A composite film and a preparation method and application thereof

Abstract

The application belongs to the technical field of heat-conducting films, and particularly relates to a composite film and a preparation method and application thereof. The application provides a composite film, which comprises a first modified PBO film, a PEEK film and a second modified PBO film which are sequentially stacked. The first modified PBO film and the second modified PBO film independently comprise a PBO film matrix and carbon material doped in the PBO film matrix. In the application, the heat-conducting carriers of the carbon material are phonons and electrons. The electrons have a high migration rate, and the phonons have the advantages of high efficiency and low thermal resistance. Therefore, the electrical conductivity and the thermal conductivity of the composite film can be further improved by adding the carbon material. Due to excellent mechanical properties and a unique one-dimensional structure, the PBO introduced into the PEEK can minimize the interface thermal resistance and form a well-arranged structure, thereby obtaining a composite film with high thermal conductivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heat-conducting films, and particularly relates to a composite film and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of high-power-density electronic industry, the demand for high-thermal-conductivity and electromagnetic-shielding composite films is increasing, which has attracted extensive research attention worldwide. Polyether ether ketone (PEEK) has excellent thermal stability, light weight, excellent mechanical properties and good chemical resistance, and is widely used in complex applications such as aerospace, military and machinery. However, the low thermal conductivity of PEEK is limited by the disordered simple harmonic vibration of the molecular chain and the low-speed phonon diffusion. At present, the improvement of the performance of polyether ether ketone-based thermal conductive composite materials mainly focuses on the following aspects: (1) how the filler forms a thermal conductive network, (2) how to improve the filler-polymer interface contact state, and (3) how to introduce high content of fillers while not significantly reducing the flexibility and lightness of the composite film.

[0003] In previous studies, the thermal conductive fillers (such as graphene nanosheets, aluminum oxide, silicon carbide, etc.) are simply introduced into the polymer matrix, but this leads to poor thermal conductivity (TC) and seriously hinders their practical application. SUMMARY

[0004] The purpose of the present application is to provide a composite film and a preparation method and application thereof. The composite film provided by the present application has excellent thermal conductivity.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] The present application provides a composite film, which comprises a first modified PBO film, a PEEK film and a second modified PBO film which are sequentially stacked.

[0007] The first modified PBO film and the second modified PBO film independently comprise a PBO film matrix and a carbon material doped in the PBO film matrix.

[0008] Preferably, the carbon material comprises graphene nanosheets and multi-walled carbon nanotube material.

[0009] Preferably, the multi-walled carbon nanotube material comprises multi-walled carbon nanotubes and / or amino multi-walled carbon nanotubes.

[0010] The mass ratio of the graphene nanosheets and the multi-walled carbon nanotube material is 1-9:1-9.

[0011] Preferably, the mass percentage of the carbon material in the composite film is 10-60%.

[0012] Preferably, the thickness of the first modified PBO film and the second modified PBO film is independently 0.01-0.08mm.

[0013] Preferably, the thickness of the PEEK film is 0.01-0.04mm.

[0014] The application also provides a preparation method of the composite film, comprising the following steps:

[0015] mixing PBO fibers, carbon materials and a polar organic solvent to obtain a sol;

[0016] after solvent replacement of the sol with water, sequentially performing crushing and filtration to form a film to obtain a modified PBO film;

[0017] stacking the modified film as a first modified PBO film and a second modified PBO film with a PEEK film, and performing hot pressing to obtain the composite film.

[0018] Preferably, the polar organic solvent comprises methanesulfonic acid and trifluoroacetic acid.

[0019] The mass ratio of the methanesulfonic acid and the trifluoroacetic acid is 1:1.

[0020] The mass ratio of the PBO fibers and the polar organic solvent is 0.6-1.0:400.

[0021] Preferably, the temperature of the hot pressing is 340-380℃, the pressure is 10-800MPa, and the time is 10-60min.

[0022] The application also provides an application of the composite film or the composite film prepared by the preparation method as a heat-conducting film.

[0023] The application provides a composite film, comprising a first modified PBO film, a PEEK film and a second modified PBO film stacked in sequence; the first modified PBO film and the second modified PBO film independently comprise a PBO film matrix and carbon materials doped in the PBO film matrix.

