Carbon fiber-carbon nanotube thermal interface material and preparation method thereof

Abstract

The application discloses a carbon fiber-carbon nanotube thermal interface material and a preparation method thereof. The preparation method comprises the following steps: pretreatment of carbon fibers, modification of carbon fibers, orientation of carbon fibers, growth of carbon nanotubes and polymer compounding. The preparation method of the carbon fiber-carbon nanotube thermal interface material realizes orientation of carbon fibers and compounding of carbon nanotubes, a primary heat conduction network is formed by the oriented carbon fibers to directly conduct heat; and a secondary heat conduction network is formed by the carbon nanotubes grown in situ on the surface of the carbon fibers to connect the oriented carbon fibers and assist heat conduction, thereby constructing a double heat conduction network. Through the synergistic effect of the double heat conduction network, the in-plane thermal conductivity and the plane-through thermal conductivity of the composite material are improved. Meanwhile, a polymer matrix is used as a matrix, air in the gap between a chip and a package can be fully extruded, the contact thermal resistance between the chip and the package is effectively reduced, and the thermal conductivity of the thermal interface material is improved.

Description

Technical Field

[0001] This invention relates to thermally conductive composite materials, and more particularly to a carbon fiber-carbon nanotube thermal interface material and its preparation method. Background Technology

[0002] With the miniaturization, integration, and functionalization of electronic products, their power density and heat flux density have increased dramatically. The enormous heat dissipation and temperature and pressure pressures within these devices affect their lifespan and reliability, thus placing more stringent demands on effective heat dissipation during operation. Thermal interface materials, possessing excellent thermal conductivity and high-temperature resistance, primarily function to bridge the microscopic gaps between heat-generating elements and heat dissipation devices, thereby significantly improving heat transfer efficiency. They have received widespread attention in recent years.

[0003] In existing technologies, carbon fiber has significant advantages in the field of thermal interface materials due to its excellent thermal conductivity, high strength, and good mechanical compliance. However, the thermal conductivity of carbon fiber is anisotropic, with its thermal conductivity reaching up to 1000 W / m·K in the axial direction, while it does not exceed 10 W / m·K in the vertical direction, resulting in the heat transfer of carbon fiber not reaching the ideal value. Summary of the Invention

[0004] The purpose of this invention is to propose a carbon fiber-carbon nanotube thermal interface material and its preparation method, so as to solve the problem that the actual thermal conductivity is poor due to the anisotropic thermal conductivity of carbon fibers.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] This invention provides a method for preparing a carbon fiber-carbon nanotube thermal interface material, comprising the following steps:

[0007] Pretreatment of carbon fiber: The carbon fiber is acid-washed and then dried;

[0008] Modification of carbon fiber: Acid-washed carbon fiber is mixed with tetraethyl silicate in an organic solvent, then the organic solvent is filtered off and dried; the carbon fiber mixed with tetraethyl silicate is then heated to obtain silicon-modified carbon fiber.

[0009] Carbon fiber orientation: By applying an external physical field to change the orientation of silicon-modified carbon fibers, the silicon-modified carbon fibers are made to form a 3D thermally conductive skeleton.

[0010] Carbon nanotube growth: First, a protective gas and a reducing gas are introduced to place the 3D thermally conductive framework in an atmosphere of protective gas and reducing gas; then the 3D thermally conductive framework is heated and a mixture of carbon source and catalyst is introduced to grow carbon nanotubes on the 3D thermally conductive framework, thus obtaining a carbon fiber-carbon nanotube framework.

[0011] Polymer composite: A polymer matrix is ​​vacuum impregnated into a carbon fiber-carbon nanotube framework, and the mixture is cured to obtain a carbon fiber-carbon nanotube thermal interface material.

[0012] In the preparation method of the carbon fiber-carbon nanotube thermal interface material, the aspect ratio of the carbon fiber is 100 to 500.

[0013] In the preparation method of the carbon fiber-carbon nanotube thermal interface material, during the carbon nanotube growth step, carbon source gas and catalyst powder are directly guided to the 3D carbon fiber skeleton through a pipeline, and the direction of introduction of carbon source gas and catalyst powder is the same as the orientation direction of carbon fiber.

