A method for preparing a composite aerogel material for thermal insulation tiles

Abstract

The application provides a preparation method of a heat insulation tile composite aerogel material, and belongs to the technical field of heat insulation tiles; the preparation method comprises the steps of preparing silane-treated basalt fibers, preparing modified silicon carbide and compounding and forming; in the step of preparing the silane-treated basalt fibers, the basalt fibers are placed in a pretreatment solution, kept at 74-77 DEG C for 1.4-1.6 h, then put into a cerium ammonium nitrate solution, immersed at 56-60 DEG C for 36-45 min, and then the immersed basalt fibers are obtained; the immersed basalt fibers are put into an ethanol solution, gamma-mercaptopropyltrimethoxysilane is added, and stirring is carried out at 70-75 DEG C for 3.0-4.0 h, and then the silane-treated basalt fibers are obtained; the heat insulation tile composite aerogel material prepared by the preparation method has good heat insulation performance and mechanical strength, good high-temperature resistance and excellent stability in a complex environment.

Description

Technical Field

[0001] This invention belongs to the field of heat insulation tile technology, specifically relating to a method for preparing a heat insulation tile composite aerogel material. Background Technology

[0002] When spacecraft enter the atmosphere of exoplanets at high speeds or re-enter the Earth's atmosphere from outer space, they experience intense aerodynamic heating due to their extremely high speeds. Therefore, implementing thermal protection measures on the surface of the spacecraft is essential. Spacecraft have stringent requirements for thermal insulation materials, as these directly affect the safety and flight stability of the spacecraft. Adding thermal insulation materials with properties such as heat insulation, high temperature resistance, wave transmission, and lightweight to the surface of the spacecraft is crucial to effectively prevent external heat from being transferred to the interior.

[0003] With the development of the aerospace industry, heat insulation tiles have gradually become a research hotspot for heat insulation materials and thermal protection technologies in aircraft.

[0004] Heat insulation tiles are a type of material with excellent temperature resistance, superior heat insulation performance, and light weight. They can effectively block the transfer of heat, provide good thermal protection for aircraft in high-temperature environments, and effectively improve the stability of the external structure of the aircraft as well as the safety and stability of the operation of internal equipment.

[0005] Thermal insulation tile composite aerogel material is a new type of material with excellent thermal insulation performance. It combines traditional thermal insulation tiles with nanoporous aerogel material. In the aerospace field, it can be used on the surface of aircraft to resist the high temperature generated by atmospheric friction during reentry to Earth. It has high application value and broad market prospects.

[0006] In the prior art, the preparation methods of heat insulation tile composite aerogel materials usually include sol-gel in-situ molding method, impregnation-supercritical method and powder sintering composite method;

[0007] Sol-gel in-situ molding method forms an aerogel layer directly on the surface of the heat insulation tile substrate, achieving a tight bond between the aerogel and the heat insulation tile substrate. However, the thickness of the aerogel layer is not easy to control, and cracking is prone to occur during the drying process, reducing the product yield.

[0008] The impregnation-supercritical method involves placing the thermal insulation tile substrate in an aerogel precursor solution and obtaining the composite material through supercritical drying. It can maintain the nanoporous structure of the aerogel relatively intact and enhance the thermal insulation performance. However, the interfacial bonding strength of the product is insufficient, and the high-temperature stability of the product is inadequate. The process is complex, the equipment requirements are high, the production cost is increased, and it is difficult to achieve large-scale production.

[0009] The powder sintering composite method involves mixing aerogel powder with the raw material of heat insulation tile and then sintering it into shape. The process is simple and suitable for mass production. However, the structure of aerogel is easily damaged during the sintering process, and the heat insulation performance is greatly reduced.

[0010] It is evident that the heat insulation tile composite aerogel materials prepared by existing technologies have the problem of low interfacial bonding strength, which reduces the mechanical strength of the composite material. Furthermore, they also have poor high-temperature stability, making them unsuitable for long-term use in high-temperature environments.

[0011] Researchers discovered that while existing heat-insulating tile composite aerogel materials possess certain high-temperature resistance, their performance is poor in environments with rapid changes in high and low temperatures, and they are prone to a sharp decline in performance.

[0012] Therefore, providing a method for preparing a heat-insulating tile composite aerogel material that enhances interfacial bonding strength, improves the heat insulation performance, mechanical properties, and high-temperature resistance of the composite material, and ensures overall performance in rapidly changing high and low temperature environments is a technical problem that urgently needs to be solved in the existing technology. Summary of the Invention

[0013] To address the technical problems existing in the prior art, this invention provides a method for preparing a heat-insulating tile composite aerogel material. The heat-insulating tile composite aerogel material has excellent heat insulation performance and mechanical strength, good high-temperature resistance, and excellent stability in complex environments.

