Janus structure electromagnetic shielding heat management rubber composite material and preparation method thereof

Abstract

The invention belongs to the technical field of functional rubber composite materials, and particularly discloses a Janus structure electromagnetic shielding heat management rubber composite material and a preparation method thereof.The preparation method includes the steps that conductive filler and phase change microcapsules are limited in different functional layers respectively, and a layer-by-layer vacuum filtration and common vulcanization combined technology is adopted; according to the invention, covalent cross-linking is carried out on molecular chains of the two layers of latex, and chemical bonding is formed in an interface area, so that extremely strong interlayer bonding force is realized, and the contradiction between electric conduction and insulation / heat storage functions is solved in space; the electromagnetic shielding layer can focus on construction of a high-conductivity network, and excellent electromagnetic shielding effectiveness is obtained; and the thermal management layer fully utilizes the latent heat energy storage characteristic of the phase change material to realize active temperature regulation and control, and meanwhile, the electrical insulation property is kept. And the composite material can be applied to the advanced technical fields with strict requirements on electromagnetic compatibility, thermal safety and flexibility, such as flexible electronic devices, wearable equipment, high-density communication modules and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional rubber composites, in particular to a Janus structure electromagnetic shielding and thermal management rubber composite and a preparation method thereof. BACKGROUND

[0002] With the rapid development of 5G, Internet of Things and artificial intelligence technologies, electronic devices are evolving towards high integration, high frequency and high power density. This trend leads to two interrelated challenges: on the one hand, increasingly complex electromagnetic interference is generated within devices and between devices, which seriously threatens signal integrity, data security and the normal operation of surrounding precision equipment; on the other hand, the heat generated by electronic components in a limited space increases dramatically, which seriously affects the reliability, life and performance of the electronic components, and increases the fire risk of electronic devices. Therefore, designing and developing high polymer functional composites that integrate thermal management, electromagnetic shielding and flame retardant properties has become a key problem that needs to be solved in the field of electronics and materials.

[0003] Rubber is an important strategic material for the country. Its excellent elasticity and sealing properties make it an indispensable key material in the field of electronic device packaging. Currently, the mainstream technology to solve the problem of electromagnetic interference of rubber materials is to add highly conductive fillers (such as carbon nanotubes, graphene, MXene, metal nanowires, etc.) to build a conductive network, which shields electromagnetic waves through reflection and absorption mechanisms. In terms of thermal management, in addition to using highly thermally conductive fillers (such as boron nitride, aluminum oxide) to build a heat conduction path for passive cooling, using the latent heat storage characteristics of phase change materials (PCM) to actively buffer and regulate temperature has also become an efficient thermal management strategy. However, there are inherent contradictions in simultaneously integrating both electromagnetic shielding and phase change thermal management functions in a single homogeneous rubber composite material: First, to achieve effective electromagnetic shielding, a high content of conductive fillers is needed to form a percolation network, but this often leads to an increase in the material's dielectric constant, deterioration of mechanical properties, and potential risk of current leakage, making it unsuitable for precision components that require electrical insulation. On the contrary, the introduction of phase change microcapsules and other materials is beneficial for thermal management, but it will disrupt the continuity of the conductive network, significantly weakening the electromagnetic shielding effectiveness. This inherent contradiction between “conductivity” and “insulation”, “shielding” and “thermal conduction” makes it difficult for traditional homogeneous composites to achieve synergistic optimization while maintaining good single performance. Second, to achieve sufficient shielding or thermal management performance, a high filler load is often required, which can lead to a sharp increase in the processing viscosity of the composite material, making it difficult to form and increasing the cost, and severely damaging the mechanical properties of the rubber matrix such as elasticity, flexibility, and impact resistance. In addition, the dispersion, orientation of fillers and their interface compatibility with the rubber matrix deeply affect the efficiency of the functional network. Disordered dispersed fillers are difficult to form an efficient path, and too many interfaces will introduce additional thermal or contact resistance, limiting further performance improvement. Therefore, how to achieve the synergy of electromagnetic shielding and thermal management without sacrificing single performance is the current technical difficulty.

