High-crosslinking high-sealing-performance organic silica gel and preparation method thereof

Abstract

The invention relates to the technical field of gel materials, in particular to high-crosslinking high-sealing-performance organic silicon gel and a preparation method thereof. The organic silica gel is prepared from a component A and a component B in parts by weight, the component A is prepared from 100 to 150 parts of simethicone, 10 to 30 parts of silicone rubber and 5 to 10 parts of composite nano material; the component B is prepared from the following components in parts by weight: 10 to 18 parts of silane coupling agent KH560, 10 to 20 parts of methyltrimethoxysilane, 1 to 3 parts of dibutyltin dilaurate and 1 to 2 parts of tetrabutyl titanate. According to the invention, a cross-linked network structure is constructed in the organic silica gel through the composite nanomaterial, and the surface porous nanosheet layers are stacked and embedded with each other to synergistically form a compact three-dimensional continuous phase system, so that the sealing performance of the material is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gel materials, in particular to a highly cross-linked and highly sealing organic silicone gel and a preparation method thereof. Background Art

[0002] Currently, some precision electronic components, bathroom fixtures, backlight sources, solar energy, connectors, electrical modules, and other products require waterproofing, moisture resistance, and gas pollution prevention during daily use and storage. Silicone gel is widely used as a moisture-proof and insulating coating and potting material for electronic components, as an internal coating material for transistors and integrated circuits, as an elastic adhesive for optical instruments, and as an agent for organs within the human body. Silicone gel has the following advantages:

[0003] After curing, the glue is in a semi-solid state, has good adhesion and sealing properties to many substrates, and has excellent resistance to hot and cold cycles; the two components will not gel quickly after mixing, so it has a long operating time, and will cure quickly once heated, and the curing time can be freely controlled; no by-products are produced during the curing process, and there is no shrinkage; it has excellent electrical insulation properties and high and low temperature resistance (-50 ~ 200 ° C); the gel can automatically heal after being cracked by external force, and also has the function of waterproofing and moisture-proofing, without affecting the use effect.

[0004] For example, the invention patent with publication number CN 106103594 A discloses an organic silicone gel composition, which contains at least one adhesion promoter (Z) and forms an organic silicone gel by curing. The organic silicone gel has a viscosity of 5.0×10 3 Dyne / cm 2 to 1.0×10 5 Dyne / cm 2 The loss modulus of elasticity is 5.0×10 4 Dyne / cm 2 to 1.0×10 6 Dyne / cm 2 The present invention relates to a silicone gel composition having a complex elastic modulus of 0.1 and a loss tangent of 0.3 or less; the silicone gel composition can inhibit the occurrence of air bubbles or cracks in the silicone gel used to seal or fill electrical or electronic components, and has excellent bonding with electrical or electronic components even when used under high temperature conditions such as in power devices; however, due to its low crosslinking density, it has poor compactness and does not have good sealing performance, resulting in significant limitations in its use and preventing it from being widely promoted and applied in the field of sealing some electronic components. Summary of the Invention

[0005] In view of the problems existing in the prior art, the object of the present invention is to provide a highly cross-linked and highly sealing organosilicon gel and a preparation method thereof, wherein the organosilicon gel has excellent high sealing performance.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A highly cross-linked and highly sealing silicone gel, wherein the silicone gel is prepared from component A and component B;

[0008] In parts by weight, the component A includes: 100-150 parts of dimethyl silicone oil (specifically 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, etc.), 10-30 parts of silicone rubber (specifically 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, etc.), and 5-10 parts of composite nanomaterials (specifically 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.);

[0009] The component B includes: 10-18 parts of silane coupling agent KH560 (specifically 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, etc.), 10-20 parts of methyltrimethoxysilane (specifically 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc.), 1-3 parts of dibutyltin dilaurate (specifically 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2.0 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, 3.0 parts, etc.), and 1-2 parts of tetrabutyl titanate (specifically 1.0 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2.0 parts, etc.).

[0010] As a further preferred embodiment of the present invention, the preparation method of the composite nanomaterial is as follows:

[0011] 1) dissolving cobalt nitrate hexahydrate, urea, and ammonium fluoride in deionized water, stirring thoroughly, and transferring to a high-pressure reactor. The nanofiber material is then repeatedly washed with hydrochloric acid, anhydrous ethanol, and deionized water, added to the high-pressure reactor, ultrasonically dispersed, and reacted at 120-130° C. for 8-12 hours. After the reaction is completed, the mixture is cooled to room temperature, and the product is repeatedly washed with deionized water and dried to obtain a composite nanofiber material.