[0024] In the application, the heat-conducting carriers of the carbon materials are phonons and electrons, the electrons have a high migration rate, and the phonons have the advantages of high efficiency and low thermal resistance, so that the electrical conductivity (σ) and the thermal conductivity (λ) of the composite film can be further improved by adding the carbon materials; due to the excellent mechanical properties and the unique one-dimensional structure, the PBO introduced into the PEEK can minimize the interface thermal resistance and form a well-arranged structure, thereby obtaining a composite film with high heat-conducting performance.

[0025] The application also provides a preparation method of the composite film, comprising the following steps: mixing PBO fibers, carbon materials and a polar organic solvent to obtain a sol; performing solvent replacement on the sol by using water, and then performing crushing and suction filtration to form a film to obtain a modified PBO film; and stacking the modified film as a first modified PBO film and a second modified PBO film with a PEEK film, and then performing hot pressing to obtain the composite film. The application adopts the method of efficient vacuum-assisted suction filtration combined with hot pressing technology to prepare the composite film with a sandwich structure, which exhibits excellent thermal conductivity, provides great hope for thermal management applications in the communication industry, aviation equipment and the field of artificial intelligence, and provides a new way for the development of high-end multifunctional thermal management composite films. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The in-plane thermal conductivity and growth rate curves of the composite films obtained in Examples 1-12;

[0027] Figure 2 The out-of-plane thermal conductivity and growth rate curves of the composite films obtained in Examples 1-12;

[0028] Figure 3 The flowchart of the preparation method of the composite film provided by the application. DETAILED DESCRIPTION

[0029] The application provides a composite film, comprising a first modified PBO film, a PEEK film and a second modified PBO film which are stacked in sequence.

[0030] The first modified PBO film and the second modified PBO film each independently comprise a PBO film matrix and carbon materials doped in the PBO film matrix.

[0031] In the application, all components are commercially available products well known to those skilled in the art unless otherwise specified.

[0032] In the application, the carbon materials preferably comprise graphene nanoplatelets (GnPs) and multi-walled carbon nanotube materials. In the application, the multi-walled carbon nanotube materials preferably comprise multi-walled carbon nanotubes (MWCNTs) and / or amino multi-walled carbon nanotubes (NH2-MWCNTs). In the application, the mass ratio of the graphene nanoplatelets and the multi-walled carbon nanotube materials is preferably 1-9:1-9, and further preferably 7:3.

[0033] In the application, the mass percentage of the carbon materials in the composite film is preferably 10-60%, further preferably 20-50%, and more preferably 30-40%.

[0034] In this invention, the thicknesses of the first modified PBO film and the second modified PBO film are preferably 0.01–0.08 mm, more preferably 0.02–0.07 mm, and even more preferably 0.03–0.05 mm. In this invention, the thickness of the PEEK film is preferably 0.01–0.04 mm, more preferably 0.02–0.03 mm.

[0035] The present invention also provides a method for preparing the composite membrane described in the above technical solution, comprising the following steps:

[0036] PBO fibers, carbon materials, and polar organic solvents are mixed to obtain a sol;

[0037] After solvent replacement of the sol with water, it is then pulverized and filtered to form a film, thus obtaining a modified PBO membrane.

[0038] The modified films are used as the first modified PBO film and the second modified PBO film, respectively. After being stacked with a PEEK film, they are hot-pressed to obtain the composite film.

[0039] This invention involves mixing PBO fibers, carbon materials, and a polar organic solvent to obtain a sol.

[0040] In this invention, the polar organic solvent preferably includes methanesulfonic acid (MSA) and trifluoroacetic acid (TFA); the mass ratio of methanesulfonic acid to trifluoroacetic acid is preferably 1:1; the mass ratio of PBO fiber to polar organic solvent is preferably 0.6 to 1.0:400, more preferably 0.8:400.

[0041] In this invention, the mixing preferably includes: dispersing PBO fibers in a polar organic solvent, and then adding carbon materials for stirring and mixing. In this invention, the dispersion is carried out under stirring conditions, the stirring time is preferably 24 hours, and the temperature is preferably room temperature; the stirring and mixing time is preferably 5 hours, and the temperature is preferably room temperature.

[0042] After obtaining the sol, the present invention uses water to replace the solvent in the sol, and then pulverizes and filters it to form a membrane, thereby obtaining a modified PBO membrane.