[0004] To break through the above bottleneck, researchers began to seek solutions from the material structure design level. In recent years, asymmetric Janus structure materials have attracted widespread attention due to their ability to integrate completely different chemical compositions or physical properties on different sides of the same object. This structure provides a novel and promising platform for multifunctional integration: in theory, one side can be enriched with conductive fillers to achieve electromagnetic shielding, and the other side can be enriched with insulating and heat-conducting fillers to achieve thermal management and electrical insulation, thereby separating the two functions in physical space and achieving functional integration. However, applying the Janus structure concept to electromagnetic shielding / thermal management integrated composites still faces a series of key scientific and technical challenges: first, a controllable, efficient, and scalable preparation method is needed to achieve precise spatial distribution and stable interfacial bonding of the two functional fillers in the rubber matrix; second, a firm covalent bond between the two layers of the Janus structure must be ensured to prevent delamination, while optimizing phonon / electron transport at the interface; finally, the influence of this asymmetric structure on electromagnetic wave dissipation mechanisms (absorption / reflection) and heat directional conduction behavior needs to be understood and synergistically regulated. Existing technologies such as layer-by-layer coating, asymmetric deposition, or simple physical bonding often have complex processes, weak interlayer bonding, easy peeling of functional layers, or poor performance stability. Therefore, developing a Janus structure rubber composite with reasonable structure design, simple process, firm interlayer bonding, and synergistic realization of efficient electromagnetic shielding and excellent thermal management performance, as well as a reliable preparation method, has important scientific significance and application value. The present invention is dedicated to solving this technical gap. SUMMARY

[0005] To solve the above technical problems, the present application provides a Janus structure electromagnetic shielding and thermal management rubber composite and a preparation method thereof.

[0006] To achieve the above purpose, the present application is implemented according to the following technical solutions: The first technical solution provided by the present application is a preparation method of a Janus structure electromagnetic shielding and thermal management rubber composite, comprising the following steps: S1, mixing silica phase change microcapsules with a first latex to obtain a phase change microcapsule-latex mixed dispersion, the mass fraction of silica phase change microcapsules in the phase change microcapsule-latex mixed dispersion being 10%-70%; S2, mixing conductive fillers with a second latex to obtain a conductive filler-latex mixed dispersion, the mass fraction of conductive fillers in the conductive filler-latex mixed dispersion being 10%-70%; S3, taking the phase change microcapsule-latex mixed dispersion liquid and the conductive filler-latex mixed dispersion liquid with a mass ratio of (1-2):(1-2), first forming a first wet green layer by vacuum suction filtration of the conductive filler-latex mixed dispersion liquid on a filter membrane; then forming a second wet green layer by vacuum suction filtration of the phase change microcapsule-latex mixed dispersion liquid on the first wet green layer, to obtain a double-layer wet green body; S4, drying the obtained double-layer wet green body at 40-80°C for 4-24 h, and then performing vulcanization treatment at 143-180°C for 30-55 min, to obtain a Janus structure electromagnetic shielding thermal management rubber composite material from the filter membrane, wherein the upper end face of the Janus structure electromagnetic shielding thermal management rubber composite material is a conductive-electromagnetic shielding layer, the lower end face is an insulating thermal management layer, and the conductive-electromagnetic shielding layer and the insulating thermal management layer are a covalently crosslinked combined interface layer, and the conductive-electromagnetic shielding layer, the covalently crosslinked combined interface layer and the insulating thermal management layer are an integrated structure without visible delamination.

[0007] Further, the conductive filler is one or a combination of carbon nanotubes, graphene, MXene, silver nanowires and conductive carbon black.

[0008] Further, the first latex and the second latex are one or a combination of pre-dispersed vulcanization aids, natural latex, epoxidized natural latex, styrene-butadiene latex, carboxylated styrene-butadiene latex, nitrile-butadiene latex and carboxylated nitrile-butadiene latex.

