A high-compression and high-rebound thermal interface material and its preparation method

Abstract

The present invention discloses a thermal interface material with high compression and resilience and a preparation method thereof. High thermal conductivity fibers and elastic polymers are introduced between the graphene sheets arranged in an oriented manner. Under the action of pressure, the graphene sheets form a curved structure on the surface of the fibers. The elastic polymer firmly binds the graphene and the high thermal conductivity fibers and improves the compression and resilience ability. Physical crosslinking is formed between the curved graphene sheets through π-π conjugation, thereby constructing a material with both a thermal conduction skeleton and an elastic microstructure. Subsequently, it is cut along the direction perpendicular to the graphene sheets to obtain an interface material containing curved graphene sheets and high thermal conductivity fibers, so that the material has both high vertical thermal conductivity, high horizontal thermal conductivity and high compressibility.

Description

Technical Field

[0001] The present invention relates to the field of graphene materials, and particularly to a high compression and rebound thermal interface material and a preparation method thereof. Background Art

[0002] With the breakthrough of the heat flux density of high-power electronic devices exceeding 200 W / cm², higher requirements are put forward for traditional thermal interface materials. Currently, high-performance thermal interface materials need to simultaneously meet strict requirements such as a vertical thermal conductivity > 15 W / mK, an equivalent thermal resistance < 0.1 Kcm 2 / W, and a compression rate > 35% under 50 psi. Conventional thermal conductive silicone pads and thermal conductive greases are difficult to meet the above requirements.

[0003] Graphene materials have extremely high theoretical thermal conductivity and have been widely used in the field of high-performance heat dissipation materials. For example, graphene heat dissipation films have been applied in many new mobile phone products, and the addition of graphene effectively improves the thermal conductivity of conventional polymer materials. However, in thermal interface materials, there are two major shortcomings in the existing technology: First, the traditional composite process makes the graphene sheets arranged flatly, with too high rigidity resulting in too low compression rate, and poor deformation ability at the interface leading to too high interface thermal resistance; Second, by introducing three-dimensional structures such as holes and wrinkles into the horizontally oriented graphene film, although the vertical thermal conductivity is improved to a certain extent, it still remains below the level of 10 W / mK, restricting its application scope.

[0004] Therefore, it is urgent to develop a new type of structural regulation strategy. Based on the vertically oriented graphene structure, precise construction of the curved morphology of graphene sheets is achieved at the mesoscopic scale (1 - 100 μm), and the heat conduction path and mechanical rebound characteristics are optimized synchronously. Summary of the Invention

[0005] Aiming at the problem that the current traditional graphene material preparation process is difficult to balance high thermal conductivity and high rebound, the present invention provides a high compression and rebound thermal interface material and a preparation method thereof. By introducing high thermal conductivity fibers between the oriented graphene sheets, the graphene sheets form a wavy curved structure on the fiber surface, and conjugate cross-linking occurs at the tangent part of the curved surface after high-temperature treatment to form a three-dimensional heat conduction channel. After vertical cutting, a thermal interface material with high vertical thermal conductivity and high compression rate can be obtained.

[0006] Specifically, the present invention adopts the following technical solutions, including the following steps:

[0007] (1) Preparation of graphene raw materials: The graphene oxide film is foamed by a plasticizing and foaming process, and then subjected to a high-temperature reduction treatment at 2700 - 3200 °C to obtain a graphene foam film with a thickness of 50 - 500 μm;

[0008] (2) Fiber array construction: Lay the high thermal conductivity fiber array with an elastic polymer precursor coated on its surface along the same direction on the surface of the graphene foam film, and meet the following requirements:

[0009] a. The fiber diameter d = 2 - 30 μm;

[0010] b. The adjacent fiber spacing s ≥ 4 μm, and s / d ≥ 0.5;

[0011] (3) Multilayer composite: Alternately stack the fiber layer and the graphene foam film, and control the total thickness of the final laminated material to be not less than 4 cm; the fiber angle between adjacent fiber layers is not greater than 3°; the highly oriented fiber layer can ensure the deformation of the rGO film between the fibers, forming a wavy structure.

[0012] (4) Hot pressing and forming: Apply a pressure of 5 - 40 MPa to the laminated material obtained in step (3), with the pressure direction perpendicular to the surface of the graphene film, and treat it at 20 - 100 °C for 1 - 6 h to obtain a composite block; due to the fiber steric hindrance, the π-π stacking of graphene sheets forms physical crosslinks.

