Graphene composite material and preparation method thereof

Abstract

The invention discloses a graphene composite material and a preparation method thereof, and the preparation method comprises the following steps: mixing a phase change material, a polymer block copolymer material and peroxide for reaction to obtain a modified phase change material; scraping the modified phase change material on the surface of the graphene substrate to obtain a composite film; and winding and cutting the composite film to obtain the graphene composite material. The preparation method comprises the following steps: heating and blade-coating a modified phase change material on a compactly assembled substrate to obtain a composite film, winding the film into a columnar cylinder, and cutting along the radial direction of the graphene-phase change material to finally obtain the graphene composite material with high vertical thermal conductivity. By introducing a polymer skeleton network to modify the phase change material, the leakage problem in the application process is avoided, the excellent deformation performance within the phase change temperature range is maintained, the contact thermal resistance can be further reduced, and the compressibility can be further improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of composite heat-conducting materials, in particular to a graphene composite material and a preparation method thereof. BACKGROUND

[0002] The waste heat problem of high-performance chips and high-power semiconductor devices has gradually become one of the key factors restricting the performance improvement of the chips and the devices, and efficient heat dissipation capacity is an important basis for guaranteeing the long-term operation of the chips and the devices. The chips and the devices are usually filled with a thermal interface material between the chips and the devices and a heat sink to discharge the gap air and enhance the interface thermal conductivity. Therefore, the thermal interface material needs to have high thermal conductivity, low contact thermal resistance, good compression deformation capacity and filling property. At present, the thermal interface materials used on the market include silicone grease, silicone pad, phase change material and liquid metal, however, the thermal conductivities of the thermal interface materials based on high polymers such as siloxane and phase change materials are mostly lower than 17 W / m·K, and the thermal conductivities of liquid metals such as gallium and indium are also lower than 86 W / m·K, which are difficult to meet the increasing demand for high-flux heat dissipation. Graphene is an atomic crystal of sp2 hybridization covalent bonding of carbon atoms, has a long phonon mean free path, and has a high in-plane thermal conductivity of 5000 W / m·K, and is a good thermal interface material heat-conducting medium. Constructing a high-thermal-conductivity connected graphene skeleton in a composite material matrix is one of the effective methods for improving the thermal conductivity of the composite material. By orienting and freezing a colloidal graphene nanosheet dispersion liquid and then performing heat treatment and a compounding process, a heat-conducting composite material is obtained, and the thermal conductivity can reach 35.5 W / m·K, however, the low density of the graphene framework caused by the limited graphene concentration of the dispersion liquid limits the improvement of the thermal conductivity.

[0003] In summary, it is an urgent problem for those skilled in the art to develop a preparation method for improving the thermal conductivity of a graphene composite material. SUMMARY

[0004] Therefore, the application provides a preparation method for a graphene composite material.

[0005] The application provides a preparation method for a graphene composite material, which comprises the following steps:

[0006] mixing and reacting a phase change material, a block copolymer material and a peroxide to obtain a modified phase change material;

[0007] applying the modified phase change material on the surface of a graphene substrate by scraping to obtain a composite film;

[0008] winding and cutting the composite film to obtain the graphene composite material.

[0009] In some embodiments, the high molecular block copolymer material comprises hydrogenated styrene-butadiene block copolymer and olefin block copolymer, and the mass ratio of the phase change material, the hydrogenated styrene-butadiene block copolymer, the olefin block copolymer and the peroxide is 120: (10-15): (10-15): (1-3).

[0010] In some embodiments, after mixing the phase change material, the hydrogenated styrene-butadiene block copolymer and the olefin block copolymer, the peroxide is added for reaction.

[0011] The temperature of the mixing is 140°C to 160°C, and the mixing is mixed to be a uniform gel state, and the stirring rate of the mixing is 100 rpm to 600 rpm.

[0012] In some embodiments, the temperature of the reaction is 170°C to 200°C, and the time of the reaction is 30 to 60 min.

[0013] In some embodiments, the phase change material comprises paraffin; the high molecular block copolymer comprises Kraton SEBS FG1901 (30 / 70) and / or Dow OBC 9530, and the peroxide comprises di-tert-butyl peroxide isopropyl benzene.

[0014] In some embodiments, the graphene substrate comprises a graphene film.

[0015] The density of the graphene substrate is 1.0 to 2.2 ;

[0016] The thickness of the graphene substrate is 10 μm to 500 μm.

[0017] The thermal conductivity of the graphene substrate is 1000 W / m·K to 1800 W / m·K.

[0018] In some embodiments, the temperature of the scraping is 80°C to 130°C.

[0019] The distance of the scraping is 10 μm to 3000 μm.

