Preparation method of a heat-conducting silicone rubber containing POSS structure

Abstract

The present invention belongs to the technical field of silicon material preparation, and particularly relates to a preparation method of a heat-conducting organosilicon rubber containing a POSS structure. By introducing polyhedral oligomeric silsesquioxane into the silicone rubber structure in a chemical bond manner, the present invention solves the problems of agglomeration of inorganic particles and weak interfacial bonding force between two phases, and it is very easy to prepare a composite material by blending a heat-conducting filler and a polymer matrix. At the same time, polyhedral oligomeric silsesquioxane can increase the service temperature of the composite material, improve the mechanical properties of the composite material, improve the processing performance of the composite material and realize the multi-functionality of the material. The chemical structure designed by the present invention is novel, and the prepared heat-conducting organosilicon rubber containing a POSS structure has excellent mechanical properties, thermal stability, heat conductivity and electrical insulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon material preparation, and particularly relates to a preparation method of a heat-conducting silicone rubber containing a POSS structure. Background Art

[0002] Temperature has a great influence on the energy density, life and discharge rate of lithium-ion batteries. For example, in the temperature range of 30 to 40 °C, when the temperature rises by 1 °C, the service life of the lithium-ion battery will be shortened by 60 days, and high temperature will exacerbate heat generation, which is likely to cause safety hazards. In addition, lithium-ion batteries are prone to chain exothermic reactions under overcharge, over-puncture, collision and other conditions, resulting in thermal runaway, leading to serious accidents such as smoking, fire and even explosion. To sum up, battery thermal management technology is one of the core technologies of new energy vehicles, and the thermal management and control of lithium-ion batteries are the key factors restricting the performance and safety of power batteries for new energy vehicles. Therefore, in this process, there is an urgent need for a new type of material with heat conduction, flame retardancy and light weight to meet the above performance requirements of power batteries.

[0003] As a polymer-based thermal conductive interface material, heat-conducting silicone rubber has gradually become one of the research hotspots of functional materials and attracted extensive attention from many researchers due to its high thermal conductivity, resistance to high and low temperatures, good stability, good sealing performance and other advantages. Heat-conducting silicone rubber is based on siloxane polymer, and its thermal conductivity is improved by adding thermal conductive fillers. Traditional thermal conductive fillers include metals (Ag, Cu, Al), metal oxides (Al 2 O 3 , MgO, ZnO) and other non-metallic materials (SiC, SigN 4 , BN).

[0004] Metal oxides generally have good thermal conductivity and can be used as thermal conductive fillers for composite materials. Such thermal conductive fillers mainly include aluminum oxide, magnesium oxide, zinc oxide, beryllium oxide, etc. The reported thermal conductive silicone rubber structures currently include those prepared with soft silicone rubber as the matrix and aluminum oxide powder as the thermal conductive filler. The results show that when the mass ratio of aluminum oxide with particle sizes of 75μm, 40μm, and 2μm is 6:2:2, the filling amount of aluminum oxide powder in silicone rubber can reach 80%, the thermal conductivity of the composite material is 4.02W / m·K, and the Shore hardness is 78 degrees, which can meet the requirements of electronic and electrical components for high thermal conductivity and ultra-soft heat dissipation materials. Thermal conductive silicone rubber was prepared by filling silicone rubber with spherical aluminum oxide of different particle sizes. It was found that as the content of spherical aluminum oxide increased, the thermal conductivity of the silicone rubber increased; when the filler content was constant, the larger the particle size, the better the thermal conductivity of the silicone rubber (Synthetic Rubber Industry, 2015, 38: 55-57). Using N990 and XC-72 carbon black as thermal conductive fillers, the effects of carbon black on the thermal conductivity and mechanical properties of silicone rubber were studied. The results show that as the amount of carbon black increases, the thermal conductivity coefficient, thermal stability, and tensile strength of the silicone rubber increase; at the same filling amount, XC-72 carbon black is more likely to form a thermal conductive network than N990 carbon black; XC-72 carbon black-filled silicone rubber has good mechanical and electrical properties (New Chemical Materials, 2020: 38-42). It can be seen from the above inventions that the addition of fillers can significantly improve the thermal conductivity, mechanical properties, and electrical properties of the rubber compound, but simple blending will cause problems such as cracking and incompatibility of the rubber compound, and there are great hidden dangers at the interface of the material during actual use, making it difficult to meet the requirements of the existing environment. There is currently no relevant report on the application of a thermal conductive silicone rubber with good mechanical properties, thermal stability, thermal conductivity, and electrical insulation properties and good interface compatibility containing a POSS structure. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a thermal conductive silicone rubber containing a POSS structure with good mechanical properties, good thermal stability, thermal conductivity, and electrical insulation properties and good interface compatibility, as well as a preparation method thereof, to solve problems such as cracking and incompatibility of most rubber compounds.