[0013] (5) Directional slicing: Slice the composite block obtained in step (3), with the cutting direction perpendicular to the surface of the graphene film and parallel to the axial direction of the high thermal conductivity fiber, and the cutting thickness is 0.2 - 1 mm. Remove the sheet material containing fibers on the surface to obtain a high compression and rebound thermal interface material.

[0014] Further, the average diameter of the graphene oxide sheets in the graphene oxide film described in step (1) is not less than 2 μm. Controlling the graphene oxide sheet diameter within a reasonable range is to effectively form a wavy bending structure and penetrate the upper and lower surfaces of the thermal interface to form a heat conduction channel. If the graphene oxide sheets are too small, the number of edges is too high, resulting in the interruption of the heat conduction channel and the decrease of the vertical thermal conductivity.

[0015] Further, the high thermal conductivity fiber array described in step (2) is one or more mixtures of pitch-based carbon fiber array, graphene fiber array, boron nitride fiber array, and carbon nanotube fiber array, and the thermal conductivity along the fiber direction is not less than 400 W / mK. The high thermal conductivity fiber array not only plays a role in assisting the deformation of the graphene film, but also has its own thermal conductivity, helping heat transfer along the horizontal direction. Compared with the traditional single vertical heat dissipation interface material, it is more conducive to the uniform distribution of heat and avoids heat accumulation.

[0016] Further, the elastic polymer precursor described in step (2) is one of uncured silica gel and polyurethane. Silica gel and polyurethane are common elastic polymer materials, which can be cured under the action of a catalyst in low-temperature hot pressing to provide good elasticity.

[0017] Further, the diameter of the high thermal conductivity fibers in the high thermal conductivity fiber array described in step (2) is 5-15 μm.

[0018] Further, the slicing method described in step (5) is one of wire cutting, ultrasonic knife cutting or laser cutting.

[0019] By reasonably regulating the thickness of the reduced graphene oxide film and the diameter and spacing of the high thermal conductivity fibers, the materials in the alternating laminate are densified under pressure. Due to the high flexibility of the wrinkled graphene sheets in the graphene foam film, they bend and deform on the fiber surface to form a wavy structure, and the wavy structure can bring a mechanical effect similar to that of a spring, enabling the thermal interface material to have high compressive performance in the vertical direction. In addition, the bent graphene sheets generate conjugate physical cross-linking on the fiber surface due to extrusion, further improving the compressibility and resilience. Moreover, the elastic polymer not only plays an adhesive role but also significantly improves the compression resilience, which is beneficial to enhancing the overall mechanical performance of the material.

[0020] The present invention also provides a highly compressible and resilient thermal interface material prepared by the above method. This material is composed of wavy graphene sheets, high thermal conductivity fibers and an elastic polymer. Among them, the wavy graphene sheets are arranged as a whole in the vertical direction, the high thermal conductivity fibers are arranged in the horizontal direction, and the elastic polymer is distributed between the graphene sheets and the high thermal conductivity fibers and plays a connecting role. Local physical cross-linking occurs at the positions of the wavy graphene sheets on both sides of the fibers. The vertical arrangement of the graphene sheets provides a heat conduction channel; the horizontal arrangement of the high thermal conductivity fibers provides horizontal heat conduction; the elastic polymer combines the fibers and the graphene, improving the horizontal strength and vertical elasticity.

[0021] Further, the high thermal conductivity fibers are one or more mixtures of pitch-based carbon fibers, graphene fibers, boron nitride fibers, and carbon nanotube fibers, and the thermal conductivity along the fiber direction is not less than 400 W / mK.

[0022] The compression resilience rate of the thermal interface material at 50% strain is not less than 90%, and the thermal impedance at 50% strain is not higher than 0.1 Kcm 2 / W.