[0043] In this invention, the solvent replacement process is preferably as follows: the sol is soaked in deionized water, the water is changed every 6 hours, and this process is repeated more than 8 times until the pH value is neutral.

[0044] The present invention does not impose any particular limitation on the pulverization and filtration film formation process, and any process well known to those skilled in the art can be used. After the filtration film formation, the present invention further preferably includes drying the obtained wet film; the drying process is preferably: sandwiching the wet film between two glass plates and then placing it in a vacuum oven at 120°C for 1 hour.

[0045] After obtaining the modified film, the modified film is respectively used as a first modified PBO film and a second modified PBO film, and is stacked with a PEEK film to obtain a composite film through hot pressing.

[0046] In the present application, the temperature of the hot pressing is preferably 340-380℃, and further preferably 350-360℃; the pressure is preferably 10-800MPa, and further preferably 30MPa; and the time is preferably 10-60min, and further preferably 15min.

[0047] The flowchart of the preparation method of the composite film provided by the present application is shown in Figure 3 .

[0048] The present application also provides the application of the composite film in the above technical solution or the composite film prepared by the preparation method in the above technical solution as a heat-conducting film.

[0049] In order to further illustrate the present application, the composite film, the preparation method and the application thereof provided by the present application are described in detail below in combination with the drawings and examples, but they should not be understood as limiting the protection scope of the present application.

[0050] Example 1

[0051] 0.8g of PBO fibers were dispersed in 400g of a mixed solvent of MSA and TFA (the mass ratio of MSA and TFA was 1:1), and mechanical stirring was carried out at room temperature for 24h to obtain a uniform and transparent PBO sol, then 0.033g of NH2-MWCNTs and 0.077g of GnPs were added to the above PBO sol, and rapid stirring was carried out at room temperature for 5h to make them completely mixed to obtain a sol;

[0052] The sol was soaked in deionized water for solvent replacement, and the water was changed every 6h, and the operation was repeated more than 8 times until the pH value of the aqueous solution reached neutral;

[0053] The replaced gel was crushed in a cell disrupter and was subjected to suction filtration to form a film, and the obtained wet film was clamped between two glass plates and placed in a vacuum oven at 120℃ for drying for 1h to obtain a modified film (denoted as GnPs&NH2-MWCNTs@PBO) with a thickness of 0.01mm;

[0054] The obtained modified film was respectively used as a first modified PBO film and a second modified PBO film, a PEEK film (with a thickness of 0.02mm and a mass of 0.2g) with the same area as the above modified film was taken as an intermediate layer, and was stacked after lamination, and was subjected to hot pressing at 380℃ and 30MPa for 15min to obtain a composite film, wherein the mass percentage content of the carbon material in the composite film was 10%.

[0055] Example 2

[0056] A composite film was prepared in the same manner as in Example 1, except that the carbon material was 0.075 g of NH2-MWCNTs and 0.175 g of GnPs, and the mass percentage of the carbon material in the composite film was 20%.

[0057] Example 3

[0058] A composite film was prepared in the same manner as in Example 1, except that the carbon material was 0.13 g of NH2-MWCNTs and 0.3 g of GnPs, and the mass percentage of the carbon material in the composite film was 30%.

[0059] Example 4

[0060] A composite film was prepared in the same manner as in Example 1, except that the carbon material was 0.20 g of NH2-MWCNTs and 0.47 g of GnPs, and the mass percentage of the carbon material in the composite film was 40%.

[0061] Example 5

[0062] A composite film was prepared in the same manner as in Example 1, except that the carbon material was 0.30 g of NH2-MWCNTs and 0.70 g of GnPs, and the mass percentage of the carbon material in the composite film was 50%.

[0063] Example 6

[0064] A composite film was prepared in the same manner as in Example 1, except that the carbon material was 0.45 g of NH2-MWCNTs and 1.05 g of GnPs, and the mass percentage of the carbon material in the composite film was 60%.

[0065] Example 7

[0066] A composite film was prepared in the same manner as in Example 1, except that NH2-MWCNTs was replaced by MWCNTs.

[0067] Example 8

[0068] A composite film was prepared in the same manner as in Example 2, except that NH2-MWCNTs was replaced by MWCNTs.

[0069] Example 9

[0070] A composite film was prepared in the same manner as in Example 3, except that NH2-MWCNTs was replaced by MWCNTs.