[0012] 2) Sodium sulfide is dissolved in deionized water, stirred thoroughly, and poured into an autoclave. The composite nanofiber material prepared in step 1) is added, ultrasonically dispersed, and reacted at 120-126° C. for 5-8 hours. After the reaction is completed, the product is cooled to room temperature, and the product is repeatedly washed with anhydrous ethanol and deionized water, and dried to obtain a composite nanomaterial.

[0013] As a further preferred embodiment of the present invention, in step 1), the usage ratio of the cobalt nitrate hexahydrate, urea, ammonium fluoride, deionized water and nanofiber material is (0.4-0.8) g: (0.3-0.7) g: (0.1-0.2) g: (300-500) mL: (2-5) g.

[0014] As a further preferred embodiment of the present invention, in step 2), the usage ratio of the sodium sulfide, deionized water, and composite nanofiber material is (0.06-0.10) g: (300-500) mL: (1-3) g.

[0015] As a further preferred embodiment of the present invention, the preparation method of the nanofiber material is as follows:

[0016] 1) adding graphite sheets and potassium permanganate to an acid solution composed of sulfuric acid and phosphoric acid, stirring and reacting at 50-55° C. for 12-15 hours, cooling to room temperature after the reaction is completed, pouring ice water dissolved in hydrogen peroxide into the system, filtering to remove the precipitate, centrifuging the filtrate, removing the supernatant, and freeze-drying to obtain graphene oxide;

[0017] 2) Measure 200-300 mL of tetrahydrofuran, add 20-30 g of p-hydroxybenzaldehyde and 35-50 g of anhydrous potassium carbonate thereto, stir thoroughly at room temperature, dissolve 8.3-9.2 g of hexachlorocyclotriphosphine in 100-160 mL of tetrahydrofuran, and then slowly add the mixture to the system. Under nitrogen protection, reflux at 65-70° C. for 36-40 hours. After the reaction is completed, filter and rotary evaporate the product, add 500-800 mL of deionized water, filter, recrystallize from ethyl acetate, and vacuum dry to obtain a dopant;

[0018] 3) adding polyacrylonitrile, a dopant, polymethyl methacrylate, and graphene oxide to N,N-dimethylformamide, stirring thoroughly, and injecting into a syringe for spinning to obtain nanofibers, which are then placed in a tubular furnace and oxidized at 250-280° C. for 2-5 hours, and then carbonized at 900-960° C. for 1-3 hours under nitrogen protection to obtain porous nanofibers;

[0019] 4) immersing the porous nanofibers in anhydrous ethanol zinc acetate solution at room temperature for 1-3 hours, heating at 150-155° C. for 10-30 minutes, cooling to room temperature, repeating the operation 2-5 times, and finally heating at 350-360° C. for 15-30 minutes to obtain pretreated porous nanofibers;

[0020] 5) Add zinc nitrate and hexamethylenetetramine to deionized water, sonicate until fully dissolved, then add the pretreated porous nanofibers, disperse them evenly, and hydrothermally react at 120-126° C. for 1-3 hours. After the reaction is completed, cool to room temperature, repeatedly wash with deionized water, and dry to obtain the nanofiber material.

[0021] As a further preferred embodiment of the present invention, in step 1), the ratio of the amount of the graphite sheet, potassium permanganate, sulfuric acid, phosphoric acid, hydrogen peroxide, and ice water is (3-6) g: (18-25) g: (360-400) mL: (40-70) mL: (3-6) mL: (50-80) mL;

[0022] The concentration of the hydrogen peroxide is 30-35 wt %.

[0023] As a further preferred embodiment of the present invention, in step 3), the ratio of the amount of polyacrylonitrile, dopant, polymethyl methacrylate, graphene oxide and N,N-dimethylformamide is (1-3) g: (0.3-0.7) g: (0.3-0.7) g: (0.001-0.005) g: (9-13) g;

[0024] The spinning parameters are: injection rate of 0.1-0.3 mL / h, voltage of 12-16 kV, spinning distance of 15-20 cm, and spinning time of 4-6 h.

