Aerogel-filled modified glass fiber mat and method of making

Abstract

The application provides an aerogel-filled modified glass fiber felt and a preparation method and application thereof, and belongs to the field of porous thermal insulation functional membrane materials. The application adopts glass fiber felt as a reinforcing phase, trimethylchlorosilane (TMCS) as a hydrophobic modifier, and precise control of solvent exchange time to construct a hierarchical structure composite system in which a glass fiber micron network and a silica aerogel nanometer network are interwoven. The three-dimensional skeleton of the glass fiber felt forms a firm "spot welding" structure between fibers, providing stable mechanical support for the material. This not only significantly improves the defect that pure aerogel is brittle and easy to break, but also effectively enhances the mechanical strength and dimensional stability of the fiber membrane, and improves its durability and service life. While realizing the hydrophobic modification and mechanical enhancement of the silica aerogel, the application also synergistically improves the thermal insulation performance of the material, expanding its application scenarios in the fields of building, aerospace, rail transit and the like.

Description

Technical Field

[0001] This invention relates to the field of porous thermal insulation functional membrane materials, specifically to an aerogel-filled modified glass fiber mat and its preparation method. Background Technology

[0002] Silica aerogel, as a novel thermal insulation and sound absorption material with low density and porous structure, has shown broad application prospects in fields such as construction, aerospace, and rail transportation. However, the abundance of hydroxyl groups on the surface of silica aerogel leads to its strong hydrophilicity, making it prone to collapse when exposed to water. It also exhibits high brittleness and low mechanical strength. Furthermore, the pore structure of a single aerogel is difficult to control, making it challenging to achieve synergistic optimization of thermal properties. This significantly limits its practical application under complex working conditions.

[0003] Sol-gel modification is a common method for optimizing the properties of silica aerogels. Specifically, it involves adjusting process parameters such as sol pH, reaction time, and solvent ratio to control the pore structure and network framework of the aerogel, followed by drying and molding to obtain the modified aerogel material. This method is controllable, easily scalable, and can improve the microstructure and some physical properties of aerogels to a certain extent. However, the sol-gel process alone cannot simultaneously address the dual deficiencies of hydrophilicity and mechanical strength in aerogels. Furthermore, pure aerogels without reinforcing phases still suffer from poor structural stability, failing to achieve the multiple objectives of hydrophobic modification, mechanical enhancement, and synergistic improvement of thermoacoustic properties.

[0004] In view of this, it is necessary to design a silica aerogel-based composite material with high hydrophobicity, excellent mechanical properties and efficient thermal insulation, and its preparation method, in order to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides an aerogel-filled modified glass fiber mat and its preparation method, aiming to solve the technical problems of existing silica aerogels having strong hydrophilicity, low mechanical strength, and difficulty in synergistically optimizing thermal insulation performance.

[0006] In a first aspect, this application provides a method for preparing aerogel-filled modified glass fiber mat, comprising the following steps: S1, Preparation of silica sol: Tetraethyl orthosilicate, anhydrous ethanol, and deionized water are mixed to obtain a mixed solution; then, the pH of the mixed solution is adjusted to 2-3, and sonication is continued until tetraethyl orthosilicate is completely hydrolyzed to obtain a uniform silica sol. S2, Preparation and aging of wet gel: The pH of the silica sol is adjusted to 6-6.5; then, the glass fiber mat is completely immersed in the silica sol to form a wet gel; the wet gel is aged in anhydrous ethanol to allow the gel network to fully crosslink. S3, Solvent exchange and hydrophobic modification: The aged wet gel is placed in a mixed solution of hexane and anhydrous ethanol for solvent exchange; then the wet gel is immersed in anhydrous ethanol solution containing trimethylchlorosilane for modification, so that hydrophobic methyl groups are grafted onto the surface of the aerogel, thus obtaining aerogel-filled modified glass fiber mat.

[0007] Furthermore, in step S3, the solvent exchange time is 6-8 hours.

[0008] Further, in step S1, the molar ratio of tetraethyl orthosilicate, anhydrous ethanol, and deionized water is 1:10:5.

