In-situ growth nanowire skeleton reinforced aerogel composite material and preparation method thereof
The preparation method of nanowire skeleton-reinforced aerogel composite material by in-situ growth has solved the problems of high temperature resistance, low thermal conductivity and high strength and toughness of aerogel composite materials in aerospace and other fields. It has achieved high strength, toughness and processability of the material, and is suitable for high temperature insulation materials in aerospace and other fields.
Patent Information
- Application Number
- CN202610330634.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-18
- Publication Date
- 2026-05-19
AI Technical Summary
Existing aerogel composite materials cannot simultaneously meet the requirements of high temperature resistance, low thermal conductivity, and high strength and toughness in fields such as aerospace, nuclear power, and high-temperature industrial furnaces, and are also difficult to process into complex structural parts.
An in-situ grown nanowire skeleton reinforced aerogel composite material was prepared using tetraethyl orthosilicate, organosilanes, ethanol and water as raw materials, and quartz fiber felt as reinforcement. The process involved in-situ growth of nanowires on the fiber felt, modification, sol impregnation and aging, and drying to form a high-strength, high-toughness, low-thermal-conductivity aerogel composite material.
It achieves high temperature resistance, low thermal conductivity, and high strength and toughness in aerogel composite materials, which can be processed into complex components and are suitable for high temperature insulation materials in aerospace and other fields.
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Figure CN122059685A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of thermal insulation materials technology, specifically relating to an in-situ grown nanowire skeleton reinforced aerogel composite material and its preparation method. Background Technology
[0002] Aerogels, due to their unique nanoporous structure, have become the solid materials with the lowest thermal conductivity at room temperature. Silica aerogel composites have been widely used in various fields such as oil pipelines, heating networks, nuclear power, storage tanks, tank armor, rail transportation, shipbuilding, and aerospace, demonstrating particularly excellent prospects for thermal insulation applications. However, their three-dimensional porous structure also leads to high brittleness and poor mechanical properties. Therefore, ceramic particles, whiskers, or fibers are typically introduced to create composite materials to enhance mechanical properties. Such materials have been successfully applied in high-speed aircraft thermal protection systems, petrochemical pipeline insulation layers, and fireproof and heat-insulating pads for new energy vehicles. However, with the rapid development of technologies in aerospace, nuclear power, and high-temperature industrial furnaces, the demand for thermal insulation materials has gone beyond simply high temperature resistance and low thermal conductivity; excellent load-bearing capacity and good processability are also required, enabling them to be processed into complex structural components.
[0003] Therefore, how to prepare aerogel insulation materials that simultaneously meet the requirements of high temperature resistance, low thermal conductivity, high strength and toughness, and can realize the molding of large-sized complex components constitutes a major challenge in this field. Summary of the Invention
[0004] To address the problems mentioned in the background section, this invention provides an in-situ grown nanowire framework reinforced aerogel composite material and its preparation method.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] This invention provides an in-situ grown nanowire skeleton reinforced aerogel composite material and its preparation method. The raw materials are tetraethyl orthosilicate, organosilane precursor, ethanol and water, glacial acetic acid and ammonia water are used as catalysts, and quartz fiber felt is used as reinforcement. The aerogel composite material with high strength and toughness, low thermal conductivity and excellent processing is obtained by in-situ growth of nanowires on fiber felt, sol impregnation and aging, and drying.
[0007] To achieve the above objectives, the present invention provides a method for preparing an in-situ grown nanowire framework-reinforced aerogel composite material, comprising the following steps:
[0008] Step 1: Place the quartz fiber felt on a stainless steel screen in the desiccator. The screen mesh size is 3-6 mm. Place two open beakers containing ammonia and organosilane precursor respectively under the screen. Then seal the desiccator and place it in an oven for in-situ treatment for 10-24 hours.
[0009] Step 2: Mix tetraethyl orthosilicate, ethanol, water, and glacial acetic acid in a molar ratio of 1:7-12:1-3:0.001-0.006, and stir uniformly in a water bath at 40-50℃ for 0.5-10 h at a stirring speed of 180-250 rpm to obtain a silica sol precursor solution.
[0010] Step 3: The treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and hydrolyzed, condensed, and aged at 30-60 °C to form a gel.