[0025] As a further preferred embodiment of the present invention, in step 4), the ratio of the porous nanofibers to the zinc acetate anhydrous ethanol solution is (2-6) g: (80-120) mL;

[0026] The concentration of the zinc acetate anhydrous ethanol solution is 0.1-0.5 mol / L.

[0027] As a further preferred embodiment of the present invention, in step 5), the ratio of zinc nitrate, hexamethylenetetramine, deionized water, and pretreated porous nanofibers is (0.01-0.05) mol: (0.01-0.05) mol: (250-320) mL: (3-6) g.

[0028] A method for preparing a highly cross-linked and highly sealing silicone gel comprises the following steps:

[0029] The raw materials are weighed in proportion, and then dimethyl silicone oil, silicone rubber, and composite nanomaterials are mixed to prepare component A; silane coupling agent KH560, methyltrimethoxysilane, dibutyltin dilaurate, and tetrabutyl titanate are mixed and reacted to obtain component B; components A and B are then fully mixed, poured into a mold and cured at room temperature to obtain the desired silicone gel with high cross-linking and high sealing properties.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] In the present invention, graphite is used as a raw material and oxidized to obtain graphene oxide with a reinforcing effect, and a dopant with a cross-linking effect is synthesized. The dopant, porogen, reinforcing agent and polyacrylonitrile are then electrostatically spun to obtain nanofibers, which are then subjected to high-temperature carbonization treatment to obtain porous nanofibers. The N and P atoms contained in the dopant can improve the wettability of the surface of the porous nanofibers and promote the interaction between the porous nanofibers and the organic material. The reinforcing agent graphene oxide, as a multi-layer structure, can be stacked on the surface of the porous nanofibers to play a reinforcing role and improve the strength of the porous nanofibers. Since the surface and edge of the graphene oxide contain a large number of oxygen-containing groups, a strong interface bond can be formed with the organic material through hydrogen bonding, thereby helping to improve the stability of the porous nanofibers in the organic material. The porous nanofibers are mutually entangled and cross-linked to form a network structure, which can effectively increase the cross-linking density of the organic material. The high-density network structure can significantly enhance the structural density of the organic material, so that it has excellent high sealing performance.

[0032] In order to further improve the sealing property of organic materials, the present invention performs a secondary treatment on the porous nanofibers. By a hydrothermal method, the porous structure on the surface of the porous nanofibers is used as a deposition site to deposit a nanorod array on its surface. Then, a two-step hydrothermal method is used to deposit porous nanosheets on its surface. The preferentially deposited nanorods can serve as connecting carriers, one end of which is embedded in the pores of the porous nanofibers, and the other end can be embedded in the pores of the porous nanosheets, thereby firmly connecting the two together, so that a high-strength interface bonding is formed between the porous nanosheets and the porous nanofibers, thereby obtaining a structurally stable composite nanomaterial. The composite nanomaterial can not only form a network structure by mutual cross-linking, but also the porous nanosheets connected on the surface can be stacked and embedded with each other. On the one hand, the network structure can be connected to each other to form a continuous phase as a whole, and a dense nanosheet layer can be formed on the surface of the network structure, thereby further improving the density of the network structure, thereby further improving the sealing property of the organic material.

[0033] In the present invention, composite nanomaterials are introduced into the organic silicone gel material to form a network structure through mutual cross-linking, and the porous nanosheets attached to the surface can be stacked and intercalated with each other. On the one hand, the network structure can be connected to each other to form a continuous phase as a whole, and on the other hand, a dense nanosheet layer can be formed on the surface of the network structure, thereby significantly improving the density of the network structure, making the organic silicone gel material have high sealing performance, so that it can better meet the needs. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0035] It should be noted that if no specific conditions are specified in the following examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0036] Example 1

[0037] A highly cross-linked and highly sealing silicone gel, the silicone gel being prepared from component A and component B;

[0038] In parts by weight, the component A comprises: 100 parts of dimethyl silicone oil, 10 parts of silicone rubber, and 5 parts of composite nanomaterials;

[0039] In parts by weight, the component B comprises: 10 parts of silane coupling agent KH560, 10 parts of methyltrimethoxysilane, 1 part of dibutyltin dilaurate, and 1 part of tetrabutyl titanate;

[0040] The preparation method of the organosilicon gel specifically comprises the following steps:

[0041] The raw materials are weighed in proportion, and then dimethyl silicone oil, silicone rubber, and composite nanomaterials are mixed to prepare component A; the silane coupling agent KH560, methyltrimethoxysilane, dibutyltin dilaurate, and tetrabutyl titanate are mixed and reacted to obtain component B; then components A and B are thoroughly mixed, poured into a mold and cured at room temperature to obtain the desired silicone gel with high cross-linking and high sealing properties.