[0014] In the preparation method of the carbon fiber-carbon nanotube thermal interface material, the acid washing step in the carbon fiber pretreatment step includes:

[0015] Carbon fiber is mixed with pickling solution and subjected to ultrasonic vibration to obtain a mixture containing carbon fiber.

[0016] The pH value of the mixture containing carbon fiber is adjusted to make the mixture neutral, and the carbon fiber in the mixture is filtered out.

[0017] The drying step includes: placing the filtered carbon fibers in anhydrous ethanol and ultrasonically dispersing them; after ultrasonic dispersion, drying is performed to completely evaporate the anhydrous ethanol, resulting in acid-washed carbon fibers.

[0018] In the preparation method of the carbon fiber-carbon nanotube thermal interface material, in the acid washing step, the ultrasonic oscillation temperature is 50-100℃ and the ultrasonic oscillation time is 0.5-3h; in the drying step, the ultrasonic dispersion temperature is 78.5-100℃ and the ultrasonic dispersion time is 0.5-3h.

[0019] In the method for preparing the carbon fiber-carbon nanotube thermal interface material, during the carbon fiber orientation step, the applied physical field includes one of a temperature field, a magnetic field, an electric field, and a force field.

[0020] In the method for preparing the carbon fiber-carbon nanotube thermal interface material, during the carbon nanotube growth step, the carbon source includes one of methane, acetylene, ethanol, acetone, benzene, and xylene, and the catalyst includes one of transition metals such as Fe, Co, Ni, Cu, Mo, Pt, and Mn, and compounds of transition metals such as Fe, Co, Ni, Cu, Mo, Pt, and Mn.

[0021] In the preparation method of the carbon fiber-carbon nanotube thermal interface material, during the carbon nanotube growth step, the heating temperature of the 3D thermally conductive framework is 500-1200℃, and the growth time is 0.5-2h.

[0022] In the preparation method of the carbon fiber-carbon nanotube thermal interface material, in the polymer composite step, the polymer matrix includes one of silicone rubber and silicone resin.

[0023] The present invention also provides a carbon fiber-carbon nanotube thermal interface material, which is prepared by the above-described method for preparing carbon fiber-carbon nanotube thermal interface materials.

[0024] One of the technical solutions in this invention can have the following beneficial effects:

[0025] The method for preparing the carbon fiber-carbon nanotube thermal interface material achieves carbon fiber orientation and composite carbon nanotubes. The oriented carbon fibers form a primary thermally conductive network for direct heat conduction. Furthermore, carbon nanotubes grown in situ on the carbon fiber surface form a secondary thermally conductive network, connecting the oriented carbon fibers and assisting in heat conduction, thus constructing a dual thermally conductive network. Through the synergistic effect of these dual networks, the in-plane thermal conductivity and through-plane thermal conductivity of the composite material are improved. Simultaneously, a polymer matrix is ​​used as the matrix, which can effectively squeeze out air from the gap between the chip and the package, effectively reducing the contact thermal resistance between the chip and the package and improving the thermal conductivity of the thermal interface material. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of one embodiment of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be further illustrated below through specific embodiments. To facilitate understanding of the present invention, a more comprehensive description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0028] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Please refer to Figure 1This invention provides a method for preparing a carbon fiber-carbon nanotube thermal interface material, comprising the following steps:

[0031] Pretreatment of carbon fiber: The carbon fiber is acid-washed and then dried;

[0032] Modification of carbon fiber: Acid-washed carbon fiber is mixed with tetraethyl silicate in an organic solvent, then the organic solvent is filtered off and dried; the carbon fiber mixed with tetraethyl silicate is then heated to obtain silicon-modified carbon fiber.

[0033] Carbon fiber orientation: By applying an external physical field to change the orientation of silicon-modified carbon fibers, the silicon-modified carbon fibers are made to form a 3D thermally conductive skeleton.

[0034] Carbon nanotube growth: First, a protective gas and a reducing gas are introduced to place the 3D thermally conductive framework in an atmosphere of protective gas and reducing gas; then the 3D thermally conductive framework is heated and a mixture of carbon source and catalyst is introduced to grow carbon nanotubes on the 3D thermally conductive framework, thus obtaining a carbon fiber-carbon nanotube framework.