[0014] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0015] A method for preparing a heat-insulating tile composite aerogel material includes the following steps: preparing silane-treated basalt fibers, preparing modified silicon carbide, and composite molding. The details are as follows:

[0016] 1. Preparation of silane-treated basalt fibers

[0017] Basalt fibers were placed in a pretreatment solution, and the temperature was raised to 74-77℃ and kept at that temperature for 1.4-1.6 hours. After the heat treatment, the fibers were washed and then immersed in a cerium ammonium nitrate solution at 56-60℃ for 36-45 minutes. After the immersion, the fibers were filtered, washed, and dried to obtain impregnated basalt fibers. The impregnated basalt fibers were then placed in an ethanol solution, and γ-mercaptopropyltrimethoxysilane was added. The temperature was raised to 70-75℃ and stirred for 3.0-4.0 hours. After filtration and washing, the fibers were vacuum dried at 80-85℃ to constant weight to obtain silane-treated basalt fibers.

[0018] The basalt fibers have a diameter of 110-130 nm and a length of 15-23 μm;

[0019] The pretreatment solution is a mixture of ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctanesulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctanesulfonate is 50:0.7-0.9:0.4-0.6; and the mass concentration of the ammonium fluoride solution is 4.8-5.2%.

[0020] The mass ratio of the basalt fiber, the pretreatment solution, and the cerium ammonium nitrate solution is 10-14:100:95-105;

[0021] The mass concentration of the cerium ammonium nitrate solution is 5.0-5.5%;

[0022] The mass ratio of the impregnated basalt fiber, ethanol solution, and γ-mercaptopropyltrimethoxysilane is 9.6-10.3:100:1.0-1.4.

[0023] The ethanol solution has a mass concentration of 26-30%.

[0024] 2. Preparation of modified silicon carbide

[0025] Silicon carbide powder was subjected to high-temperature treatment in an oxygen stream at a temperature of 410-430℃ for 2.0-3.0 h. After treatment, pretreated silicon carbide was obtained. The pretreated silicon carbide powder was then placed in an ethanol solution, and an amino-modified chitosan solution was added at a rate of 0.8-1.2 g / min. After addition, the mixture was stirred at 34-36℃ for 48-52 min. After stirring, vinyltrimethoxysilane was added, and the temperature was raised to 66-70℃. The mixture was stirred and reacted for 1.8-2.2 h. After filtration, washing, and drying, modified silicon carbide was obtained.

[0026] The oxygen stream is a mixture of ozone and oxygen, with a volume ratio of ozone to oxygen of 4-6:94-96.

[0027] The mass ratio of the pretreated silicon carbide powder, ethanol solution, amino-modified chitosan solution, and vinyltrimethoxysilane is 7.2-7.6:78-83:42-46:0.80-0.85.

[0028] The mass concentration of the ethanol solution is 20-25%;

[0029] The amino-modified chitosan solution is a mixture of amino-modified chitosan and acetic acid solution, wherein the mass ratio of amino-modified chitosan to acetic acid solution is 3.3-3.7:100;

[0030] The acetic acid solution has a mass concentration of 4.8-5.3%;

[0031] The method for preparing amino-modified chitosan is as follows: chitosan is added to an acetic acid solution and stirred at room temperature for 2.0-2.5 h. 6.3-6.6 wt% sodium hydroxide solution is added to adjust the pH to 5.6-6.0. Amino-modifying solution is added at a rate of 1.4-1.6 g / min. After addition, the mixture is stirred at 38-42℃ for 57-65 min. After stirring, glutaraldehyde solution is added, the temperature is raised to 52-57℃, and the reaction is maintained for 2.0-3.0 h. After the reaction is completed, the mixture is filtered, washed, and dried to obtain amino-modified chitosan.

[0032] The mass ratio of chitosan, acetic acid solution, amino-modified liquid, and glutaraldehyde solution is 8.0-8.5:68-73:47-53:10-15;

[0033] The acetic acid solution has a mass concentration of 4.0-4.5%;

[0034] The mass concentration of the glutaraldehyde solution is 9.5-10.8%;

[0035] The amino-modified liquid is a mixture of spermine, hexamethylenediamine and deionized water, wherein the mass ratio of spermine, hexamethylenediamine and deionized water is 1.0-1.5:2.1-2.6:100.

[0036] 3. Composite molding

[0037] Modified silicon carbide was added to N,N-dimethylformamide and stirred until homogeneous. Basalt fibers were then treated with silane. The temperature was increased to 60-65℃ at a rate of 0.4-0.6℃ / min, and the reaction was stirred for 3.0-3.5 hours. After the reaction was complete, the solid was filtered off, washed, and dried to constant weight. The solid was then added to zirconium sol, and polyethyleneimine was added. The temperature was increased to 60-64℃ at a rate of 0.4-0.6℃ / min, and the mixture was ultrasonically treated for 2.3 hours. 2.7h, ultrasonic power of 135-146W, ultrasonic frequency of 40-45kHz. After ultrasonic treatment, it is poured into a mold for molding, and then freeze-dried for 18-22h at a temperature of -47 to -42℃. After demolding, the temperature is raised to 806-814℃ at a rate of 1.8-2.2℃ / min in an argon atmosphere and held for 78-82min. After naturally cooling to room temperature, the heat insulation tile composite aerogel material is obtained.