[0023] The beneficial effects of the present invention:

[0024] (1)Enhancing the compression resilience of the thermal interface material in terms of both structure and material: Structurally, by introducing highly thermally conductive fibers and forming a curved structure, a wavy structure is spontaneously formed on the cross-section of the material. Different from traditional simple stacking, firstly, it avoids excessive rigidity caused by the sheet-like vertical structure. Secondly, the wavy graphene sheets will produce a spring-back effect after in-plane compression, showing a higher resilience rate. Thirdly, conjugate cross-linking is formed between the graphene sheets on the outside of the fibers under extrusion, further improving the heat dissipation capacity and lateral strength between the sheets. In terms of material, after introducing elastic polymers, it not only improves the interaction between graphene and highly thermally conductive fibers through adhesive action, significantly optimizing the horizontal tensile strength of the material, but also provides additional elasticity for the compression and resilience of the material, comprehensively improving the vertical compression and resilience performance of the material.

[0025] (2)Constructing a three-dimensional heat conduction channel: The two-dimensional characteristics of graphene determine that its in-plane thermal conductivity is high while its thermal conductivity in the vertical direction is low. After introducing highly thermally conductive fibers, heat can be rapidly transmitted along the fibers in the horizontal direction. At the same time, after inducing the graphene sheets to form a wavy structure, local cross-linking is generated, which also significantly improves the heat conduction ability in the horizontal direction. Meanwhile, the vertically arranged graphene sheets construct rich heat conduction channels, enabling the material to achieve a balance between horizontal and vertical heat conduction.

[0026] (3)The method is simple and easy to scale up: Based on the conventional forming method of graphene materials, by introducing highly thermally conductive fibers, batch preparation can be simply achieved, with low requirements for equipment, materials, and personnel. Description of the Drawings

[0027] Figure 1 It is the flow chart of the preparation method of the present invention.

[0028] Figure 2 It is the cross-sectional scanning electron micrograph of the thermal interface material obtained in Example 1.

[0029] Figure 3 It is the cross-sectional scanning electron micrograph of the thermal interface material obtained in Example 2.

[0030] Figure 4 It is the compression and resilience curve graph of Example 1.

[0031] Figure 5 It is the compression and resilience curve graph of Comparative Example 1. Detailed Embodiments

[0032] The following examples are used to further illustrate the present invention. Their purpose is to illustrate the present invention and should not be construed as limiting the scope of the present invention. Unless otherwise specified below, all are in parts by weight and weight percentages.

[0033] The raw materials used in the present invention are all conventional commercially available products unless otherwise specified; the methods used in the present invention are all conventional methods in the art unless otherwise specified.

[0034] The embodiments of the present invention will be further described below with reference to multiple examples.

[0035] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0036] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0037] As common general knowledge in the art, the thermal impedance is the sum of the thermal resistance of the material itself and the thermal resistance between the contact surfaces, and is measured by the ASTM D 5470 method, and the equipment is the LW-9389MD interfacial material thermal resistance and thermal conductivity measuring instrument. The compression and rebound test is carried out by using a universal testing tensile machine. Among them, the compression strength is the stress at the required strain during compression, and the test method for the compression and rebound rate is: measure the initial thickness T1 of the test sample, compress the sample to 50% deformation, hold for 1 minute, wait for 10 minutes after releasing the external force and then measure the thickness T2, and the rebound rate = T2 / T1 * 100%.

[0038] Example 1

[0039] (1) Preparation of graphene raw material: The graphene oxide film is foamed by a plasticizing and foaming process, and then reduced by high-temperature treatment at 3200 °C to obtain a graphene foam film with a thickness of 200 μm, wherein the graphene oxide sheet diameter is 5 - 10 μm;

[0040] (2) Construction of fiber array: An array of graphene fibers (thermal conductivity ≥ 1000 W / mK) coated with a silicone AB component mixture on the surface is laid on the surface of the graphene foam film in the same direction, and the following conditions are met:

[0041] a. The fiber diameter d = 5 - 8 μm;

[0042] b. The adjacent fiber spacing s = 4 μm;

[0043] (3) Multilayer composite: The fiber layer and the graphene foam film are alternately stacked, and the total thickness of the final laminated material is controlled to be 8 cm, and the fibers between adjacent layers of the fiber layer are parallel to each other;

[0044] (4) Hot pressing: Apply a pressure of 20 MPa to the laminated material obtained in step (3), with the pressure direction perpendicular to the surface of the graphene film, and process it at 80 °C for 4 h to obtain a composite block;

[0045] (5) Directional slicing: Use wire cutting to slice the composite block obtained in step (4), with the cutting direction perpendicular to the surface of the graphene film and parallel to the axial direction of the high thermal conductivity fiber. The cutting thickness is 0.3 mm, and the sheet material containing fibers on the surface is removed to obtain a high compression and rebound thermal interface material.

