A composite aerogel aerospace fabric

Abstract

This invention discloses a composite aerogel aerospace fabric, comprising, from the inside out, a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer. The aerogel fiber layer has a thickness of not less than 1 mm and is prepared by adding aerogel powder to a spinning solution, mixing thoroughly, and then extruding the mixture through a spinneret. The mixture is then subjected to fiber forming, stretching and orientation, setting, and winding to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer. The aerogel powder is obtained by sequentially subjecting silica aerogel powder to rehydration and heat treatment. This invention incorporates an aerogel fiber layer into the fabric, contributing to the lightweighting of aerospace fabrics. The aerogel powder used undergoes rehydration and heat treatment, significantly improving its mechanical strength while effectively reducing pore collapse and powder aggregation during crystal transformation, thus maintaining the advantages of aerogel in terms of heat insulation and lightweight properties.

Description

Technical Field

[0001] This invention relates to the field of fabric preparation technology, specifically to a composite aerogel aerospace fabric. Background Technology

[0002] Aerospace fabrics, used in the aerospace field, have a series of stringent performance requirements, such as high-temperature resistance, abrasion and damage resistance, and flame retardancy, to ensure they can meet extreme operating environments and safety standards. Existing aerospace fabrics are typically composed of a combination of materials, including chemical fibers such as cotton, glass fiber, and nylon, as well as polycarbonate, polyurethane, Teflon, and neoprene rubber, which can be compounded according to different needs. However, in order to achieve comprehensive performance standards, these material combinations often have a significant drawback: they are relatively heavy and somewhat cumbersome, which is detrimental to astronauts' movement and operations.

[0003] Aerogels, as nanoscale porous solid materials, have extremely low density. The lightest silica aerogel to date has a density of only 0.16 milligrams per cubic centimeter and only melts at temperatures reaching 1200 degrees Celsius. These properties make aerogels suitable for use in aerospace fabrics.

[0004] However, while aerogels, as a special material, possess many unique advantages, they also have some significant drawbacks. The most prominent of these is their low density and loose structure, resulting in weak mechanical strength and making them easily crushed or damaged. This significantly limits their use, especially in applications requiring high mechanical strength. Therefore, when preparing aerogel aerospace fabrics, it is necessary to overcome these mechanical strength deficiencies. Summary of the Invention

[0005] The purpose of this invention is to provide a composite aerogel aerospace fabric that solves the mechanical strength defects of aerogel in aerospace fabrics.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] A composite aerogel aerospace fabric includes a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer arranged sequentially from the inside out. The thickness of the aerogel fiber layer is not less than 1 mm. The preparation method is as follows: aerogel powder is added to spinning solution and mixed evenly. The mixture is then spun out through a spinneret and subjected to fiber forming, stretching and orientation, setting and winding to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer.

[0008] The aerogel powder is obtained by sequentially subjecting silica aerogel powder to rehydration treatment and heat treatment.

[0009] A further improvement is that the skin-friendly layer is selected from one of the following: pure cotton fiber layer, hemp fiber layer, silk fiber layer, or wool fiber layer.

[0010] A further improvement is that the spinning solution is selected from polyurethane resin spinning solution or polyacrylonitrile spinning solution.

[0011] A further improvement is that the aerogel powder accounts for 60-80% of the mass of the spinning solution.

[0012] A further improvement is that the moisture regain treatment refers to placing the silica aerogel powder in a constant temperature and humidity chamber at a temperature of 40-50℃ and a humidity of 80-90% for 2-5 hours, so that the moisture regain rate of the silica aerogel powder reaches 8-12%.

[0013] A further improvement is that, during the rehumidification process, isoamyl alcohol vapor is introduced into the chamber and the pressure inside the chamber is controlled at 300-320 kPa.

[0014] A further improvement is that the heat treatment refers to: placing the silica aerogel powder in a crucible, heating it from room temperature to 800-850℃ at a heating rate of 10-12℃ / min under a nitrogen atmosphere, and then holding it at that temperature for 0.2-0.5h.

[0015] A further improvement is that the flame-retardant layer is made of aramid fiber with a warp and weft density of 15-20 threads / cm and a fabric tightness of 40-60%.

[0016] A further improvement is that the sealing layer uses a PBAT high-temperature moisture-resistant sealing membrane.

[0017] The beneficial effects of this invention are as follows: This invention incorporates an aerogel fiber layer into the fabric, which helps achieve lightweight aerospace fabrics. The aerogel powder used undergoes rehydration and heat treatment. The heat treatment transforms the aerogel powder from amorphous to crystalline, significantly improving its mechanical strength and effectively preventing scratches, pressure damage, or wear. The rehydration treatment effectively reduces pore collapse and powder aggregation during the crystalline transformation process, maintaining the porous framework structure of the aerogel and preserving its advantages in heat insulation and lightweight properties. Furthermore, after rehydration, heat treatment at temperatures above 800℃ can be performed, further enhancing the degree of crystalline transformation. Additionally, the use of isoamyl alcohol vapor and high pressure during the rehydration process reduces the surface tension of the powder and improves compatibility, thereby enhancing the rehydration effect. Attached Figure Description

[0018] Figure 1 Here is a SEM image of silica aerogel powder from Example 4;

[0019] Figure 2This is a SEM image of silica aerogel powder in Comparative Example 1.

