Graphene aramid fiber heat-conducting composite film

Abstract

The invention belongs to the technical field of heat-conducting films, and particularly relates to a graphene aramid fiber heat-conducting composite film. A precursor is subjected to heat treatment and calendering to obtain the composite material, the precursor is composed of a sandwich structure of a central aramid fiber film and graphene oxide films on the two sides, the aramid fiber film and the graphene oxide films are connected through a connecting solution, and the connecting solution comprises a small-sheet-diameter graphene oxide filter cake with the sheet diameter being 0.5-5 microns, carbon powder and water. The solid content of the connecting solution is 0.1-2% in percentage by mass. According to the technical scheme provided by the invention, the sandwich structure is utilized, the respective effects of the aramid film and the graphene film are exerted, the synergistic advantages complement each other, the high heat conduction characteristic of the aramid-based graphite film and the physical characteristics of the graphene film are well cooperated, and the binding force between different materials is increased by adopting a method of increasing the carbon-series material and the small-sheet-diameter graphene, so that the heat conduction performance of the graphene film is improved. The high thermal conductivity and good physical characteristics of the composite material are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal conductive films, and in particular relates to a graphene aramid thermal conductive composite film. Background Art

[0002] Nowadays, people's requirements for electronic products tend to be multifunctional and stable. At the same time, the electronic components inside the products are becoming increasingly miniaturized and integrated with the development of electronic technology. In order for electronic products to maintain good working conditions in various application scenarios, stable heat dissipation of electronic components has become a key issue.

[0003] The current mainstream heat dissipation method is to use thermal conductive film, and the outstanding materials in thermal conductive film are graphene film and aramid-based graphite film. Although aramid-based graphite film exhibits ultra-high thermal conductivity, it has defects such as poor flexibility and powder loss. At the same time, although graphene film exhibits good physical properties, the thermal conductivity of mass production is far from the theoretical value.

[0004] In view of the above facts, a thermally conductive film that can take into account the advantages of both graphene film and aramid-based graphite film will have a very ideal market prospect. However, the composite of graphene film and aramid-based graphite film has not been reported yet. Summary of the invention

[0005] The invention provides a graphene-aramid thermal conductive composite film, which is used to solve the problem of composite of current graphene film and aramid-based graphite film.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: the graphene aramid thermal conductive composite film is obtained by heat treatment and calendering of a precursor, the precursor is composed of a sandwich structure of a central aramid film and graphene oxide films on both sides, the aramid film and the graphene oxide film are connected by a connecting solution, the connecting solution includes a small-diameter graphene oxide filter cake with a sheet diameter of 0.5 to 5 μm, a carbon-based powder and water, and the solid content of the connecting solution is 0.1-2% by mass.

[0007] Optionally, the water content of the graphene oxide film is 8-20wt%.

[0008] Optionally, the graphene oxide film is obtained by coating and drying a graphene oxide slurry, and the graphene oxide slurry is obtained by dispersing, grinding, homogenizing and degassing a graphene oxide filter cake and a carbon-based powder, and the solid content of the graphene oxide slurry is 3-5wt% and the viscosity is 10000-30000cps.

[0009] Optionally, the solid content of the graphene oxide filter cake is above 30 wt %, and the amount of carbon-based powder added to the graphene oxide slurry is 0.05-1% of the solid weight of the graphene oxide filter cake.

[0010] Optionally, the connection solution is obtained by dispersing, grinding, homogenizing and degassing small-diameter graphene oxide filter cakes and carbon-based powders, and the connection solution has a solid content of 0.1-2wt% and a viscosity of 500-2000cps.

[0011] Optionally, the solid content of the small-diameter graphene oxide filter cake is above 30 wt %, and the amount of carbon-based powder added to the connecting solution is 0.05-1% of the solid weight of the small-diameter graphene oxide filter cake.

[0012] Optionally, the carbon-based powder is selected from one or more of carbon black powder, graphene powder, carbon nanotubes and carbon fibers.

[0013] Optionally, the preparation of the precursor comprises: spraying the connection solution on one side of the graphene oxide film, with a spraying amount of 0.1-2 g / m 3 , place the aramid film in the middle, stack the graphene oxide film on the upper and lower sides, and adhere the side sprayed with the connecting solution to the aramid film.

[0014] Optionally, the heat treatment refers to subjecting the precursor to low-temperature pretreatment, carbonization, and graphitization to form a graphene-aramid composite foam film, wherein the temperature of the low-temperature pretreatment is 200-400°C for 30-50h; the temperature of the carbonization is 900-1500°C for 10-30h; the temperature of the graphitization is 2800-3500°C for 36-50h.

[0015] Optionally, the calendering refers to applying pressure to the graphene aramid composite foam film using a hydraulic press, with the pressure increasing sequentially from 1 to 18 MPa for a duration of 1.5 hours.

