A flexible and elastic double-silica aerogel / glass fiber composite material, a preparation method and application thereof

Abstract

The present application provides a kind of flexible elasticity double silicon aerogel / glass fiber composite material and its preparation method and application, belong to thermal insulation material technical field, the present application is prepared aerogel with methyl trimethoxysilane and dimethyl dimethoxysilane as double organosilicon source, can make the double silicon aerogel / glass fiber composite material prepared have more excellent flexibility, solve the problem that aerogel thermal insulation material generally exists in prior art, powder and slag drop, material is fragile and does not have flexibility, preparation process is complicated, lacks security, preparation cycle is long etc.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation materials technology, and particularly relates to a flexible and elastic dual silica aerogel / glass fiber composite material, its preparation method and application. Background Technology

[0002] Aerogel materials are lightweight nanomaterials composed of nano-sized ultrafine particles aggregated to form a nanoporous network structure, with gaseous dispersion media filling the pores of the network. Developed starting in the 1930s, these nanoporous super-insulating materials possess a high specific surface area (600–1200 m²). 2 The SiO2 aerogel has a porosity of over 90% and an average pore size of tens of nanometers. A key property of the SiO2 aerogel's pore structure is its openness and interconnectivity. This unique spatial structure endows the aerogel with many excellent properties, including extremely low thermal conductivity, high adsorption, loading capacity, and catalytic activity.

[0003] Compared to inorganic aerogels, organic aerogels have attracted more attention from researchers due to their excellent flexibility and thermal insulation properties. Among them, organosilicon aerogels are the most widely studied. However, the current macroscopic morphology of organosilicon aerogels is mostly blocky, and the preparation and drying processes are mostly freeze drying and supercritical drying, which have high preparation costs and seriously limit the large-scale production and industrialization of organosilicon aerogels.

[0004] Therefore, the composite of aerogel and fiber has become a research hotspot. However, in terms of current development, the main material for the composite of aerogel and fiber is inorganic aerogel. Inorganic aerogel fiber felt has disadvantages such as powder and residue shedding and complex preparation process.

[0005] For example, Guo Jianye et al. from the Aerospace Special Materials and Process Technology Research Institute prepared a composite material of inorganic aerogel and glass fiber mat using supercritical drying, which has excellent thermal insulation performance. However, the drying method is complex and takes about 5 days (10.19964 / j.issn.1006-4990.2023-0027); Bhuiyan et al. prepared a sandwich-structured nanofiber aerogel mat by adding aerogel particles to the spinning solution. They mainly used electrospinning, and the resulting aerogel fiber mat has good thermal insulation performance. However, the aerogel modifies the spinning raw materials, affecting normal spinning and spinning stability (10.1177 / 1528083720939670); Wu Tianfu disclosed a molded aerogel fiber composite board, in which SiO2 aerogel, nanoporous silicon fiber, and nano-antimony oxide are added to expanded vermiculite, mixed evenly, and then extruded in an infrared reflective screen mold. This method allows for the addition of a larger amount of aerogel, but the product's flexibility is not as good as the product prepared by the methods mentioned above.

[0006] The above-mentioned drawbacks, such as flaking and powdering, poor stability, and the hardness and lack of flexibility of the composite material, limit the application of aerogel fiber composites in various fields. Summary of the Invention

[0007] This invention utilizes a sol-gel method to prepare a dual-silicon source material under ambient temperature and pressure. This material exhibits no powder or residue shedding, excellent flexibility, and superior thermal insulation properties, making it particularly suitable for application in the automotive industry as a flexible dual-silicon aerogel / glass fiber composite material. The introduction of the dual-silicon source enhances the flexibility of the organic aerogel. The composite of the flexible dual-silicon aerogel and glass fiber is cost-effective, safe, environmentally friendly, easy to operate, and possesses excellent flame-retardant and thermal insulation properties. It solves the common problems of powder and residue shedding, fragility, lack of flexibility, cumbersome preparation processes, lack of safety, and long preparation cycles found in other aerogel insulation materials.