[0046] As Figure 2 shown, the thermal interface material is composed of wavy graphene sheets, graphene fibers, and silica gel. Among them, the wavy graphene sheets are arranged vertically as a whole, the graphene fibers are arranged horizontally, and the silica gel is distributed between the graphene sheets and the graphene fibers and plays a connecting role. Local physical cross-linking occurs at the positions of the wavy graphene sheets on both sides of the fibers. The compression and rebound rate of the material at 50% strain is 97%, the thermal impedance at 50% strain is 0.08 Kcm 2 / W, and the stress required to compress to 50% is 39 psi.

[0047] Example 2

[0048] (1) Preparation of graphene raw material: Use the plasticizing and foaming process to foam the graphene oxide film, and then reduce it by high-temperature treatment at 3200 °C to obtain a graphene foam film with a thickness of 350 μm, where the diameter of the graphene oxide flakes is 5 - 10 μm;

[0049] (2) Construction of fiber array: Lay an array of graphene fibers (thermal conductivity ≥ 1000 W / mK) coated with a mixture of silica gel AB components on the surface of the graphene foam film in the same direction, and satisfy:

[0050] a. The fiber diameter d = 10 - 15 μm;

[0051] b. The adjacent fiber spacing s = 8 μm;

[0052] (3) Multilayer composite: Alternately stack fiber layers and graphene foam films, and control the total thickness of the final laminated material to be 8 cm, with the included angle between adjacent fiber layers being 0 - 1°;

[0053] (4) Hot pressing: Apply a pressure of 20 MPa to the laminated material obtained in step (3), with the pressure direction perpendicular to the surface of the graphene film, and process it at 80 °C for 4 h to obtain a composite block;

[0054] (5) Oriented slicing: Use wire cutting to slice the composite block obtained in step (4). The cutting direction is perpendicular to the surface of the graphene film and parallel to the axial direction of the high thermal conductivity fiber. The cutting thickness is 0.3 mm. Remove the sheet material containing fibers on the surface to obtain a thermal interface material with high compression and resilience. As Figure 3 shown, wavy graphene sheets, graphene fibers, and silica gel can be seen. The silica gel connects adjacent graphene sheets and graphene fibers.

[0055] The compression and resilience rate of the material at 50% strain is 96%, the thermal impedance at 50% strain is 0.084 Kcm 2 / W, and the stress required to compress to 50% is 35 psi.

[0056] Example 3

[0057] (1) Preparation of graphene raw material: Use the plasticizing and foaming process to foam the graphene oxide film, and then reduce it by high-temperature treatment at 3000 °C to obtain a graphene foam film with a thickness of 500 μm, where the graphene oxide sheet diameter is 2 - 6 μm;

[0058] (2) Fiber array construction: Lay an array of pitch-based carbon fibers (thermal conductivity ≥ 800 W / mK) coated with a silica gel AB component mixture on the surface of the graphene foam film in the same direction, and satisfy:

[0059] a. Fiber diameter d = 25 - 30 μm;

[0060] b. Adjacent fiber spacing s = 15 μm;

[0061] (3) Multilayer composite: Alternately stack fiber layers and graphene foam films, and control the total thickness of the final laminated material to be 16 cm, and the angle between adjacent fiber layers to be 2 - 3°;

[0062] (4) Hot pressing and forming: Apply a pressure of 40 MPa to the laminated material obtained in step (3). The pressure direction is perpendicular to the surface of the graphene film, and it is treated at 100 °C for 1 h to obtain a composite block;

[0063] (5) Oriented slicing: Use wire cutting to slice the composite block obtained in step (4). The cutting direction is perpendicular to the surface of the graphene film and parallel to the axial direction of the high thermal conductivity fiber. The cutting thickness is 1 mm. Remove the sheet material containing fibers on the surface to obtain a thermal interface material with high compression and resilience.

[0064] The compression and resilience rate of the thermal interface material at 50% strain is 93%, the thermal impedance at 50% strain is 0.095 Kcm2 / W, and the stress required to compress to 50% is 41 psi.