[0009] Preferably, the preparation method of the silica phase change microcapsule is as follows: Taking 30 mL of tetraethyl orthosilicate and 10-15 g of microcapsule core material, mixing them at 50-60°C for 15-20 min to form a uniform mixed solution; taking 4.3-4.8 g of cetyltrimethylammonium bromide, 300 mL of deionized water and 100 mL of anhydrous ethanol, adding them to the above mixed solution, mixing them at 65-70°C at a speed of 480-500 rpm for 20-30 min on a magnetic stirrer, then performing ultrasonic treatment at 50-55°C for 10 min, adding 5.0 mL of ammonia water, stirring at 300 rpm at 65-70°C for 18-24 h, washing by suction filtration, and drying in an oven at 40°C for 24 h to obtain silica phase change microcapsules.

[0010] Further, in step S3, the pore size of the filter membrane used in vacuum suction filtration is 0.05-1.2 μm.

[0011] Preferably, the microcapsule core material is one of n-dodecane, stearic acid, lauric acid and polyethylene glycol.

[0012] The second technical solution provided by the application is a Janus structure electromagnetic shielding thermal management rubber composite material prepared by the above method.

[0013] Compared with the prior art, the application has the following beneficial effects: 1. By designing the Janus structure of the rubber composite material, the conductive filler and the phase change microcapsule are respectively limited in different functional layers, thereby solving the contradiction between the conductive and insulating / heat storage functions in space. The electromagnetic shielding layer can focus on building a high-conductive network to obtain excellent electromagnetic shielding efficiency; the thermal management layer fully utilizes the latent heat storage characteristics of the phase change material to realize active temperature regulation while maintaining electrical insulation. The two work together to realize multifunctional integration in a single material system.

[0014] 2. The application adopts the process of layer-by-layer vacuum filtration combined with co-vulcanization, so that the molecular chains of the two layers of latex are covalently crosslinked to form chemical bonds in the interface area, thereby realizing strong interlayer bonding force, effectively avoiding the delamination problem during use, and ensuring the structural integrity and long-term reliability of the material. It can be applied to advanced technical fields such as flexible electronic devices, wearable devices, high-density communication modules, etc. which have strict requirements on electromagnetic compatibility, thermal safety and flexibility.

[0015] 3. The preparation process of the application is simple in equipment and convenient to operate, and the conditions are mild. The thickness and composition of each functional layer can be accurately and independently controlled by adjusting the concentration of the dispersion liquid and the filtration amount. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The transmission electron microscope image of the silicon dioxide phase change microcapsule prepared for the embodiment 1 of the application; Figure 2 The structure schematic diagram of the Janus structure electromagnetic shielding thermal management rubber composite material prepared for the embodiment 1 of the application; Figure 3 The thermal management performance of the Janus structure electromagnetic shielding thermal management rubber composite material prepared for the embodiment 1 of the application; Figure 4 The electromagnetic shielding performance of the Janus structure electromagnetic shielding thermal management rubber composite material prepared for the embodiment 1 of the application; Figure 5 The flame retardant performance of the Janus structure electromagnetic shielding thermal management rubber composite material prepared for the embodiment 1 of the application; Figure 6 The thermal management performance of the Janus structure electromagnetic shielding thermal management rubber composite material prepared for the embodiment 2 of the application; Figure 7 The electromagnetic shielding performance of the Janus structure electromagnetic shielding thermal management rubber composite material prepared for the embodiment 2 of the application; Figure 8 The flame retardant properties of the Janus structure electromagnetic shielding thermal management rubber composite material prepared in Example 2 of this invention. Detailed Implementation

