Aerogel composite glass fiber needled felt acoustic panel and preparation method thereof

Abstract

The invention discloses an aerogel composite glass fiber needled felt acoustic board and a preparation method thereof, and relates to the technical field of composite board materials. The preparation method of the aerogel composite glass fiber needled felt acoustic panel at least comprises the following preparation steps that after ultrasonic treatment is conducted on needled glass fiber felt through a silane coupling agent solution, the needled glass fiber felt is soaked in porous nanofiber-reduced graphene oxide-silicon dioxide sol for vacuum impregnation, after gel aging, an alcoholic solution of a hydrophobic modifier is added, and the aerogel composite glass fiber needled felt acoustic panel is obtained. Carrying out hydrophobic modification and solvent replacement, and drying to obtain an aerogel needled glass fiber felt; soaking the aerogel needled glass fiber felt in a zinc borate solution, washing and drying to obtain a modified needled glass fiber felt; the modified needled glass fiber felt is arranged between two plates, and the aerogel composite glass fiber needled felt acoustic panel is obtained through compounding of an adhesive. The aerogel composite glass fiber needled felt acoustical board prepared by the invention has excellent sound absorption performance, flame retardance and heat insulation performance.

Description

Technical Field

[0001] This invention relates to the field of composite board materials technology, specifically to an aerogel composite glass fiber needled felt sound-absorbing board and its preparation method. Background Technology

[0002] With the development of science and technology, noise pollution has become a hidden danger threatening public health and the environment. Due to imbalances in urban planning, noise pollution problems persist in many cities, severely impacting people's lifestyles. This noise pollution not only causes various diseases such as heart disease, learning disabilities, and tinnitus, but may also shorten lifespan. Therefore, reducing noise pollution is crucial for protecting people's health. Optimizing the living and working environment directly helps improve people's quality of life and has a positive significance for maintaining long-term social harmony and stability.

[0003] Measures to control noise pollution include the application of sound-absorbing materials, such as resonant sound-absorbing materials and porous sound-absorbing materials. Currently, the most widely used sound-absorbing material is the porous sound-absorbing material, which consists of channels, cracks, or pores that allow sound waves to enter the material. Sound absorption by porous materials is a physical energy conversion process; the main sound absorption mechanisms are intrinsic damping and viscous loss at the pore surface. When sound waves propagate through porous sound-absorbing materials, the sound wave energy is converted into heat energy. This heat energy is then further transmitted and diffused into the surrounding air through viscous resistance, compression and expansion, or vibration. Furthermore, porous sound-absorbing materials, with their low cost, ease of molding, and lightweight properties, have become an ideal choice for noise control in fields such as construction and transportation.

[0004] Porous sound-absorbing materials are among the most widely used sound-absorbing materials. They consist of numerous interconnected or unconnected pores, exhibiting a network structure. Porous materials have a wide range of applications in daily life. Compared to continuous, dense media, porous materials have lower relative density, higher specific strength and specific surface area, while also exhibiting excellent mechanical properties, air permeability, and adsorption properties, as well as superior sound insulation. Therefore, porous materials are widely used in the manufacture of sound insulation and vibration damping materials.

[0005] Silica aerogel is a porous bulk material formed by interconnected nanoscale silica particles. Due to its nanoscale framework and internal pores, silica aerogel possesses extremely low density, extremely low thermal conductivity, and excellent thermal insulation properties, making it widely used in building insulation, aerospace thermal protection, sound absorption and noise reduction, and weapons manufacturing. However, while its unique spatial structure endows it with excellent thermal insulation properties, it also results in drawbacks such as low strength, poor continuity of the aerogel nanonetwork framework, poor physicochemical bonding of the nanoporous structure, and relatively brittle products. Therefore, developing novel silica aerogels that combine thermal protection and load-bearing functions has been a key research focus both domestically and internationally. Summary of the Invention

[0006] The purpose of this invention is to provide an aerogel composite fiberglass needled felt sound-absorbing board and its preparation method, thereby solving the following technical problems: Existing silica aerogels used in sound-absorbing panels suffer from poor mechanical properties, susceptibility to moisture degradation, and poor flame retardancy.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing an aerogel composite fiberglass needled felt sound-absorbing panel includes at least the following preparation steps: After being ultrasonically treated with a silane coupling agent solution, the needled fiberglass felt was immersed in a porous nanofiber-reduced graphene oxide-silica sol for vacuum impregnation. After gel aging, an alcohol solution of a hydrophobic modifier was added to perform hydrophobic modification and solvent replacement. After drying, aerogel needled fiberglass felt was obtained. The aerogel needled fiberglass felt was soaked in zinc borate solution, washed and dried to obtain modified needled fiberglass felt. The modified needle-punched fiberglass felt is placed between two plates and bonded together with an adhesive to obtain an aerogel composite fiberglass needle-punched felt sound-absorbing board.