[0020] Figure 3 This is a SEM image of silica aerogel powder from Comparative Example 2. Detailed Implementation

[0021] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0022] I. Main Instruments and Materials

[0023] Silica aerogel powder: Commercially available hydrophilic silica aerogel powder is used. It is white and slightly transparent, with a particle size between 0.02-0.05 mm and a density of 92.4 kg / m³. 3 The Brunau-Emmett-Teller (BET) model calculates its porosity to be 96.5%.

[0024] Electron microscope: A Hitachi S4800 scanning electron microscope (SEM) was used.

[0025] II. Conducting the Experiment

[0026] Example 1

[0027] A composite aerogel aerospace fabric includes, from the inside out, a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer (each layer is connected by adhesive, the same below). The aerogel fiber layer has a thickness of 1 mm and is prepared by adding aerogel powder to polyurethane resin spinning solution, wherein the aerogel powder accounts for 60% of the mass of the spinning solution. After mixing evenly, the mixture is spun out through a spinneret, and then subjected to fiber forming, stretching and orientation, setting and winding to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer.

[0028] The aerogel powder is obtained by sequentially subjecting silica aerogel powder to rehumidification and heat treatment. The rehumidification process involves placing the silica aerogel powder in a constant temperature and humidity chamber at 40°C and 80% humidity for 5 hours (at normal pressure) to achieve a moisture regain of 8%. The heat treatment involves placing the silica aerogel powder in a crucible and heating it from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere, then holding it at that temperature for 0.5 hours.

[0029] In addition, the skin-friendly layer is made of pure cotton fiber. The flame-retardant layer is made of aramid fiber with a warp and weft density of 15 threads / cm and a fabric tightness of 40%. The sealing layer is made of PBAT high-temperature resistant moisture-sealing film.

[0030] Example 2

[0031] A composite aerogel aerospace fabric includes a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer arranged sequentially from the inside out. The thickness of the aerogel fiber layer is 1.2 mm. The preparation method is as follows: aerogel powder is added to polyacrylonitrile spinning solution, with the aerogel powder accounting for 70% of the mass of the spinning solution. After being mixed evenly, the mixture is spun out through a spinneret. Then, the fibers are formed, drawn, oriented, shaped, and wound to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer.

[0032] The aerogel powder is obtained by sequentially subjecting silica aerogel powder to rehumidification and heat treatment. The rehumidification process involves placing the silica aerogel powder in a constant temperature and humidity chamber at 45°C and 85% humidity for 3 hours (at normal pressure) to achieve a moisture regain of 10%. The heat treatment involves placing the silica aerogel powder in a crucible and heating it from room temperature to 820°C at a rate of 11°C / min under a nitrogen atmosphere, then holding it at that temperature for 0.4 hours.

[0033] In addition, the skin-friendly layer is made of silk fiber. The flame-retardant layer is made of aramid fiber with a warp and weft density of 18 threads / cm and a fabric tightness of 50%. The sealing layer is made of PBAT high-temperature resistant moisture-sealing film.

[0034] Example 3

[0035] A composite aerogel aerospace fabric includes a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer arranged sequentially from the inside out. The thickness of the aerogel fiber layer is 1.2 mm. The preparation method is as follows: aerogel powder is added to polyurethane resin spinning solution, with the aerogel powder accounting for 80% of the mass of the spinning solution. After being mixed evenly, the mixture is spun out through a spinneret. Then, the fibers are formed, drawn, oriented, shaped, and wound to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer.

[0036] The aerogel powder is obtained by sequentially subjecting silica aerogel powder to rehumidification and heat treatment. The rehumidification process involves placing the silica aerogel powder in a constant temperature and humidity chamber at 50°C and 90% humidity for 2 hours (at normal pressure) to achieve a moisture regain of 12%. The heat treatment involves placing the silica aerogel powder in a crucible and heating it from room temperature to 850°C at a rate of 12°C / min under a nitrogen atmosphere, then holding it at that temperature for 0.2 hours.

[0037] In addition, the skin-friendly layer is made of wool fibers. The flame-retardant layer is made of aramid fibers with a warp and weft density of 20 threads / cm and a fabric tightness of 60%. The sealing layer is made of PBAT high-temperature resistant moisture-sealing film.