[0042] The preparation method of the composite nanomaterial is as follows:

[0043] 1) 3 g of graphite flakes and 18 g of potassium permanganate were added to an acid solution consisting of 360 mL of sulfuric acid and 40 mL of phosphoric acid, and the mixture was stirred at 50° C. for 12 h. After the reaction was completed, the mixture was cooled to room temperature, and 50 mL of ice water containing 3 mL of 30 wt% hydrogen peroxide was poured into the system. The precipitate was removed by filtration, and the filtrate was centrifuged at 4000 rpm for 4 h. The supernatant was removed and the mixture was freeze-dried to obtain graphene oxide;

[0044] 2) Measure 200 mL of tetrahydrofuran, add 20 g of p-hydroxybenzaldehyde and 35 g of anhydrous potassium carbonate thereto, stir thoroughly at room temperature, dissolve 8.3 g of hexachlorocyclotriphosphine in 100 mL of tetrahydrofuran, and then slowly add the mixture to the system. Under nitrogen protection, reflux at 65° C. for 36 hours. After the reaction is completed, filter and rotary evaporate the product, add 500 mL of deionized water, filter, recrystallize from ethyl acetate, and vacuum dry to obtain a dopant;

[0045] 3) 1 g of polyacrylonitrile, 0.3 g of dopant, 0.3 g of polymethyl methacrylate, and 0.001 g of graphene oxide were added to 9 g of N,N-dimethylformamide, stirred thoroughly, and injected into a syringe for spinning at a rate of 0.1 mL / h, a voltage of 12 kV, a spinning distance of 15 cm, and a spinning time of 4 h to obtain nanofibers, which were then placed in a tubular furnace and oxidized at 250 ° C for 2 h, and then carbonized at 900 ° C for 1 h under nitrogen protection to obtain porous nanofibers;

[0046] 4) Immerse 2 g of porous nanofibers in 80 mL of 0.1 mol / L zinc acetate anhydrous ethanol solution at room temperature for 1 hour, remove and heat at 150°C for 10 minutes, cool to room temperature, repeat this operation twice, and finally heat at 350°C for 15 minutes to obtain pretreated porous nanofibers;

[0047] 5) Add 0.01 mol zinc nitrate and 0.01 mol hexamethylenetetramine to 250 mL deionized water, sonicate until fully dissolved, then add 3 g pretreated porous nanofibers, disperse evenly, and hydrothermally react at 120° C. for 1 h. After the reaction is complete, cool to room temperature, repeatedly wash with deionized water, and dry to obtain a nanofiber material;

[0048] 6) Dissolve 0.4 g of cobalt nitrate hexahydrate, 0.3 g of urea, and 0.1 g of ammonium fluoride in 300 mL of deionized water, stir thoroughly, and transfer to an autoclave. Then, wash 2 g of the nanofiber material repeatedly with hydrochloric acid, anhydrous ethanol, and deionized water, add it to the autoclave, ultrasonically disperse it, and react at 120° C. for 8 h. After the reaction is completed, cool it to room temperature, wash the product repeatedly with deionized water, and dry it to obtain a composite nanofiber material.

[0049] 7) Dissolve 0.06 g of sodium sulfide in 300 mL of deionized water, stir thoroughly, and pour into a high-pressure reactor. Add 1 g of the composite nanofiber material, disperse evenly by ultrasonication, and react at 120°C for 5 h. After the reaction is completed, cool to room temperature, wash the product repeatedly with anhydrous ethanol and deionized water, and vacuum dry at 60°C for 5 h to obtain a composite nanomaterial.