[0008] To achieve the above objectives, the present invention provides a method for preparing a flexible and elastic dual silica aerogel / glass fiber composite material, comprising the following steps:

[0009] Mix hexadecyltrimethylammonium bromide, methanol, and acetic acid, stir well, and prepare the first solution;

[0010] Methyltrimethoxysilane, dimethyldimethoxysilane and N,N-dimethylformyl were added to the first solution, and the solution was stirred at a constant temperature and the pH was adjusted to alkaline to obtain the second solution.

[0011] After the second solution is stirred at a constant temperature until homogeneous, glass fiber is immersed in it, sealed, and then subjected to gel treatment to obtain a wet gel composite material.

[0012] Isopropanol was added to the wet gel composite material, and after sealing and aging treatment, the aged wet gel composite material was obtained.

[0013] Hexane was added to the aged wet gel composite material, and after sealing and aging treatment, a flexible bissilica aerogel / glass fiber composite material was obtained after drying.

[0014] This invention uses methyltrimethoxysilane and dimethyldimethoxysilane as dual organosilicon sources to prepare aerogels, which can make the prepared dual-silicon aerogel / glass fiber composite material have better flexibility. It solves the problems of powder and slag shedding, brittleness and lack of flexibility, complicated preparation process, lack of safety and long preparation cycle that are common in existing aerogel thermal insulation materials.

[0015] Furthermore, the mass ratio of hexadecyltrimethylammonium bromide, methanol, and acetic acid is 1:40:80. Hexadecyltrimethylammonium bromide acts as a surfactant to assist in constructing the microstructure of the aerogel, methanol acts as a solvent, and acetic acid acts as an acid-base agent to induce the subsequent hydrolysis reaction of the silicon source.

[0016] Furthermore, the mass ratio of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformyl is 27:16:7. Methyltrimethoxysilane and dimethyldimethoxysilane serve as dual silicon sources, are fused in a solvent, and undergo a hydrolysis reaction. N,N-dimethylformyl acts as a pore-forming agent, assisting in constructing the porous structure of the aerogel.

[0017] Furthermore, the pH is adjusted to alkaline by adjusting the pH to 8 with ammonia.

[0018] Furthermore, the temperature of the constant-temperature stirring is 30°C.

[0019] Furthermore, the gel treatment time is 6 hours; the aging treatment time is 6 hours in both cases.

[0020] Furthermore, the volume ratio of aerogel to glass fiber is (2-10):(1-7), preferably 10:1, 5:1, 10:3, 5:2, 2:1, 5:3 or 10:7, more preferably 5:3.

[0021] Furthermore, the preparation method of the flexible dual silica aerogel / glass fiber composite material specifically includes the following steps:

[0022] 1) Weigh out hexadecyltrimethylammonium bromide, methanol and acetic acid according to a mass ratio of 1:40:80, prepare a solution, and stir at 30°C for 5 minutes to ensure complete mixing;

[0023] 2) Weigh out methyltrimethoxysilane, dimethyldimethoxysilane and N,N-dimethylformyl in a mass ratio of 27:16:7 and add them to the solution in step 1). Stir at 30°C for 1 hour and then add ammonia water to adjust the pH of the solution to 8.

[0024] 3) After stirring the solution from step 2) at a constant temperature of 30°C for 5 minutes, soak and composite it with glass fiber cut to a size of 5cm*5cm*0.5cm, seal it with plastic wrap, and place it in an oven for gelation for 6 hours.

[0025] 4) Add 20 mL of isopropanol to the wet gel composite material obtained in step 3), seal it with plastic wrap, and place it in an oven for aging for 6 hours.

[0026] 5) Add 20 mL of n-hexane to the aged wet gel composite material in step 4), seal it with plastic wrap, and place it in an oven for aging for 6 hours. After aging, remove the plastic wrap and dry at room temperature to obtain a flexible double silica aerogel / glass fiber composite material.

[0027] A flexible dual-silica aerogel / glass fiber composite material is prepared by the above method.

[0028] The application of the aforementioned flexible dual-silica aerogel / glass fiber composite material in the preparation of thermal insulation materials.