[0020] In some embodiments, the rate of the winding is 2 mm / min to 100 mm / min.

[0021] The diameter after the winding is 10 mm to 500 mm.

[0022] In some embodiments, the cutting is a radial cutting after the winding, and the thickness of the cutting is 0.5 mm to 10 mm.

[0023] The application also provides a graphene composite material prepared according to the preparation method as described above.

[0024] The application obtains the graphene composite material by heating and sputtering the phase change material on the compactly assembled graphene film substrate to obtain a composite film, then winding the film into a cylindrical cylinder, and cutting along the radial direction of the graphene-phase change material.

[0025] The vertical graphene-modified paraffin layered structure design makes the high thermal conductivity plane of graphene parallel to the heat flow direction, improving the heat dissipation efficiency; and the ratio of graphene and modified paraffin can be controlled by the thickness of graphene and the sputtering size, so as to effectively control the thermal conductivity, mechanical properties and contact thermal resistance performance.

[0026] By introducing a high molecular skeleton network to modify the phase change material, the leakage problem in the application process is avoided, the excellent deformation performance in the phase change temperature range is maintained, and the contact thermal resistance and compressibility can be further reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The preparation schematic diagram of the graphene composite material provided by the application is shown in the figure;

[0028] Figure 2 The structure characterization diagram of the graphene composite material provided by the application is shown in the figure;

[0029] Figure 3 The graphene substrate thickness and ratio of the graphene composite material provided by the application examples 2, 3 and 4 and the graphene film are shown in the figure;

[0030] Figure 4 The thermal conductivity diagram of the graphene composite material provided by the application examples 2, 3 and 4 is shown in the figure. DETAILED DESCRIPTION

[0031] It should be understood that the expression "one or more of" individually includes each object recited after the expression and various different combinations of two or more of the recited objects, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited objects should be understood to have the same meaning, unless otherwise understood from the context.

[0032] The terms "comprise", "have" or "contain", including the use of their grammatical synonyms, should generally be understood as open and non-limiting, for example, not excluding other unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0033] It should be understood that the order of steps or order for performing certain actions is immaterial so long as the application remains operable. Moreover, two or more steps or actions can be conducted simultaneously.

[0034] The use of any and all examples, or exemplary language herein, for example, merely to better illuminate the application, does not pose a limitation on the scope of the application. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the application.

[0035] Further, the numerical ranges and parameters setting forth the broadest scope of the application are approximations, and are merely intended to convey general information as to the scope of the application. Consistent with the application as claimed, consi stent with good practice, the numerical ranges and parameters are approximations, and are only intended to convey general information as to the scope of the application. Consistent with the application as claimed, consi stent with good practice, the numerical ranges and parameters are approximations, and are only intended to convey general information as to the scope of the application. Within the scope of the numerical ranges, the numerical values are approximations only, and likely, reflect an expectation or preference of the skilled artisan. In this manner, conclusions presented by the numerical values are not to be construed as limited by the specific values present.

[0036] The application provides a preparation method of a graphene composite material, comprising:

[0037] Mixing and reacting a phase change material, a polymer block copolymer material and a peroxide to obtain a modified phase change material;

[0038] Scratching and coating the modified phase change material on the surface of a graphene base to obtain a composite film;

[0039] Winding and cutting the composite film to obtain a graphene composite material.

[0040] The application obtains a graphene-phase change material double-layer composite film by heating and scratching a phase change material on a densely assembled graphene base, then winds the film into a cylindrical column, and cuts along the circumference of the graphene-phase change material, and finally obtains a vertical graphene-phase change material layered composite material.

[0041] To avoid leakage of the phase change material, a chemical cross-linking skeleton is introduced to modify the phase change material. First, the phase change material, hydrogenated styrene-butadiene block copolymer and olefin block copolymer are mixed, and then peroxide is added for reaction. In some specific implementations, the high molecular block copolymer material includes hydrogenated styrene-butadiene block copolymer and olefin block copolymer, and the mass ratio of the phase change material, hydrogenated styrene-butadiene block copolymer, olefin block copolymer and peroxide is 120: (10-15): (10-15): (1-3), preferably 120: 15: 15: 1. In some specific implementations, the mixing temperature is 140-160°C, which can be 140°C, 145°C, 150°C, 155°C, 160°C, and the mixing is carried out until a uniform gel is obtained. The stirring speed is 100-600 rpm, which can be 100 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 5600 rpm, or 600 rpm. In some specific implementations, the reaction temperature is 170-200°C, which can be 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, or 200°C, and the reaction time is 30-60 min, which can be 30 min, 40 min, 50 min, or 60 min. In some specific implementations, the phase change material includes but is not limited to paraffin wax; the high molecular block copolymer includes but is not limited to Kraton SEBS FG1901 (30 / 70) and / or Dow OBC 9530, and the peroxide includes di-tert-butyl peroxide isopropyl benzene. The addition of di-tert-butyl peroxide isopropyl benzene induces the formation of bonds between the molecular chains of SEBS and OBC to obtain modified paraffin wax.