[0038] Example 4

[0039] A composite aerogel aerospace fabric includes a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer arranged sequentially from the inside out. The thickness of the aerogel fiber layer is 1.2 mm. The preparation method is as follows: aerogel powder is added to polyacrylonitrile spinning solution, with the aerogel powder accounting for 70% of the mass of the spinning solution. After being mixed evenly, the mixture is spun out through a spinneret. Then, the fibers are formed, drawn, oriented, shaped, and wound to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer.

[0040] The aerogel powder is obtained by sequentially subjecting silica aerogel powder to rehumidification and heat treatment. The rehumidification process involves placing the silica aerogel powder in a constant temperature and humidity chamber at 45°C and 85% humidity for 3 hours, achieving a moisture regain of 10%. During the rehumidification process, isoamyl alcohol vapor is introduced into the chamber while maintaining the chamber pressure at 300 kPa. The heat treatment involves placing the silica aerogel powder in a crucible and heating it from room temperature to 820°C at a rate of 11°C / min under a nitrogen atmosphere, then holding it at that temperature for 0.4 hours.

[0041] The SEM image of the obtained silica aerogel powder is shown below. Figure 1 As shown, it can be seen that crystallization has occurred, but the microporous structure is rarely damaged, and the phenomena of pore collapse and powder aggregation are not obvious.

[0042] In addition, the skin-friendly layer is made of silk fiber. The flame-retardant layer is made of aramid fiber with a warp and weft density of 18 threads / cm and a fabric tightness of 50%. The sealing layer is made of PBAT high-temperature resistant moisture-sealing film.

[0043] Comparative Example 1

[0044] A composite aerogel aerospace fabric includes a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer arranged sequentially from the inside out. The thickness of the aerogel fiber layer is 1.2 mm. The preparation method is as follows: aerogel powder is added to polyacrylonitrile spinning solution, with the aerogel powder accounting for 70% of the mass of the spinning solution. After being mixed evenly, the mixture is spun out through a spinneret. Then, the fibers are formed, drawn, oriented, shaped, and wound to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer.

[0045] The aerogel powder is obtained by heat treatment of silica aerogel powder. The heat treatment refers to placing the silica aerogel powder in a crucible, heating it from room temperature to 820°C at a heating rate of 11°C / min under a nitrogen atmosphere, and then holding it at that temperature for 0.4 hours.

[0046] The SEM image of the obtained silica aerogel powder is shown below. Figure 2 As shown, it can be seen that it is completely crystallized, and the microporous structure is completely destroyed, with the particles becoming larger and agglomerating together.

[0047] In addition, the skin-friendly layer is made of silk fiber. The flame-retardant layer is made of aramid fiber with a warp and weft density of 18 threads / cm and a fabric tightness of 50%. The sealing layer is made of PBAT high-temperature resistant moisture-sealing film.

[0048] Comparative Example 2

[0049] A composite aerogel aerospace fabric includes a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer, and a sealing layer arranged sequentially from the inside out. The thickness of the aerogel fiber layer is 1.2 mm. The preparation method is as follows: aerogel powder is added to polyacrylonitrile spinning solution, with the aerogel powder accounting for 70% of the mass of the spinning solution. After being mixed evenly, the mixture is spun out through a spinneret. Then, the fibers are formed, drawn, oriented, shaped, and wound to obtain aerogel fibers. Finally, the aerogel fibers are woven to obtain the aerogel fiber layer.

[0050] The aerogel powder used is ordinary silica aerogel powder, and its SEM image is shown below. Figure 3 As shown in the figure, its porous structure is obvious and the particles are dispersed.

[0051] In addition, the skin-friendly layer is made of silk fiber. The flame-retardant layer is made of aramid fiber with a warp and weft density of 18 threads / cm and a fabric tightness of 50%. The sealing layer is made of PBAT high-temperature resistant moisture-sealing film.

[0052] III. Performance Testing

[0053] The aerogel fiber layers obtained in Examples 1-4 and Comparative Examples 1-2, as well as the final composite aerogel aerospace fabric samples, were subjected to the following performance tests:

[0054] (1) Thermal insulation performance: Take six sealable glass bottles containing 90℃ water (5 bottles in each group). Each group is wrapped with the composite aerogel aviation fabric samples prepared in Examples 1-4 and Comparative Examples 1-2. After wrapping, place them in a normal temperature environment and record the water temperature in the glass bottles after 2 hours. Calculate the average temperature loss rate of each group. The calculation formula is: Temperature loss rate = (initial temperature - temperature after 2 hours) / initial temperature * 100%. The calculation results are statistically obtained in Table 1 below.

[0055] (2) Abrasion resistance: In accordance with GB / T21196.2-2007 "Textiles - Determination of abrasion resistance of fabrics by Martindale method", abrasion resistance tests were conducted on the aerogel fiber layer samples prepared in Examples 1-4 and Comparative Examples 1-2 in their initial state and after 10,000 folds. The abrasion resistance index Ai (average mass loss per friction) was detected, and the statistical results are shown in Table 2 below.