[0006] In order to achieve the above invention purpose, the technical scheme adopted by the present invention is as follows:

[0007] A preparation method of a thermal conductive silicone rubber containing a POSS structure, comprising the following steps:

[0008] (1) In N 2Under an inert atmosphere, an organic ammonium hydroxide and a polyalkoxysilane compound are dissolved in an organic solvent, and the pH value of the solution is adjusted to 10 - 12 using an aqueous solution of a water-soluble salt. Stir at room temperature to obtain a colorless transparent liquid; then slowly add the above-obtained liquid dropwise to a n-pentane solution of chlorosilane, heat and stir to react. After the reaction is completed, let it stand, separate the liquid by decantation, perform rotary evaporation, wash with methanol, and after drying, perform recrystallization using a methanol / dichloromethane system to obtain a white silicon-hydrogen bond-containing active polyhedral cage-shaped polyhedral oligomeric silsesquioxane POSS solid;

[0009] (2) Weigh an appropriate amount of methyl vinyl silicone rubber, place it on a two-roll mill and mix it evenly. Then, successively add glass powder, nano-graphite, aluminum oxide, silicone resin, the polyhedral oligomeric silsesquioxane solid obtained in step (1), and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber;

[0010] (3) Put the composite silicone rubber obtained in step (2) into a flat vulcanizer and vulcanize it at 170 °C for 8 min. After cooling, put it into a muffle furnace for secondary vulcanization to finally obtain a heat-conductive silicone rubber containing a POSS structure.

[0011] Furthermore, in step (1), the organic ammonium hydroxide is any one of tetrapropylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, or tetramethylammonium hydroxide pentahydrate; the polyalkoxysilane compound is any one of 3-chloropropyltrimethoxysilane, tetraethyl orthosilicate, or 3-mercaptopropyltrimethoxysilane; the organic solvent is any one of tetrahydrofuran, methanol, or acetone.

[0012] Furthermore, in step (1), the molar ratio of the organic ammonium hydroxide to the polyalkoxysilane compound is 1:1; the concentration of the n-pentane solution of chlorosilane is 3 mol / L, and the amount of the n-pentane solution of chlorosilane used is 25 g; the aqueous solution of the water-soluble salt is any one of potassium carbonate, sodium carbonate, sodium hydroxide, or potassium hydroxide aqueous solution, and the concentration of the aqueous solution of the water-soluble salt is 0.4 g / mL.

[0013] Furthermore, in step (1), the stirring time at room temperature is 24 h, and the stirring speed is 100 - 200 rpm.

[0014] Furthermore, in step (1), the temperature of heating and stirring is 80 - 100 °C, and the stirring reaction time is 24 h.

[0015] Furthermore, in step (2), the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: aluminum oxide: silicone resin: polyhedral oligomeric silsesquioxane solid: vulcanizing agent is 100:5:(8 - 12):(35 - 70):10:5:2; the particle size of the aluminum oxide is 20 - 30 nm.

[0016] Further, in step (3), the temperature of the second-stage vulcanization in the muffle furnace is 140 - 200 °C, and the vulcanization time is 1 h.

[0017] The beneficial effects achieved by the present invention are as follows: By introducing polyhedral oligomeric silsesquioxane into the silicone rubber structure in a chemical bond manner, selecting aluminum oxide and nano-graphite as compound thermal conductive fillers, and obtaining a thermally conductive silicone rubber through a blending method. As an inorganic component, polyhedral oligomeric silsesquioxane solves the problems of agglomeration of inorganic particles and weak interfacial bonding force between two phases. It is very easy to compound the thermal conductive filler with the polymer matrix through a blending method. At the same time, polyhedral oligomeric silsesquioxane can increase the service temperature of the composite material, improve the mechanical properties of the composite material, improve the processing performance of the composite material, and realize the multi-functionality of the material. The structure designed by the present invention is novel, with excellent performance and a simple preparation process. Description of the Drawings

[0018] Figure 1 It is the Fourier transform infrared spectrum diagram of Example 1;

