal boron nitride powder has the lowest back-fired surface temperature, and its excellent high-temperature thermal stability and anisotropic thermal conductivity form an effective thermal insulation barrier. However, under the physical impact of a cold water column, interlayer slippage and collapse occur directly inside the ceramic body, resulting in low residual compressive strength. This is because its interlayers have extremely strong self-lubricating properties and its surface chemical inertness is extremely high, making it impossible for molten zinc borosilicate glass to effectively wet and bind it.

[0051] The good residual compressive strength of lamellar alumina is due to its extremely high hardness, which provides good mechanical support to the skeleton after sintering. However, the equilibrium torque of the mixing system is too high because the friction and shear resistance of lamellar alumina at high concentrations is large. In actual mass production, this will directly lead to overload and seizure of the extrusion equipment, making industrialization impossible.

[0052] In samples where the mixing torque is maintained within a moderate processing range, fluorophlogopite powder exhibits excellent overall performance. It combines the heat-insulating barrier effect of high-temperature densification with the interfacial wetting and consolidation ability with zinc borosilicate glass melt, and maintains macroscopic mechanical stability under extreme heat and rapid cooling shocks. Therefore, it was selected as the high-temperature skeletal support phase for composite materials.

[0053] 1.3 Screening of Electromagnetic Shielding Materials After determining the ceramizable basic system of the composite material, it is necessary to screen the most suitable electromagnetic shielding material. While constructing a continuous electromagnetic attenuation network, it is necessary to ensure compatibility with high-temperature fire environments, and to ensure that the overall structural integrity of the material is maintained during the pyrolysis retreat of the polymer substrate and the ceramic phase transformation. The shielding filler should not undergo drastic volume changes or interfacial repulsion, which could damage the dense inorganic skeleton.

[0054] Experimental groups: D1 with 4.5 parts by mass of multi-walled carbon nanotubes, D2 with 6.4 parts by mass of nickel-plated carbon nanotubes, D3 with 11 parts by mass of truncated carbon fibers, D4 with 14 parts by mass of silicon carbide whiskers, D5 with 8 parts by mass of graphene microflakes, D6 with 17 parts by mass of flake graphite, D7 with 38 parts by mass of iron-silicon-aluminum alloy powder, D8 with 13 parts by mass of nano-titanium nitride powder, and D9 with 16 parts by mass of conductive carbon black powder.

[0055] Each group of shielding materials was added to the composite system in a fixed ratio to prepare test pieces of standard thickness. In addition to testing the elongation at break, a vector network analyzer was used to determine its electromagnetic shielding effectiveness in a specified frequency band (e.g., X-band 8.2-12.4 GHz). This was used to evaluate the material's fundamental ability to construct an electromagnetic attenuation network at room temperature.

[0056] Composite material specimens were calcined in a muffle furnace at 1000℃ for 30 minutes. After the polymer was completely pyrolyzed and the ceramic skeleton was constructed, the specimens were cooled to room temperature in the furnace. Then, a standard cold water column at a set pressure was used to continuously spray the front surface of the specimens to rapidly cool them to room temperature. The electromagnetic shielding effectiveness of the skeleton under high-temperature continuous cooling and the skeleton after rapid cooling impact were measured. The influence of the shielding material on the skeleton was evaluated by measuring the residual compressive strength after extreme heat and rapid cooling.

[0057] The test results are as follows: Among the components that performed well in electromagnetic shielding at room temperature, graphene microsheets and multi-walled carbon nanotubes had high initial effectiveness at room temperature, but suffered severe thermal oxidation loss at high temperatures, resulting in large-area burnout of the conductive network and low residual shielding effectiveness after high temperature and rapid cooling. Although iron-silicon-aluminum alloy powder had less thermal decay at high temperature, its thermal expansion mismatch with the inorganic framework resulted in low residual compressive strength under extreme heat and rapid cooling impact, large-area tearing inside the ceramic body, and physical severing of the electromagnetic shielding network.