[0038] The mass ratio of N,N-dimethylformamide, modified silicon carbide, silane-treated basalt fiber, zirconium sol, and polyethyleneimine is 200:9.2-9.6:2.4-2.8:115-124:0.8-1.2.

[0039] The method for preparing the zirconium sol is as follows: zirconium oxychloride is added to a mixed solvent and stirred evenly. Then, acetylacetone is added and the mixture is stirred for 0.8-1.2 h. Then, gadolinium oxide and yttrium oxide are added and the mixture is stirred for 2.4-2.6 h at 63-67 °C. Then, ammonia solution is added to adjust the pH to 3.5-3.7 and the mixture is kept at 38-42 °C for 22-26 h to obtain the zirconium sol.

[0040] The mixed solvent is a mixture of anhydrous ethanol and deionized water, wherein the mass ratio of anhydrous ethanol to deionized water is 57-65:10.

[0041] The mass ratio of zirconium oxychloride, mixed solvent, acetylacetone, gadolinium oxide, and yttrium oxide is 14.2-14.7:68-73:3.8-4.2:2.0-2.4:1.6-1.8.

[0042] The mass concentration of the ammonia solution is 7.5-8.2%.

[0043] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0044] 1. In the method for preparing composite aerogel materials for heat-insulating tiles, this invention uses silicon carbide powder as the matrix and basalt fiber as the reinforcing skeleton, which can enhance the mechanical strength of the product. However, the bonding force between basalt fiber and silicon carbide powder is poor. This invention first treats the basalt fiber with ammonium fluoride solution to etch the fiber surface, increasing the surface roughness and active sites. Combined with polyvinylpyrrolidone and potassium perfluorooctyl sulfonate, this enhances the dispersibility and surface activity of the basalt fiber, promotes the wetting performance of the pretreatment solution on the fiber, prevents fiber agglomeration, and promotes the uniformity of etching. Then, it treats the fiber with cerium ammonium nitrate, which can decompose to generate Ce. 4+To enhance surface reactivity, basalt fibers are treated with a mercaptosilane coupling agent, introducing mercapto groups onto the fiber surface. These mercapto groups provide reaction sites with the modified silicon carbide, improving fiber-matrix compatibility and reducing interfacial defects. The invention also involves ozone high-temperature treatment of silicon carbide, which generates a silica layer on the surface, increasing the number of hydroxyl groups. Then, amino-modified chitosan is introduced. This amino-modified chitosan is prepared using spermine and hexamethylenediamine, introducing a large number of amino groups. Its long chains enhance molecular chain flexibility and reaction sites. Finally, glutaraldehyde crosslinking yields a tri-... Amino-modified chitosan with a three-dimensional network structure is used to coat the surface of silicon carbide, improving the dispersion performance of silicon carbide. Then, through the hydrolysis of vinyl silane coupling agent and the condensation of hydroxyl groups on the surface of chitosan, a stable cross-linked modified silicon carbide network is obtained. In the composite molding step, silane-treated basalt fibers and modified silicon carbide are chemically bonded to form an interpenetrating network, further enhancing the mechanical strength and high-temperature resistance of the product. Combined with zirconium sol treatment, the zirconium sol penetrates into the network formed by basalt fibers and silicon carbide, ensuring the thermal insulation performance of the product and giving it excellent stability.

[0045] 2. The thermal insulation tile composite aerogel material prepared by the method of the present invention has a fracture toughness of 1.10-1.13 MPa·m. 1 / 2 The compressive strength is 5.39-5.47 MPa, the compressive strength is 6.07-6.18 MPa, and the thermal conductivity is 0.036-0.039 W / (m·K).

[0046] 3. The thermal insulation tile composite aerogel material prepared by the method of the present invention was kept at 1200℃ for 12 hours, and the fracture toughness was measured again to be 1.05-1.09 MPa·m. 1 / 2 The compressive strength is 5.10-5.22 MPa, and the compressive strength is 5.77-5.91 MPa;

[0047] 4. The heat-insulating tile composite aerogel material prepared by the method of the present invention was heated to 1200°C at a rate of 30°C / min, held at that temperature for 30 min, and then cooled to 26°C at a rate of 50°C / min. This process was repeated as one treatment cycle, and the treatment cycle was repeated 20 times. The fracture toughness was then measured to be 1.00-1.04 MPa·m. 1 / 2 The compressive strength is 4.86-4.98 MPa, and the compressive strength is 5.48-5.65 MPa. Detailed Implementation

[0048] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.

[0049] Example 1

[0050] 1. Preparation of silane-treated basalt fibers

[0051] 12g of basalt fiber was placed in 100g of pretreatment solution, the temperature was raised to 76℃, and the solution was kept at this temperature for 1.5h. After the heat treatment, the fiber was washed and then immersed in 100g of 5.2wt% cerium ammonium nitrate solution at 58℃ for 40min. After the immersion, the fiber was filtered, washed, and dried to obtain impregnated basalt fiber. 10g of impregnated basalt fiber was placed in 100g of 28wt% ethanol solution, 1.2g of γ-mercaptopropyltrimethoxysilane was added, the temperature was raised to 73℃, and the solution was kept at this temperature and stirred for 3.5h. After filtration and washing, the fiber was vacuum dried at 82℃ to constant weight to obtain silane-treated basalt fiber.