[0019] Figure 2 It is the comparison of the thermal conductivity and volume resistivity of the silicone rubbers of Examples 1 - 7 and Comparative Examples 1 - 4;

[0020] Figure 3 It is the comparison of the mechanical properties of the silicone rubbers of Examples 1 - 7 and Comparative Examples 1 - 4;

[0021] Figure 4 It is the comparison of the Shore hardness of the silicone rubbers of Examples 1 - 7 and Comparative Examples 1 - 4;

[0022] Figure 5 It is the comparison of the thermogravimetric analysis of Example 1 and Comparative Examples 1 - 4. Detailed Embodiments

[0023] The thermal conductivity is tested using a TC3000E type hot wire method thermal conductivity meter; the test standard is an experimental voltage of 1.8 V, a normal acquisition mode, an acquisition time of 2 s, a time interval of 3 min, and three repetitions. The average value is taken; the thermally conductive silicone rubber sample is cut to an appropriate size and placed above and below the coil for testing.

[0024] Mechanical property test: Use a WDT - 10 type microcomputer controlled electronic universal testing machine to test the tensile strength and elongation at break of the silicone rubber. The test standard is GB / T528 - 2009. The sample is cut into a dumbbell shape (length 10.0 ± 0.5 cm, thickness 2.0 ± 0.2 mm), and the number is not less than three. The pulling rate is 50 mm / min.

[0025] Use a VXMGZ type high-resistance measuring instrument to test the electrical insulation of the thermally conductive silicone rubber. The test sample is a plate-shaped material with a diameter > 50 mm and a thickness < 3 mm. The sample surface is required to be smooth, without cracks, bubbles, mechanical impurities and other defects.

[0026] Use a TG4000 type thermogravimetric analyzer to test the thermal stability of the thermally conductive silicone rubber. The test temperature range is from room temperature (30 °C) to 800 °C, and the heating rate is 20 °C / min. The air environment is used as the test gas atmosphere.

[0027] Use an XHS type Shore A durometer to test the hardness of the thermally conductive silicone rubber.

[0028] Example 1

[0029] (1) Dissolve tetrapropylammonium hydroxide (15 g) and 3-chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml), then add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid. The stirring speed is controlled at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction is completed, let it stand. The mixed liquid is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate, wash with methanol multiple times, and after drying, perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-type polyhedral oligomeric silsesquioxane (POSS) solid. The equations involved in the reaction are as follows:

[0030]

[0031] (2) Place the methyl vinyl silicone rubber on a two-roll mill and mix it evenly, then successively add glass powder, nano-graphite, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them evenly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: aluminum oxide: silicone resin: POSS solid: vulcanizing agent is 100:5:9:53:10:5:2.

[0032] (3) Put the composite silicone rubber obtained in step (2) into a flat vulcanizer for tablet pressing at a pressure of 10 MPa, then vulcanize at 170 °C for 8 min. After cooling, put it into a muffle furnace and vulcanize at 152 °C for 1 h. Finally, obtain a thermally conductive organosilicon rubber containing POSS structure.

[0033] Figure 1 This is the infrared spectrum diagram of the thermally conductive organosilicon rubber prepared in this example. It can be seen from the figure that at about 1440 cm -1 and 2910 cm -1 around is -CH2 Characteristic peaks, 1000 - 1130 cm -1 The strong absorption band that appears is the characteristic peak of Si - O - Si, 890 cm -1 , 1060 cm -1 and 1210 cm -1 Around is the characteristic peak of Si - R, 2000 - 2200 cm -1 The strong absorption band that appears is the characteristic peak of Si - H, proving that the POSS structure is successfully introduced into the product. The appearance of the above characteristic peaks indicates the successful synthesis of the thermally conductive silicone rubber containing the POSS structure.

[0034] Example 2

[0035] (1) Dissolve tetrapropylammonium hydroxide (15 g) and 3 - chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml), then add an aqueous sodium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid, with the stirring speed controlled at 100 - 200 rpm; subsequently, slowly drop the above - mentioned mixed solution into a n - pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h, and after the reaction is completed, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper - layer liquid with a separatory funnel, concentrate it by rotary evaporation, wash it with methanol multiple times, and after drying, perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage - type polyhedral oligomeric silsesquioxane (POSS) solid.

[0036] (2) Mix the methyl vinyl silicone rubber evenly on a two - roll mill, and then successively add glass powder, nano - graphite, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them evenly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano - graphite: aluminum oxide: silicone resin: POSS solid: vulcanizing agent is 100:5:8:53:10:5:2.