[0042] The application adopts a vertical graphene-modified paraffin wax layered structure design, so that the high thermal conductivity in-plane direction of graphene is parallel to the heat flow direction, thereby improving the heat dissipation efficiency. The ratio of graphene and modified paraffin wax can be controlled by the thickness of graphene and the size of the scraped coating, thereby effectively controlling the thermal conductivity, mechanical properties and contact thermal resistance performance. By introducing a high molecular skeleton network to modify the paraffin wax, the leakage problem in the application process is avoided, the excellent deformation performance in the phase change temperature range is maintained, and the contact thermal resistance and compressibility can be further reduced.

[0043] Then, the modified material is scraped on the surface of the graphene substrate to obtain a composite film. In some specific implementations, the graphene substrate includes but is not limited to a graphene film. The density of the graphene substrate is 1.0 to 2.2 , which can be 1.0 , 1.2 , 1.4 1.5 1.8 2 2.2 ; the thickness of the graphene substrate is 10 μm to 500 μm, which can be 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm; the thermal conductivity of the graphene substrate is 1000 W / m·K to 1800 W / m·K, which can be 1000 W / m·K, 1100 W / m·K, 1200 W / m·K, 1300 W / m·K, 1400 W / m·K, 1500 W / m·K, 1600 W / m·K, 1700 W / m·K, 1800 W / m·K. In some specific embodiments, the temperature of the doctoring is 80℃ to 130℃, which can be 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, so as to ensure that the modified paraffin has good deformation ability; the distance of the doctoring is 100 μm to 3000 μm, which can be 100 μm, 200 μm, 500 μm, 800 μm, 1000 μm, 1500 μm, 2000 μm, 25800 μm, 3000 μm.

[0044] The application then winds and cuts the composite film to obtain a graphene composite material. In some specific embodiments, the winding rate is 2 mm / min to 100 mm / min, which can be 2 mm / min, 5 mm / min, 10 mm / min, 15 mm / min, 20 mm / min, 30 mm / min, 50 mm / min, 70 mm / min, 80 mm / min, 90 mm / min, 100 mm / min; the winding obtains a cylindrical material with a diameter of 10 mm to 500 mm, which can be 10 mm, 50 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm. In some specific embodiments, the cutting is a radial cutting after winding, and the thickness of the cutting is 0.5 mm to 10 mm, which can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm.

[0045] The application also provides a graphene composite material prepared according to the preparation method described above.

[0046] In some specific embodiments, the density of the graphene composite material is 0.85 to 1.08 .

[0047] In some specific implementations, the thickness of the graphene composite material is 72 μm to 205 μm, and the volume ratio of graphene in the graphene composite material is 44% to 80.5%.

[0048] The application will be further described in conjunction with the examples. The protection scope of the application is not limited by the following examples.

[0049] The hydrogenated styrene-butadiene block copolymer used in the examples of the application is Kraton SEBS FG1901 (30 / 70), the olefin block copolymer is Dow OBC 9530, and the graphene film is a rich graphene film P series.

[0050] Example 1

[0051] The example provides a graphene composite material, and a preparation method of the graphene composite material comprises:

[0052] Figure 1 The preparation schematic of the graphene composite material provided in the application is as follows: first, paraffin, hydrogenated styrene-butadiene block copolymer (SEBS) and olefin block copolymer (OBC) are added in proportions of 8:1:1, respectively, at 30 g, 3.75 g and 3.75 g, the heating temperature is 150°C, and the stirring rate is 300 rpm. After mixing uniformly, the temperature is raised to 180°C, and 0.25 g of di-tert-butyl peroxide isopropyl benzene is added to obtain modified paraffin. Then, a graphene film with a density of 2.2 μm, and a thermal conductivity of 1300 W / m·K is used as a doctor blade substrate, the doctor blade temperature is set to 100°C, the doctor blade spacing is controlled to be 500 μm, and a graphene-modified paraffin double-layer composite film (modified phase change material) is obtained. Then, the obtained graphene-modified paraffin double-layer composite film is wound at a winding rate of 5 mm / min, and a graphene-modified paraffin composite cylinder with a diameter of 10 mm is obtained by winding. The graphene-modified paraffin composite cylinder is cut to a thickness of 1 mm to obtain a graphene-modified paraffin layered composite material (graphene composite material). The layered composite structure is characterized by X-ray tomography technology, as shown in FIG. 1, the graphene film layer and the modified paraffin layer are closely attached, and present a layered cylindrical winding structure. Figure 2