[0052] The basalt fibers have a diameter of 120 nm and a length of 20 μm;

[0053] The pretreatment solution is a mixture of ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctyl sulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctyl sulfonate is 50:0.8:0.5; and the mass concentration of the ammonium fluoride solution is 5.0%.

[0054] 2. Preparation of modified silicon carbide

[0055] Silicon carbide powder was subjected to high-temperature treatment in an oxygen stream at 420°C for 2.5 hours. After treatment, pretreated silicon carbide was obtained. 7.4 g of pretreated silicon carbide powder was placed in 80 g of 23 wt% ethanol solution, and 44 g of amino-modified chitosan solution was added at a rate of 1.0 g / min. After addition, the mixture was stirred at 35°C for 50 minutes. After stirring, 0.82 g of vinyltrimethoxysilane was added, the temperature was raised to 68°C, and the mixture was stirred for 2.0 hours. After filtration, washing, and drying, modified silicon carbide was obtained.

[0056] The oxygen stream is a mixture of ozone and oxygen, with a volume ratio of ozone to oxygen of 5:95.

[0057] The amino-modified chitosan solution is a mixture of amino-modified chitosan and 5.0 wt% acetic acid solution, wherein the mass ratio of amino-modified chitosan to 5.0 wt% acetic acid solution is 3.5:100.

[0058] The preparation method of the amino-modified chitosan is as follows: 8.2g of chitosan is added to 70g of 4.2wt% acetic acid solution and stirred at room temperature for 2.3h. 6.5wt% sodium hydroxide solution is added to adjust the pH to 5.8. 50g of amino-modifying solution is added at a rate of 1.5g / min. After the addition is complete, the mixture is stirred at 40℃ for 60min. After stirring, 12g of 10wt% glutaraldehyde solution is added, the temperature is raised to 54℃, and the reaction is maintained for 2.5h. After the reaction is complete, the mixture is filtered, washed, and dried to obtain amino-modified chitosan.

[0059] The amino-modified liquid is a mixture of spermine, hexamethylenediamine, and deionized water, wherein the mass ratio of spermine, hexamethylenediamine, and deionized water is 1.2:2.3:100.

[0060] 3. Composite molding

[0061] Add 9.4g of modified silicon carbide to 200g of N,N-dimethylformamide, stir evenly, then add 2.6g of silane-treated basalt fiber, raise the temperature to 62℃ at a rate of 0.5℃ / min, stir and react for 3.3h. After the reaction is complete, filter out the solid, wash and dry to constant weight, add to 120g of zirconium sol, add 1.0g of polyethyleneimine, raise the temperature to 62℃ at a rate of 0.5℃ / min, and perform ultrasonic treatment for 2.5h, ultrasonic power of 140W, and ultrasonic frequency of 43kHz. After ultrasonic treatment, pour into a mold to form, then freeze dry for 20h at a temperature of -45℃. After demolding, raise the temperature to 810℃ at a rate of 2.0℃ / min in an argon atmosphere, hold for 80min, and then allow to cool naturally to room temperature to obtain the heat-insulating tile composite aerogel material.

[0062] The method for preparing the zirconium sol is as follows: 14.5g of zirconium oxychloride is added to 70g of mixed solvent and stirred evenly. Then, 4.0g of acetylacetone is added and the mixture is stirred for 1.0h. Then, 2.2g of gadolinium oxide and 1.7g of yttrium oxide are added and the mixture is stirred for 2.5h at 65℃. Then, 8.0wt% ammonia solution is added to adjust the pH to 3.6 and the mixture is kept at 40℃ for 24h to obtain the zirconium sol.

[0063] The mixed solvent is a mixture of anhydrous ethanol and deionized water, wherein the mass ratio of anhydrous ethanol to deionized water is 60:10.

[0064] Example 2

[0065] 1. Preparation of silane-treated basalt fibers

[0066] 10g of basalt fiber was placed in 100g of pretreatment solution, the temperature was raised to 74℃, and the solution was kept at this temperature for 1.4h. After the heat treatment, the fiber was washed and then immersed in 95g of 5.0wt% cerium ammonium nitrate solution at 56℃ for 36min. After the immersion, the fiber was filtered, washed, and dried to obtain impregnated basalt fiber. 9.6g of impregnated basalt fiber was placed in 100g of 26wt% ethanol solution, 1.0g of γ-mercaptopropyltrimethoxysilane was added, the temperature was raised to 70℃, and the solution was kept at this temperature and stirred for 3.0h. After filtration and washing, the fiber was vacuum dried at 80℃ to constant weight to obtain silane-treated basalt fiber.

[0067] The basalt fibers have a diameter of 110 nm and a length of 23 μm;

[0068] The pretreatment solution is a mixture of ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctanesulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctanesulfonate is 50:0.7:0.4; and the mass concentration of the ammonium fluoride solution is 4.8%.