[0009] Further, in step S3, the volume ratio of n-hexane to anhydrous ethanol in the mixed solution of n-hexane and anhydrous ethanol is 1:1.

[0010] Further, in step S2, the mass ratio of the glass fiber mat to the silica sol is 1:20 to 1:38.

[0011] Furthermore, in step S2, the aging time is 12-24 hours.

[0012] Furthermore, the glass fiber mat has a porosity of 70-90% and a density of 150-300 kg / m³. 3 Its thermal conductivity is 0.030-0.045 W / (m·K).

[0013] Secondly, this application provides an aerogel-filled modified glass fiber mat, which is prepared by the preparation method described in any of the aforementioned technical solutions; the aerogel-filled modified glass fiber mat includes hydrophobic modified silica aerogel in a three-dimensional network structure generated in situ inside the glass fiber mat; the hydrophobic modified silica aerogel and the glass fiber mat form a hierarchical structure in which the glass fiber micro-network and the silica aerogel nano-network are intertwined.

[0014] The beneficial effects of this application are as follows: This application constructs a micro-nano hierarchical network structure by introducing glass fiber mat as a reinforcing phase and trimethylchlorosilane (TMCS) as a hydrophobic modifier, combined with precise control of solvent exchange time. Specifically, in this application, silicon source (TEOS) undergoes hydrolysis and condensation to generate nanoscale silica aerogel particles; the silica aerogel particles continuously aggregate and cross-link, forming a continuous three-dimensional network (i.e., wet gel) in the pores of the glass fiber mat. Then, water / ethanol in the gel pores is removed by solvent exchange, followed by drying to avoid capillary forces causing network shrinkage and collapse, resulting in a complete nanoscale silica aerogel network; the glass fiber mat is a network structure composed of micron-sized fibers, forming a hierarchical composite system in which the glass fiber micron network and the silica aerogel nano network intertwine.

[0015] The micro-nano hierarchical pore structure suppresses thermal convection of gas molecules, and the three-dimensional skeleton of the glass fiber mat increases the heat conduction path. The resulting modified glass fiber mat has a much better thermal insulation effect than traditional insulation materials.

[0016] This application achieves hydrophobic modification and mechanical enhancement of silica aerogel while synergistically improving the thermal insulation properties of the material, expanding its application scenarios in fields such as construction, aerospace, and rail transportation.

[0017] In this application, after modification with the low surface energy material trimethylchlorosilane (TMCS), a robust hydrophobic layer can be formed on the material surface, with a static water contact angle exceeding 150°, exhibiting superhydrophobic properties. This not only enables the prepared modified glass fiber mat to effectively prevent structural collapse and performance degradation caused by water infiltration in high humidity or oil mist environments, significantly improving environmental adaptability and service stability, but also solves the problem of easy collapse of pure aerogels due to surface hydroxyl groups when exposed to water.

[0018] In terms of mechanical properties, the three-dimensional skeleton of the glass fiber mat forms a strong "spot weld" structure between the fibers, providing stable mechanical support for the material. This not only significantly improves the defects of pure aerogels, such as high brittleness and fragility, but also effectively enhances the mechanical strength and dimensional stability of the fiber membrane, thereby improving its durability and service life.

[0019] Furthermore, in this application, the in-situ generated silica gel particles are uniformly distributed on the fiber surface and at the intersections, significantly improving the retention efficiency of fine particles (such as PM2.5) (up to over 99%). Simultaneously, because the gel is mainly deposited at the fiber intersections rather than completely blocking the pores, it effectively maintains the original air permeability of the substrate. Therefore, this modified glass fiber mat can be widely used in processes such as air purification, industrial dust control, oil-water separation, and thermal insulation.

[0020] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0022] Figure 1 This is a schematic diagram of the process flow for preparing aerogel-filled modified glass fiber mat in the embodiments of this application.

[0023] Figure 2 The image shows an SEM image of the aged glass fiber obtained in step S2 of Example 1 before solvent exchange with the mixed solution of hexane and anhydrous ethanol.

[0024] Figure 3 This is a SEM image of the solvent exchanged 6 hours after Example 2.

[0025] Figure 4 This is a SEM image of the solvent exchanged 8 hours after Example 1.

