Heat-conducting silicone grease with synergistic effect of modified hexagonal boron nitride and graphene nanoribbons and preparation method of heat-conducting silicone grease

Abstract

The invention relates to heat-conducting silicone grease with synergistic effect of modified hexagonal boron nitride and graphene nanoribbons and a preparation method of the heat-conducting silicone grease. Comprising the following steps: (1) modifying hexagonal boron nitride by using gamma-aminopropyltriethoxysilane, so as to obtain gamma-aminopropyltriethoxysilane modified hexagonal boron nitride; and (2) uniformly mixing gamma-aminopropyltriethoxysilane modified hexagonal boron nitride, graphene nanobelts and polydimethylsiloxane, carrying out ball milling, and carrying out vacuum centrifugal defoaming to obtain the heat-conducting silicone grease with the synergistic effect of the modified hexagonal boron nitride and the graphene nanobelts. Through gamma-aminopropyltriethoxysilane modification, the dispersity and interface bonding force of boron nitride in polydimethylsiloxane are improved, the problem that the hydrophilicity of boron nitride is incompatible with a matrix is effectively solved, the compatibility of boron nitride and polydimethylsiloxane is improved, a heat conduction network is effectively constructed, and the heat conduction efficiency is improved. And the graphene nanobelt and boron nitride generate a synergistic effect, so that the interface thermal resistance is greatly reduced.

Description

Technical Field

[0001] The invention relates to a thermally conductive silicone grease with synergistic effects of gamma-aminopropyltriethoxysilane-modified hexagonal boron nitride and graphene nanoribbons and a preparation method thereof, belonging to the technical field of thermally conductive silicone grease material preparation. Background Art

[0002] In recent years, with the miniaturization and increase in power of electronic devices, the dissipated power density of these miniaturized devices has increased rapidly. Heat dissipation has become one of the most critical issues limiting the performance, power, reliability and further miniaturization of electronic devices. It is well known that the reliability of a device is exponentially related to the operating temperature of the junction, so a small difference in operating temperature may result in a two-fold reduction in device life. Therefore, the heat generated from the device should be removed as quickly and efficiently as possible to keep the temperature of the device at the desired level. Traditionally, heat sinks are used to dissipate heat from devices. However, the heat dissipation performance of heat sinks is severely limited due to the interfacial thermal resistance caused by the mismatch of the non-surface flatness and surface roughness of the device and heat sink. In order to reduce the interfacial thermal resistance, a suitable thermal interface material (TIM) is used to bond the contact surface of the heat sink and the device. The ideal interface material must have high thermal conductivity and strong deformation, and be able to adapt to the surface morphology of the mating surface and fill the interface gap instead of air.

[0003] Thermal grease is a thixotropic paste with high thermal conductivity and a certain fluidity, which can more effectively fill the gaps of mating surfaces. Thermal grease is usually made of two main components, namely polymer base and ceramic filler. Hexagonal boron nitride has extremely high thermal conductivity. In addition, hexagonal boron nitride has excellent insulation properties. At the same time, hexagonal boron nitride has passivation for reaction with acids and melts, excellent oxidation resistance and low friction coefficient. This allows hexagonal boron nitride to be used under conditions where insulation and heat dissipation are required. However, hexagonal boron nitride is difficult to have a good combination with most substrates, resulting in its poor compatibility. Graphene nanoribbons have excellent thermal conductivity. The lightweight characteristics of graphene nanoribbons enable thermal grease to reduce the weight of the overall material while maintaining performance, while enhancing the mechanical properties of the grease and improving the strength and toughness of the material. However, the production cost of graphene nanoribbons is high, and its poor dispersion in the matrix may lead to uneven performance of the composite material.

[0004] Therefore, it is necessary to develop a route to process and functionalize hexagonal boron nitride and graphene nanoribbons to improve the dispersibility and compatibility of fillers in polydimethylsilane matrix materials to further improve the thermal conductivity of thermal grease. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a thermal conductive silicone grease with synergistic effect of modified hexagonal boron nitride and graphene nanoribbons and a preparation method thereof. The present invention adopts γ-aminopropyltriethoxysilane to modify the surface of hexagonal boron nitride, the preparation method is simple, green and environmentally friendly, and the thermal conductivity of the thermal conductive silicone grease prepared by using the modified hexagonal boron nitride and graphene nanoribbons as thermal conductive fillers is significantly improved.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a thermally conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons comprises the following steps:

[0008] (1) adding γ-aminopropyltriethoxysilane to anhydrous ethanol to obtain a γ-aminopropyltriethoxysilane solution, and adjusting the pH value to 4-5; then adding hexagonal boron nitride to the γ-aminopropyltriethoxysilane solution, and filtering, washing and vacuum drying after ultrasonic treatment and magnetic stirring to obtain γ-aminopropyltriethoxysilane modified hexagonal boron nitride (APTES-HBN);

[0009] (2) Gamma-aminopropyltriethoxysilane-modified hexagonal boron nitride, graphene nanoribbons and polydimethylsiloxane are uniformly mixed, ball-milled and then vacuum centrifuged for degassing to obtain a thermal conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons.

[0010] Preferably according to the present invention, in step (1), the mass concentration of the γ-aminopropyltriethoxysilane solution is 1-2 mg / ml.

[0011] Preferably, according to the present invention, in step (1), acetic acid is used to adjust the pH value to 4-5.

[0012] Preferably according to the present invention, in step (1), the particle size of the hexagonal boron nitride is 0.1 to 100 μm.

[0013] Preferably according to the present invention, in step (1), the mass ratio of hexagonal boron nitride to γ-aminopropyltriethoxysilane is (8-12):1.

[0014] Preferably, in step (1), the ultrasonic treatment time is 55 to 65 min, the power is 80 to 120 W; the magnetic stirring speed is 800 to 1200 rpm, the time is 24 to 48 h; and the vacuum drying is carried out at 110 to 125 ° C for 24 to 48 h.

[0015] Preferably, according to the present invention, in step (2), the mass ratio of the γ-aminopropyltriethoxysilane modified hexagonal boron nitride, graphene nanoribbons and polydimethylsiloxane is (100-137):10:(185-223).

[0016] Preferably according to the present invention, in step (2), the ball milling time is 1 to 3 hours and the rotation speed is 200 to 600 rpm.

[0017] Preferably according to the present invention, in step (2), the vacuum centrifugal degassing time is 5 to 10 minutes, and the rotation speed is 400 to 1000 rpm.

[0018] A thermally conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons is prepared according to the method.

[0019] Preferably according to the present invention, the mass fraction of modified hexagonal boron nitride in the thermally conductive silicone grease accounts for 10-60%, and the mass fraction of graphene nanoribbons accounts for 2-5%.

[0020] Further preferably, the mass fraction of modified hexagonal boron nitride in the thermal grease is 40%, and the mass fraction of graphene nanoribbons is 3%.

[0021] The technical features and beneficial effects of the present invention are as follows:

[0022] 1. The present invention first uses γ-aminopropyltriethoxysilane to modify hexagonal boron nitride, then fills γ-aminopropyltriethoxysilane modified hexagonal boron nitride (APTES-HBN) and graphene nanoribbons into a polydimethylsiloxane matrix, and after ball milling, obtains a thermal conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons. This method improves the dispersibility and interfacial bonding strength of boron nitride in polydimethylsiloxane through modification with γ-aminopropyltriethoxysilane, effectively solving the problem of hydrophilicity of boron nitride and matrix incompatibility.

[0023] 2. The present invention not only improves the compatibility of boron nitride and polydimethylsiloxane, but also effectively constructs a heat conduction network, so that graphene nanoribbons and boron nitride produce a synergistic effect, greatly reducing the interfacial thermal resistance. When the mass fraction of modified hexagonal boron nitride and graphene nanoribbons in the prepared thermal grease with synergistic effect is 40% and the mass fraction of graphene nanoribbons is 3%, the thermal conductivity can reach 8W / (m·K), which greatly improves the thermal conductivity of the thermal grease. At the same time, it also ensures its superior thermal stability and electrical insulation, effectively improves the heat dissipation efficiency, and ensures the safe and stable operation of high-power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a real photo of the thermal conductive silicone grease with synergistic effect of modified hexagonal boron nitride and graphene nanoribbons of the present invention;

[0025] In the figures, the left picture is embodiment 1, the middle picture is embodiment 2, and the right picture is embodiment 3. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention.