[0065] Example 4

[0066] (1)Preparation of graphene raw material: The graphene oxide film is foamed by a plasticizing and foaming process, and then reduced by high-temperature treatment at 2700 °C to obtain a graphene foam film with a thickness of 50 μm, where the graphene oxide sheet diameter is 15 - 20 μm;

[0067] (2)Construction of fiber array: An array of boron nitride fibers (thermal conductivity ≥ 400 W / mK) with a surface coated with a prepolymer polyurethane solution is laid on the surface of the graphene foam film in the same direction, and the following conditions are met:

[0068] a. The fiber diameter d = 2 - 5 μm;

[0069] b. The adjacent fiber spacing s = 4 μm;

[0070] (3)Multi-layer composite: The fiber layer and the graphene foam film are alternately stacked, and the total thickness of the final laminated material is controlled at 4 cm, and the included angle between adjacent fiber layers is 0 - 1°;

[0071] (4)Hot pressing and forming: A pressure of 5 MPa is applied to the laminated material obtained in step (3), the pressure direction is perpendicular to the surface of the graphene film, and it is treated at 20 °C for 6 h to obtain a composite block;

[0072] (5)Directional slicing: The composite block obtained in step (4) is sliced using an ultrasonic scalpel, the cutting direction is perpendicular to the surface of the graphene film and parallel to the axial direction of the high thermal conductivity fiber, the cutting thickness is 0.2 mm, and the sheet material containing fibers on the surface is removed to obtain a high compression and rebound thermal interface material.

[0073] The compression and rebound rate of the thermal interface material at 50% strain is 90%, the thermal impedance at 50% strain is 0.1 Kcm2 / W, and the stress required to compress to 50% is 48 psi.

[0074] Comparative Example 1

[0075] (1)Preparation of graphene raw material: The graphene oxide film is foamed by a plasticizing and foaming process, and then reduced by high-temperature treatment at 3200 °C to obtain a graphene foam film with a thickness of 300 μm, where the graphene oxide sheet diameter is 5 - 10 μm;

[0076] (2)Multi-layer composite: A silicone AB component mixture is coated on the surface of the graphene foam film, and then layer control is performed to make the total thickness of the final laminated material 8 cm;

[0077] (3)Hot pressing and forming: A pressure of 20 MPa is applied to the laminated material obtained in step (2), the pressure direction is perpendicular to the surface of the graphene film, and it is treated at 80 °C for 4 h to obtain a composite block;

[0078] (4)Directional slicing: Use wire cutting to slice the composite block obtained in step (3). The cutting direction is perpendicular to the surface of the graphene film, and the cutting thickness is 0.3 mm to obtain the thermal interface material.

[0079] The compression and rebound rate of the thermal interface material at 50% strain is 84%, the thermal impedance at 50% strain is 0.18 Kcm 2 / W, and the stress required to compress to 50% is 39 psi.

[0080] In Comparative Example 1, high thermal conductivity fibers were not added, and only an elastic polymer was used to bond the graphene foam film, resulting in a decrease in compression and rebound performance and an increase in thermal resistance. The main reasons are as follows: First, without fibers, a good bending structure and interlayer stacking structure of graphene sheets cannot be formed. The graphene sheets are loosely arranged in the vertical direction and are easily collapsed under external force without rebounding. Second, without a lateral heat dissipation channel, heat transfer is slower. Third, after the silicone is cured, a poor heat conduction channel runs through the upper and lower parts of the thermal interface material, resulting in an increase in thermal resistance under compression. In contrast, due to the deformation of the graphene film on the fiber surface, a wrapping structure is generated (as shown in Figure 2 、 3 ), the silicone does not penetrate the upper and lower surfaces of the entire material, so the influence on heat conduction is small, but it can still provide excellent rebound performance.

[0081] Comparative Example 2

[0082] (1)Graphene raw material preparation: Use the plasticizing and foaming process to foam the graphene oxide film, and then reduce it by high-temperature treatment at 2700 °C to obtain a graphene foam film with a thickness of 50 μm, where the graphene oxide sheet diameter is 15 - 20 μm;

[0083] (2)Fiber array construction: Lay an array of boron nitride fibers (thermal conductivity ≥ 400 W / mK) on the surface of the graphene foam film in the same direction, and meet the following conditions:

[0084] a. Fiber diameter d = 2 - 5 μm;

[0085] b. Adjacent fiber spacing s = 4 μm;