[0053] Example 2

[0054] The example provides a graphene composite material, and a preparation method of the graphene composite material comprises:

[0055] ​Firstly, paraffin wax, high molecular material hydrogenated styrene-butadiene block copolymer (SEBS), and olefin block copolymer (OBC) are mixed in a ratio of 10:1.25:1.25, the heating temperature is 140℃, and the stirring rate is 200 rpm. After mixing uniformly, the temperature is raised to 170℃ and 0.2 g of di-tert-butyl peroxide isopropyl benzene is added to obtain modified paraffin wax. Subsequently, a graphene film with a density of 2.2 , a thickness of 40 μm, and a thermal conductivity of 1350 W / m·K is used as a doctor blade substrate, the doctor blade temperature is set to 110℃, the doctor blade spacing is controlled to 250 μm, a graphene-modified paraffin wax double-layer composite film (modified phase change material) is obtained, and then the obtained graphene-modified paraffin wax double-layer composite film is wound at a winding rate of 3 mm / min to obtain a graphene-modified paraffin wax composite cylinder with a diameter of 12 mm. The graphene-modified paraffin wax composite cylinder is cut to a thickness of 1 mm to obtain a graphene-modified paraffin wax layered composite material (graphene composite material). Figure 3 The graphene substrate thickness and proportion diagram of the graphene composite material provided in Embodiments 2, 3, and 4 of the present application is shown in FIG. 1. The GPOS1 sample is Embodiment 2, the measured original thickness of the graphene is 40 μm, the modified paraffin wax layer thickness is 32 μm, and the graphene-modified paraffin wax composite film thickness is 72 μm. Thus, the volume proportion of the modified paraffin wax can be evaluated as 44%, and the graphene content is 56 vol.%. The laser flash method is used to measure the thermal conductivity of the vertical graphene-modified paraffin wax layered composite material, Figure 4 The thermal conductivity diagram of the graphene composite material provided in Embodiments 2, 3, and 4 of the present application is shown in FIG. 2. The GPOS1 sample is Embodiment 2, and the corresponding vertical thermal conductivities of the sample at 22℃, 55℃, and 80℃ are 699 W / m·K, 657 W / m·K, and 533 W / m·K, respectively.

[0056] Embodiment 3

[0057] The present embodiment provides a graphene composite material, and a preparation method thereof includes:

[0058] Firstly, paraffin wax, high molecular material hydrogenated styrene-butadiene block copolymer (SEBS), and olefin block copolymer (OBC) are mixed in a ratio of 10:1.25:1.25, the heating temperature is 140℃, and the stirring rate is 200 rpm. After mixing uniformly, the temperature is raised to 170℃ and 0.2 g of di-tert-butyl peroxide isopropyl benzene is added to obtain modified paraffin wax. Subsequently, a graphene film with a density of 2.2 , thickness of 40 pm, thermal conductivity of 1350 W / m K graphene film as a scraping base, set the scraping temperature to 120°C, control the scraping interval to 500 pm, obtain graphene-modified paraffin double-layer composite film (modified phase change material), then wind the obtained graphene-modified paraffin double-layer composite film, the winding rate is 4 mm / min, winding obtains graphene-modified paraffin composite cylinder, the diameter is 14 mm. And cut the graphene-modified paraffin composite cylinder, the thickness is 1 mm, obtain graphene-modified paraffin layered composite material (graphene composite material). Figure 3 The graphene composite material provided in embodiments 2, 3, and 4 of the present application and the graphene base thickness and proportion diagram of the graphene film (graphene film), the GPOS2 sample is embodiment 3, the measured original thickness of graphene is 40 pm, the modified paraffin layer thickness is 109 pm, and the graphene-modified paraffin composite film thickness is 149 pm, and then the volume proportion of the modified paraffin can be evaluated as 73%, and the graphene content is 27 vol.%. The thermal conductivity of the vertical graphene-modified paraffin layered composite material is measured by a laser flash method, Figure 4 The thermal conductivity diagram of the graphene composite material provided in embodiments 2, 3, and 4 of the present application, the GPOS2 sample is embodiment 3, wherein the corresponding vertical thermal conductivity of the sample at 22°C, 55°C, and 80°C is 745 W / m K, 789 W / m K, and 261 W / m K, respectively.