[0027] Example 1

[0028] A method for preparing a thermally conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons comprises the following steps:

[0029] (1) 150 mg of γ-aminopropyltriethoxysilane was added to 100 ml of anhydrous ethanol to obtain a γ-aminopropyltriethoxysilane solution with a concentration of 1.5 mg / mL, and the pH value was adjusted to 4.5 with acetic acid; then 1.5 g of hexagonal boron nitride was added to the γ-aminopropyltriethoxysilane solution, and ultrasonic treatment was performed at 100 W for 60 min, and magnetic stirring was performed at 1000 rpm for 36 h, followed by suction filtration, washing with deionized water for 3 times, and drying at 120° C. for 36 h to obtain γ-aminopropyltriethoxysilane modified hexagonal boron nitride (APTES-HBN); wherein the particle size of the hexagonal boron nitride was 50 μm;

[0030] (2) 1.096 g of γ-aminopropyltriethoxysilane modified hexagonal boron nitride, 0.082 g of graphene nanoribbons and 1.56 g of polydimethylsiloxane were mixed evenly, then placed in a ball mill, and ball milled at a speed of 400 rpm for 2 h. After ball milling, the sample was taken out and vacuum centrifuged for degassing at a speed of 700 rpm for 8 min to obtain a thermal conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons.

[0031] In the thermal conductive silicone grease prepared in this embodiment with the synergistic effect of modified hexagonal boron nitride and graphene nanoribbons, the mass fraction of modified hexagonal boron nitride accounts for 40%, and the mass fraction of graphene nanoribbons accounts for 3%. The actual photo is shown in FIG. Figure 1 Shown in the middle left picture.

[0032] Example 2

[0033] A method for preparing a thermally conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons comprises the following steps:

[0034] (1) 150 mg of γ-aminopropyltriethoxysilane was added to 100 ml of anhydrous ethanol to obtain a γ-aminopropyltriethoxysilane solution with a concentration of 1.5 mg / mL, and the pH value was adjusted to 4.5 with acetic acid; then 1.5 g of hexagonal boron nitride was added to the γ-aminopropyltriethoxysilane solution, and ultrasonic treatment was performed at 100 W for 60 min, and magnetic stirring was performed at 1000 rpm for 36 h, followed by suction filtration, washing with deionized water for 3 times, and drying at 120° C. for 36 h to obtain γ-aminopropyltriethoxysilane modified hexagonal boron nitride (APTES-HBN); wherein the particle size of the hexagonal boron nitride was 50 μm;

[0035] (2) 0.882 g of γ-aminopropyltriethoxysilane-modified hexagonal boron nitride, 0.076 g of graphene nanoribbons and 1.56 g of polydimethylsiloxane were mixed evenly, then placed in a ball mill, and ball milled at a speed of 200 rpm for 3 h. After ball milling, the sample was taken out and vacuum centrifuged for degassing at a speed of 400 rpm for 10 min to obtain a thermal conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons.

[0036] In the thermal conductive silicone grease prepared in this embodiment with the synergistic effect of modified hexagonal boron nitride and graphene nanoribbons, the mass fraction of modified hexagonal boron nitride accounts for 35%, and the mass fraction of graphene nanoribbons accounts for 3%. The actual photo is shown in FIG. Figure 1 As shown in the middle picture.

[0037] Example 3

[0038] A method for preparing a thermally conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons comprises the following steps:

[0039] (1) 150 mg of γ-aminopropyltriethoxysilane was added to 100 ml of anhydrous ethanol to obtain a γ-aminopropyltriethoxysilane solution with a concentration of 1.5 mg / mL, and the pH value was adjusted to 4.5 with acetic acid; then 1.5 g of hexagonal boron nitride was added to the γ-aminopropyltriethoxysilane solution, and ultrasonic treatment was performed at 100 W for 60 min, and magnetic stirring was performed at 1000 rpm for 36 h, followed by suction filtration, washing with deionized water for 3 times, and drying at 120° C. for 36 h to obtain γ-aminopropyltriethoxysilane modified hexagonal boron nitride (APTES-HBN); wherein the particle size of the hexagonal boron nitride was 50 μm;

[0040] (2) 0.699 g of γ-aminopropyltriethoxysilane-modified hexagonal boron nitride, 0.070 g of graphene nanoribbons and 1.56 g of polydimethylsiloxane were mixed evenly, then placed in a ball mill, and ball milled at a speed of 600 rpm for 4 h. After ball milling, the sample was taken out and vacuum centrifuged for degassing at a speed of 1000 rpm for 5 min to obtain a thermal conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons.