[0011] Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, the material is dried at 20–70℃ and 10–15 MPa for 10–36 h to obtain in-situ grown nanowire skeleton reinforced aerogel composite material.
[0012] Preferably, in step one, the method for preparing the organosilane precursor includes the following steps:
[0013] Slowly add organosilane to N,N-dimethylformamide and stir continuously for 25–35 min. The volume ratio of N,N-dimethylformamide to silane is 1:1–4.
[0014] Preferably, the organosilane is one or more of methyltrimethoxysilane, methyltriethoxysilane, and octyltriethoxysilane.
[0015] Compared with the prior art, the beneficial effects of the present invention are:
[0016] 1) The in-situ technology of this invention controls the temperature range of 80-110 ℃ to grow silicon oxide nanowires, which improves the problems of high growth temperature and high requirements for production process equipment in traditional nanowires, and reduces costs.
[0017] 2) The in-situ produced silica nanofibers further hinge the quartz fiber mat, improving the strength and toughness of the fiber mat and enhancing the processability of the material.
[0018] 3) Nanowires germinate and grow in the pores of the quartz fiber felt, further refining the macroporous structure of the fiber felt, optimizing the pore structure of the quartz fiber felt, and improving the thermal insulation performance of the fiber felt itself.
[0019] 4) The mechanical interlocking effect of in-situ grown nanowires fully supports the aerogel, preventing structural collapse and interface failure under long-term vibration and other conditions, thereby enhancing the structural stability of the aerogel and improving the processing performance of the composite material.
[0020] 5) The internal pores of the nanowire-reinforced aerogel composite material prepared by this invention are refined and segmented by the in-situ grown nanowire network. The nanowires enhance the interfacial bonding with the aerogel through interlocking, preventing breakage under external force and improving the structural performance of the aerogel composite material. It has the characteristics of high temperature resistance, low thermal conductivity, high strength and toughness, and can be processed into complex components, and can be used as a high temperature thermal insulation material in the field of aerospace thermal protection. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the preparation process of the composite material of the present invention;
[0023] Figure 2 This is a scanning electron microscope image of the in-situ modified quartz fiber felt in Example 1;
[0024] Figure 3 This is a scanning electron microscope image of the quartz fiber felt in Comparative Example 1 before in-situ treatment.
[0025] Figure 4 This is a scanning electron microscope image of the quartz fiber felt after in-situ treatment in Example 2. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0027] Preparation Example 1
[0028] The preparation method of organosilane precursors includes the following steps:
[0029] Methyltriethoxysilane was slowly added to N,N-dimethylformamide and stirred continuously for 25 minutes. The volume ratio of N,N-dimethylformamide to silane was 1:1.
[0030] Preparation Example 2
[0031] The preparation method of organosilane precursors includes the following steps:
[0032] Methyltrimethoxysilane was slowly added to N,N-dimethylformamide and stirred continuously for 30 minutes. The volume ratio of N,N-dimethylformamide to silane was 1:2.
[0033] Preparation Example 3
[0034] The preparation method of organosilane precursors includes the following steps:
[0035] Methyltrimethoxysilane was slowly added to N,N-dimethylformamide and stirred continuously for 35 minutes. The volume ratio of N,N-dimethylformamide to silane was 1:4.
[0036] Example 1
[0037] Step 1: Place the quartz fiber felt on a stainless steel sieve with a pore size of 3 mm in the desiccator. Place two open beakers containing ammonia water and the organosilane precursor in Preparation Example 1, respectively, under the sieve. Then seal the desiccator and place it in an oven at 90°C for in-situ treatment for 10 h.
[0038] Step 2: Mix tetraethyl orthosilicate, ethanol, water, and glacial acetic acid in a molar ratio of 1:10:3:0.001, and stir uniformly in a water bath at 50°C for 0.5 h at a stirring speed of 180 rpm to obtain a silica sol precursor solution.
[0039] Step 3: The treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and hydrolyzed, condensed, and aged at 30 °C to form a gel.
[0040] Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, the material is dried at 40℃ and 15MPa pressure for 24 h to obtain an in-situ grown nanowire skeleton reinforced aerogel composite material.