[0035] Polymer composite: A polymer matrix is ​​vacuum impregnated into a carbon fiber-carbon nanotube framework, and the mixture is cured to obtain a carbon fiber-carbon nanotube thermal interface material.

[0036] The thermally conductive framework of the carbon fiber-carbon nanotube thermal interface material is composed of carbon fiber-carbon nanotube fillers to achieve thermal conductivity. By using composite polymers, an elastic polymer is wrapped around the outer periphery of the thermally conductive framework, allowing the carbon fiber-carbon nanotube thermal interface material to fill the gap between the chip and the package, preventing air from existing between the chip and the package, thereby improving thermal conductivity.

[0037] By modifying the carbon fibers, they can better adsorb catalysts, thereby increasing the number and length of carbon nanotubes. In one specific embodiment of the invention, the carbon fibers are heated in a tube furnace using anhydrous ethanol as the organic solvent, causing tetraethyl silicate to pyrolyze and generate silicon dioxide, which is then adsorbed onto the surface of the carbon fibers.

[0038] Before carbon fibers form an ordered thermally conductive network, the thermal interface material's thermally conductive skeleton is randomly arranged, and heat is randomly transferred within the material, making effective heat transfer impossible. After the carbon fiber orientation process, an ordered thermally conductive network is formed, and heat is transferred along the filler's alignment direction, effectively transferring heat and improving the material's thermal conductivity.

[0039] The method for preparing the carbon fiber-carbon nanotube thermal interface material achieves carbon fiber orientation and composite carbon nanotubes. The oriented carbon fibers form a primary thermally conductive network for direct heat conduction. Furthermore, carbon nanotubes grown in situ on the carbon fiber surface form a secondary thermally conductive network, connecting the oriented carbon fibers and assisting in heat conduction, thus constructing a dual thermally conductive network. Through the synergistic effect of these dual networks, the in-plane thermal conductivity and through-plane thermal conductivity of the composite material are improved. Simultaneously, a polymer matrix is ​​used as the matrix, which can effectively squeeze out air from the gap between the chip and the package, effectively reducing the contact thermal resistance between the chip and the package and improving the thermal conductivity of the thermal interface material.

[0040] The carbon fiber-carbon nanotube thermal interface material prepared by the above-mentioned method can be applied in the fields of thermal engineering and electronics. As a thermal conductive material for electronic components, it can improve the heat transfer efficiency and effectively reduce thermal resistance, thereby ensuring the stability and performance of equipment in high-temperature environments.

[0041] In a specific embodiment of the present invention, the organic solvent in the carbon fiber modification step is anhydrous ethanol, and the heating device is a tube furnace. Heating causes tetraethyl silicate to pyrolyze and generate silicon dioxide, which is then adsorbed onto the carbon fiber surface. In the carbon nanotube growth step, argon is used as a protective gas, and hydrogen is used as a reducing gas. The 3D thermally conductive framework is situated in an atmosphere of both protective and reducing gases, thus preventing oxidation of the 3D thermally conductive framework under heating conditions.

[0042] Specifically, the aspect ratio of the carbon fiber is 100 to 500. Compared with carbon fibers with a smaller aspect ratio, using the above aspect ratio reduces the contact thermal resistance between carbon fibers, allowing heat to be directly conducted through the carbon fibers.

[0043] Specifically, in the carbon nanotube growth step, carbon source gas and catalyst powder are directly guided to the 3D carbon fiber skeleton through a pipeline, and the direction of introduction of carbon source gas and catalyst powder is the same as the orientation direction of carbon fiber.

[0044] The orientation direction of the carbon fiber must be parallel to the direction of the carbon source gas to ensure full contact between the carbon source gas and the carbon fiber. This will enable the growth of higher quality carbon nanotubes, and the carbon nanotubes will grow along the orientation direction of the carbon fiber, thereby realizing a secondary heat conduction network.

[0045] Furthermore, in the carbon fiber pretreatment step, the acid washing step includes:

[0046] Carbon fiber is mixed with pickling solution and subjected to ultrasonic vibration to obtain a mixture containing carbon fiber.