[0050] Example 2

[0051] A highly cross-linked and highly sealing silicone gel, the silicone gel being prepared from component A and component B;

[0052] In parts by weight, the component A comprises: 130 parts of dimethyl silicone oil, 20 parts of silicone rubber, and 7 parts of composite nanomaterials;

[0053] In parts by weight, the component B comprises: 15 parts of silane coupling agent KH560, 15 parts of methyltrimethoxysilane, 2 parts of dibutyltin dilaurate, and 1.5 parts of tetrabutyl titanate;

[0054] The preparation method of the organosilicon gel specifically comprises the following steps:

[0055] According to parts by weight, dimethyl silicone oil, silicone rubber, and composite nanomaterials are mixed to prepare component A, and silane coupling agent KH560, methyltrimethoxysilane, dibutyltin dilaurate, and tetrabutyl titanate are mixed and reacted to obtain component B. Components A and B are then fully mixed, poured into a mold, and cured at room temperature to obtain the desired silicone gel with high cross-linking and high sealing properties.

[0056] The preparation method of the composite nanomaterial is as follows:

[0057] 1) 5 g of graphite flakes and 20 g of potassium permanganate were added to an acid solution consisting of 380 mL of sulfuric acid and 50 mL of phosphoric acid, and the mixture was stirred at 53° C. for 13 h. After the reaction was completed, the mixture was cooled to room temperature, and 70 mL of ice water containing 5 mL of 32 wt% hydrogen peroxide was poured into the system. The precipitate was removed by filtration, and the filtrate was centrifuged at 5000 rpm for 5 h. The supernatant was removed and freeze-dried to obtain graphene oxide;

[0058] 2) Measure 250 mL of tetrahydrofuran, add 25 g of p-hydroxybenzaldehyde and 40 g of anhydrous potassium carbonate thereto, stir thoroughly at room temperature, dissolve 8.7 g of hexachlorocyclotriphosphine in 150 mL of tetrahydrofuran, and then slowly add the mixture to the system. Under nitrogen protection, reflux at 68° C. for 38 hours. After the reaction is completed, filter and rotary evaporate the product, add 700 mL of deionized water, filter, recrystallize from ethyl acetate, and vacuum dry to obtain a dopant;

[0059] 3) 2 g of polyacrylonitrile, 0.5 g of dopant, 0.5 g of polymethyl methacrylate, and 0.003 g of graphene oxide were added to 10 g of N,N-dimethylformamide, stirred thoroughly, and injected into a syringe for spinning at a rate of 0.2 mL / h, a voltage of 15 kV, a spinning distance of 18 cm, and a spinning time of 5 h to obtain nanofibers, which were then placed in a tubular furnace and oxidized at 260 ° C for 3 h, and then carbonized at 950 ° C for 2 h under nitrogen protection to obtain porous nanofibers;

[0060] 4) 5 g of porous nanofibers were immersed in 100 mL of 0.3 mol / L zinc acetate anhydrous ethanol solution at room temperature for 2 h. After removal, the fibers were heated at 153°C for 20 min, cooled to room temperature, and repeated three times. Finally, the fibers were heated at 355°C for 25 min to obtain pretreated porous nanofibers.

[0061] 5) Add 0.03 mol zinc nitrate and 0.03 mol hexamethylenetetramine to 300 mL deionized water, sonicate until fully dissolved, then add 5 g pretreated porous nanofibers, disperse evenly, and hydrothermally react at 125° C. for 2 h. After the reaction is complete, cool to room temperature, repeatedly wash with deionized water, and dry to obtain a nanofiber material;

[0062] 6) Dissolve 0.6 g of cobalt nitrate hexahydrate, 0.5 g of urea, and 0.1 g of ammonium fluoride in 400 mL of deionized water, stir thoroughly, and transfer to an autoclave. Then, wash 3 g of the nanofiber material repeatedly with hydrochloric acid, anhydrous ethanol, and deionized water, add it to the autoclave, ultrasonically disperse it, and react at 125° C. for 10 h. After the reaction is completed, cool it to room temperature, wash the product repeatedly with deionized water, and dry it to obtain a composite nanofiber material.

[0063] 7) Dissolve 0.08 g of sodium sulfide in 400 mL of deionized water, stir thoroughly, and pour into a high-pressure reactor. Add 2 g of the composite nanofiber material, disperse evenly by ultrasonication, and react at 125°C for 7 h. After the reaction is completed, cool to room temperature, wash the product repeatedly with anhydrous ethanol and deionized water, and vacuum dry at 65°C for 8 h to obtain a composite nanomaterial.