[0058] Nickel-plated carbon nanotubes retain highly stable comprehensive electromagnetic attenuation capabilities even after high-temperature calcination and rapid water cooling. Furthermore, their room-temperature elongation at break and residual compressive strength after extreme heat quenching remain among the highest in the overall sequence. This indicates that the external nickel plating layer not only creates a synergistic effect of dielectric and magnetic loss with the internal carbon nanotubes but also effectively delays the high-temperature oxidation of the carbon-based network. Moreover, it does not undergo drastic volumetric abrupt changes during polymer pyrolysis and ceramic phase transformation, balancing the processing flexibility of the substrate under normal conditions with the macroscopic mechanical integrity after ceramicization in a calcination process. Therefore, it was selected as an electromagnetic shielding filler for composite materials.

[0059] 1.4 Screening of surface coupling agents After determining the ceramicizable skeleton system and electromagnetic shielding filler of the composite material, in order to solve the interfacial compatibility problem between a large number of inorganic powders and organic polymer substrates, improve the dispersion uniformity of the filler in the system, and further reduce the processing rheological resistance under high filling conditions, it is necessary to screen the most suitable surface coupling agent.

[0060] To ensure that the coupling agent can effectively cover the microscopic surface of the filler and fully exert its interfacial bridging effect, the ratio of the coupling agent in this experiment was based on the conventional industrial recommended dosage, and 2% of the mass percentage of the shielding material to be modified (the conventional usable range is 1%~3%) was used as the addition benchmark.

[0061] Experimental groups: E1 silane coupling agent KH-550, E2 silane coupling agent KH-560, E3 silane coupling agent KH-570, E4 silane coupling agent A-171, E5 titanate coupling agent KR-TTS, E6 titanate coupling agent NDZ-201, E7 aluminate coupling agent DL-411, E8 aluminum-titanium composite coupling agent, E9 stearic acid.

[0062] In addition to detecting elongation at break and equilibrium torque, the maximum breaking stress must be recorded simultaneously during the tensile test to extract the room-temperature tensile strength of the specimen. This is used to evaluate the rigidity of the chemical bond network established by the coupling agent between the organic substrate and the inorganic filler. Low tensile strength indicates that the functional groups at both ends of the coupling agent have failed to form a strong bridge with the interface of the two phases with different properties. Under stress, the interface is prone to peeling and slippage, resulting in low overall mechanical transfer efficiency.

[0063] The test results are as follows: Among them, stearic acid has a high elongation at break, but its room temperature tensile strength is low. This is because stearic acid only plays a purely physical role in lubrication and plasticization in the system and fails to effectively establish a chemical bonding network between the inorganic filler and the organic substrate. Under stress, the interface is very easy to peel off and slip.

[0064] The high room-temperature tensile strength of the silane coupling agent KH-570 is due to the slight cross-linking of its end-group double bond structure with the polymer matrix, forming a highly rigid bridging network. However, the high mixing equilibrium torque and low elongation at break of the system are because the rigid cross-linked network severely restricts the free movement of the polymer molecular chains, resulting in a significant increase in the flow friction resistance of the filler in the matrix.

[0065] The low mixing equilibrium torque of the titanate coupling agent KR-TTS is due to the extremely efficient coating of inorganic powders by titanates, which significantly reduces their surface energy. However, its room temperature tensile strength is poor because the polarity matching between its molecular chain segments and the POE substrate is limited, failing to provide sufficient mechanical transfer.

[0066] Vinyltrimethoxysilane exhibits the best overall balance. Its mixing equilibrium torque, room temperature tensile strength, and elongation at break are all among the top in the series, thus it is selected as a surface coupling agent for composite materials.

[0067] Example 2 Reference Figures 1 to 3 This is the second embodiment of the present invention. After determining the raw materials of the composite material, in order to further stimulate the cross-scale synergistic effect of the multiphase material system and maximize the comprehensive performance of the material, it is necessary to optimize the proportion of each component.

[0068] 2.1 Optimization of Ceramic Substrate Proportioning Excessive use of ceramic powder can lead to overload of the polymer matrix's nucleation rate, causing the composite material to lose its flexibility at room temperature and completely collapse its processing rheology. Insufficient filler will prevent the formation of a continuous inorganic support network in the high temperatures of a fire, causing the polymer to lose its physical barrier and burn through directly after pyrolysis. An improper ratio of mica framework to glass powder can cause structural liquefaction collapse or dry fragmentation in the high-temperature ceramic state. At the microscopic level, this is mainly due to the mismatch between the volume of the high-temperature liquid-phase glass and the mesh voids of the two-dimensional sheets, resulting in interfacial wetting instability and stress concentration inside the melt.