[0086] (3)Multi-layer composite: Alternately stack fiber layers and graphene foam films, and control the total thickness of the final laminated material to be 4 cm, and the angle between adjacent fiber layers is 0 - 1°;

[0087] (4)Hot pressing and forming: Apply a pressure of 5 MPa to the laminated material obtained in step (3). The pressure direction is perpendicular to the surface of the graphene film, and it is treated at 20 °C for 6 h to obtain a composite block;

[0088] Directional slicing: Use a harmonic scalpel to slice the composite block obtained in step (4). The cutting direction is perpendicular to the surface of the graphene film and parallel to the axial direction of the high thermal conductivity fiber. The cutting thickness is 0.2 mm. Remove the sheet material containing fibers on the surface to obtain a thermal interface material.

[0089] The compression and rebound rate of the thermal interface material at 50% strain is 14%, the thermal impedance at 50% strain is 0.11 Kcm 2 / W, and the stress required to compress to 50% is 41 psi.

[0090] In Comparative Example 2, no silicone was added, and only the π-π conjugation between graphene sheets was relied on to wrap the fibers inside the material, which could not play a good role in rebound under compression.

[0091] The above embodiments have detailed the structure, characteristics and effects of the present invention. The above are only the preferred embodiments of the present invention. Any changes made according to the concept of the present invention, or equivalent embodiments modified to equivalent changes, still within the scope covered by the specification, shall be within the protection scope of the present invention.

Claims

1. A method for preparing a thermal interface material with high compression rebound, characterized in that: The following steps are involved: (1) Preparation of graphene raw materials: The graphene oxide film is foamed by a plasticizing foaming process, and then a graphene foam film with a thickness of 50 to 500 μm is obtained by high-temperature reduction treatment at 2700 to 3200 °C; (2) Fiber array construction: A high thermal conductivity fiber array coated with an elastic polymer precursor is laid on the surface of the graphene foam film in the same direction and meets the following requirements: a. Fiber diameter d = 2 ~ 30 μm; b. The spacing between adjacent fibers s≥4μm and satisfies s / d≥0.5; the high thermal conductivity fiber array is a mixture of one or more of a pitch-based carbon fiber array, a graphene fiber array, a boron nitride fiber array, and a carbon nanotube fiber array, and the thermal conductivity along the fiber direction is not less than 400W / mK; (3) Multilayer composite: alternately stack fiber layers and graphene foam films, and control the total thickness of the final laminated material to be no less than 4 cm; the fiber angle between adjacent fiber layers is no more than 3°; (4) Hot pressing: applying a pressure of 5 to 40 MPa to the laminated material obtained in step (3), with the pressure direction perpendicular to the surface of the graphene foam film, and treating at 20 to 100° C. for 1 to 6 hours to obtain a composite block; (5) Directional slicing: Slice the composite block obtained in step (4), with the cutting direction perpendicular to the surface of the graphene foam film and parallel to the axis of the high thermal conductivity fiber. The cutting thickness is 0.2~1mm, and the sheet containing fibers on the surface is removed to obtain a thermal interface material with high compression rebound.

2. The method according to claim 1, characterized in that: The average diameter of the graphene oxide sheets in the graphene oxide film in step (1) is not less than 2 μm.

3. The method according to claim 1, characterized in that The elastic polymer precursor in step (2) is one of uncured silicone and polyurethane.

4. The method according to claim 1, characterized in that: The diameter of the high thermal conductivity fibers in the high thermal conductivity fiber array in step (2) is 5-15 μm.

5. The method according to claim 1, characterized in that The slicing method in step (5) is one of wire cutting, ultrasonic knife cutting or laser cutting.

6. A high compression rebound thermal interface material prepared by the method of claim 1, characterized in that: It is composed of wavy graphene sheets, high thermal conductivity fibers and elastic polymers, wherein the wavy graphene sheets are arranged in the vertical direction as a whole, the high thermal conductivity fibers are arranged in the horizontal direction, the elastic polymers are distributed between the graphene sheets and the high thermal conductivity fibers and play a connecting role, and the wavy graphene sheets produce local physical cross-linking at both sides of the fibers.

7. The material according to claim 6, characterized in that The thermal interface material has a compression rebound rate of not less than 90% under 50% strain, and a thermal impedance of not more than 0.1 Kcm under 50% strain. 2 / W.

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