[0064] Example 3

[0065] A highly cross-linked and highly sealing silicone gel, the silicone gel being prepared from component A and component B;

[0066] In parts by weight, the component A comprises: 150 parts of dimethyl silicone oil, 30 parts of silicone rubber, and 10 parts of composite nanomaterials;

[0067] In parts by weight, the component B comprises: 18 parts of silane coupling agent KH560, 20 parts of methyltrimethoxysilane, 3 parts of dibutyltin dilaurate, and 2 parts of tetrabutyl titanate;

[0068] The preparation method of the organosilicon gel specifically comprises the following steps:

[0069] According to parts by weight, dimethyl silicone oil, silicone rubber, and composite nanomaterials are mixed to prepare component A, and silane coupling agent KH560, methyltrimethoxysilane, dibutyltin dilaurate, and tetrabutyl titanate are mixed and reacted to obtain component B. Components A and B are then fully mixed, poured into a mold, and cured at room temperature to obtain the desired silicone gel with high cross-linking and high sealing properties.

[0070] The preparation method of the composite nanomaterial is as follows:

[0071] 1) 6 g of graphite flakes and 25 g of potassium permanganate were added to an acid solution consisting of 400 mL of sulfuric acid and 70 mL of phosphoric acid, and the mixture was stirred at 55° C. for 15 h. After the reaction was completed, the mixture was cooled to room temperature, and 80 mL of ice water containing 6 mL of 35 wt% hydrogen peroxide was poured into the system. The precipitate was removed by filtration, and the filtrate was centrifuged at 6000 rpm for 6 h. The supernatant was removed and the mixture was freeze-dried to obtain graphene oxide;

[0072] 2) 300 mL of tetrahydrofuran was weighed, and 30 g of p-hydroxybenzaldehyde and 50 g of anhydrous potassium carbonate were added thereto. After thorough stirring at room temperature, 9.2 g of hexachlorocyclotriphosphine was dissolved in 160 mL of tetrahydrofuran and then slowly added to the system. Under nitrogen protection, the reaction was refluxed at 70° C. for 40 h. After the reaction was completed, the product was filtered, rotary evaporated, added to 800 mL of deionized water, filtered, recrystallized from ethyl acetate, and vacuum dried to obtain a dopant;

[0073] 3) 3 g of polyacrylonitrile, 0.7 g of dopant, 0.7 g of polymethyl methacrylate, and 0.005 g of graphene oxide were added to 13 g of N,N-dimethylformamide, stirred thoroughly, and injected into a syringe for spinning at a rate of 0.3 mL / h, a voltage of 16 kV, a spinning distance of 20 cm, and a spinning time of 6 h to obtain nanofibers, which were then placed in a tubular furnace and oxidized at 280 ° C for 5 h, and then carbonized at 960 ° C for 3 h under nitrogen protection to obtain porous nanofibers;

[0074] 4) Immersing 6 g of porous nanofibers in 120 mL of a 0.5 mol / L zinc acetate anhydrous ethanol solution at room temperature for 3 h, removing the porous nanofibers and heating them at 155°C for 30 min, cooling them to room temperature, and repeating this operation five times. Finally, heating them at 360°C for 30 min to obtain pretreated porous nanofibers.

[0075] 5) Add 0.05 mol zinc nitrate and 0.05 mol hexamethylenetetramine to 320 mL of deionized water, sonicate until fully dissolved, then add 6 g of pretreated porous nanofibers, disperse evenly, and hydrothermally react at 126° C. for 3 h. After the reaction is complete, cool to room temperature, repeatedly wash with deionized water, and dry to obtain a nanofiber material;

[0076] 6) Dissolve 0.8 g of cobalt nitrate hexahydrate, 0.7 g of urea, and 0.2 g of ammonium fluoride in 500 mL of deionized water, stir thoroughly, and transfer to an autoclave. Then, wash 5 g of the nanofiber material repeatedly with hydrochloric acid, anhydrous ethanol, and deionized water, add it to the autoclave, ultrasonically disperse it, and react at 130° C. for 12 h. After the reaction is completed, cool it to room temperature, wash the product repeatedly with deionized water, and dry it to obtain a composite nanofiber material.