[0069] Using 100 parts by mass of POE as the baseline, groups were set up with the amount of fluorophlogopite powder added from 30 to 70 (step size 5), and groups were set up with the amount of zinc borosilicate low melting point glass powder added from 10 to 34 (step size 3) to conduct cross-factor experimental groups.

[0070] The composite materials of each formulation were extruded and calendered using a twin-screw extruder to prepare rectangular strips and circular specimens of standard dimensions. In addition to testing the elongation at break at room temperature, residual compressive strength at 1000℃, and residual electromagnetic shielding effectiveness at high temperature, the initial central axis length of the rectangular strips before calcination also needed to be measured. Subsequently, they were placed in a muffle furnace and calcined at 1000℃ for 30 minutes. After slow cooling to room temperature with the furnace, the residual length of the central axis was measured again. The linear dimensional shrinkage rate was calculated to evaluate the macroscopic volumetric stability of the ceramic skeleton after calcination at 1000℃. An excessively large linear shrinkage rate indicates excessive flow of the glass liquid phase at high temperature, which can easily lead to severe cracking of the ceramic body after cooling; while an excessively large expansion rate means that the skeleton structure is loose and porous, losing its physical density.

[0071] Test results are as follows Figure 1 and Figure 2 As shown, polymer composite shielding panels, in practical applications (such as modular shelter assembly and encapsulation of irregularly shaped electronic equipment structures), need to possess a certain degree of fit and bending capability. If the elongation at break at room temperature is too low, the material is prone to brittle fracture under construction stress, leading to premature damage to the internal shielding network. Based on actual construction tolerance, the industrial lower limit for elongation at break at room temperature is set at 250%, defining a preliminary safety ratio window.

[0072] The addition of ceramicized aggregates physically dilutes the conductive network in the matrix, leading to an irreversible decrease in the basic shielding effectiveness. During the phase transition process at 1000℃, both excessive liquid phase shrinkage (crushing the conductive network) and excessive solid phase foaming expansion (tearing the conductive network) can cause devastating damage to the microscopic shielding circuit.

[0073] By extracting contour lines showing the rate of change in line dimensions from the 3D data model, 0% dimension change does not necessarily result in optimal shielding retention. Due to the thermal stress difference between the inside and outside of the skeleton during the cooling phase, an absolutely rigid skeleton is highly susceptible to microcracks. Through surface optimization, a contour line showing a micro-expansion of +1.53% was found to be the theoretically optimal dimensional state. This slight positive expansion acts as a stress sponge during the cooling contraction phase, effectively buffering and offsetting internal cold contraction stress, thus maximizing the protection of the continuity of the conductive network. Linear fitting along this +1.53% contour line yielded an optimal mass ratio of fluorophlogopite to glass powder of 2.4:1.

[0074] Residual compressive strength and electromagnetic shielding effectiveness data were obtained from the baseline profile of a 2.4:1 mix ratio. As the total filler content increased, the high-temperature residual compressive strength of the material continuously increased, but the electromagnetic shielding effectiveness continued to decrease due to the aggregate compression effect. By calculating the compressive strength improvement rate per unit shielding loss, it was found that in the initial stage, a minimal sacrifice in shielding effectiveness could yield a significant increase in compressive strength. However, once the total filler content exceeded the critical point, the curve showed a clear diminishing marginal benefit. At this point, further increasing the filler content resulted in a very slight increase in compressive strength, while the shielding effectiveness continued to decline due to the accumulation of insulating aggregate.

[0075] After fitting calculations, the theoretical stationary point where the marginal utility drops sharply occurs occurs at (59.43 parts fluorophlogopite and 24.76 parts glass powder). Considering the metering accuracy and feeding errors in large-scale industrial production, the final optimal ratio is determined to be 60 parts fluorophlogopite and 25 parts glass powder.

[0076] 2.3 Optimization of Electromagnetic Shielding Material Proportion Carbon nanotubes are the core medium for constructing conductive and electromagnetic shielding networks in composite materials. If the amount added is too small, the nanoparticles cannot cross the percolation threshold in the complex gaps between the polymer matrix and inorganic aggregates, making it difficult to effectively build a continuous and dense three-dimensional microscopic shielding circuit and failing to meet electromagnetic shielding requirements. If excessive amounts are added in pursuit of shielding effectiveness, it will not only increase production costs and lose the price advantage for large-scale commercialization, but also significantly increase melt viscosity due to the agglomeration of nanoscale particles, inducing deterioration of processing rheology.