[0047] The pH value of the mixture containing carbon fiber is adjusted to make the mixture neutral, and the carbon fiber in the mixture is filtered out.

[0048] The drying step includes: placing the filtered carbon fibers in anhydrous ethanol and ultrasonically dispersing them; after ultrasonic dispersion, drying is performed to completely evaporate the anhydrous ethanol, resulting in acid-washed carbon fibers.

[0049] The above-described acid washing step effectively removes dirt from the surface of carbon fibers, making them cleaner. Simultaneously, it adjusts the microstructure of the carbon fiber surface, facilitating subsequent modification treatments. In a specific embodiment of the invention, the pH adjustment and filtration steps are as follows: a mixture containing carbon fibers is poured into a vacuum filtration device, and a water pump draws the mixture into a filter flask. Subsequently, distilled water is continuously poured in to rinse and dilute the carbon fibers until the filtrate is neutral, while the carbon fibers remain on the filter membrane. The acid washing solution is obtained from dilute sulfuric acid and concentrated nitric acid.

[0050] By employing the above drying steps, moisture and solvents on the surface of carbon fibers can be quickly removed, thereby improving drying efficiency.

[0051] Furthermore, in the pickling step, the ultrasonic oscillation temperature is 50–100°C and the ultrasonic oscillation time is 0.5–3 h; in the drying step, the ultrasonic dispersion temperature is 78.5–100°C and the ultrasonic dispersion time is 0.5–3 h.

[0052] By using the parameters of ultrasonic oscillation and ultrasonic dispersion mentioned above, the dispersibility of carbon fibers can be improved, allowing the carbon fibers to fully contact the pickling solution or alcohol, which can improve surface roughness, effectively remove impurities, and facilitate the subsequent growth of carbon nanotubes and the formation of the skeleton.

[0053] Specifically, in the carbon fiber orientation step, the applied physical field includes one of a temperature field, a magnetic field, an electric field, and a force field.

[0054] When the applied physical field is a temperature field, carbon fiber orientation is achieved through radial cryogenic casting. The specific steps are: vertical freezing with liquid nitrogen, followed by sublimation of ice in a freeze-drying oven. When the applied physical field is a magnetic field, carbon fiber orientation is achieved through magnetic field orientation. When the applied physical field is an electric field, carbon fiber orientation is achieved through electrospinning. When the applied physical field is a force field, carbon fiber orientation is achieved through shear force flow. All of the above orientation methods are existing technologies and will not be elaborated upon here.

[0055] Specifically, in the carbon nanotube growth step, the carbon source includes one of methane, acetylene, ethanol, acetone, benzene, and xylene, and the catalyst includes one of transition metals such as Fe, Co, Ni, Cu, Mo, Pt, and Mn, and compounds of transition metals such as Fe, Co, Ni, Cu, Mo, Pt, and Mn.

[0056] In specific embodiments of the present invention, the carbon source can be methane, acetylene, ethanol, acetone, benzene, or xylene. The catalyst can be one of the transition metals Fe, Co, Ni, Cu, Mo, Pt, Mn, and their compounds.

[0057] Using the aforementioned carbon source and catalyst is beneficial for the rapid growth of carbon nanotubes.

[0058] Specifically, in the carbon nanotube growth process, the heating temperature of the 3D thermally conductive framework is 500–1200℃, and the growth time is 0.5–2 hours.

[0059] In a specific embodiment of the present invention, the oriented carbon fibers are placed in a tube furnace and heated to a temperature of 500–1200°C for a growth time of 0.5–2 hours. Using the above parameters, high-quality carbon nanotubes can be formed on the carbon fibers.

[0060] Specifically, in the polymer compounding step, the polymer matrix includes one of silicone rubber and silicone resin.

[0061] Both silicone rubber and silicone resin are highly elastic materials. Using silicone rubber or silicone resin as a matrix, the high deformation characteristics of the carbon fiber-carbon nanotube thermal interface material can be brought into the material. This can effectively squeeze out the air in the gap between the chip and the package, thereby reducing the contact thermal resistance between the chip and the package and improving the thermal conductivity of the thermal interface material.

[0062] This invention provides a carbon fiber-carbon nanotube thermal interface material, which is prepared by the above-described method for preparing carbon fiber-carbon nanotube thermal interface materials.