[0037] (3) Put the composite silicone rubber obtained in step (2) into a flat vulcanizer for tablet pressing at a pressure of 10 MPa, then vulcanize at 170 °C for 8 min, after cooling, put it into a muffle furnace and vulcanize at 170 °C for 1 h, and finally obtain the thermally conductive silicone rubber containing the POSS structure.

[0038] Example 3

[0039] (1) Dissolve tetrapropylammonium hydroxide (12 g) and 3-chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml), then add an aqueous potassium hydroxide solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid. The stirring speed is controlled at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction is completed, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate, wash it with methanol multiple times, and after drying, perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-shaped polyhedral oligomeric silsesquioxane (POSS) solid.

[0040] (2) Place methyl vinyl silicone rubber on a two-roll mill and mix it evenly, then successively add glass powder, nano-graphite, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them evenly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber : glass powder : nano-graphite : aluminum oxide : silicone resin : POSS solid : vulcanizing agent is 100 : 5 : 9 : 70 : 10 : 5 : 2.

[0041] (3) Place the composite silicone rubber obtained in step (2) into a flat vulcanizer and perform tablet pressing treatment at a pressure of 10 MPa, then vulcanize at 170 °C for 8 min. After cooling, put it into a muffle furnace and vulcanize at 200 °C for 1 h. Finally, obtain a heat-conducting silicone rubber containing a POSS structure.

[0042] Example 4

[0043] (1) Dissolve tetraethylammonium hydroxide (12 g) and tetraethyl orthosilicate (12 g) in tetrahydrofuran (32 ml), then add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid. The stirring speed is controlled at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction is completed, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate, wash it with methanol multiple times, and after drying, perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-shaped polyhedral oligomeric silsesquioxane (POSS) solid.

[0044] (2) Place the methyl vinyl silicone rubber on a two-roll mill and mix it evenly. Then, sequentially add glass powder, nano-graphite, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: aluminum oxide: silicone resin: POSS solid: vulcanizing agent is 100:5:9:53:10:10:2.

[0045] (3) Place the composite silicone rubber obtained in step (2) into a flat vulcanizer and perform tablet pressing at a pressure of 10 MPa. Then, vulcanize it at 170 °C for 8 min. After cooling, place it in a muffle furnace and vulcanize it at 100 °C for 1 h. Finally, a thermally conductive silicone rubber containing a POSS structure is obtained.

[0046] Example 5

[0047] (1) Dissolve tetrapropylammonium hydroxide (15 g) and tetraethyl orthosilicate (15 g) in tetrahydrofuran (32 ml). Then, add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid. Control the stirring speed at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction ends, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate it, wash it with methanol multiple times, and perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-shaped polyhedral oligomeric silsesquioxane (POSS) solid.

[0048] (2) Place the methyl vinyl silicone rubber on a two-roll mill and mix it evenly. Then, sequentially add glass powder, nano-graphite, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: aluminum oxide: silicone resin: POSS solid: vulcanizing agent is 100:5:12:50:10:5:2.

[0049] (3) Place the composite silicone rubber obtained in step (2) into a flat vulcanizer and perform tablet pressing at a pressure of 10 MPa. Then, vulcanize it at 170 °C for 8 min. After cooling, place it in a muffle furnace and vulcanize it at 152 °C for 1 h. Finally, a thermally conductive silicone rubber containing a POSS structure is obtained.

[0050] Example 6

[0051] (1) Dissolve tetrapropylammonium hydroxide (15 g) and 3-chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml), then add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid. The stirring speed is controlled at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction is completed, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate, wash it with methanol multiple times, and after drying, perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-shaped polyhedral oligomeric silsesquioxane (POSS) solid.

[0052] (2) Place methyl vinyl silicone rubber on a two-roll mill and mix it evenly, then successively add glass powder, nano-graphite, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them evenly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber : glass powder : nano-graphite : aluminum oxide : silicone resin : POSS solid : vulcanizing agent is 100 : 5 : 9 : 70 : 10 : 4 : 2.

[0053] (3) Put the composite silicone rubber obtained in step (2) into a flat vulcanizer and perform tablet pressing treatment at a pressure of 10 MPa, then vulcanize at 170 °C for 8 min. After cooling, put it into a muffle furnace and vulcanize at 170 °C for 1 h. Finally, obtain a heat-conducting silicone rubber containing POSS structure.