[0008] As a further aspect of the present invention: the thickness of the modified needle-punched glass fiber mat is 3-20 mm, and the modified needle-punched glass fiber mat contains at least 30-55 wt% porous nanofiber-reduced graphene oxide-silica aerogel, 3-8 wt% zinc borate, 1-3 wt% silane coupling agent and 1-3 wt% hydrophobic modifier.

[0009] As a further aspect of the present invention, the preparation method of the porous fiber-reduced graphene oxide-silica sol includes the following steps: Ethylenediamine was added to an aqueous solution of graphene oxide, sealed and heated, washed and freeze-dried to obtain reduced graphene oxide aerogel. Tetraethoxysilane, anhydrous ethanol and deionized water were stirred and mixed, and the pH was adjusted to 2-3. Then 3-aminopropyltriethoxysilane was added, and the mixture was added to the reduced graphene oxide aerogel to obtain reduced graphene oxide-silica sol. Porous polylactic acid nanofibers were added to the reduced graphene oxide-silica sol and ultrasonically dispersed to obtain porous fiber-reduced graphene oxide-silica sol.

[0010] As a further aspect of the present invention: the volume ratio of the tetraethoxysilane, the anhydrous ethanol and the deionized water is 0.5-2:1-5:0.1-1, and the content of the reduced graphene oxide in the reduced graphene oxide-silica sol is 1-3 wt%.

[0011] As a further aspect of the present invention, the content of the porous polylactic acid nanofibers in the porous fiber-reduced graphene oxide-silica sol is 2-5 wt%.

[0012] As a further aspect of the present invention, the method for preparing the porous nanofibers includes the following steps: A non-solvent cyclohexane was introduced into a dichloromethane / dimethyl sulfoxide system, and polylactic acid was added to obtain a polylactic acid spinning solution. After spinning and grinding, porous nanofibers were obtained.

[0013] As a further aspect of the present invention: the length of the porous nanofiber is 0.1-1 mm, the content of polylactic acid in the spinning solution is 8-12 wt%, and the mass ratio of dichloromethane, dimethyl sulfoxide and cyclohexane is 7-9:1-2:1.

[0014] As a further aspect of the present invention: the board is poplar board, the thickness of the board is 5-10mm, and the adhesive is at least one of epoxy resin adhesive, water-based acrylic adhesive, phenolic adhesive or silica sol adhesive.

[0015] As a further aspect of the present invention: the silane coupling agent is one or a mixture of two of methyltrimethoxysilane or octadecyltrichlorosilane, the hydrophobic modifier is one or a mixture of several of the modifiers, including silane coupling agents, siloxane compounds or silazane compounds, and the alcohol solution is at least one of ethanol and tert-butanol.

[0016] An aerogel composite fiberglass needled felt sound-absorbing board is prepared by any one of the above methods.

[0017] The beneficial effects of this invention are: This invention combines needle-punched fiberglass felt and modified silica aerogel to prepare the core material, which is then bonded to the board with an adhesive to form an aerogel composite fiberglass needle-punched felt sound-absorbing board. The three-dimensional interpenetrating network structure of the needle-punched fiberglass felt and aerogel solves the problem of aerogel brittleness, improving the sound absorption performance and compressive strength of the sound-absorbing board. Furthermore, the further modification of the needle-punched fiberglass felt also improves the waterproof performance, heat insulation performance, and flame retardant performance of the sound-absorbing board, while reducing the thickness of silica aerogel used to meet the same requirements, facilitating construction, thereby improving worker construction efficiency and reducing overall construction costs. Moreover, the use of atmospheric pressure drying technology reduces production costs by more than 30% compared to supercritical processes, making it suitable for large-scale industrial production.

[0018] The modified silica aerogel in this invention is a porous nanofiber-reduced graphene oxide-silica aerogel. The silica aerogel itself possesses nanoscale pores, enabling it to absorb mid-to-high frequency sound waves. The porous polylactic acid nanofibers form a hierarchical porous structure within the aerogel network, effectively capturing low-frequency sound waves, significantly increasing sound energy dissipation, broadening the effective sound absorption band, and greatly improving sound absorption performance. The synergistic effect of the reduced graphene oxide aerogel framework and the silica aerogel imparts an extremely low thermal conductivity to the material, improving the thermal insulation performance of the sound-absorbing panel. Furthermore, the porous polylactic acid nanofibers and reduced graphene oxide also act as a reinforcing framework within the aerogel network, enhancing the mechanical properties of the aerogel.