[0041] In this embodiment, tiny nano-bumps grow on the surface of the quartz fibers in the treated fiber felt. The average length of the nano-bumps is less than or equal to 3 μm, the average pore size of the fiber felt is 200 μm, and the prepared aerogel composite material has a thermal conductivity of less than 0.018 W / (m×K) at room temperature, can be processed into any shape, and has a compressive strength of 0.4 MPa.
[0042] Example 2
[0043] Step 1: Place the quartz fiber felt on a stainless steel sieve with a 4 mm aperture in the desiccator. Place two open beakers containing ammonia and the organosilane precursor from Preparation Example 2, respectively, under the sieve. Then seal the desiccator and place it in an oven for in-situ treatment for 18 hours.
[0044] Step 2: Using a molar ratio of tetraethyl orthosilicate: ethanol: water: glacial acetic acid = 1:11:2:0.02, stir uniformly in a water bath at 45℃ for 1 h at a stirring speed of 200 rpm to obtain a silica sol precursor solution.
[0045] Step 3: The treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and hydrolyzed, condensed, and aged at 40 °C to form a gel.
[0046] Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, the material is dried at 50℃ and 12MPa pressure for 24 hours to obtain an in-situ grown nanowire skeleton reinforced aerogel composite material.
[0047] In this embodiment, slender nanowires grow on the surface of quartz fibers in the treated fiber felt, intertwining to form a three-dimensional network. The average length of the nanowires is 100 μm, and the average pore size of the fiber felt is 50 μm. The prepared aerogel composite material has a thermal conductivity of less than 0.016 W / (m×K) at room temperature and a compressive strength of 0.6 MPa.
[0048] Example 3
[0049] Step 1: Place the quartz fiber felt on a 6 mm stainless steel sieve in the desiccator, and place two open beakers containing ammonia and the organosilane precursor from Example 3, respectively, under the sieve. Then seal the desiccator and place it in an oven for in-situ treatment for 24 h.
[0050] Step 2: Using a molar ratio of tetraethyl orthosilicate: ethanol: water: glacial acetic acid = 1:10:3:0.03, stir uniformly in a water bath at 40℃ for 2 h at a stirring speed of 250 rpm to obtain a silica sol precursor solution.
[0051] Step 3: The treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and hydrolyzed, condensed, and aged at 40 °C to form a gel.
[0052] Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, the material is dried at 50℃ and 12MPa pressure for 24 hours to obtain an in-situ grown nanowire skeleton reinforced aerogel composite material.
[0053] In this embodiment, fluffy nanowires grow on the surface of quartz fibers in the treated fiber felt, intertwining to form a three-dimensional network. The quartz fibers are fixed by the nanofiber clusters hinges, and the macropores of the fiber felt are completely filled with nanowires. The average length of the nanowires is greater than or equal to 500 μm, and the average pore diameter of the fiber felt is 10 μm. The aerogel composite material prepared after being combined with aerogel has a thermal conductivity of less than 0.015 W / (m×K) at room temperature and a compressive strength of 0.8 MPa.
[0054] Comparative Example 1
[0055] Step 1: Place the quartz fiber felt on a stainless steel screen with a 6 mm aperture in the dryer, then seal the dryer and place it in an oven for 24 hours of heat treatment.
[0056] Step 2: Using a molar ratio of tetraethyl orthosilicate: ethanol: water: glacial acetic acid = 1:11:2:0.02, stir uniformly in a water bath at 40℃ for 1 h at a stirring speed of 200 rpm to obtain a silica sol precursor solution.
[0057] Step 3: The treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and hydrolyzed, condensed, and aged at 40 °C to form a gel.
[0058] Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, the aerogel composite material is dried at 50℃ and 12MPa pressure for 24 hours to obtain the aerogel composite material.
[0059] The aerogel composite material obtained in this comparative example has a thermal conductivity of 0.021 W / (m×K) at room temperature and a compressive strength of 0.32 MPa.
[0060] Comparative Example 2
[0061] Step 1: Place the quartz fiber felt on a stainless steel sieve with a 3 mm aperture in the desiccator, place two open beakers containing ammonia and tetraethyl orthosilicate respectively under the sieve, and then seal the desiccator and place it in an oven at 90℃ for in-situ treatment for 10 hours.