[0077] 7) Dissolve 0.10 g of sodium sulfide in 500 mL of deionized water, stir thoroughly, and pour into a high-pressure reactor. Add 3 g of the composite nanofiber material, disperse evenly with ultrasound, and react at 126°C for 8 h. After the reaction is completed, cool to room temperature, wash the product repeatedly with anhydrous ethanol and deionized water, and vacuum dry at 70°C for 10 h to obtain a composite nanomaterial.

[0078] Comparative Example 1: This comparative example is basically the same as Example 1, except that it does not contain composite nanomaterials.

[0079] Comparative Example 2: This comparative example is basically the same as Example 1, except that step 1) is omitted in the preparation of the composite nanomaterial.

[0080] Comparative Example 3: This comparative example is basically the same as Example 1, except that step 2) is omitted in the preparation of the composite nanomaterial.

[0081] Comparative Example 4: This comparative example is basically the same as Example 1, except that, in the preparation of the composite nanomaterial, steps 1) to 3) are omitted, and carbon nanofibers are used instead of porous nanofibers.

[0082] Comparative Example 5: This comparative example is basically the same as Example 1, except that, in the preparation of the composite nanomaterial, steps 4) to 5) are omitted.

[0083] Test experiment:

[0084] The silicone gel samples provided in Examples 1-3 and Comparative Examples 1-5 were used to seal electronic components, respectively. The components were then placed in water and pressurized to 5 MPa for 24 hours. The water was then observed for bubbles. The results are shown in Table 1.

[0085] Table 1

[0086]

[0087] As can be seen from Table 1, the organic silicone gel in the present invention has high sealing performance, can be used to well encapsulate electronic components, and has broad application prospects.

[0088] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A highly cross-linked and highly sealing silicone gel, characterized in that: The organic silicone gel is prepared from component A and component B; In parts by weight, the component A comprises: 100-150 parts of dimethyl silicone oil, 10-30 parts of silicone rubber, and 5-10 parts of composite nanomaterials; The component B comprises: 10-18 parts of silane coupling agent KH560, 10-20 parts of methyltrimethoxysilane, 1-3 parts of dibutyltin dilaurate, and 1-2 parts of tetrabutyl titanate.

2. The highly cross-linked and highly sealing silicone gel according to claim 1, characterized in that: The preparation method of the composite nanomaterial is as follows: 1) dissolving cobalt nitrate hexahydrate, urea, and ammonium fluoride in deionized water, stirring thoroughly, and transferring to an autoclave; then washing the nanofiber material with hydrochloric acid, anhydrous ethanol, and deionized water once, adding the nanofiber material to the autoclave, ultrasonically dispersing the nanofiber material, reacting the nanofiber material at 120-130° C. for 8-12 hours, cooling the nanofiber material to room temperature, and repeatedly washing the nanofiber material with deionized water and drying the nanofiber material to obtain a composite nanofiber material; 2) Sodium sulfide is dissolved in deionized water, stirred thoroughly, and poured into an autoclave. The composite nanofiber material prepared in step 1) is added thereto. After ultrasonic dispersion, the mixture is reacted at 120-126° C. for 5-8 hours. After the reaction is completed, the mixture is cooled to room temperature. The product is repeatedly washed with anhydrous ethanol and deionized water, and dried to obtain a composite nanomaterial.

3. The highly cross-linked and highly sealing silicone gel according to claim 2, characterized in that: In step 1), the ratio of the mass g of the cobalt nitrate hexahydrate, the mass g of urea, the mass g of ammonium fluoride, the volume mL of deionized water and the mass g of the nanofiber material is 0.4-0.8:0.3-0.7:0.1-0.2:300-500:2-5.

4. The highly cross-linked and highly sealing silicone gel according to claim 2, characterized in that: In step 2), the ratio of the mass g of the sodium sulfide, the volume mL of deionized water, and the mass g of the composite nanofiber material is 0.06-0.10:300-500:1-3.