[0071] Example 10

[0072] The composite film was prepared in the same manner as in Example 4, except that NH2-MWCNTs were replaced by MWCNTs.

[0073] Example 11

[0074] The composite film was prepared in the same manner as in Example 5, except that NH2-MWCNTs were replaced by MWCNTs.

[0075] Example 12

[0076] The composite film was prepared in the same manner as in Example 6, except that NH2-MWCNTs were replaced by MWCNTs.

[0077] Performance test

[0078] The in-plane thermal conductivity and out-of-plane thermal conductivity of the composite films obtained in Examples 1-12 were tested, and the test results are shown in Table 1 and Figures 1-2 , Figure 1 Fig. 1 is a graph of the in-plane thermal conductivity and growth rate curve of the composite films obtained in Examples 1-12, Figure 2 Fig. 2 is a graph of the out-of-plane thermal conductivity and growth rate curve of the composite films obtained in Examples 1-12;

[0079] Table 1 Thermal conductivity (W·m -1 ·K -1 ) of the composite films obtained in Examples 1-12

[0080]

[0081]

[0082] As can be seen from Table 1, with the continuous addition of carbon materials, the in-plane thermal conductivity and the out-of-plane thermal conductivity both monotonically increase, and the change trends are basically the same.

[0083] At the same time, the thermal conductivity of the composite film added with NH2-MWCNTs is significantly higher than that of MWCNTs. When the filler content increases to 60%, the in-plane and out-of-plane thermal conductivities of the composite film are 36.78 W·m -1 ·K -1 and 2.81 W·m -1 ·K -1 , respectively, and the thermal conductivity growth rates are 15891% and 1122% times, respectively, compared with the pure PEEK film. The in-plane and out-of-plane thermal conductivities of the composite film added with MWCNTs are 30.77 W·m -1 ·K -1 and 1.06 W·m -1 ·K -1 , respectively, which shows that the introduction of PBO and the modification of micro-nano carbon fillers together promote the enhancement of thermal conductivity.

[0084] Although the above embodiments have been described in detail, they are only some embodiments of the present application, not all embodiments, and other embodiments can be obtained under the premise of not being creative according to the above embodiments, and these embodiments all belong to the protection scope of the present application.

Claims

1. A composite film, characterized by, The composite film comprises a first modified PBO film, a PEEK film and a second modified PBO film which are sequentially stacked. The first modified PBO film and the second modified PBO film each independently comprise a PBO film matrix and a carbon material doped in the PBO film matrix; The carbon material is graphene nanosheets and amino multi-walled carbon nanotubes; The mass percentage of the carbon material in the composite film is 60%, and the mass ratio of the graphene nanosheets to the amino multi-walled carbon nanotubes is 7:3; The preparation method of the composite film comprises the following steps: mixing PBO fibers, a carbon material and a polar organic solvent to obtain a sol; after solvent replacement of the sol with water, sequentially performing crushing and suction filtration to form a film to obtain a modified PBO film; stacking the modified PBO film as the first modified PBO film and the second modified PBO film with the PEEK film, and then performing hot pressing to obtain the composite film.

2. The composite film according to claim 1, characterized by, The thickness of the first modified PBO film and the second modified PBO film is independently 0.01-0.08mm.

3. The composite film according to claim 1 or 2, characterized by, The thickness of the PEEK film is 0.01-0.04mm.

4. The method of producing the composite film according to any one of claims 1 to 3, characterized by, The preparation method comprises the following steps: mixing PBO fibers, a carbon material and a polar organic solvent to obtain a sol; after solvent replacement of the sol with water, sequentially performing crushing and suction filtration to form a film to obtain a modified PBO film; stacking the modified PBO film as the first modified PBO film and the second modified PBO film with the PEEK film, and then performing hot pressing to obtain the composite film.

5. The preparation method according to claim 4, characterized in that, The polar organic solvent comprises methanesulfonic acid and trifluoroacetic acid; The mass ratio of the methanesulfonic acid to the trifluoroacetic acid is 1:1; The mass ratio of the PBO fibers to the polar organic solvent is 0.6-1.0:

400.

6. The preparation method according to claim 4, characterized in that, The temperature of the hot pressing is 340-380℃, the pressure is 10-800MPa, and the time is 10-60min.

7. Application of the composite film of any one of claims 1-3 or the composite film prepared by the preparation method of any one of claims 4-6 as a heat-conducting film.

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