[0062] Step 2: Mix tetraethyl orthosilicate, ethanol, water, and glacial acetic acid in a molar ratio of 1:10:3:0.001, and stir uniformly in a water bath at 50°C for 0.5 h at a stirring speed of 180 rpm to obtain a silica sol precursor solution.
[0063] Step 3: The treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and hydrolyzed, condensed, and aged at 30 °C to form a gel.
[0064] Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, the material is dried at 40℃ and 15MPa pressure for 24 h to obtain an in-situ grown nanowire skeleton reinforced aerogel composite material.
[0065] In this comparative example, the surface of the quartz fiber in the treated fiber felt is smooth and no nanowire structure has grown. The aerogel composite material obtained in this comparative example has a thermal conductivity of 0.02 W / (m×K) and a compressive strength of 0.35 MPa at room temperature.
[0066] Comparative Example 3
[0067] Step 1: Place the quartz fiber felt on a 6 mm stainless steel sieve in the desiccator, and place two open beakers containing ammonia and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane respectively under the sieve. Then seal the desiccator and place it in an oven for in-situ treatment for 24 hours.
[0068] Step 2: Using a molar ratio of tetraethyl orthosilicate: ethanol: water: glacial acetic acid = 1:10:3:0.03, stir uniformly in a water bath at 40℃ for 2 h at a stirring speed of 250 rpm to obtain a silica sol precursor solution.
[0069] Step 3: The treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and hydrolyzed, condensed, and aged at 40 °C to form a gel.
[0070] Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, the material is dried at 50℃ and 12MPa pressure for 24 hours to obtain an in-situ grown nanowire skeleton reinforced aerogel composite material.
[0071] In this comparative example, fine bump-shaped nanowires are grown on the surface of the quartz fibers in the treated fiber felt. The average length of the nanowires is 5 μm, and no hinge structure is formed between the nanowires. The average pore size of the fiber felt is 180 μm. The aerogel composite material prepared after being combined with aerogel has a thermal conductivity of less than 0.0175 W / (m·K) at room temperature and a compressive strength of 0.42 MPa.
[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing an in-situ grown nanowire framework reinforced aerogel composite material, characterized in that, Includes the following steps: Step 1: In-situ nanowire framework growth. Quartz fiber felt is placed on a stainless steel screen in a desiccator. Two open beakers containing ammonia and organosilane precursors are placed under the screen. The desiccator is then sealed and placed in an oven for heat treatment. Step 2: Mix tetraethyl orthosilicate, ethanol, water and glacial acetic acid in a molar ratio, and stir evenly in a water bath at 40-50°C to obtain a silica sol precursor solution. Step 3: The heat-treated fiber felt obtained in Step 1 is impregnated in the silica sol precursor solution in Step 2, and then hydrolyzed, condensed, and aged to form a gel. Step 4: Using supercritical drying technology with liquid carbon dioxide as the drying medium, drying is carried out at a certain temperature and pressure to obtain in-situ grown nanowire skeleton reinforced aerogel composite material.
2. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 1, characterized in that: In step one, the oven temperature is 80–110 ℃, and the heat treatment time is 6–24 h.
3. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 1, characterized in that: Step one, the preparation method of the organosilane precursor includes the following steps: Slowly add organosilane to N,N-dimethylformamide and stir continuously for 25–35 min. The volume ratio of N,N-dimethylformamide to silane is 1:1–4.
4. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 3, characterized in that: The organosilane is one or more of methyltrimethoxysilane, methyltriethoxysilane, and octyltriethoxysilane.
5. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 1, characterized in that: In step one, the stainless steel screen mesh has a aperture of 3 to 6 mm.
6. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 1, characterized in that: In step two, the molar ratio of tetraethyl orthosilicate, ethanol, water and glacial acetic acid is 1:7-12:1-3:0.001-0.
006.
7. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 1, characterized in that: In step two, the stirring time is 0.5–10 h; the stirring speed is 180–250 rpm.
8. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 1, characterized in that: The hydrolysis temperature in step three is 30–60℃.
9. The method for preparing an in-situ grown nanowire framework reinforced aerogel composite material according to claim 1, characterized in that: In step four, the product is dried at 20–70°C and 10–15 MPa for 10–36 hours.
10. An in-situ grown nanowire framework reinforced aerogel composite material, characterized in that, It is prepared according to the preparation method according to any one of claims 1 to 9.