[0026] Figure 5 The image shows the SEM image of Comparative Example 1 after solvent exchange for 10 h.

[0027] Figure 6 The image shows the SEM image of Comparative Example 2 after solvent exchange for 12 h.

[0028] Figure 7 The image shows the SEM image of Comparative Example 3 after solvent exchange for 14 h.

[0029] Figure 8 Photographs of the water contact angle of the composite material at different solvent exchange times; where (a)-(f) are the water contact angles of the glass fiber mat without solvent exchange and after solvent exchange for 6 h, 8 h, 10 h, 12 h and 14 h, respectively.

[0030] Figure 9 Photographs of the oil contact angle of the composite material at different solvent exchange times are shown; where (a)-(f) are the oil contact angles of the glass fiber mat without solvent exchange and after solvent exchange for 6 h, 8 h, 10 h, 12 h and 14 h, respectively.

[0031] Figure 10Infrared thermal images of the composite material under different solvent exchange times are shown; where (a)-(f) are thermal insulation test images of the composite material without solvent exchange and after solvent exchange for 6 h, 8 h, 10 h, 12 h and 14 h, respectively.

[0032] Figure 11 The tensile stress-strain curves of the composite material under different solvent exchange times are shown. Detailed Implementation

[0033] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0035] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] To address the technical challenges of existing silica aerogels, such as high hydrophilicity, low mechanical strength, and difficulty in synergistically optimizing their thermoacoustic insulation properties, this application provides an aerogel-filled modified glass fiber mat and its preparation method. In this application, by using glass fiber mat as the reinforcing phase, combined with TMCS hydrophobic modification and precise control of solvent exchange time, a hierarchical composite system in which glass fiber micro-networks and silica aerogel nano-networks intertwine is constructed. This achieves the technical effect of synergistically improving high hydrophobicity, excellent mechanical properties, and efficient thermoacoustic insulation performance.

[0038] This application provides a method for preparing aerogel-filled modified glass fiber mat, comprising the following steps: S1, Preparation of silica sol: Tetraethyl orthosilicate, anhydrous ethanol, and deionized water are mixed to obtain a mixed solution; then, the pH of the mixed solution is adjusted to 2-3, and sonication is continued until tetraethyl orthosilicate is completely hydrolyzed to obtain a uniform silica sol. S2, Preparation and aging of wet gel: The pH of the silica sol is adjusted to 6-6.5; then, the glass fiber mat is completely immersed in the silica sol to form a wet gel; the wet gel is aged in anhydrous ethanol to allow the gel network to fully crosslink. S3, Solvent exchange and hydrophobic modification: The aged wet gel is placed in a mixed solution of hexane and anhydrous ethanol for solvent exchange; then the wet gel is immersed in anhydrous ethanol solution containing trimethylchlorosilane for modification, so that hydrophobic methyl groups are grafted onto the surface of the aerogel, thus obtaining aerogel-filled modified glass fiber mat.

[0039] The aerogel-filled modified glass fiber mat prepared using the aforementioned technical solution includes hydrophobically modified silica aerogel formed in situ within a three-dimensional network structure inside the glass fiber mat. This hydrophobically modified silica aerogel forms a hierarchical structure with the glass fiber mat, where the glass fiber micro-network and the silica aerogel nano-network intertwine. This achieves both hydrophobic modification and mechanical reinforcement of the silica aerogel, synergistically improving the material's thermal insulation, making it suitable for applications such as air purification, industrial dust control, and oil-water separation.

[0040] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0041] I. Preparation Method Example 1 A method for preparing aerogel-filled modified glass fiber mat includes the following steps: S1, Preparation of silica sol: 22.33 ml of tetraethyl orthosilicate (TEOS), 58.4 ml of anhydrous ethanol (EtOH) and 9 ml of deionized water were measured separately to prepare a mixed solution, which was then sonicated at 50℃ for 10 min. Subsequently, the pH of the solution was adjusted to 2 with HCl and sonicated for another 1 h to obtain a homogeneous silica sol.