[0059] Embodiment 4

[0060] The embodiment provides a graphene composite material, and a preparation method of the graphene composite material comprises:

[0061] First, the paraffin, the high molecular material hydrogenated styrene-butadiene block copolymer (SEBS), and the olefin block copolymer (OBC) are added in a proportion of 10:1.75:1.75, the heating temperature is 160°C, and the stirring rate is 500 rpm. After being uniformly mixed, the temperature is increased to 200°C, and 0.35 g of di-tert-butyl peroxide isopropyl benzene is added to obtain modified paraffin. Then, the density of 2.2 , thickness of 40 pm, thermal conductivity of 1350 W / m K graphene film as a scraping base, set the scraping temperature to 120°C, control the scraping interval to 500 pm, obtain graphene-modified paraffin double-layer composite film (modified phase change material), then wind the obtained graphene-modified paraffin double-layer composite film, the winding rate is 4 mm / min, winding obtains graphene-modified paraffin composite cylinder, the diameter is 14 mm. And cut the graphene-modified paraffin composite cylinder, the thickness is 1 mm, obtain graphene-modified paraffin layered composite material (graphene composite material). Figure 3The thickness and proportion of the graphene base of the graphene composite material provided in the embodiments 2, 3 and 4 of the present application are shown in the figure, the GPOS3 sample is the embodiment 4, the measured original thickness of the graphene is 40 μm, the thickness of the modified paraffin layer is 165 μm, the thickness of the graphene-modified paraffin composite film is 205 μm, and then the volume proportion of the modified paraffin can be evaluated as 80.5%, and the corresponding graphene content is 19.5 vol.%. The laser flash method is used to measure the thermal conductivity of the vertical graphene-modified paraffin layered composite material, Figure 4 The thermal conductivity of the graphene composite material provided in the embodiments 2, 3 and 4 of the present application is shown in the figure, the GPOS3 sample is the embodiment 4, and the corresponding vertical thermal conductivity at 22℃, 55℃ and 80℃ is 292 W / m·K, 387 W / m·K and 178 W / m·K, respectively.

[0062] The thermal conductivity of the graphene-modified paraffin composite thermal interface material prepared in the above embodiments is far higher than the thermal conductivity of the traditional silicone grease and phase change material-based thermal interface material, indicating the high-efficiency heat transfer performance of the vertical graphene-modified paraffin layered design.

[0063] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art within the technical scope disclosed in the present application, according to the technical solution and application concept of the present application, equivalent replacement or change, should be covered in the protection scope of the present application.

Claims

1. A method for preparing a graphene composite material, characterized in that, include: Modified phase change materials are obtained by mixing and reacting phase change materials, polymer block copolymer materials, and peroxides. A modified phase change material was coated onto the surface of a graphene substrate to obtain a composite film; The composite film is rolled and cut to obtain a graphene composite material.

2. The preparation method according to claim 1, characterized in that, The polymer block copolymer material includes hydrogenated styrene-butadiene block copolymer and olefin block copolymer; The mass ratio of the phase change material, hydrogenated styrene-butadiene block copolymer, olefin block copolymer and peroxide is 120:(10-15):(10-15):(1-3).

3. The preparation method according to claim 1, characterized in that, After the phase change material is mixed with the polymer block copolymer material, peroxide is added to carry out the reaction. The mixing temperature is between 140°C and 160°C, and the mixing speed is between 100 rpm and 600 rpm.

4. The preparation method according to claim 1, characterized in that, The reaction temperature is 170°C to 200°C, and the reaction time is 30 to 60 minutes.

5. The preparation method according to claim 1, characterized in that, The phase change material includes paraffin; The polymer block copolymers include Kraton SEBS FG1901 (30 / 70) and / or Dow OBC 9530; The peroxide includes di-tert-butylperoxide isopropylbenzene.

6. The preparation method according to claim 1, characterized in that, The graphene substrate includes a graphene film; The density of the graphene substrate is 1.

0. Up to 2.2 ; The thickness of the graphene substrate is from 10 μm to 500 μm; The thermal conductivity of the graphene substrate is from 1000 W / m·K to 1800 W / m·K.

7. The preparation method according to claim 1, characterized in that, The temperature for the scraping process is 80°C to 130°C. The spacing of the coating is from 10 μm to 3000 μm.

8. The preparation method according to claim 1, characterized in that, The winding rate is from 2 mm / min to 100 mm / min; The diameter of the wound portion is between 10 mm and 500 mm.

9. The preparation method according to claim 1, characterized in that, The cutting is a radial cut after winding, and the thickness of the cut is 0.5 mm to 10 mm.

10. A graphene composite material, characterized in that, It is prepared according to the preparation method described in any one of claims 1 to 9.

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