[0029] Applications of the aforementioned flexible dual-silica aerogel / glass fiber composite material in the automotive field.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] Compared with other aerogel composites, the flexible and elastic dual-silica aerogel / glass fiber composite material prepared in this invention uses dual organosilicones as organosilicon sources, which makes the composite material have better flexibility.

[0032] Compared with other aerogel composite materials, the flexible and elastic dual silica aerogel / glass fiber composite material prepared by this invention has a lower preparation cost and a shorter preparation cycle.

[0033] Compared with other aerogel composite materials, the flexible and elastic dual silica aerogel / glass fiber composite material prepared in this invention has superior thermal insulation and thermal stability.

[0034] Compared with other aerogel composite materials, the flexible and elastic dual silica aerogel / glass fiber composite material prepared in this invention has excellent properties of not shedding powder or slag. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0036] Figure 1 This is a physical image of the flexible dual-silica aerogel / glass fiber composite material prepared in Example 6 of the present invention.

[0037] Figure 2 These are the thermogravimetric and micro-thermogravimetric diagrams of the flexible double silica aerogel / glass fiber composite material prepared in Example 6 of this invention.

[0038] Figure 3 The stress-strain curve (left) and testing equipment (right) of the flexible double silica aerogel / glass fiber composite material prepared in Example 6 of this invention.

[0039] Figure 4 This is a comparison of the thickness of the flexible double silica aerogel / glass fiber composite material prepared in Example 6 of the present invention before and after 10,000 cycles of cyclic compression. Detailed Implementation

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0042] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0043] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0044] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0045] In this embodiment of the invention, room temperature refers to 25±2℃; normal pressure refers to one standard atmosphere.

[0046] To better highlight the inventive aspects of this invention, several sets of prior art will be cited below:

[0047] Existing technology 1: The team from the University of Science and Technology of China (10.1007 / s10971-017-4312-4) used water glass as an inexpensive inorganic silicon source to prepare wet gel through the sol-gel method. The wet gel was then processed by mechanical crushing and filtration to obtain powdered SiO2 aerogel. The incomplete structure limited the application range of SiO2 aerogel materials. Moreover, as a silicon source, water glass contains a lot of impurity ions in the solution, which are difficult to remove, making it difficult to obtain high-purity SiO2 aerogel. This has a great impact on the structure and performance of SiO2 aerogel.

[0048] Existing technology 2: The Luo Dan research group at Guizhou University (10.19817 / j.cnki.issn1006-3536.2022.04.032) prepared a glass fiber reinforced silica aerogel composite material using tetraethyl orthosilicate as a precursor and glass fiber as a reinforcing phase. However, the interfacial bonding between the glass fiber and the silica particle matrix is ​​poor, resulting in a silica aerogel composite material with poor mechanical properties and a high thermal conductivity of 0.0410 W / (m·K).

[0049] Existing technology 3: The He Xiangmei research group at Guanghua University (Guangdong Chemical Industry, 2014, 41(01):21-22+34) prepared aerogels using methyltrimethylsilane as a single silicon source, with a thermal conductivity between 0.030-0.040 W / (m·K). However, the prepared aerogels did not have flexibility. The Kanamrio research group at the University of Tokyo (10.14853 / PCERSJ.2003F.0.171.0) also prepared aerogels using MTMS as a single silicon source. During the preparation process, strong acids and bases were added as catalysts, which greatly increased the risk factor of the experimental process and the consequences of environmental pollution.

[0050] Existing technology 4: The Tianjin University team (10.1016 / j.ceramint.2018.01.089) used zirconia fiber felt (ZFF) with good heat resistance as the skeleton and ZrO2-SiO2 aerogel as the filler to prepare a composite material with a high porosity of 89% by vacuum impregnation method, while the thermal conductivity is only 0.046W / (m·K); The Naval University of Engineering team (10.1007 / S10971-021-05701-Z) prepared polymethylsiloxane aerogel composite material with polyimide short fibers as the reinforcing phase. Although it has a low thermal conductivity, it has a resilience of only 46% and a maximum compressive strength of only 0.023MPa.