[0042] S2, Preparation and Aging of Wet Gel: The pH of the silica sol was adjusted to 6 using ammonium hydroxide solution, and then the prepared glass fiber mat was completely immersed in the sol to form a wet gel. The wet gel was aged in anhydrous ethanol for 24 h. This glass fiber mat has a three-dimensional interconnected microporous structure, with chopped fibers of 25-50 mm in length, a thickness of 4 mm, an apparent density of 250 kg / m³, and an appearance of a smooth, white nonwoven fabric. The porosity of this glass fiber mat is 70-90%, and its density is 150-300 kg / m³. 3 Its thermal conductivity is 0.030-0.045 W / (m·K).

[0043] This glass fiber mat is mechanically isotropic and has moderate strength; its surface is hydrophilic and has a moderate specific surface area, making it easy to impregnate and composite with silica sol, thus making it an ideal reinforcing skeleton for preparing thermal insulation composite materials.

[0044] S3. The aged wet gel was placed in a mixed solution of n-hexane and anhydrous ethanol (volume ratio of 1:1, i.e., 100 ml of each) for 8 hours of solvent exchange. Subsequently, the wet gel was immersed in an anhydrous ethanol solution containing 20% ​​TMCS for 2 hours of modification, so that hydrophobic methyl groups were grafted onto the surface of the aerogel, thus obtaining aerogel-filled modified glass fiber mat.

[0045] Example 2 The difference from Example 1 is that in step S3, the solvent exchange time is 6 hours. Everything else is the same as in Example 1 and will not be repeated here.

[0046] Comparative Example 1 The difference from Example 1 is that in step S3, the solvent exchange time is 10 hours. Everything else is the same as in Example 1 and will not be repeated here.

[0047] Comparative Example 2 The difference from Example 1 is that in step S3, the solvent exchange time is 12 hours. Everything else is the same as in Example 1 and will not be repeated here.

[0048] Comparative Example 3 The difference from Example 1 is that in step S3, the solvent exchange time is 14 hours. Everything else is the same as in Example 1 and will not be repeated here.

[0049] Comparative Example 4 The difference from Example 1 is that in step S2, the glass fiber mat is replaced with glass fiber with a length of 4.5 mm. Everything else is the same as in Example 1 and will not be repeated here.

[0050] Experiments show that the high porosity and large specific surface area of ​​glass fiber mat can provide a uniform impregnation space for aerogel precursors, ensuring that the aerogel is uniformly filled in the fiber gaps, forming an interpenetrating hierarchical structure of "micron fiber skeleton + nano aerogel network", thus achieving synergistic optimization of thermal insulation and mechanical properties.

[0051] II. Testing Methods 1. Microstructure testing of materials: The microstructure of the composite material cross-section under different solvent exchange times was observed using a scanning electron microscope (SEM).

[0052] 2. Material wettability test: The contact angle of water droplets (5μL) and oil droplets on the surface of the composite material was measured using a contact angle meter under different solvent exchange times.

[0053] 3. Thermal insulation performance test of materials: Place the sample on a hot stage at 120°C and use an infrared thermal imager to record the change in the center temperature of the sample surface within 70 seconds.

[0054] 4. Mechanical property testing of materials: Using a universal testing machine, tensile tests were performed on composite material samples under different solvent exchange times, and their stress-strain curves were recorded.

[0055] III. Analysis of Test Results for Each Embodiment and Comparative Example Figure 2 The image shows an SEM image of the aged glass fiber obtained in step S2 of Example 1 before solvent exchange with the mixed solution of hexane and anhydrous ethanol.

[0056] Figure 3 This is a SEM image of the solvent exchanged 6 hours after Example 2.

[0057] Figure 4 This is a SEM image of the solvent exchanged 8 hours after Example 1.

[0058] Figures 5 to 7 The images shown are SEM images of solvent exchanged in Comparative Examples 1-3.

[0059] As can be seen, without solvent exchange, the aerogel shrinks significantly during drying, forming only a discontinuous thin layer on the fiber surface. Figure 2 As the solvent exchange time was extended to 6 h, the aerogel filling degree gradually increased, but fiber exposure still existed. Figure 3 After 8 hours of solvent exchange, the aerogel uniformly encapsulates the fibers and fills the gaps, forming a complete micro-nano interpenetrating network. Figure 4 ); continue to extend to 10-14 hours ( Figures 5 to 7 When the aerogel swells, cracks, or even falls off, its structural integrity is gradually lost.