[0063] Example 1

[0064] A method for preparing a carbon fiber-carbon nanotube thermal interface material includes the following steps:

[0065] Pretreatment of carbon fiber: Carbon fiber is mixed with pickling solution and ultrasonically vibrated at 100℃ for 0.5 hours to obtain a mixture containing carbon fiber. The mixture is then poured into a vacuum filtration device, and a water pump is used to filter the mixture into a filter flask. Distilled water is continuously added to rinse and dilute the carbon fiber until the filtrate is neutral and the carbon fiber remains on the filter membrane. The filtered carbon fiber is placed in anhydrous ethanol and ultrasonically dispersed at 78.5℃ for 3 hours. After ultrasonic dispersion, the carbon fiber is dried to completely evaporate the anhydrous ethanol, yielding the pickled carbon fiber. The pickling solution is a mixture of dilute sulfuric acid and concentrated nitric acid.

[0066] Modification of carbon fiber: Acid-washed carbon fiber is mixed with tetraethyl silicate in anhydrous ethanol, the anhydrous ethanol is filtered and then dried naturally; the carbon fiber mixed with tetraethyl silicate is then heated in a tube furnace to obtain silicon-modified carbon fiber.

[0067] Carbon fiber orientation: The orientation of silicon-modified carbon fibers is changed by applying an external temperature field; a radial cryogenic casting method is adopted, that is, after vertical freezing with liquid nitrogen, the carbon fibers are placed in a freeze-drying oven to sublimate ice, so that the silicon-modified carbon fibers form a 3D thermally conductive skeleton.

[0068] Carbon nanotube growth: The 3D thermally conductive framework is placed in a tube furnace, and argon and hydrogen are first introduced to place the 3D thermally conductive framework in a protective gas and reducing gas atmosphere; then the 3D thermally conductive framework is placed in the tube furnace for heating at a temperature of 850℃ for a growth time of 0.5h; and a mixture of xylene and ferrocene is injected along the carbon fiber orientation direction using an injection pump to grow carbon nanotubes on the 3D thermally conductive framework, thus obtaining a carbon fiber-carbon nanotube framework.

[0069] Polymer composite: Silicone rubber is mixed with a carbon fiber-carbon nanotube framework under vacuum conditions, and the mixture is cured to obtain a carbon fiber-carbon nanotube thermal interface material.

[0070] The carbon fiber has an aspect ratio of 110, the carbon source is xylene, and the catalyst is ferrocene.

[0071] Example 2

[0072] The steps of Example 2 are the same as those of Example 1, except that: the aspect ratio of the carbon fiber is 110; in the carbon fiber pretreatment step, the ultrasonic oscillation temperature is 50°C and the ultrasonic oscillation time is 3h; the ultrasonic dispersion temperature is 100°C and the ultrasonic dispersion time is 0.5h; in the carbon nanotube growth step, the heating temperature is 1200°C and the growth time is 0.5h.

[0073] Example 3

[0074] The steps of Example 3 are the same as those of Example 1, except that: the aspect ratio of the carbon fiber is 500; in the carbon fiber pretreatment step, the ultrasonic oscillation temperature is 75°C and the ultrasonic oscillation time is 1.5h; the ultrasonic dispersion temperature is 85°C and the ultrasonic dispersion time is 2h; in the carbon nanotube growth step, the heating temperature is 500°C and the growth time is 2h.

[0075] Comparative Example 1

[0076] The steps of Comparative Example 1 are the same as those of Example 1, except that in the carbon nanotube growth step, a mixture of xylene and ferrocene is injected along the direction perpendicular to the carbon fiber orientation.

[0077] Comparative Example 2

[0078] The steps of Comparative Example 2 are basically the same as those of Example 1, except that the carbon fiber modification step is not performed in the preparation steps of Comparative Example 2.

[0079] Comparative Example 3

[0080] The steps of Comparative Example 3 are basically the same as those of Example 1, except that the carbon nanotube growth step is not performed in the preparation steps of Comparative Example 3.

[0081] The thermal interface materials obtained in Examples 1-3 and Comparative Examples 1-3 were tested for their thermal conductivity, including the thermal conductivity in the length direction and the thermal conductivity in the thickness direction. The test results are shown in Table 1.