[0016] The technical solution provided by the present invention utilizes a "sandwich" structure, brings out the respective roles of the aramid film and the graphene film and synergizes their advantages to complement each other, and well coordinates the high thermal conductivity of the aramid-based graphite film with the physical properties of the graphene film. The method of adding carbon-based materials and small-diameter graphene is used to increase the bonding force between different materials, thereby achieving high thermal conductivity and good physical properties of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a process flow chart of preparing the graphene aramid thermal conductive composite film of the present invention;

[0018] Figure 2 It is a schematic diagram of the structure of the precursor of the present invention.

[0019] As shown in the figure:

[0020] 10-aramid membrane, 20-connection solution, 30-graphene oxide membrane. DETAILED DESCRIPTION

[0021] For ease of understanding, the graphene aramid thermally conductive composite film is described below in conjunction with examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0022] Example 1

[0023] like Figure 1 As shown, the preparation method of the graphene aramid thermal conductive composite film comprises the following steps:

[0024] 1) adding pure water and graphene oxide filter cake into a double planetary stirring tank at a solid content ratio of 5wt%, stirring and dispersing, wherein the solid content of the graphene oxide filter cake is above 30wt%; then adding carbon nanotubes, wherein the addition amount of the carbon nanotubes is 0.5% of the solid weight of the graphene oxide filter cake, and then adding ammonia water to adjust the slurry pH to 6.5, stirring for 2h, and then grinding, homogenizing, degassing and other treatments to obtain a slurry viscosity of 23000cps; applying the slurry on a substrate through a comma scraper, drying through a drying channel until a film is formed, and obtaining a graphene oxide film with a water content of 11.3%.

[0025] 2) pure water and a small-diameter graphene oxide filter cake with a sheet diameter of 1 μm are added into a double planetary stirring tank at a solid content ratio of 1% and stirred and dispersed. The solid content of the small-diameter graphene oxide filter cake is

[0026] 30wt% or more; then add carbon nanotubes, the amount of carbon nanotubes added is 1% of the solid weight of the small-diameter graphene oxide filter cake, and then add ammonia water to adjust the slurry pH to 6.5, stir for 2h, and then grind, homogenize, degas, etc. to obtain a connection solution with a viscosity of 2000cps.

[0027] 3) Spray the connection solution 20 obtained in step 2) on one side of the graphene oxide film prepared in step 1) at a spraying amount of 1.5 g / m 3 , according to two graphene oxide films 30 sandwiching one aramid film 10

[0028] (purchased from Jiangxi Enboli New Material Technology Co., Ltd. GC110), the film is laminated, and one side of the spray connection solution is bonded to the aramid film, such as Figure 2 The precursor was obtained as shown.

[0029] 4) The precursor prepared in step 3) is subjected to low-temperature pretreatment, high-temperature carbonization, and graphitization to obtain a graphene foam film; wherein the low-temperature pretreatment process parameters are: from room temperature to 350°C within 40 hours, the high-temperature carbonization process parameters are: in a vacuum environment, from room temperature to 1400°C within 26 hours, and the graphitization process parameters are: in an argon protective gas environment, from room temperature to 3150°C within 36 hours.

[0030] 5) The graphene foam film prepared in step 4) is subjected to calendering treatment, with the pressure increasing from 1 to 18 MPa in sequence, and the duration is 1.5 hours.

[0031] Example 2

[0032] The difference from Example 1 is that the aramid film in step 3) is GC130 produced by Jiangxi Enboli New Material Technology Co., Ltd., which is thicker than GC110, that is, the amount of aramid film per unit area is more.

[0033] Example 3

[0034] The difference from Example 1 is that the spraying amount in step 3) is 0.5 g / m 3 .

[0035] Comparative Example 1

[0036] This example is a comparative sample, in which no carbon nanotubes are added in step 1) and step 2) in Example 1.

[0037] Comparative Example 2

[0038] This example is a comparative sample, in which the connection solution is not sprayed between the graphene oxide film and the aramid film in Example 1.

[0039] Comparative Example 3

[0040] This example is a comparative sample, in which the graphene oxide film prepared in step 1) of Example 1 is directly subjected to the heat treatment step of step 4) to obtain a graphene film.

[0041] Comparative Example 4

[0042] This example is a comparative sample, which is an aramid-based graphite film obtained by directly subjecting the aramid film GC110 in Example 1 to the heat treatment step of step 4).

[0043] Performance Test:

[0044] Thermal conductivity: To investigate the thermal conductivity of the film, a laser thermal conductivity meter (LFA467, NETZSCH, Germany) was used to test the thermal conductivity. The results are shown in Table 1.

[0045] Cohesion: To examine the cohesion of the film, a universal testing machine was used to test the cohesion according to GB / T 2790-1995. The results are shown in Table 1.

[0046] Powder loss degree: In order to investigate the powder loss degree of the film, a 1-2gf / 25mm release film was used to test the powder loss of the film. The results are shown in Table 1.