[0060] The wettability of the prepared modified glass fiber mat was tested, and the test results are shown in Table 1 and 2. Figure 8 As shown.

[0061] Table 1 Experiments show that without solvent exchange, the material surface has a relatively low contact angle due to aerogel shrinkage and exposed fibers. Figure 8 As shown in (a) above; with the extension of solvent exchange time to 6-8 h, the aerogel network structure gradually becomes complete, the hydrophobic modification of TMCS is sufficient, and the contact angle is significantly improved, reaching its maximum at 8 h, as shown in (a). Figure 8 As shown in (b) and (c) in the figure; with continued extension of solvent exchange time (10h-12h), the aerogel network gradually breaks down and detaches, the micro-nano rough structure disappears, and the contact angle gradually decreases, as shown in the figure. Figure 8 As shown in (d), (e), and (f).

[0062] The modified glass fiber mat was subjected to oil wetting behavior tests, and the test results are shown in Table 2 and... Figure 9 As shown.

[0063] Table 2 Experiments show that from 0h to 12h, oil droplets spread and wetted significantly on the surface of the material (modified glass fiber mat) without a significant contact angle, exhibiting oleophilicity. When the solvent exchange time was 14h, the oil droplets on the surface of the material (modified glass fiber mat) appeared as weak droplets with a slight contact angle, and the wettability was reduced.

[0064] That is, the material as a whole exhibits oleophilic characteristics. As the solvent exchange time increases, the material's wettability to oil gradually weakens, and the oleophilicity is lowest at 14 h.

[0065] The modified glass fiber mat was subjected to infrared thermal imaging heat insulation test, and the test results are shown in Table 3. Figure 10 As shown.

[0066] Table 3 As shown in Table 3, the thermal insulation performance of all solvent-exchanged samples was significantly better than that of the control group without solvent exchange.

[0067] In terms of temperature rise rate, the 8-hour solvent exchange sample performed best, with a temperature rise of only 10.7℃ within 70 seconds, significantly lower than the 15.6℃ of the 14-hour sample, indicating the slowest heat penetration rate and the best thermal insulation stability. The center temperature of the 12-hour and 14-hour samples at 70 seconds was slightly lower than that of the 8-hour sample, mainly due to the difference in initial test temperature and the influence of sample surface condition. Combining temperature rise rate and microstructure analysis, the complete micro-nano interpenetrating network formed in the 8-hour sample is the key to achieving long-term stable thermal insulation, while the aerogel network in the 12-14-hour samples partially detached, and the thermal insulation performance began to deteriorate, lacking long-term application advantages.

[0068] Figure 11 Tensile stress-strain curves of modified glass fiber mats prepared under different solvent exchange times.

[0069] Experiments show that the sample without solvent exchange (0 h) exhibits high strength but significant brittle fracture. With solvent exchange time extended to 6-8 h, the sample strength slightly decreases, but the stress after fracture decays slowly, and the toughness significantly improves, indicating enhanced interfacial bonding between the aerogel and fiber, achieving fiber bridging and pull-out toughening. The sample strength decreases significantly at 10 h, indicating that excessive solvent exchange leads to aerogel network destruction and weakened interfacial bonding. The sample at 12 h shows the highest peak strength while retaining good toughness, exhibiting excellent comprehensive mechanical properties. This phenomenon stems from a change in the stress mode: partial aerogel detachment allows the glass fiber skeleton to become the main load-bearing component again, while the remaining aerogel bonding points at fiber nodes effectively improve the load transfer efficiency between fibers, still consuming energy through interfacial debonding. However, the thermal insulation and hydrophobic properties are inferior to the 8 h sample. The 14 h sample has higher strength but increased brittleness, indicating a further weakening of the aerogel toughening effect. These results demonstrate that solvent exchange time significantly affects the tensile strength and fracture toughness of the material by regulating the interfacial bonding state between the aerogel and fiber.