[0069] 2. Preparation of modified silicon carbide

[0070] Silicon carbide powder was subjected to high-temperature treatment in an oxygen stream at a temperature of 410℃ for 3.0 h. After treatment, pretreated silicon carbide was obtained. 7.2 g of pretreated silicon carbide powder was placed in 78 g of 20 wt% ethanol solution, and 42 g of amino-modified chitosan solution was added at a rate of 0.8 g / min. After addition, the mixture was stirred at 34℃ for 48 min. After stirring, 0.80 g of vinyltrimethoxysilane was added, the temperature was raised to 66℃, and the mixture was stirred for 1.8 h. After filtration, washing, and drying, modified silicon carbide was obtained.

[0071] The oxygen stream is a mixture of ozone and oxygen, with a volume ratio of ozone to oxygen of 4:96.

[0072] The amino-modified chitosan solution is a mixture of amino-modified chitosan and 4.8 wt% acetic acid solution, wherein the mass ratio of amino-modified chitosan to 4.8 wt% acetic acid solution is 3.3:100;

[0073] The preparation method of the amino-modified chitosan is as follows: 8.0g of chitosan is added to 68g of 4.0wt% acetic acid solution and stirred at room temperature for 2.0h. 6.3wt% sodium hydroxide solution is added to adjust the pH to 5.6. 47g of amino-modifying solution is added at a rate of 1.4g / min. After the addition is complete, the mixture is stirred at 38℃ for 65min. After stirring, 10g of 10.8wt% glutaraldehyde solution is added, the temperature is raised to 52℃, and the reaction is maintained for 3.0h. After the reaction is complete, the mixture is filtered, washed, and dried to obtain amino-modified chitosan.

[0074] The amino-modified liquid is a mixture of spermine, hexamethylenediamine, and deionized water, wherein the mass ratio of spermine, hexamethylenediamine, and deionized water is 1.0:2.1:100.

[0075] 3. Composite molding

[0076] Add 9.2g of modified silicon carbide to 200g of N,N-dimethylformamide, stir evenly, then add 2.4g of silane-treated basalt fiber, raise the temperature to 60℃ at a rate of 0.4℃ / min, stir and react for 3.0h. After the reaction is complete, filter out the solid, wash and dry to constant weight, add to 115g of zirconium sol, add 0.8g of polyethyleneimine, raise the temperature to 60℃ at a rate of 0.4℃ / min, and perform ultrasonic treatment for 2.3h, with an ultrasonic power of 135W and an ultrasonic frequency of 40kHz. After ultrasonic treatment, pour into a mold to form, then freeze-dry for 22h at a temperature of -42℃. After demolding, raise the temperature to 806℃ at a rate of 1.8℃ / min in an argon atmosphere, hold for 78min, and then allow to cool naturally to room temperature to obtain the heat-insulating tile composite aerogel material.

[0077] The method for preparing the zirconium sol is as follows: 14.2g of zirconium oxychloride is added to 68g of mixed solvent and stirred evenly. Then, 3.8g of acetylacetone is added and the mixture is stirred for 0.8h. Then, 2.0g of gadolinium oxide and 1.6g of yttrium oxide are added and the mixture is stirred at 63℃ for 2.4h. Then, 7.5wt% ammonia solution is added to adjust the pH to 3.5 and the mixture is kept at 38℃ for 26h to obtain the zirconium sol.

[0078] The mixed solvent is a mixture of anhydrous ethanol and deionized water, wherein the mass ratio of anhydrous ethanol to deionized water is 65:10.

[0079] Example 3

[0080] 1. Preparation of silane-treated basalt fibers

[0081] 14g of basalt fiber was placed in 100g of pretreatment solution, the temperature was raised to 77℃, and the solution was kept at this temperature for 1.6h. After the heat treatment, the fiber was washed and then immersed in 105g of 5.5wt% cerium ammonium nitrate solution at 60℃ for 45min. After the immersion, the fiber was filtered, washed, and dried to obtain impregnated basalt fiber. 10.3g of impregnated basalt fiber was placed in 100g of 30wt% ethanol solution, 1.4g of γ-mercaptopropyltrimethoxysilane was added, the temperature was raised to 75℃, and the solution was kept at this temperature and stirred for 4.0h. After filtration and washing, the fiber was vacuum dried at 85℃ to constant weight to obtain silane-treated basalt fiber.

[0082] The basalt fibers have a diameter of 130 nm and a length of 15 μm;

[0083] The pretreatment solution is a mixture of ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctanesulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctanesulfonate is 50:0.9:0.6; and the mass concentration of the ammonium fluoride solution is 5.2%.

[0084] 2. Preparation of modified silicon carbide

[0085] Silicon carbide powder was subjected to high-temperature treatment in an oxygen stream at 430°C for 2.0 h. After treatment, pretreated silicon carbide was obtained. 7.6 g of pretreated silicon carbide powder was placed in 83 g of 25 wt% ethanol solution, and 46 g of amino-modified chitosan solution was added at a rate of 1.2 g / min. After addition, the mixture was stirred at 36°C for 52 min. After stirring, 0.85 g of vinyltrimethoxysilane was added, the temperature was raised to 70°C, and the mixture was stirred for 2.2 h. After filtration, washing, and drying, modified silicon carbide was obtained.