[0047] Table 1

[0048] Thermal conductivity (W / (m·k)) Cohesion (gf) Powder loss (g) Example 1 1739.08 30.67 0.0002 Example 2 1790.33 28.32 0.0005 Example 3 1700.12 25.45 0.0002 Comparative Example 1 1734.33 20.44 0.0003 Comparative Example 2 1061.19 10.34 0.0004 Comparative Example 3 1325.38 34.42 0.0002 Comparative Example 4 1872.49 15.31 0.0050

[0049] Thermal conductivity

[0050] The thermal conductivity coefficient of the aramid-based graphite film in Comparative Example 4 is the largest. The graphene-aramid thermal conductive composite film prepared in Example 2 can reach 1790.33W / (m·k). By comparing Example 1 and Example 2, it can be found that the proportion of the aramid film will also affect the thermal conductivity. The composite film in Comparative Example 2 that is not sprayed has a delamination phenomenon due to poor interlayer bonding, resulting in a lower thermal conductivity coefficient than the graphene film in Comparative Example 3.

[0051] Cohesion

[0052] The graphene film of comparative example 3 has the largest cohesive force, reaching 34.42gf, and the smallest is the composite film of comparative example 2 without spraying, which is 10.34gf. Although the connection solution was sprayed in comparative example 2, it was still larger than that without carbon nanotubes because carbon nanotubes were not added. This shows that the small-diameter graphene filter cake may have more advantages in dispersion and distribution, which helps to reduce stress concentration and enhance the cohesive force of the composite film. After adding carbon powder, it plays a bridging role between the films and increases the cohesive force of the composite film. And the greater the spraying amount within a certain range, the stronger the cohesive force.

[0053] Powder loss

[0054] Compared with Comparative Example 4, the powder loss of the remaining embodiments and comparative examples is less than or equal to 0.0005 g, which is only 1 / 10 of that of Comparative Example 4. This shows that when the graphene film is used as the outer surface, there is almost no powder loss on the release film, and using the graphene film to sandwich the aramid film is a good way to solve the powder loss problem.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graphene aramid thermal conductive composite film, characterized in that: The precursor is obtained by heat treatment and calendering. The precursor is composed of a sandwich structure of a central aramid film and graphene oxide films on both sides. The aramid film and the graphene oxide film are connected by a connecting solution. The connecting solution includes a small-diameter graphene oxide filter cake with a sheet diameter of 0.5 to 5 μm, a carbon-based powder and water. The solid content of the connecting solution is 0.1-2wt% by mass.

2. The graphene aramid thermal conductive composite film according to claim 1, characterized in that: The water content of the graphene oxide film is 8-20 wt %.

3. The graphene aramid thermal conductive composite film according to claim 1, characterized in that: The graphene oxide film is obtained by coating and drying graphene oxide slurry, and the graphene oxide slurry is obtained by dispersing, grinding, homogenizing and degassing graphene oxide filter cake and carbon powder. The solid content of the graphene oxide slurry is 3-5wt%, and the viscosity is 10000-30000cps.

4. The graphene aramid thermal conductive composite film according to claim 3, characterized in that: The amount of carbon powder added to the graphene oxide slurry is 0.05-1% of the solid weight in the graphene oxide filter cake.

5. The graphene aramid thermal conductive composite film according to claim 1, characterized in that: The connection solution is obtained by dispersing, grinding, homogenizing and degassing small-diameter graphene oxide filter cakes and carbon powders. The connection solution has a solid content of 0.1-2wt% and a viscosity of 500-2000cps.

6. The graphene aramid thermally conductive composite film according to claim 5, characterized in that: The amount of carbon powder added to the connection solution is 0.05-1% of the solid weight in the small-diameter graphene oxide filter cake.

7. The graphene aramid thermal conductive composite film according to claim 1, characterized in that: The carbon-based powder is selected from one or more of carbon black powder, graphene powder, carbon nanotubes and carbon fibers.

8. The graphene aramid thermally conductive composite film according to claim 1, characterized in that: The preparation of the precursor comprises: spraying the connection solution on one side of the graphene oxide film, with the spraying amount being 0.1-2 g / m 3 , place the aramid film in the middle, stack the graphene oxide film on the upper and lower sides, and adhere the side sprayed with the connecting solution to the aramid film.

9. The graphene aramid thermal conductive composite film according to claim 1, characterized in that: The heat treatment refers to subjecting the precursor to low-temperature pretreatment, carbonization, and graphitization to form a graphene-aramid composite foam film, wherein the low-temperature pretreatment temperature is 200-400°C for 30-50h; the carbonization temperature is 900-1500°C for 10-30h; the graphitization temperature is 2800-3500°C for 36-50h.

10. The graphene aramid thermal conductive composite film according to claim 1, characterized in that: The calendering refers to applying pressure to the graphene-aramid composite foam film using a hydraulic press, with the pressure increasing in sequence from 1 to 18 MPa for a duration of 1.5 hours.

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