[0051] The following embodiments further illustrate the solution of the present invention:

[0052] Example 1

[0053] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid (methanol to acetic acid mass ratio 1:2, the same below), and stir at 30 °C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution, cover with plastic wrap, and stir at 30 °C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia water to adjust the pH of the mixture to 8, and stir at 30 °C for 5 min. Then, mix with pre-cut glass fibers (5 cm in size). A 5cm x 0.5cm aerogel (hereinafter the same) was soaked and laminated with glass fiber at a volume ratio of 10:1. The aerogel was then sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20mL of isopropanol was added, the aerogel was sealed again, and the wet gel was placed in an oven for aging. After another 6 hours, 20mL of n-hexane was added, the aerogel was sealed again, and the gel was placed in an oven for secondary aging. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, double-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.249 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3 It has a thermal conductivity of 0.036 M / (m·K), a rebound rate of 95.8% after 10,000 compression cycles, a maximum compressive strength of 5.432 MPa, excellent flexibility, and does not shed powder or slag.

[0054] Example 2

[0055] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The aerogel to glass fiber volume ratio was 5:1. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, double-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.228 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3It has a thermal conductivity of 0.0358 M / (m·K), a rebound rate of 96.2% after 10,000 compression cycles, a maximum compressive strength of 6.113 MPa, excellent flexibility, and does not shed powder or slag.

[0056] Example 3

[0057] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The aerogel to glass fiber volume ratio was 10:3. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, elastic dual-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.193 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3 It has a thermal conductivity of 0.0331 M / (m·K), a rebound rate of 96.6% after 10,000 compression cycles, a maximum compressive strength of 8.478 MPa, excellent flexibility, and does not shed powder or slag.

[0058] Example 4

[0059] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The aerogel to glass fiber volume ratio was 5:2. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, double-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.171 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3 It has a thermal conductivity of 0.0321 M / (m·K), a rebound rate of 97.1% after 10,000 compression cycles, a maximum compressive strength of 7.934 MPa, excellent flexibility, and does not shed powder or slag.

[0060] Example 5

[0061] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate with pre-cut glass fibers. The volume ratio of gel to glass fiber was 2:1. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, elastic bis-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.136 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3It has a thermal conductivity of 0.0292 M / (m·K), a rebound rate of 97.3% after 10,000 compression cycles, a maximum compressive strength of 8.669 MPa, excellent flexibility, and does not shed powder or slag.

[0062] Example 6

[0063] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The aerogel to glass fiber volume ratio was 5:3. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, elastic dual-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.122 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3 It has a thermal conductivity of 0.0286 M / (m·K), a rebound rate of 98.7% after 10,000 compression cycles, a maximum compressive strength of 10.685 MPa, excellent flexibility, and does not shed powder or slag.

[0064] A physical image of the flexible, elastic silica aerogel / glass fiber composite material prepared in Example 6 of this invention is shown below. Figure 1 The thickness of the flexible double silica aerogel / glass fiber composite material is about 2mm, which has a certain degree of flexibility and a smooth surface.

[0065] The thermogravimetric and derivative thermogravimetric plots of the flexible, elastic, dual-silica aerogel / glass fiber composite material prepared in Example 6 of this invention are shown below. Figure 2 Data shows that the residual weight of the composite material is 78%, proving that the composite material has excellent thermal stability.

[0066] The vibration mass loss rate of the flexible double silica aerogel / glass fiber composite material prepared in Example 6 was tested at the National Glass Fiber Product Quality Inspection and Testing Center of Nanjing Guocai Testing Co., Ltd., a subsidiary of the China National Testing and Inspection Holding Group (GNC Testing). The test results are shown in Table 1. The vibration mass loss rate of the composite material is as low as 0.1%, which proves that the flexible double silica aerogel / glass fiber composite material prepared in this invention has excellent properties of not shedding powder or slag.

[0067] Table 1

[0068] 1 Vibration mass loss rate / % Appendix B of GB / T 34336-2017 0.1

[0069] Note: Serial number 1 was tested at Andrei Laboratory No. 30.