[0077] Referring to the addition range of nickel-plated carbon nanotubes, using 100 parts by weight of POE, 60 parts by weight of fluorophlogopite, and 25 parts by weight of glass powder as the base, the addition amount of nickel-plated carbon nanotubes ranged from 1 to 10 parts, with 1 part as the step size for experimental groups. The effects of different addition amounts on the performance of the finished product were comprehensively analyzed by detecting the electromagnetic shielding effectiveness at room temperature, the residual electromagnetic shielding effectiveness after calcination, the equilibrium torque, and the residual compressive strength.

[0078] Test results are as follows Figure 3 As shown. 70 N·m is the safety limit for conventional twin-screw extruders. Calculations show the corresponding addition amount is 6.37. Excessive torque can lead to severe shear heat generation and polymer matrix degradation, while also causing drastic fluctuations in extrusion pressure. Considering equipment protection and process stability in industrial production, the effective addition amount should be limited to below 6 parts. Through fitting calculations, the inflection point of residual compressive strength is 5.18 parts, and the marginal benefit point of shielding effectiveness improvement is 4.73 parts. The average of these two is 4.95 parts. Considering the metering accuracy, feeding error, and processing stability of long-term continuous extrusion in actual workshop production, the addition amount of nickel-plated carbon nanotubes is selected as 5 parts.

[0079] Example 3 Reference Figure 4 and Figure 5 This is the third embodiment of the present invention. Considering that during the transition from laboratory-scale testing to industrial-scale mass production, the heat transfer efficiency, shear heat accumulation, and mixing uniformity of the material will all experience significant amplification effects, leading to deviations in the material's rheological behavior and molding state, optimization and adjustment of relevant core extrusion and molding process parameters are necessary to eliminate the deviations caused by the amplification effect and ensure the process stability and macroscopic performance consistency of continuous production.

[0080] 3.1 Surface activation treatment of inorganic fillers Take 25 parts of zinc borosilicate low-melting-point glass powder, 60 parts of fluorophlogopite powder, and 5 parts of nickel-plated carbon nanotubes, and put them into a high-speed mixer. Stir at 80℃~90℃ for 10~20 minutes to dry the filler. After drying, keep the mixer stirring, and evenly spray 1~3 parts of vinyltrimethoxysilane coupling agent, pre-diluted with anhydrous ethanol (or alternatively methanol or toluene), onto the tumbling filler surface using an atomizing spraying device. Continue stirring and heat to 110℃~120℃, maintaining the temperature for 15~25 minutes to allow the coupling agent molecules to fully graft and coat the surface of the various inorganic fillers, forming an activated filler mixture. After discharge, allow it to cool naturally to room temperature for later use.

[0081] 3.2 Pre-distribution of the mixing process Set and stabilize the roller temperature of the two-roll mill at 130℃~140℃, and add 100 parts of ethylene-octene copolymer (POE) to the mill for plasticizing. After the matrix material is completely melted and evenly coated on the surface of the mill rollers, add 1~2 parts of antioxidant 1010 (antioxidant 168 or antioxidant B215 can also be selected) and 1~2 parts of dicumyl peroxide (di-tert-butyl peroxide or 2,5-dimethyl-2,5-di-tert-butylhexane peroxide) for preliminary mixing. To avoid agglomeration and disruption of the continuous network caused by the instantaneous addition of a large amount of inorganic powder, adjust the mill roller gap to 2~3mm. Add only one-third of the total filler volume (which can be divided into 3~5 parts and added in batches) of the activated filler mixture in the first batch, and disperse it initially in the resin through continuous tamping and turning operations.

[0082] After the first batch of filler has been completely absorbed by the resin and there is no obvious dry powder on the surface, the remaining activated filler mixture is added evenly in two batches. The roller temperature of the open mill is gradually increased to 150℃~160℃. Utilizing the continuous high temperature and mechanical shear force, the nickel-plated carbon nanotubes and ceramicized powders are encouraged to overlap at the polymer phase interface, gradually constructing a complete three-dimensional inorganic filler network. The mixture is continuously mixed for 15~20 minutes until the surface of the compound is smooth and there are no obvious particle protrusions. Then, it is rolled into sheets and cooled to obtain the composite compound.