[0054] Example 7

[0055] (1) Dissolve tetrapropylammonium hydroxide (15 g) and 3-chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml), then add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid. The stirring speed is controlled at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction is completed, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate, wash it with methanol multiple times, and after drying, perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-shaped polyhedral oligomeric silsesquioxane (POSS) solid.

[0056] (2) Place the methyl vinyl silicone rubber on a two-roll mill and mix it evenly. Then, sequentially add glass powder, nano-graphite, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: aluminum oxide: silicone resin: POSS solid: vulcanizing agent is 100:5:12:35:10:4:2.

[0057] (3) Place the composite silicone rubber obtained in step (2) into a flat vulcanizer and perform tablet pressing at a pressure of 10 MPa. Then, vulcanize it at 170 °C for 8 min. After cooling, put it into a muffle furnace and vulcanize it at 140 °C for 1 h. Finally, a thermally conductive silicone rubber containing POSS structure is obtained.

[0058] Control Example 1

[0059] (1) Place the methyl vinyl silicone rubber on a two-roll mill and mix it evenly. Then, sequentially add glass powder, nano-graphite, aluminum oxide, silicone resin, and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: aluminum oxide: silicone resin: vulcanizing agent is 100:5:9:53:10:2.

[0060] (2) Place the composite silicone rubber obtained in step (1) into a flat vulcanizer and perform tablet pressing at a pressure of 10 MPa. Then, vulcanize it at 170 °C for 8 min. After cooling, put it into a muffle furnace and vulcanize it at 152 °C for 1 h. Finally, a thermally conductive silicone rubber containing POSS structure is obtained.

[0061] Control Example 2

[0062] (1) Dissolve tetrapropylammonium hydroxide (15 g) and 3-chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml). Then, add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid, with the stirring speed controlled at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction ends, let it stand, and the mixed solution is divided into two layers, each layer being colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate it, wash it with methanol multiple times, and perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-type polyhedral oligomeric silsesquioxane (POSS) solid.

[0063] (2) Place the methyl vinyl silicone rubber on a two-roll mill and mix it evenly. Then, sequentially add glass powder, aluminum oxide, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: aluminum oxide: silicone resin: POSS solid: vulcanizing agent is 100:5:53:10:5:2.

[0064] (3) Place the composite silicone rubber obtained in step (2) into a flat vulcanizer and perform tablet pressing at a pressure of 10 MPa. Then, vulcanize it at 170 °C for 8 min. After cooling, place it in a muffle furnace and vulcanize it at 152 °C for 1 h. Finally, a thermally conductive silicone rubber containing a POSS structure is obtained.

[0065] Control Example 3

[0066] (1) Dissolve tetrapropylammonium hydroxide (15 g) and 3-chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml). Then, add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid. The stirring speed is controlled at 100 - 200 rpm. Subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h. After the reaction ends, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, rotary evaporate and concentrate it, wash it with methanol multiple times, and perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-type polyhedral oligomeric silsesquioxane (POSS) solid.

[0067] (2) Place the methyl vinyl silicone rubber on a two-roll mill and mix it evenly. Then, sequentially add glass powder, nano-graphite, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: silicone resin: POSS solid: vulcanizing agent is 100:5:9:10:5:2.

[0068] (3) Place the composite silicone rubber obtained in step (2) into a flat vulcanizer and perform tablet pressing at a pressure of 10 MPa. Then, vulcanize it at 170 °C for 8 min. After cooling, place it in a muffle furnace and vulcanize it at 152 °C for 1 h. Finally, a thermally conductive silicone rubber containing a POSS structure is obtained.

[0069] Control Example 4

[0070] (1) Dissolve tetrapropylammonium hydroxide (15 g) and 3-chloropropyltrimethoxysilane (15 g) in tetrahydrofuran (32 ml), then add an aqueous potassium carbonate solution (0.4 g / mL) to adjust the pH value to 10, and then stir at room temperature for 24 h to obtain a colorless transparent liquid, with the stirring speed controlled at 100 - 200 rpm; subsequently, slowly drop the above mixed solution into a n-pentane solution of chlorosilane (25 g, 3 mol / L), heat and stir the reaction at 90 °C for 24 h, and after the reaction is completed, let it stand. The mixed solution is divided into two layers and each layer is colorless and transparent. Separate the upper layer liquid with a separatory funnel, concentrate it by rotary evaporation, wash it several times with methanol, and after drying, perform recrystallization with a methanol / dichloromethane system to obtain a white polyhedral cage-like polyhedral oligomeric silsesquioxane (POSS) solid.