[0041] In the thermal conductive silicone grease prepared in this embodiment with the synergistic effect of modified hexagonal boron nitride and graphene nanoribbons, the mass fraction of modified hexagonal boron nitride accounts for 30%, and the mass fraction of graphene nanoribbons accounts for 3%. The actual photo is shown in FIG. Figure 1 As shown in the middle right picture.

[0042] Test example

[0043] The thermal conductivity of the modified hexagonal boron nitride in the thermal conductive silicone grease with synergistic effect of modified hexagonal boron nitride and graphene nanoribbons prepared in Examples 1 to 3 was measured using a DRL-Ⅲ heat flow method thermal conductivity tester. The results are shown in Table 1.

[0044] Table 1

[0045] Group Thermal conductivity Example 1 8W / (m·K) Example 2 6.9W / (m·K) Example 3 5W / (m·K)

[0046] As can be seen from Table 1, when the mass fraction of modified hexagonal boron nitride and graphene nanoribbons in the thermal conductive silicone grease prepared by the present invention is 40% and the mass fraction of graphene nanoribbons is 3%, the thermal conductivity can reach 8W / (m·K). This result shows that the modification treatment not only improves the compatibility of hBN with the matrix, but also effectively constructs a heat conduction network, so that the graphene nanoribbons and hBN work together, greatly reducing the interfacial thermal resistance. This study provides new ideas for the development of efficient heat dissipation materials for electronic devices, and shows the good application prospects of γ-aminopropyltriethoxysilane modified hBN and graphene nanoribbon composite materials.

[0047] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a thermally conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons, characterized in that: The steps include: (1) adding γ-aminopropyltriethoxysilane to anhydrous ethanol to obtain a γ-aminopropyltriethoxysilane solution, and adjusting the pH value to 4-5; then adding hexagonal boron nitride to the γ-aminopropyltriethoxysilane solution, and filtering, washing and vacuum drying after ultrasonic treatment and magnetic stirring to obtain γ-aminopropyltriethoxysilane modified hexagonal boron nitride; (2) Gamma-aminopropyltriethoxysilane-modified hexagonal boron nitride, graphene nanoribbons and polydimethylsiloxane are uniformly mixed, ball-milled and then vacuum centrifuged for degassing to obtain a thermal conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons.

2. The preparation method according to claim 1, characterized in that In step (1), the mass concentration of the γ-aminopropyltriethoxysilane solution is 1-2 mg / ml.

3. The preparation method according to claim 1, characterized in that: In step (1), acetic acid is used to adjust the pH value to 4-5; the particle size of the hexagonal boron nitride is 0.1-100 μm.

4. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of hexagonal boron nitride to γ-aminopropyltriethoxysilane is (8-12):

1.

5. The preparation method according to claim 1, characterized in that: In step (1), the ultrasonic treatment time is 55 to 65 minutes, the power is 80 to 120 W; the speed of the magnetic stirring is 800 to 1200 rpm, and the time is 24 to 48 hours; the vacuum drying is carried out at 110 to 125° C. for 24 to 48 hours.

6. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of the γ-aminopropyltriethoxysilane modified hexagonal boron nitride, graphene nanoribbons and polydimethylsiloxane is (100-137):10:(185-223).

7. The preparation method according to claim 1, characterized in that: In step (2), the ball milling time is 1 to 3 hours, and the rotation speed is 200 to 600 rpm; the vacuum centrifugal degassing time is 5 to 10 minutes, and the rotation speed is 400 to 1000 rpm.

8. A thermally conductive silicone grease with synergistic effects of modified hexagonal boron nitride and graphene nanoribbons, characterized in that: It is prepared according to the method according to any one of claims 1 to 7.

9. The thermally conductive silicone grease with synergistic effect of modified hexagonal boron nitride and graphene nanoribbons as claimed in claim 8, characterized in that: The mass fraction of modified hexagonal boron nitride in the thermal conductive silicone grease is 10-60%, and the mass fraction of graphene nanoribbons is 2-5%.

10. The thermally conductive silicone grease with synergistic effect of modified hexagonal boron nitride and graphene nanoribbons as claimed in claim 9, characterized in that: The mass fraction of modified hexagonal boron nitride in the thermal conductive silicone grease accounts for 40%, and the mass fraction of graphene nanoribbons accounts for 3%.

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