[0017] 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 specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0018] Example 1: 30 mL of tetraethyl orthosilicate (TEOS) and 10 mL of n-dodecane were mixed and stirred at 50 °C for 15 min to form a homogeneous mixture. 4.336 g of hexadecyltrimethylammonium bromide (CTAB), 300 mL of deionized water, and 100 mL of anhydrous ethanol were added to the mixture. The mixture was stirred at 500 rpm for 20 min at 68 °C using a magnetic stirrer. Subsequently, the mixture was sonicated at 50 °C for 10 min. 5.0 mL of ammonia was added, and the mixture was stirred at 300 rpm for 24 h at 66 °C. After filtration and washing, the mixture was dried in an oven at 40 °C for 24 h to obtain phase change microcapsules. The transmission electron microscopy (TEM) image is shown below. Figure 1 As shown, by Figure 1 It can be seen that the phase change microcapsules in this embodiment were successfully prepared.

[0019] 20 mg of silica phase change microcapsules containing docosane were dispersed into 160 mg of pre-dispersed vulcanizing agent in natural rubber latex (50% solid content), and filtered using a 0.05 μm pore size filter membrane to obtain a first wet preform layer. Subsequently, 20 mg of MXene was dispersed into 160 mg of pre-dispersed vulcanizing agent in natural rubber latex and filtered to obtain a double-layer wet preform. The wet preforms were dried in a 60 °C oven for 4 h, followed by vulcanization at 143 °C for 30 min to obtain a Janus-structured electromagnetic shielding thermal management rubber composite material, the structure of which is as follows. Figure 2 As shown, by Figure 2 It is known that the rubber molecular chains between the two layers of the Janus structure electromagnetic shielding thermal management rubber composite material are entangled and diffused before vulcanization. After high-temperature vulcanization, the molecular chains form covalent chemical bonds, significantly improving the interfacial bonding between the layers. For example... Figure 3 As shown, when the Janus structure electromagnetic shielding thermal management rubber composite material prepared in Example 1 is used for equipment thermal management, after 150 seconds of energization, the surface temperature of the LED chips on both sides of the Janus structure electromagnetic shielding thermal management rubber composite material is only 78.9℃, while the surface temperature of the pure rubber chip can reach 86.2℃. The electromagnetic shielding performance test results show that the total shielding effectiveness (SE) of the Janus structure electromagnetic shielding thermal management rubber composite material is high. TUp to 45dB ( Figure 4 Furthermore, thanks to the barrier effect of two-dimensional Mxene and the endothermic effect of phase change microcapsules, the peak value of the heat release rate curve (HRR curve) of the Janus structure electromagnetic shielding thermal management rubber composite material is 513.1 W / g with a relatively flat peak shape, and the total heat release curve (THR curve) is 39.39 KJ / g. Figure 5 The HRR curve of pure rubber reached a peak of 1460.1 W / g with a sharp peak shape, indicating more intense combustion, and the total heat release curve reached 68.2 KJ / g. These results demonstrate that the Janus structure electromagnetic shielding thermal management rubber composite material possesses excellent heat dissipation, electromagnetic shielding, and flame retardant properties.

[0020] Example 2: 50 mg of the silica phase change microcapsules containing docosane prepared in Example 1 were dispersed into natural rubber latex (solid content 50%) containing 100 mg of pre-dispersed vulcanizing agent, and filtered using a filter membrane with a pore size of 0.1 μm to obtain a first wet preform layer; then 50 mg of MXene was dispersed into natural rubber latex containing 100 mg of pre-dispersed vulcanizing agent and filtered to obtain a double-layer wet preform; the wet preform was dried in an oven at 60 °C for 5 h, and then vulcanized at 143 °C for 30 min to obtain a Janus structure electromagnetic shielding thermal management rubber composite material.