[0019] In this invention, after forming a porous nanofiber-reduced graphene oxide-silica aerogel in needle-punched fiberglass felt silane, zinc borate is introduced. Zinc borate decomposes at high temperatures to generate borosilicate glass, which covers the surface of the fiberglass felt to form a flame-retardant barrier, isolating oxygen from combustibles. Simultaneously, zinc borate synergistically works with silica in the fiberglass to suppress smoke release during combustion, improving the flame-retardant performance of the sound-absorbing panel. Furthermore, this invention involves pretreatment of the needle-punched fiberglass felt silane coupling agent and subsequent hydrophobic modification, grafting hydrophobic groups onto the aerogel and fiber surfaces, giving the material superhydrophobicity. This effectively prevents performance degradation caused by moisture intrusion and extends service life. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: The preparation method of porous nanofibers includes the following steps: 80g of dichloromethane and 10g of dimethyl sulfoxide were mixed to form a dichloromethane / dimethyl sulfoxide system. 10g of non-solvent cyclohexane was introduced, and 10g of polylactic acid was weighed to prepare a spinning solution with a polylactic acid mass fraction of 10%. The spinning conditions were set as follows: spinning voltage 16kV, solution flow rate 1mL / h, and curing distance 18cm. The relative humidity was controlled at (60±5)% and the ambient temperature was controlled at (25±5)℃. The fibers were spun and ground to obtain porous nanofibers.

[0022] Example 2: The preparation method of porous nanofiber-reduced graphene oxide-silica sol includes the following steps: 220 μL of ethylenediamine was added to an aqueous solution of graphene oxide with a concentration of 2 mg / mL, sealed and heated at 90 °C for 12 h, excess impurities were washed 10 times with deionized water, and the mixture was freeze-dried for 48 h to obtain reduced graphene oxide aerogel. 15 mL of tetraethoxysilane, 30 mL of anhydrous ethanol and 5 mL of deionized water were stirred and mixed at room temperature for 10 min. The pH was adjusted to 2 by adding 1 mol / L oxalic acid to hydrolyze the tetraethoxysilane. Then 3-aminopropyltriethoxysilane was added and the mixture was stirred for another 10 min. The mixture was then added to the above-mentioned reduced graphene oxide aerogel to make the mass fraction of reduced graphene oxide 3%, thus obtaining reduced graphene oxide-silica sol. The porous polylactic acid nanofibers prepared in Example 1 were added to the above-mentioned reduced graphene oxide-silica sol to make the mass fraction of porous polylactic acid nanofibers 4%, and ultrasonically dispersed to obtain porous fiber-reduced graphene oxide-silica sol.

[0023] Example 3: The preparation method of porous nanofiber-reduced graphene oxide-silica sol includes the following steps: 220 μL of ethylenediamine was added to an aqueous solution of graphene oxide with a concentration of 2 mg / mL, sealed and heated at 90 °C for 12 h, excess impurities were washed 10 times with deionized water, and the mixture was freeze-dried for 48 h to obtain reduced graphene oxide aerogel. 15 mL of tetraethoxysilane, 30 mL of anhydrous ethanol and 5 mL of deionized water were stirred and mixed at room temperature for 10 min. The pH was adjusted to 2 by adding 1 mol / L oxalic acid to hydrolyze the tetraethoxysilane. Then 3-aminopropyltriethoxysilane was added and the mixture was stirred for another 10 min. The mixture was then added to the above-mentioned reduced graphene oxide aerogel to make the mass fraction of reduced graphene oxide 2%, thus obtaining reduced graphene oxide-silica sol. The porous polylactic acid nanofibers prepared in Example 1 were added to the above-mentioned reduced graphene oxide-silica sol to make the mass fraction of porous polylactic acid nanofibers 3%, and ultrasonically dispersed to obtain porous fiber-reduced graphene oxide-silica sol.