[0056] IV. Results Analysis

[0057] (1) Thermal insulation performance.

[0058] Table 1: Temperature loss rate results for each embodiment and comparative example

[0059] Group initial temperature Temperature after 2 hours Average temperature loss rate / % Example 1 90.0℃ 62.1℃ 31.0％ Example 2 90.0℃ 61.4℃ 31.8％ Example 3 90.0℃ 63.0℃ 30.0％ Example 4 90.0℃ 73.7℃ 18.1％ Comparative Example 1 90.0℃ 52.9℃ 41.2％ Comparative Example 2 90.0℃ 74.2℃ 17.6％

[0060] (2) Wear resistance.

[0061] Table 2: Abrasion resistance index Ai results for each embodiment and comparative example

[0062]

[0063] Analysis: As can be seen from Tables 1 and 2 above, Examples 1-3 of the present invention use silica aerogel powder that has undergone rehydration and heat treatment, and its overall thermal insulation performance is good, showing a significant improvement compared to Comparative Example 1 (without rehydration treatment). The wear resistance of Examples 1-3 is also good, close to the level of Comparative Example 1, and significantly better than Comparative Example 2 (ordinary silica aerogel powder). Based on Example 2, Example 4 of the present invention adds isoamyl alcohol vapor and high pressure auxiliary conditions during the rehydration process, which further improves the thermal insulation performance, making it comparable to Comparative Example 2. In addition, the silica aerogel powder of Comparative Example 1 only underwent heat treatment, and although its wear resistance performance was the best, its thermal insulation performance was the worst. Comparative Example 2 uses ordinary silica aerogel powder, which has the best thermal insulation performance, but its wear resistance performance is the worst.

[0064] In summary, this invention utilizes silica aerogel powder that has undergone rehydration and heat treatment, effectively reducing pore collapse and powder aggregation during crystal transformation, maintaining the porous framework structure of the aerogel, and thus preserving its advantages in thermal insulation performance. This allows the fabric fiber layer to possess both thermal insulation and mechanical strength. Furthermore, the rehydration treatment allows for heat treatment at temperatures above 800℃ (generally, heat treatment above 700℃ would completely destroy the aerogel structure, causing it to lose its function), which helps to deepen the crystal transformation. Additionally, the use of isoamyl alcohol vapor and high pressure during the rehydration process reduces the powder's surface tension and improves compatibility, thereby enhancing the rehydration effect and ultimately resulting in further improvements in thermal insulation performance.

[0065] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A composite aerogel aerospace fabric, characterized in that, It includes a skin-friendly layer, an aerogel fiber layer, a flame-retardant layer and a sealing layer arranged sequentially from the inside to the outside. The thickness of the aerogel fiber layer is not less than 1 mm, and the preparation method is as follows: take spinning solution and add aerogel powder, mix evenly and then spray it out through the spinneret hole, then go through fiber forming, stretching orientation, shaping and winding to obtain aerogel fiber, and finally weave the aerogel fiber to obtain the aerogel fiber layer. The aerogel powder is obtained by sequentially subjecting silica aerogel powder to rehydration treatment and heat treatment. The moisture regain treatment refers to placing the silica aerogel powder in a constant temperature and humidity chamber at a temperature of 40-50℃ and a humidity of 80-90% for 2-5 hours, so that the moisture regain rate of the silica aerogel powder reaches 8-12%. During the rehumidification process, isoamyl alcohol vapor is introduced into the chamber and the pressure inside the chamber is controlled at 300-320 kPa. The heat treatment refers to placing silica aerogel powder in a crucible, heating it from room temperature to 800-850℃ at a heating rate of 10-12℃ / min under a nitrogen atmosphere, and then holding it at that temperature for 0.2-0.5h.

2. The composite aerogel aerospace fabric according to claim 1, characterized in that, The skin-friendly layer is selected from one of the following: pure cotton fiber layer, hemp fiber layer, silk fiber layer, or wool fiber layer.

3. The composite aerogel aerospace fabric according to claim 1, characterized in that, The spinning solution is selected from polyurethane resin spinning solution or polyacrylonitrile spinning solution.

4. The composite aerogel aviation fabric according to claim 1, characterized in that, The aerogel powder accounts for 60-80% of the mass of the spinning solution.

5. The composite aerogel aerospace fabric according to claim 1, characterized in that, The flame-retardant layer is made of aramid fiber with a warp and weft density of 15-20 threads / cm and a fabric tightness of 40-60%.

6. The composite aerogel aerospace fabric according to claim 1, characterized in that, The sealing layer is made of PBAT high-temperature resistant water vapor sealing membrane.

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