[0021] like Figure 6 As shown, when the Janus structure electromagnetic shielding thermal management rubber composite material prepared in Example 2 is used for equipment thermal management, after 150 s of energization, the chip surface temperature stabilizes at 71.1℃ when the MXene layer is attached to the LED chip, and at 74.3℃ when the phase change microcapsule layer is attached to the LED chip, both of which are further reduced compared to Example 1. The electromagnetic shielding performance test results show that the total shielding effectiveness (SE) of the Janus structure electromagnetic shielding thermal management rubber composite material is [insert value here]. T Up to 53.3dB ( Figure 7 Furthermore, thanks to the barrier effect of two-dimensional Mxene and the endothermic effect of phase change microcapsules, in the flame retardant performance test, its heat release rate curve (HRR curve) peaked at 266.1 W / g with a relatively flat peak shape, and the total heat release curve (THR curve) reached 25.44 KJ / g. Figure 8 The above results demonstrate that the Janus structure electromagnetic shielding thermal management rubber composite material has good heat dissipation, electromagnetic shielding, and flame retardant effects, and its performance can be controlled by adjusting the ratio of silica phase change microcapsules and conductive fillers.

[0022] Example 3: 30 mL of tetraethyl orthosilicate (TEOS) and 12 g of stearic acid were mixed and stirred at 60 °C for 20 min to form a homogeneous mixture. 4.336 g of cetyltrimethylammonium bromide (CTAB), 300 mL of deionized water, and 100 mL of anhydrous ethanol were added to the mixture. The mixture was stirred at 68 °C and 480 rpm for 30 min using a magnetic stirrer. Subsequently, the mixture was sonicated at 50 °C for 10 min, and 5.0 mL of ammonia was added. The mixture was stirred at 65 °C and 300 rpm for 24 h. After filtration and washing, the mixture was dried in an oven at 40 °C for 24 h to obtain phase change microcapsules.

[0023] 10 mg of silica phase change microcapsules containing stearic acid were dispersed into natural rubber latex (50% solid content) containing 180 mg of pre-dispersed vulcanizing agent, and filtered using a 1.2 μm pore size filter membrane to obtain the first wet preform layer; then 20 mg of carbon nanotubes were dispersed into natural rubber latex containing 360 mg of pre-dispersed vulcanizing agent and filtered to obtain a double-layer wet preform; the wet preform was dried in an oven at 60 °C for 4 h, and then vulcanized at 143 °C for 40 min to obtain a Janus structure electromagnetic shielding thermal management rubber composite material.

[0024] When the Janus-structured electromagnetic shielding thermal management rubber composite material prepared in Example 3 was used for equipment thermal management, after 150 s of energization, the chip surface temperature stabilized at 79.2℃ when the carbon nanotube layer was attached to the LED chip, and at 79.6℃ when the phase change microcapsule layer was attached to the LED chip, both significantly lower than the chip temperature when pure rubber was attached. The electromagnetic shielding performance test results show that the total shielding effectiveness (SE) of the Janus-structured electromagnetic shielding thermal management rubber composite material is significantly higher than that of the pure rubber-attached chip. T The maximum value can reach 47.3 dB. The above results demonstrate that the Janus structure electromagnetic shielding thermal management rubber composite material has good heat dissipation and electromagnetic shielding capabilities.

[0025] Example 4: 30 mL of tetraethyl orthosilicate (TEOS) and 10 g of lauric acid were mixed and stirred at 55 °C for 15 min. 4.5 g of hexadecyltrimethylammonium bromide (CTAB), 300 mL of deionized water and 100 mL of anhydrous ethanol were added to the above mixture. The mixture was stirred at 70 °C and 500 rpm for 30 min using a magnetic stirrer. Subsequently, the mixture was sonicated at 55 °C for 10 min. 5.0 mL of ammonia was added, and the mixture was stirred at 65 °C and 300 rpm for 24 h. After filtration and washing, the mixture was dried in an oven at 40 °C for 24 h to obtain phase change microcapsules.