[0082] Table 1 - Thermal conductivity test results for each embodiment

[0083]

[0084] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these equivalent variations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for preparing a carbon fiber-carbon nanotube thermal interface material, characterized in that, Includes the following steps: Pretreatment of carbon fiber: The carbon fiber is acid-washed and then dried; Modification of carbon fiber: Acid-washed carbon fiber is mixed with tetraethyl silicate in an organic solvent, then the organic solvent is filtered off and dried; the carbon fiber mixed with tetraethyl silicate is then heated to obtain silicon-modified carbon fiber. Carbon fiber orientation: By applying an external physical field to change the orientation of silicon-modified carbon fibers, the silicon-modified carbon fibers are made to form a 3D thermally conductive skeleton. Carbon nanotube growth: First, a protective gas and a reducing gas are introduced to place the 3D thermally conductive framework in an atmosphere of protective gas and reducing gas; then the 3D thermally conductive framework is heated and a mixture of carbon source and catalyst is introduced to grow carbon nanotubes on the 3D thermally conductive framework, thus obtaining a carbon fiber-carbon nanotube framework. Polymer composite: A polymer matrix is ​​vacuum impregnated into a carbon fiber-carbon nanotube framework, and the mixture is cured to obtain a carbon fiber-carbon nanotube thermal interface material. In the carbon nanotube growth process, carbon source gas and catalyst powder are directly guided into the 3D carbon fiber skeleton through a pipeline, and the direction of introduction of carbon source gas and catalyst powder is the same as the orientation direction of carbon fiber.

2. The method for preparing a carbon fiber-carbon nanotube thermal interface material according to claim 1, characterized in that, The aspect ratio of the carbon fiber is 100 to 500.

3. The method for preparing a carbon fiber-carbon nanotube thermal interface material according to claim 1, characterized in that, In the pretreatment step of carbon fiber, the acid washing step includes: Carbon fiber is mixed with pickling solution and subjected to ultrasonic vibration to obtain a mixture containing carbon fiber. The pH value of the mixture containing carbon fiber is adjusted to make the mixture neutral, and the carbon fiber in the mixture is filtered out. The drying step includes: placing the filtered carbon fibers in anhydrous ethanol and ultrasonically dispersing them; after ultrasonic dispersion, drying is performed to completely evaporate the anhydrous ethanol, resulting in acid-washed carbon fibers.

4. The method for preparing a carbon fiber-carbon nanotube thermal interface material according to claim 3, characterized in that, In the pickling step, the ultrasonic oscillation temperature is 50–100°C and the ultrasonic oscillation time is 0.5–3 h; in the drying step, the ultrasonic dispersion temperature is 78.5–100°C and the ultrasonic dispersion time is 0.5–3 h.

5. The method for preparing a carbon fiber-carbon nanotube thermal interface material according to claim 1, characterized in that, In the carbon fiber orientation step, the applied physical field includes one of a temperature field, a magnetic field, an electric field, and a force field.

6. The method for preparing a carbon fiber-carbon nanotube thermal interface material according to claim 1, characterized in that, In the carbon nanotube growth step, the carbon source includes one of methane, acetylene, ethanol, acetone, benzene, and xylene, and the catalyst includes one of transition metals such as Fe, Co, Ni, Cu, Mo, Pt, and Mn, and compounds of transition metals such as Fe, Co, Ni, Cu, Mo, Pt, and Mn.

7. The method for preparing a carbon fiber-carbon nanotube thermal interface material according to claim 1, characterized in that, In the carbon nanotube growth process, the heating temperature of the 3D thermally conductive framework is 500–1200℃, and the growth time is 0.5–2h.

8. The method for preparing a carbon fiber-carbon nanotube thermal interface material according to claim 1, characterized in that, In the polymer compounding step, the polymer matrix includes one of silicone rubber and silicone resin.

9. A carbon fiber-carbon nanotube thermal interface material, characterized in that, The carbon fiber-carbon nanotube thermal interface material is prepared by the preparation method of the carbon fiber-carbon nanotube thermal interface material according to any one of claims 1 to 8.

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