[0071] (2) Place methyl vinyl silicone rubber on a two-roll mill and mix it evenly, then successively add aluminum oxide, nano-graphite, glass powder, silicone resin, the POSS solid obtained in step (1), and a vulcanizing agent, and mix them thoroughly to obtain a composite silicone rubber. Among them, the mass ratio of methyl vinyl silicone rubber: glass powder: nano-graphite: aluminum oxide: silicone resin: POSS solid: vulcanizing agent is 100:5:9:53:10:5:2.

[0072] (3) Put the composite silicone rubber obtained in step (2) into a flat vulcanizer for tablet pressing at a pressure of 10 MPa, then vulcanize it at 170 °C for 8 min, after cooling, put it into a muffle furnace and vulcanize it at 152 °C for 1 h, and finally obtain a heat-conductive silicone rubber containing a POSS structure.

Claims

1. Preparation method of a heat-conductive silicone rubber containing POSS structure, characterized in that, it comprises the following steps: (1) Under an N 2 atmosphere, dissolve organic ammonium hydroxide and polyalkoxysilane compounds in an organic solvent, adjust the pH value of the solution to 10 - 12 using a water-soluble base solution, stir at room temperature to obtain a colorless transparent liquid; then slowly drop the above-obtained liquid into a n-pentane solution of chlorosilane, heat and stir for reaction, after the reaction is completed, let it stand, separate the liquid, rotary evaporate, wash, dry, and recrystallize to obtain a white silicon-hydrogen bond-containing active polyhedral cage-shaped polysilsesquioxane POSS solid; (2) Weigh an appropriate amount of methyl vinyl silicone rubber, place it on a two-roll mill and mix evenly, then successively add glass powder, nano-graphite, aluminum oxide, silicone resin, the polyhedral oligomeric silsesquioxane solid obtained in step (1), and a vulcanizing agent, and mix thoroughly to obtain a composite silicone rubber; (3) Put the composite silicone rubber obtained in step (2) into a flat vulcanizing machine and vulcanize at 170 °C for 8 min. After cooling, put it into a muffle furnace for secondary vulcanization, and finally obtain a heat-conductive silicone rubber containing POSS structure.

2. The preparation method of the heat-conductive silicone rubber containing POSS structure according to claim 1, characterized in that, in step (1), the organic ammonium hydroxide is any one of tetrapropylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide or tetramethylammonium hydroxide pentahydrate; the polyalkoxysilane compound is any one of 3-chloropropyltrimethoxysilane, tetraethyl orthosilicate or 3-mercaptopropyltrimethoxysilane; the organic solvent is any one of tetrahydrofuran, methanol or acetone.

3. The preparation method of the heat-conductive silicone rubber containing POSS structure according to claim 1, characterized in that, in step (1), the molar ratio of the organic ammonium hydroxide to the polyalkoxysilane compound is 1:1; the concentration of the n-pentane solution of the chlorosilane is 3 mol / L, and the amount of the n-pentane solution of the chlorosilane used is 25 g; the water-soluble alkali solution is any one of potassium carbonate, sodium carbonate, sodium hydroxide or potassium hydroxide aqueous solution, and the concentration of the water-soluble alkali solution is 0.4 g / mL.

4. The preparation method of the heat-conductive silicone rubber containing POSS structure according to claim 1, characterized in that, in step (1), the stirring time at room temperature is 24 h, and the stirring speed is 100 - 200 rpm.

5. The preparation method of the heat-conductive silicone rubber containing POSS structure according to claim 1, characterized in that, in step (1), the temperature of heating and stirring is 80 - 100 °C, and the stirring reaction time is 24 h.

6. The preparation method of the heat-conductive silicone rubber containing POSS structure according to claim 1, characterized in that, in step (2), the mass ratio of methyl vinyl silicone rubber : glass powder : nano-graphite : aluminum oxide : silicone resin : polyhedral oligomeric silsesquioxane solid : vulcanizing agent is 100 : 5 : (8 - 12) : (35 - 70) : 10 : 5 : 2; the particle size of the aluminum oxide is 20 - 30 nm.

7. The preparation method of the heat-conductive silicone rubber containing POSS structure according to claim 1, characterized in that, in step (3), the temperature of the secondary vulcanization in the muffle furnace is 140 - 200 °C, and the vulcanization time is 1 h.

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