[0026] 20 mg of silica phase change microcapsules containing lauric acid were dispersed into 160 mg of pre-dispersed vulcanizing agent styrene-butadiene rubber latex (solid content 50%), and filtered using a filter membrane with a pore size of 0.05 μm to obtain the first wet preform layer; then 20 mg of carbon nanotubes were dispersed into 160 mg of pre-dispersed vulcanizing agent carboxylated styrene-butadiene rubber latex and filtered to obtain a double-layer wet preform; the wet preform was dried in an oven at 80 °C for 6 h, and then vulcanized at 160 °C for 55 min to obtain a Janus structure electromagnetic shielding thermal management rubber composite material.

[0027] Although the Janus-structured electromagnetic shielding thermal management rubber composite material prepared in Example 4 consists of two layers composed of different rubber matrices (styrene-butadiene rubber and carboxylated styrene-butadiene rubber), the interface bonding is strong after vulcanization. This is due to the mutual entanglement and diffusion of molecular chains before vulcanization, and the synergistic effect of the covalent cross-linked network formed during vulcanization. Furthermore, when the prepared Janus-structured electromagnetic shielding thermal management rubber composite material was used for equipment thermal management, after 150 s of energization, the chip surface temperature stabilized at 75.2℃ when the carbon nanotube layer was attached to the LED chip, and at 74.6℃ when the phase change microcapsule layer was attached to the LED chip, both significantly lower than the chip temperature when only pure rubber was attached. The electromagnetic shielding performance test results show that the total shielding effectiveness (SE) of the Janus-structured electromagnetic shielding thermal management rubber composite material is high. T The maximum value can reach 49.3 dB. The above results demonstrate that the Janus structure electromagnetic shielding thermal management rubber composite material has good heat dissipation and electromagnetic shielding capabilities.

[0028] Example 5: 30 mL of tetraethyl orthosilicate (TEOS) and 15 g of polyethylene glycol 2000 were mixed and stirred at 55°C for 15 min to form a homogeneous mixture. 4.8 g of hexadecyltrimethylammonium bromide (CTAB), 300 mL of deionized water, and 100 mL of anhydrous ethanol were added to the above mixture. The mixture was stirred at 500 rpm for 30 min at 65°C using a magnetic stirrer. Subsequently, the mixture was sonicated at 55°C for 10 min, and 5.0 mL of ammonia was added. The mixture was stirred at 300 rpm for 18 h at 70°C. After filtration and washing, the mixture was dried in an oven at 50°C for 24 h to obtain phase change microcapsules.

[0029] 70 mg of silica phase change microcapsules containing polyethylene glycol 2000 were dispersed into nitrile latex (50% solid content) containing 60 mg of pre-dispersed vulcanizing agent, and filtered using a 0.1 μm pore size filter membrane to obtain the first wet preform layer; then 35 mg of silver nanowires were dispersed into nitrile latex containing 30 mg of pre-dispersed vulcanizing agent and filtered to obtain a double-layer wet preform; the wet preform was dried in an oven at 40 °C for 24 h, and then vulcanized at 180 °C for 42 min to obtain a Janus structure electromagnetic shielding thermal management rubber composite material.

[0030] When the Janus-structured electromagnetic shielding thermal management rubber composite material prepared in Example 5 was used for equipment thermal management, after 150 s of energization, the chip surface temperature stabilized at 62.2℃ when the silver nanowire layer was attached to the LED chip, and at 69.4℃ when the phase change microcapsule layer was attached to the LED chip, both significantly lower than the chip temperature when the pure rubber was attached. The electromagnetic shielding performance test results show that the total shielding effectiveness (SE) of the Janus-structured electromagnetic shielding thermal management rubber composite material is significantly higher than that of the pure rubber-attached chip. T The maximum value can reach 69.2 dB, which proves that the Janus structure electromagnetic shielding thermal management rubber composite material has good heat dissipation and electromagnetic shielding capabilities.

[0031] In summary, this invention spatially resolves the contradiction between conductivity and insulation / heat storage functions by confining the conductive filler and phase change microcapsules within different functional layers. The electromagnetic shielding layer can focus on building a highly conductive network to achieve excellent electromagnetic shielding performance; the thermal management layer fully utilizes the latent heat storage characteristics of the phase change material to achieve active temperature control while maintaining electrical insulation. The two layers work synergistically to achieve multifunctional integration within a single material system.