[0083] 3.3 Hot pressing Based on the free radical-triggered half-life of the cross-linked system and the viscosity of the high-filler melt, the preheating temperature of the upper and lower molds of the flat vulcanizing machine is set to 170℃~180℃. The cooled compound is cut into blocks that match the mold cavity size and placed flat into the flat vulcanizing machine. Under a low initial pressure of 5~10MPa, rapid venting is performed 2~4 times for 2~4 seconds each time, with alternating hot and pressure action to remove tiny air bubbles trapped inside the dense rubber blocks, preventing voids and defects from remaining inside the product.

[0084] After degassing, a significant physical-chemical coupling interaction effect exists in the crosslinking and setting stage. Molding pressure dominates the forced flow of the polymer melt and the physical compaction of the inorganic interface, while holding time determines the degree of curing of the free radical crosslinking network and the stress relaxation state of the macromolecular chains. Variable groups were set up with a step size of 1 MPa from 11 MPa to 20 MPa, and variable groups were set up with a step size of 2 min from 4 min to 20 min. Cross-variable settings were used to create experimental groups.

[0085] After the pressure holding process is completed, cold water is circulated into the flat vulcanizing machine to cool the mold to room temperature. The mold is then opened and the sample is removed. In addition to testing the electromagnetic shielding effectiveness and elongation at break at room temperature, the sample needs to undergo liquid nitrogen brittle fracture treatment. The complete morphology of the cross-section is then scanned using a scanning electron microscope, and the porosity inside the matrix is ​​statistically calculated using image processing software. Micropores can disrupt the compactness of the matrix interface and can also become stress concentration points during demolding cooling and high-temperature calcination, leading to a significant decrease in the residual strength of the material.

[0086] Test results are as follows Figure 4 and Figure 5 As shown, in the low-pressure molding zone, a relatively high porosity remains within the matrix. These insulating micropores physically block the contact between carbon nanotubes, preventing the effective construction of the micro-conductive network and resulting in low macroscopic electromagnetic shielding effectiveness. With increasing molding pressure and holding time, the porosity gradually decreases, and the shielding effectiveness significantly improves. In the extremely high energy input zone, although the material porosity is low, the shielding effectiveness exhibits an abnormal decline. Excessive cross-linking curing and high-pressure densification lead to the accumulation of enormous elastic internal stress within the system. At the moment of mold opening and pressure release, the rigid network undergoes violent microscopic volume rebound, tearing apart the already assembled carbon nanotube nodes and damaging the microscopic shielding circuit.

[0087] The evolution of elongation at break at room temperature exhibits a significant, gentle, and broad plateau region. A dynamic equilibrium is reached between the physical compaction effect of high pressure and the chemical cross-linking and macromolecular chain stress relaxation resulting from a moderate holding time. Under these conditions, the polymer chain segments achieve appropriate cross-linking node anchoring while avoiding glass transition and retaining sufficient space for deformation under stress.

[0088] The optimal plateau region for electromagnetic shielding effectiveness and the peak region for elongation at break do not completely coincide in spatial coordinates. Using polynomial surface fitting to extract extreme coordinates, the fitted extreme point for electromagnetic shielding effectiveness is (18.24 MPa, 10.61 min), while the fitted extreme point for elongation at break is (14.63 MPa, 13.14 min). Averaging these values ​​yields the theoretically optimal process node as (16.43 MPa, 11.87 min). Considering the control precision and operational error tolerance of the actual industrial flat-plate vulcanizing unit, the optimal cross-linking and setting process parameters for this embodiment are finally determined to be a holding pressure of 16 MPa for 12 min.