5. The highly cross-linked and highly sealing silicone gel according to claim 2, characterized in that: The preparation method of the nanofiber material comprises the following steps: 1) adding graphite sheets and potassium permanganate to an acid solution composed of sulfuric acid and phosphoric acid, stirring and reacting at 50-55° C. for 12-15 hours, cooling to room temperature after the reaction is completed, pouring ice water dissolved in hydrogen peroxide into the system, filtering to remove the precipitate, centrifuging the filtrate, removing the supernatant, and freeze-drying to obtain graphene oxide; 2) Measure 200-300 mL of tetrahydrofuran, add 20-30 g of p-hydroxybenzaldehyde and 35-50 g of anhydrous potassium carbonate thereto, stir thoroughly at room temperature, dissolve 8.3-9.2 g of hexachlorocyclotriphosphine in 100-160 mL of tetrahydrofuran, and then slowly add the mixture to the system. Under nitrogen protection, reflux at 65-70° C. for 36-40 hours. After the reaction is completed, filter and rotary evaporate the product, add 500-800 mL of deionized water, filter, recrystallize from ethyl acetate, and vacuum dry to obtain a dopant; 3) adding polyacrylonitrile, the dopant prepared in step 2), polymethyl methacrylate, and the graphene oxide prepared in step 1) to N,N-dimethylformamide, stirring thoroughly, and injecting into a syringe for spinning to obtain nanofibers, which are then placed in a tubular furnace and oxidized at 250-280° C. for 2-5 hours, and then carbonized at 900-960° C. for 1-3 hours under nitrogen protection to obtain porous nanofibers; 4) immersing the porous nanofibers prepared in step 3) in an anhydrous ethanol solution of zinc acetate at room temperature for 1-3 hours, removing the porous nanofibers, heating them at 150-155° C. for 10-30 minutes, cooling them to room temperature, repeating the operation 2-5 times, and finally heating them at 350-360° C. for 15-30 minutes to obtain pretreated porous nanofibers; 5) Add zinc nitrate and hexamethylenetetramine to deionized water, sonicate until fully dissolved, then add the pretreated porous nanofibers, disperse them evenly, and hydrothermally react at 120-126° C. for 1-3 hours. After the reaction is completed, cool to room temperature, repeatedly wash with deionized water, and dry to obtain the nanofiber material.

6. The highly cross-linked and highly sealing silicone gel according to claim 5, characterized in that: In step 1), the ratio of the mass g of the graphite sheet, the mass g of potassium permanganate, the volume mL of sulfuric acid, the volume mL of phosphoric acid, the volume mL of hydrogen peroxide, and the volume mL of ice water is 3-6:18-25:360-400:40-70:3-6:50-80; The concentration of the hydrogen peroxide is 30-35 wt %.

7. The highly cross-linked and highly sealing silicone gel according to claim 5, characterized in that: In step 3), the mass ratio of the polyacrylonitrile, dopant, polymethyl methacrylate, graphene oxide and N,N-dimethylformamide is 1-3:0.3-0.7:0.3-0.7:0.001-0.005:9-13; The spinning parameters are: injection rate of 0.1-0.3 mL / h, voltage of 12-16 kV, spinning distance of 15-20 cm, and spinning time of 4-6 h.

8. The highly cross-linked and highly sealing silicone gel according to claim 5, characterized in that: In step 4), the ratio of the mass g of the porous nanofiber to the volume mL of the zinc acetate anhydrous ethanol solution is 2-6:80-120; The concentration of the zinc acetate anhydrous ethanol solution is 0.1-0.5 mol / L.

9. The highly cross-linked and highly sealing silicone gel according to claim 5, characterized in that: In step 5), the usage ratio of the amount mol of zinc nitrate, the amount mol of hexamethylenetetramine, the volume mL of deionized water, and the mass g of pretreated porous nanofibers is 0.01-0.05:0.01-0.05:250-320:3-6.

10. The method for preparing a highly cross-linked and highly sealing silicone gel according to any one of claims 1 to 9, characterized in that: The specific steps include: The raw materials are weighed in proportion, and then dimethyl silicone oil, silicone rubber, and composite nanomaterials are mixed to prepare component A; silane coupling agent KH560, methyltrimethoxysilane, dibutyltin dilaurate, and tetrabutyl titanate are mixed and reacted to obtain component B; components A and B are then fully mixed, poured into a mold and cured at room temperature to obtain the desired silicone gel with high cross-linking and high sealing properties.

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