[0032] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a Janus-structured electromagnetic shielding thermal management rubber composite material, characterized in that, Includes the following steps: S1. Mix silica phase change microcapsules with the first latex to obtain a phase change microcapsule-latex mixed dispersion, wherein the mass fraction of silica phase change microcapsules in the phase change microcapsule-latex mixed dispersion is 10%-70%; S2. The conductive filler is mixed with the second latex to obtain a conductive filler-latex mixed dispersion, wherein the mass fraction of the conductive filler in the conductive filler-latex mixed dispersion is 10%-70%; S3. Take a phase change microcapsule-latex mixed dispersion and a conductive filler-latex mixed dispersion with a mass ratio of (1-2):(1-2). First, the conductive filler-latex mixed dispersion is vacuum filtered to form a first wet preform layer on a filter membrane. Then, the phase change microcapsule-latex mixed dispersion is vacuum filtered to form a second wet preform layer on the first wet preform layer, thus obtaining a double-layer wet preform. S4. The obtained double-layer wet blank is dried at 40~80℃ for 4-24 h, and then vulcanized at 143~180℃ for 30-55 min. The Janus structure electromagnetic shielding thermal management rubber composite material is peeled off from the filter membrane to obtain the Janus structure electromagnetic shielding thermal management rubber composite material. The upper end surface of the Janus structure electromagnetic shielding thermal management rubber composite material is a conductive-electromagnetic shielding layer, and the lower end surface is an insulating thermal management layer. The conductive-electromagnetic shielding layer and the insulating thermal management layer are covalently cross-linked interface layers. The conductive-electromagnetic shielding layer, the covalently cross-linked interface layer and the insulating thermal management layer are an integrated structure without visible delamination.

2. The method for preparing the Janus structure electromagnetic shielding thermal management rubber composite material according to claim 1, characterized in that: The conductive filler is one or more of carbon nanotubes, graphene, MXene, silver nanowires, and conductive carbon black.

3. The method for preparing the Janus structure electromagnetic shielding thermal management rubber composite material according to claim 1, characterized in that: Both the first latex and the second latex are one or more combinations of natural latex, epoxidized natural latex, styrene-butadiene latex, carboxylated styrene-butadiene latex, nitrile latex, and carboxylated nitrile latex with pre-dispersed vulcanization aids.

4. The method for preparing the Janus structure electromagnetic shielding thermal management rubber composite material according to claim 1, characterized in that: The method for preparing the silica phase change microcapsules is as follows: Take 30 mL of tetraethyl orthosilicate and 10-15 g of microcapsule core material and mix them at 50-60℃ for 15-20 min to form a homogeneous mixture. Take 4.3-4.8 g of cetyltrimethylammonium bromide, 300 mL of deionized water and 100 mL of anhydrous ethanol and add them to the above mixture. Mix at 65-70℃ and 480-500 rpm for 20-30 min with a magnetic stirrer. Then, sonicate at 50-55℃ for 10 min, add 5.0 mL of ammonia water, and stir at 65-70℃ and 300 rpm for 18-24 h. After filtration and washing, dry in an oven at 40℃ for 24 h to obtain silica phase change microcapsules.

5. The method for preparing the Janus structure electromagnetic shielding thermal management rubber composite material according to claim 1, characterized in that: In step S3, the pore size of the filter membrane used during vacuum filtration is 0.05-1.2 μm.

6. The method for preparing the Janus structure electromagnetic shielding thermal management rubber composite material according to claim 4, characterized in that: The microcapsule core material is one of n-dodecane, stearic acid, lauric acid, and polyethylene glycol.

7. A Janus-structured electromagnetic shielding thermal management rubber composite material prepared by the method according to any one of claims 1-6.

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