[0086] The oxygen stream is a mixture of ozone and oxygen, with a volume ratio of ozone to oxygen of 6:94.

[0087] The amino-modified chitosan solution is a mixture of amino-modified chitosan and 5.3 wt% acetic acid solution, wherein the mass ratio of amino-modified chitosan to 5.3 wt% acetic acid solution is 3.7:100.

[0088] The preparation method of the amino-modified chitosan is as follows: 8.5g of chitosan is added to 73g of 4.5wt% acetic acid solution and stirred at room temperature for 2.5h. 6.6wt% sodium hydroxide solution is added to adjust the pH to 6.0. 53g of amino-modifying solution is added at a rate of 1.6g / min. After the addition is complete, the mixture is stirred at 42℃ for 57min. After stirring, 15g of 9.5wt% glutaraldehyde solution is added, the temperature is raised to 57℃, and the reaction is maintained for 2.0h. After the reaction is complete, the mixture is filtered, washed, and dried to obtain amino-modified chitosan.

[0089] The amino-modified liquid is a mixture of spermine, hexamethylenediamine, and deionized water, wherein the mass ratio of spermine, hexamethylenediamine, and deionized water is 1.5:2.6:100.

[0090] 3. Composite molding

[0091] Add 9.6g of modified silicon carbide to 200g of N,N-dimethylformamide, stir evenly, then add 2.8g of silane-treated basalt fiber, raise the temperature to 65℃ at a rate of 0.6℃ / min, stir and react for 3.5h. After the reaction is complete, filter out the solid, wash and dry to constant weight, add to 124g of zirconium sol, add 1.2g of polyethyleneimine, raise the temperature to 64℃ at a rate of 0.6℃ / min, and perform ultrasonic treatment for 2.7h, ultrasonic power of 146W, and ultrasonic frequency of 45kHz. After ultrasonic treatment, pour into a mold to form, then freeze dry for 18h at a temperature of -47℃. After demolding, raise the temperature to 814℃ at a rate of 2.2℃ / min in an argon atmosphere, hold for 82min, and then allow to cool naturally to room temperature to obtain the heat-insulating tile composite aerogel material.

[0092] The method for preparing the zirconium sol is as follows: 14.7g of zirconium oxychloride is added to 73g of mixed solvent and stirred evenly. Then, 4.2g of acetylacetone is added and the mixture is stirred for 1.2h. Then, 2.4g of gadolinium oxide and 1.8g of yttrium oxide are added and the mixture is stirred at 67℃ for 2.6h. Then, 8.2wt% ammonia solution is added to adjust the pH to 3.7 and the mixture is kept at 42℃ for 22h to obtain the zirconium sol.

[0093] The mixed solvent is a mixture of anhydrous ethanol and deionized water, with a mass ratio of anhydrous ethanol to deionized water of 57:10.

[0094] In this invention, a method for preparing composite aerogel materials for thermal insulation tiles is used. Silicon carbide powder is used as the matrix, and basalt fiber is used as the reinforcing skeleton, which enhances the mechanical strength of the product. However, the bonding force between basalt fiber and silicon carbide powder is poor. This invention first treats the basalt fiber with ammonium fluoride solution to etch the fiber surface, increasing the surface roughness and active sites. Combined with polyvinylpyrrolidone and potassium perfluorooctyl sulfonate, this enhances the dispersibility and surface activity of the basalt fiber, promotes the wetting performance of the pretreatment solution on the fiber, prevents fiber agglomeration, and promotes uniform etching. Then, cerium ammonium nitrate is used for treatment, which decomposes to generate Ce. 4+To enhance surface reactivity, basalt fibers are treated with a mercaptosilane coupling agent, introducing mercapto groups onto the fiber surface. These mercapto groups provide reaction sites with the modified silicon carbide, improving fiber-matrix compatibility and reducing interfacial defects. The invention also involves ozone high-temperature treatment of silicon carbide, which generates a silica layer on the surface, increasing the number of hydroxyl groups. Then, amino-modified chitosan is introduced. This amino-modified chitosan is prepared using spermine and hexamethylenediamine, introducing a large number of amino groups. Its long chains enhance molecular chain flexibility and reaction sites. Finally, glutaraldehyde crosslinking yields a tri-... Amino-modified chitosan with a three-dimensional network structure is used to coat the surface of silicon carbide, improving the dispersion performance of silicon carbide. Then, through the hydrolysis of vinyl silane coupling agent and the condensation of hydroxyl groups on the surface of chitosan, a stable cross-linked network of modified silicon carbide is obtained. In the composite molding step, silane-treated basalt fibers and modified silicon carbide are chemically bonded to form an interpenetrating network, further enhancing the mechanical strength and high-temperature resistance of the product. Combined with zirconium sol treatment, the zirconium sol penetrates into the network formed by basalt fibers and silicon carbide, ensuring the thermal insulation performance of the product and giving it excellent stability.