[0070] In summary, this application uses flexible porous glass fiber mat as a substrate and employs an in-situ sol-gel method to hydrolyze and condense the silicon precursor tetraethyl orthosilicate (TEOS) in situ within the fiber surface and internal pores, forming silica gel nanoparticles. Furthermore, a low surface energy modifier, trimethylchlorosilane (TMCS), is introduced to graft hydrophobic groups into the gel network. This process achieves in-situ filling and bonding of the silica gel to the three-dimensional network structure of the fiber membrane, rather than a simple surface coating.

[0071] After modification with low surface energy materials, a robust hydrophobic layer forms on the surface of the fiber membrane, with a static water contact angle exceeding 150°, exhibiting superhydrophobic properties. This effectively prevents efficiency degradation and resistance increase caused by moisture infiltration in high humidity or oil mist environments, maintaining stable filtration performance.

[0072] Furthermore, the silicone gel forms a strong "spot weld" structure between the fibers, which can significantly enhance the mechanical strength and dimensional stability of the fiber membrane, thereby improving its durability and service life.

[0073] The in-situ generated silicone gel particles are evenly distributed on the fiber surface and at the intersections. While significantly improving the retention efficiency of small particles (such as PM2.5) (up to 99% or more), the gel is mainly deposited at the fiber intersections rather than completely blocking the pores, which can better maintain the original air permeability of the substrate.

[0074] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing aerogel-filled modified glass fiber mat, characterized in that, Includes the following steps: S1, Preparation of silica sol: Tetraethyl orthosilicate, anhydrous ethanol, and deionized water are mixed to obtain a mixed solution; then, the pH of the mixed solution is adjusted to 2-3, and sonication is continued until tetraethyl orthosilicate is completely hydrolyzed to obtain a uniform silica sol. S2, Preparation and aging of wet gel: The pH of the silica sol is adjusted to 6-6.5; then, the glass fiber mat is completely immersed in the silica sol to form a wet gel; The wet gel was aged in anhydrous ethanol to allow the gel network to fully cross-link. S3, Solvent exchange and hydrophobic modification: The aged wet gel is placed in a mixed solution of hexane and anhydrous ethanol for solvent exchange; then the wet gel is immersed in anhydrous ethanol solution containing trimethylchlorosilane for modification, so that hydrophobic methyl groups are grafted onto the surface of the aerogel, thus obtaining aerogel-filled modified glass fiber mat.

2. The method for preparing aerogel-filled modified glass fiber mat according to claim 1, characterized in that, In step S3, the solvent exchange time is 6-8 hours.

3. The method for preparing aerogel-filled modified glass fiber mat according to claim 1, characterized in that, In step S1, the molar ratio of tetraethyl orthosilicate, anhydrous ethanol, and deionized water is 1:10:

5.

4. The method for preparing aerogel-filled modified glass fiber mat according to claim 1, characterized in that, In step S3, the volume ratio of n-hexane to anhydrous ethanol in the mixed solution of n-hexane and anhydrous ethanol is 1:

1.

5. The method for preparing aerogel-filled modified glass fiber mat according to claim 1, characterized in that, In step S2, the mass ratio of the glass fiber mat to the silica sol is 1:20 to 1:

38.

6. The method for preparing aerogel-filled modified glass fiber mat according to claim 1, characterized in that, In step S2, the aging time is 12-24 hours.

7. The method for preparing aerogel-filled modified glass fiber mat according to claim 1, characterized in that, The glass fiber mat has a porosity of 70-90% and a density of 150-300 kg / m³. 3 Its thermal conductivity is 0.030-0.045 W / (m·K).

8. An aerogel-filled modified glass fiber mat, characterized in that, The aerogel-filled modified glass fiber mat is prepared by any one of the preparation methods described in claims 1-7; the aerogel-filled modified glass fiber mat includes hydrophobic modified silica aerogel in a three-dimensional network structure generated in situ inside the glass fiber mat; the hydrophobic modified silica aerogel and the glass fiber mat form a hierarchical structure in which the glass fiber micro-network and the silica aerogel nano-network are intertwined.

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