[0070] Figure 3 The left image shows the stress-strain curve of the flexible double silica aerogel / glass fiber composite material prepared in Example 6 of this invention, and the right image shows the testing equipment. It can be seen that the prepared composite material has good stretchability, and the maximum tensile stress can reach 10.685 MPa.

[0071] Figure 4 This is a comparison of the thickness of the flexible double silica aerogel / glass fiber composite material prepared in Example 6 of the present invention before and after 10,000 cycles of compression. The resilience of the composite material after 10,000 cycles of compression can be calculated from the thickness comparison before and after compression. The formula is E=(H2 / H1)*100%. After calculation, the resilience of the composite material after 10,000 cycles of compression is 98.7%.

[0072] In the formula:

[0073] E – Rebound Rate (%)

[0074] H1 — Thickness of the composite material before compression (cm)

[0075] H2 — Thickness of the composite material after compression (cm)

[0076] Example 7

[0077] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The volume ratio of aerogel to glass fiber was 10:7. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, elastic bis-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.147 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3 It has a thermal conductivity of 0.0301 M / (m·K), a rebound rate of 96.9% after 10,000 compression cycles, a maximum compressive strength of 6.227 MPa, excellent flexibility, and does not shed powder or slag.

[0078] Example 8

[0079] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The aerogel to glass fiber volume ratio was 5:4. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, double-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.155 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3It has a thermal conductivity of 0.0307 M / (m·K), a rebound rate of 96.2% after 10,000 compression cycles, a maximum compressive strength of 5.779 MPa, good flexibility, and does not shed powder or slag.

[0080] Example 9

[0081] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, dimethyldimethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The aerogel to glass fiber volume ratio was 10:9. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, double-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.187 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3 It has a thermal conductivity of 0.0333 M / (m·K), a rebound rate of 95% after 10,000 compression cycles, a maximum compressive strength of 3.121 MPa, good flexibility, and does not shed powder or slag.

[0082] Comparative Example 1

[0083] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of a mixed solution of methyltrimethoxysilane, vinyltriethoxysilane, and N,N-dimethylformamide to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The aerogel to glass fiber volume ratio was 5:3. The gel was sealed with plastic wrap and placed in an oven to stand for 6 hours. Afterward, 20 mL of isopropanol was added, the gel was sealed again with plastic wrap, and placed in the oven for aging. After another 6 hours, 20 mL of n-hexane was added, the gel was sealed again with plastic wrap, and placed in the oven for a second aging process. After 6 hours, the plastic wrap was removed, and the gel was dried at room temperature and pressure to obtain a flexible, double-silica aerogel / glass fiber composite material. The density of the composite material was calculated to be 0.223 kg / cm³ using the formula ρ = M / V, based on the mass and volume of the composite material. 3 It has a thermal conductivity of 0.0477 M / (m·K), a rebound rate of 84.9% after 10,000 compression cycles, a maximum compressive strength of 4.029 MPa, moderate flexibility, and exhibits powdering and flaking.

[0084] This comparative example successfully prepared aerogel / glass fiber composite material, but the performance of the prepared composite material was much worse than that of the material in this application. It had poorer flexibility, increased thermal conductivity, and also exhibited powder and slag shedding.

[0085] Comparative Example 2

[0086] Dissolve 0.40 g of hexadecyltrimethylammonium bromide in 46 mL of a mixed solution of methanol and acetic acid. Stir at 30°C for 5 min until completely dissolved. Add 11.5 mL of tetraethyl orthosilicate solution to the above solution. Cover with plastic wrap and stir at 30°C for 1 h to obtain a homogeneous mixture. Add 0.3 mL of ammonia to adjust the pH of the mixture to 8, and stir at 30°C for 5 min. Then, impregnate and laminate the mixture with pre-cut glass fibers. The volume ratio of aerogel to glass fiber is 5:1. 3. Cover with plastic wrap and place in an oven to allow the gel to stand for 6 hours. Add 20 mL of isopropanol, cover with plastic wrap again, and place in an oven to age the wet gel. After 6 hours, add 20 mL of n-hexane, cover with plastic wrap again, and place in an oven for a second aging process. After 6 hours, remove the plastic wrap and dry at room temperature and pressure to obtain a flexible bis-silica aerogel / glass fiber composite material. The density of the composite material, calculated using the formula ρ = M / V, is 0.205 kg / cm³.3 It has a thermal conductivity of 0.0433 M / (m·K), a rebound rate of 78.6% after 10,000 compression cycles, a maximum compressive strength of 4.622 MPa, moderate flexibility, and exhibits powdering and flaking.