[0095] Comparative Example 1

[0096] The technical solution of Example 1 is adopted, except that the step of preparing silane-treated basalt fibers is omitted; in the composite molding step, basalt fibers without any treatment are used to replace silane-treated basalt fibers in an equal amount, wherein the basalt fibers have a diameter of 120 nm and a length of 20 μm.

[0097] Comparative Example 1 directly replaced the silane-treated basalt fibers with untreated basalt fibers, omitting the silane treatment step. Basalt fibers are highly inert and only have a weak physical adsorption effect with the silicon carbide matrix, resulting in poor interfacial bonding and easy formation of interfacial defects. This leads to a decrease in crack propagation resistance, making the product prone to cracking, reducing fracture toughness and strength. Furthermore, the unevenly dispersed basalt fibers can interrupt the heat conduction path, thereby increasing the thermal conductivity and reducing the thermal insulation performance. In addition, the product has poor high-temperature resistance and stability, limiting its application.

[0098] Comparative Example 2

[0099] The technical solution of Embodiment 1 is adopted, except that:

[0100] (1) The steps for preparing modified silicon carbide are as follows: silicon carbide powder is placed in an oxygen stream for high-temperature treatment at a temperature of 420°C for 2.5 hours. After the treatment, modified silicon carbide is obtained. The oxygen stream is a mixture of ozone and oxygen, and the volume ratio of ozone to oxygen is 5:95.

[0101] (2) In the preparation method of zirconium sol in the composite molding step, the operation of "then add 2.2g gadolinium oxide and 1.7g yttrium oxide, and stir the reaction at 65°C for 2.5h" is omitted.

[0102] Comparative Example 2 only used ozone-oxygen treatment on silicon carbide without introducing amino-modified chitosan and vinyl silane coupling agents. This resulted in fewer active sites on the silicon carbide surface and weaker bonding force with the fibers, thereby reducing the strength and toughness of the product. Furthermore, Comparative Example 2 omitted the addition of gadolinium oxide and yttrium oxide, which would reduce the high-temperature resistance and stability of the product. It would also cause densification during the sintering process and uneven pore structure of the zirconium sol, resulting in higher thermal conductivity and poorer thermal insulation performance.

[0103] Performance testing

[0104] The fracture toughness, compressive strength, thermal conductivity, high-temperature resistance, and stability of the thermal insulation tile composite aerogel materials prepared by the methods of Examples 1-3 and Comparative Examples 1-2 were tested respectively, as follows:

[0105]

[0106] Among them, the high temperature resistance was tested by keeping the heat insulation tile composite aerogel material prepared by the preparation methods of Examples 1-3 and Comparative Examples 1-2 at 1200℃ for 12 hours, and then testing the fracture toughness, compressive strength and compressive strength of the product.

[0107] The stability performance was determined by raising the temperature of the heat-insulating tile composite aerogel material prepared by the preparation methods of Examples 1-3 and Comparative Examples 1-2 to 1200°C at a rate of 30°C / min, holding it at that temperature for 30 min, and then lowering the temperature to 26°C at a rate of 50°C / min. This process was repeated as one treatment cycle, and 20 treatment cycles were performed continuously. The fracture toughness, compressive strength, and compressive strength of the product were then tested again.

[0108] Unless otherwise stated, all percentages used in this invention are mass percentages.

[0109] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a heat-insulating tile composite aerogel material, characterized in that, The process includes steps such as preparing silane-treated basalt fibers, preparing modified silicon carbide, and composite molding. The steps for preparing silane-treated basalt fibers are as follows: basalt fibers are placed in a pretreatment solution and kept at 74-77℃ for 1.4-1.6 hours; then immersed in a cerium ammonium nitrate solution and impregnated at 56-60℃ for 36-45 minutes to obtain impregnated basalt fibers; the impregnated basalt fibers are then placed in an ethanol solution, γ-mercaptopropyltrimethoxysilane is added, and the solution is stirred at 70-75℃ for 3.0-4.0 hours to obtain silane-treated basalt fibers. The pretreatment solution is a mixture of ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctyl sulfonate; The steps for preparing modified silicon carbide are as follows: pretreated silicon carbide powder is placed in an ethanol solution, amino-modified chitosan solution is added, the mixture is stirred at 34-36℃ for 48-52 min, vinyltrimethoxysilane is added, and the mixture is reacted at 66-70℃ for 1.8-2.2 h to obtain modified silicon carbide. The method for preparing the pretreated silicon carbide is to place silicon carbide powder in an oxygen stream for high-temperature treatment, wherein the oxygen stream is a mixture of ozone and oxygen. The amino-modified chitosan solution is a mixture of amino-modified chitosan and acetic acid solution. The preparation method of the amino-modified chitosan is as follows: chitosan is added to acetic acid solution and stirred for 2.0-2.5 h; sodium hydroxide solution is added to adjust the pH to 5.6-6.0; amino-modified solution is added; stirring is carried out at 38-42℃ for 57-65 min; glutaraldehyde solution is added; and reaction is carried out at 52-57℃ for 2.0-3.0 h to obtain amino-modified chitosan. The composite molding step is as follows: Modified silicon carbide is added to N,N-dimethylformamide and stirred until homogeneous. Then, silane is added to treat basalt fibers. The temperature is increased to 60-65℃ at a rate of 0.4-0.6℃ / min, and the reaction is stirred for 3.0-3.5 hours. After the reaction is complete, the solid is filtered out, washed, and dried to constant weight. The solid is then added to zirconium sol, and polyethyleneimine is added. The temperature is increased to 60-64℃ at a rate of 0.4-0.6℃ / min, and ultrasonic treatment is performed for [duration missing]. The ultrasonic treatment process takes 2.3-2.7 hours, with an ultrasonic power of 135-146W and an ultrasonic frequency of 40-45kHz. After ultrasonic treatment, the material is poured into a mold for molding and then freeze-dried for 18-22 hours at a temperature of -47 to -42℃. After demolding, the temperature is increased to 806-814℃ at a rate of 1.8-2.2℃ / min in an argon atmosphere and held for 78-82 minutes. After naturally cooling to room temperature, the heat-insulating tile composite aerogel material is obtained. The method for preparing the zirconium sol is as follows: zirconium oxychloride is added to a mixed solvent and stirred evenly. Then, acetylacetone is added and the mixture is stirred for 0.8-1.2 h. Then, gadolinium oxide and yttrium oxide are added and the mixture is stirred for 2.4-2.6 h at 63-67 °C. Then, ammonia solution is added to adjust the pH to 3.5-3.7 and the mixture is kept at 38-42 °C for 22-26 h to obtain the zirconium sol.