[0089] Example 4 Reference Figure 6 This is the fourth embodiment of the present invention. This embodiment provides a method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network. Specifically, it includes the following steps: Surface activation treatment of S1 inorganic filler Accurately weigh 25 parts by weight of zinc borosilicate glass powder, 60 parts by weight of fluorophlogopite powder, and 5 parts by weight of nickel-plated carbon nanotubes, and simultaneously add them to a high-speed mixer. Set the mixer temperature to 85°C and stir at high speed for 15 minutes to dry the surface moisture of the filler. While maintaining stirring, evenly spray 2 parts by weight of vinyltrimethoxysilane coupling agent, pre-diluted with anhydrous ethanol, onto the filler surface using an atomizing spraying device. Subsequently, raise the temperature to 115°C and maintain the reaction for 20 minutes. After discharging, allow it to cool naturally to room temperature to obtain the activated filler mixture.

[0090] S2 composite material mixing pre-distribution The initial roll temperature of the two-roll mill was set to 135°C. 100 parts of ethylene-octene copolymer (POE) substrate were added for plasticizing. After the substrate was completely melted and wrapped around the rolls, 1 part of antioxidant 1010 and 1.5 parts of dicumyl peroxide (DCP) were added. The roll gap of the mill was adjusted to 2 mm, and the resulting activated filler mixture was added in four batches sequentially. After each addition, mechanical turning and tamping were maintained until the powder of that batch was completely absorbed by the resin and there was no obvious dry powder on the surface before adding the next batch. After all the fillers were added, the roll temperature of the mill was increased to 155°C. The continuous high temperature and mechanical shear force promoted the overlap of the filler network. The mixture was continuously mixed for 18 minutes, rolled into sheets, and cooled to obtain the composite compound.

[0091] S3 composite material is hot-pressed crosslinked and shaped. Preheat the upper and lower mold plates of the flat vulcanizing machine to 175°C. Place the cut composite rubber block flat into the mold cavity. First, perform three rapid venting operations under a pressure of 8 MPa, each lasting 3 seconds, to completely remove any tiny air bubbles trapped inside the rubber block. After venting, quickly increase the molding pressure to 16 MPa and maintain this pressure for 12 minutes for cross-linking and setting. After holding the pressure, maintain a constant pressure of 16 MPa and introduce cold water into the flat vulcanizing machine to cool the entire mold to room temperature. Open the mold and remove the product to obtain a ceramicizable electromagnetic shielding composite material with an inorganic filler network.

[0092] The obtained sample had an elongation at break of 285.0% at room temperature, an electromagnetic shielding effectiveness of 48.5dB at room temperature, and a porosity of 2.03% at fracture. After calcination at 1000℃ and natural cooling, the thermal phase transformation line dimensional change rate was +1.53%, the residual compressive strength was 29.2MPa, and the residual electromagnetic shielding effectiveness was 36.8dB.

[0093] In summary, this invention solves the technical problem of balancing electromagnetic shielding effectiveness and structural stability at high temperatures in protective materials by employing a multi-dimensional inorganic filler gradation and step-by-step network construction process strategy.

[0094] The flexible carrier can maintain the bending compliance of the material at room temperature. Low melting point glass powder and mica powder can undergo phase change melting and bond together in a high temperature environment, transforming into a ceramic physical framework. Nickel-plated carbon nanotubes provide a high-frequency electromagnetic wave reflection and absorption interface through the metallic nickel layer on their surface, and their one-dimensional tubular structure is interspersed in the inorganic framework, so that the material can maintain a continuous three-dimensional electromagnetic shielding path in both room temperature and high temperature ashing states.

[0095] Under normal conditions, it can adhere to the surface of electronic components, providing electromagnetic interference attenuation. In high-temperature flame scenarios, as the polymer matrix pyrolyzes, the low-melting-point glass powder melts in situ and encapsulates mica powder and carbon nanotubes, shrinking to form a ceramic body. The ceramicized shell blocks the intrusion of external oxygen and heat, and anchors the internal nickel-plated carbon nanotube network in its original position, preventing the collapse and breakage of the conductive network after the polymer material burns. This constructs a physical isolation and electromagnetic protection system that provides flexible shielding at room temperature and structural support when exposed to fire.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network, characterized in that... Includes the following steps: S1, by mass, takes 22-28 parts of zinc borosilicate glass powder, 50-70 parts of fluorophlogopite powder, and 3-7 parts of nickel-plated carbon nanotubes, puts them into a high-speed mixer, dries them, and then sprays the vinyltrimethoxysilane coupling agent solution onto the surface of the filler to obtain an activated filler mixture. S2 plasticizes 100 parts of ethylene-octene copolymer base through a two-roll mill. After the base is melted, antioxidants and crosslinking agents are added. The activated filler mixture is added in batches and then continuously mixed to obtain a composite compound. S3 preheats the upper and lower molds of the flat vulcanizing machine, places the composite compound into the mold of the flat vulcanizing machine, first closes the mold to vent the air, then holds the pressure at 14~18MPa for 10~14min, cools the mold after holding the pressure, and takes it out to obtain the ceramicizable electromagnetic shielding composite material.

2. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 1, characterized in that, In step S1, the zinc borosilicate glass powder is 25 parts, the fluorophlogopite powder is 60 parts, and the nickel-plated carbon nanotubes are 5 parts.

3. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 1, characterized in that, In step S3, the pressure during the pressure holding process is 16 MPa, and the pressure holding time is 12 minutes.

4. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 1, characterized in that, In step S1, the drying process parameters are: stirring at 80℃~90℃ for 10~20 minutes; after spraying, heating to 110℃~120℃ and holding for 15~25 minutes to remove organic solvent.

5. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 4, characterized in that, The amount of the vinyltrimethoxysilane coupling agent is 1 to 3 parts, and the solution for dissolving the vinyltrimethoxysilane coupling agent is one of anhydrous ethanol, methanol, and toluene.

6. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 1, characterized in that, In step S2, the initial roll temperature of the two-roll open mill is 130℃~140℃. Before adding the activated filler mixture, the roll gap needs to be adjusted to 2~3mm. The antioxidant is one of antioxidant 1010, antioxidant 168, and antioxidant B215, and the addition amount is 1~2 parts. The crosslinking agent is one of dicumyl peroxide, di-tert-butyl peroxide, or bis(2,5-dimethyl-2,5-di-tert-butylhexane)peroxide, and the addition amount is 1~2 parts.

7. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 1, characterized in that, In step S2, the activated filler mixture is added in 3 to 5 batches. After adding, mechanical mixing is maintained until the powder is completely coated by the resin and there is no obvious dry powder on the surface of the mixture. Then the next batch is added. After mixing is completed, the roller temperature is raised to 150°C to 160°C and mixing is continued for 15 to 20 minutes.

8. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 1, characterized in that, In step S3, the preheating temperature of the upper and lower mold plates is 170℃~180℃; the mold closing and venting process requires 2~4 rapid venting cycles of 2~4 seconds each at 5~10MPa.

9. The method for preparing a ceramizable electromagnetic shielding composite material with an inorganic filler network according to claim 1, characterized in that, In step S3, the process of cooling the mold involves introducing cold water into the flat vulcanizing machine to cool the entire mold to room temperature.

10. A ceramizable electromagnetic shielding composite material with an inorganic filler network, prepared by the method according to any one of claims 1 to 9, characterized in that, The ceramicizable electromagnetic shielding composite material exhibits a dense cross-linked multiphase structure with low porosity at room temperature. Its interior contains a thermosetting cross-linked continuous phase formed by ethylene-octene copolymer, an insulating rigid support phase composed of zinc borosilicate glass powder and fluorophlogopite powder, and surface-activated nickel-plated carbon nanotubes that are interwoven and enriched between the microscopic interface of the insulating rigid support phase and the thermosetting cross-linked continuous phase, forming a three-dimensional continuous room temperature electromagnetic shielding network. During the high-temperature calcination phase transformation process, which is higher than the melting temperature of the zinc borosilicate glass powder, the thermosetting cross-linked continuous phase undergoes pyrolysis dissipation, and the zinc borosilicate glass powder softens and melts into a high-temperature liquid phase. It also wets and binds the fluorophlogopite powder and the nickel-plated carbon nanotubes in situ to form a solid skeleton. After the polymer substrate is burned off, the physical continuity of the electromagnetic shielding circuit is maintained. During the cooling and ceramicization stage, the high-temperature liquid phase solidifies into a dense inorganic ceramic phase, accompanied by micro-expansion of the lattice to buffer the internal thermal stress of cold contraction, restricting the initiation of microcracks and volume collapse of the ceramic skeleton, so that the nickel-plated carbon nanotubes are rigidly anchored and locked in the micro-gap of the inorganic ceramic phase.

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