[0087] Comparative Example 3

[0088] 0.40 g of hexadecyltrimethylammonium bromide was dissolved in 46 mL of a mixed solution of methanol and acetic acid. The solution was stirred at 30 °C for 5 min until completely dissolved. 11.5 mL of water glass solution was added to the above solution. The mixture was covered with plastic wrap and stirred at 30 °C for 1 h to obtain a homogeneous mixture. 0.3 mL of ammonia was added to adjust the pH of the mixture to 8, and the mixture was stirred at 30 °C for 5 min. The mixture was then impregnated and laminated with pre-cut glass fibers. The volume ratio of aerogel to glass fiber was 5:1. 3. Cover with plastic wrap and place in an oven to allow the gel to stand for 6 hours. Add 20 mL of isopropanol, cover again with plastic wrap, and place in the oven to age the wet gel. After 6 hours, add 20 mL of n-hexane, cover again with plastic wrap, and place in the oven for a second aging process. After 6 hours, remove the plastic wrap and dry at room temperature and pressure to obtain a flexible bis-silica aerogel / glass fiber composite material. Based on the mass and volume calculation of the flexible bis-silica aerogel / glass fiber composite material, the density of the composite material was calculated to be 0.768 kg / cm³ using the formula ρ = M / V. 3 It has a thermal conductivity of 0.0625 M / (m·K), a rebound rate of 60.4% after 10,000 compression cycles, a maximum compressive strength of 3.792 MPa, poor flexibility, and exhibits powdering and flaking.

[0089] As can be seen from the above examples and comparative examples, the present invention uses methyltrimethoxysilane and dimethyldimethoxysilane as dual organosilicon sources to prepare aerogels, which can give the prepared dual-silicon aerogel / glass fiber composite materials superior flexibility. This solves the problems commonly found in existing aerogel insulation materials, such as powder and flaking, fragility and lack of flexibility, cumbersome preparation processes, lack of safety, and long preparation cycles. The composite material prepared by the method of the present invention not only has low thermal conductivity and excellent thermal insulation performance, but also features simple preparation, safety, environmental friendliness, and low cost, showing good application prospects in the automotive field.

[0090] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a flexible, elastic, dual-silica aerogel / glass fiber composite material, characterized in that, Includes the following steps: Mix hexadecyltrimethylammonium bromide, methanol, and acetic acid, stir well, and prepare the first solution; Methyltrimethoxysilane, dimethyldimethoxysilane and N,N-dimethylformamide were added to the first solution, and the solution was stirred at a constant temperature of 30°C. The pH was then adjusted to 8 with ammonia to obtain the second solution. After stirring the second solution at a constant temperature of 30°C until homogeneous, glass fiber is immersed in it, sealed, and then subjected to gel treatment for 6 hours to obtain a wet gel composite material. Isopropanol was added to the wet gel composite material, and after sealing, it was aged for 6 h to obtain the aged wet gel composite material. Add n-hexane to the aged wet gel composite material, seal and age it, and then dry to obtain a flexible bissilica aerogel / glass fiber composite material. The mass ratio of hexadecyltrimethylammonium bromide, methanol and acetic acid is 1:40:80; The mass ratio of methyltrimethoxysilane, dimethyldimethoxysilane and N,N-dimethylformamide is 27:16:7; The volume ratio of aerogel precursor to glass fiber is 5:

3.

2. A flexible dual-silica aerogel / glass fiber composite material, characterized in that, Prepared according to the method of claim 1.

3. The application of the flexible dual-silica aerogel / glass fiber composite material according to claim 2 in the field of preparing thermal insulation materials.

4. The application of the flexible dual-silica aerogel / glass fiber composite material according to claim 2 in the automotive field.

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