2. The method for preparing a heat-insulating tile composite aerogel material according to claim 1, characterized in that, In the step of preparing silane-treated basalt fibers, the basalt fibers have a diameter of 110-130 nm and a length of 15-23 μm. The mass ratio of the basalt fiber, the pretreatment solution, and the cerium ammonium nitrate solution is 10-14:100:95-105. The mass concentration of the cerium ammonium nitrate solution is 5.0-5.5%; The mass ratio of the impregnated basalt fiber, ethanol solution, and γ-mercaptopropyltrimethoxysilane is 9.6-10.3:100:1.0-1.

4. The ethanol solution has a mass concentration of 26-30%.

3. The method for preparing a heat-insulating tile composite aerogel material according to claim 1, characterized in that, In the pretreatment solution, the mass ratio of the ammonium fluoride solution, polyvinylpyrrolidone, and potassium perfluorooctyl sulfonate is 50:0.7-0.9:0.4-0.6; and the mass concentration of the ammonium fluoride solution is 4.8-5.2%.

4. The method for preparing a heat-insulating tile composite aerogel material according to claim 1, characterized in that, In the step of preparing modified silicon carbide, the method for preparing pretreated silicon carbide is to place silicon carbide powder in an oxygen stream for high-temperature treatment at a temperature of 410-430°C for 2.0-3.0 hours. After the treatment, pretreated silicon carbide is obtained. In the oxygen stream, the volume ratio of ozone to oxygen is 4-6:94-96.

5. The method for preparing a heat-insulating tile composite aerogel material according to claim 1, characterized in that, In the step of preparing modified silicon carbide, the mass ratio of the pretreated silicon carbide powder, ethanol solution, amino-modified chitosan solution, and vinyltrimethoxysilane is 7.2-7.6:78-83:42-46:0.80-0.

85. The mass concentration of the ethanol solution is 20-25%; In the amino-modified chitosan solution, the mass ratio of amino-modified chitosan to acetic acid solution is 3.3-3.7:100; The mass concentration of the acetic acid solution is 4.8-5.3%.

6. The method for preparing a heat-insulating tile composite aerogel material according to claim 1, characterized in that, In the preparation method of the amino-modified chitosan, the mass ratio of chitosan, acetic acid solution, amino-modified liquid, and glutaraldehyde solution is 8.0-8.5:68-73:47-53:10-15. The acetic acid solution has a mass concentration of 4.0-4.5%; The mass concentration of the glutaraldehyde solution is 9.5-10.8%; The amino-modified liquid is a mixture of spermine, hexamethylenediamine and deionized water, wherein the mass ratio of spermine, hexamethylenediamine and deionized water is 1.0-1.5:2.1-2.6:

100.

7. The method for preparing a heat-insulating tile composite aerogel material according to claim 1, characterized in that, In the composite molding step, the mass ratio of N,N-dimethylformamide, modified silicon carbide, silane-treated basalt fiber, zirconium sol, and polyethyleneimine is 200:9.2-9.6:2.4-2.8:115-124:0.8-1.

2.

8. The method for preparing a heat-insulating tile composite aerogel material according to claim 1, characterized in that, In the preparation method of the zirconium sol, the mixed solvent is a mixture of anhydrous ethanol and deionized water, and the mass ratio of anhydrous ethanol to deionized water is 57-65:

10. The mass ratio of zirconium oxychloride, mixed solvent, acetylacetone, gadolinium oxide, and yttrium oxide is 14.2-14.7:68-73:3.8-4.2:2.0-2.4:1.6-1.

8. The mass concentration of the ammonia solution is 7.5-8.2%.

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