[0024] Example 4: A method for preparing an aerogel composite fiberglass needled felt sound-absorbing panel includes the following steps: A 10 mm thick needled fiberglass felt was immersed in an ethanol solution of 2 wt% methyltrimethoxysilane and ultrasonically treated for 30 min. Then it was immersed in the porous nanofiber-reduced graphene oxide-silica sol prepared in Example 2 and vacuum impregnated at 0.5 MPa for 30 min. The pH of the system was then adjusted to 8 and allowed to stand in an oven at 50 °C. After the sol gelled, an appropriate amount of ethanol was added and the mixture was aged for 24 h. Then, a mixture of hexamethyldisilazane and tert-butanol in a volume ratio of 4:5 was added to the beaker every 8 h for solvent replacement and hydrophobic modification. This was repeated 3 times. Finally, the mixture was placed in an atmospheric pressure drying oven and heated to 80 °C at a rate of 5 °C / h and dried for 24 h to obtain aerogel needled fiberglass felt. The above-mentioned aerogel needled fiberglass mat was soaked in a 4wt% zinc borate solution for 12 hours, washed with deionized water to remove residual chemical reagents, and then dried at 110℃ for 1.5 hours to obtain modified needled fiberglass mat. The modified needle-punched fiberglass felt was placed between two poplar wood boards with a thickness of 8mm, and then hot-pressed with epoxy resin adhesive at a temperature of 120℃ and a pressure of 1.2MPa for 30 minutes to obtain an aerogel composite fiberglass needle-punched felt sound-absorbing board.

[0025] Example 5: A method for preparing an aerogel composite fiberglass needled felt sound-absorbing panel includes the following steps: A 10 mm thick needled fiberglass felt was immersed in an ethanol solution of 2 wt% methyltrimethoxysilane and ultrasonically treated for 30 min. Then it was immersed in the porous nanofiber-reduced graphene oxide-silica sol prepared in Example 3 and vacuum impregnated at 0.5 MPa for 30 min. The pH of the system was then adjusted to 8 and allowed to stand in an oven at 50 °C. After the sol gelled, an appropriate amount of ethanol was added and the mixture was aged for 24 h. Then, a mixture of hexamethyldisilazane and tert-butanol in a volume ratio of 4:5 was added to the beaker every 8 h for solvent replacement and hydrophobic modification. This was repeated 3 times. Finally, the mixture was placed in an atmospheric pressure drying oven and heated to 80 °C at a rate of 5 °C / h and dried for 24 h to obtain aerogel needled fiberglass felt. The above-mentioned aerogel needled fiberglass mat was soaked in a 4wt% zinc borate solution for 12 hours, washed with deionized water to remove residual chemical reagents, and then dried at 110℃ for 1.5 hours to obtain modified needled fiberglass mat. The modified needle-punched fiberglass felt was placed between two poplar wood boards with a thickness of 8mm, and then hot-pressed with epoxy resin adhesive at a temperature of 120℃ and a pressure of 1.2MPa for 30 minutes to obtain an aerogel composite fiberglass needle-punched felt sound-absorbing board.

[0026] Example 6: A method for preparing an aerogel composite fiberglass needled felt sound-absorbing panel includes the following steps: A 20 mm thick needled fiberglass felt was immersed in an ethanol solution of 2 wt% methyltrimethoxysilane and ultrasonically treated for 30 min. Then it was immersed in the porous nanofiber-reduced graphene oxide-silica sol prepared in Example 2 and vacuum impregnated at 0.5 MPa for 30 min. The pH of the system was then adjusted to 8 and allowed to stand in an oven at 50 °C. After the sol gelled, an appropriate amount of ethanol was added and the mixture was aged for 24 h. Then, a mixture of hexamethyldisilazane and tert-butanol in a volume ratio of 4:5 was added to the beaker every 8 h for solvent replacement and hydrophobic modification. This was repeated 3 times. Finally, the mixture was placed in an atmospheric pressure drying oven and heated to 80 °C at a rate of 5 °C / h and dried for 24 h to obtain aerogel needled fiberglass felt. The above-mentioned aerogel needled fiberglass mat was soaked in a 6wt% zinc borate solution for 12 hours, washed with deionized water to remove residual chemical reagents, and then dried at 110℃ for 1.5 hours to obtain modified needled fiberglass mat. The modified needle-punched fiberglass felt was placed between two 10mm thick poplar boards and hot-pressed with epoxy resin adhesive at a temperature of 120℃ and a pressure of 1.2MPa for 30 minutes to obtain an aerogel composite fiberglass needle-punched felt sound-absorbing board.

[0027] Example 7 A method for preparing an aerogel composite fiberglass needle-punched felt sound-absorbing panel includes the following steps: A 20 mm thick needled fiberglass felt was immersed in an ethanol solution of 2 wt% methyltrimethoxysilane and ultrasonically treated for 30 min. Then it was immersed in the porous nanofiber-reduced graphene oxide-silica sol prepared in Example 3 and vacuum impregnated at 0.5 MPa for 30 min. The pH of the system was then adjusted to 8 and allowed to stand in an oven at 50 °C. After the sol gelled, an appropriate amount of ethanol was added and the mixture was aged for 24 h. Then, a mixture of hexamethyldisilazane and tert-butanol in a volume ratio of 4:5 was added to the beaker every 8 h for solvent replacement and hydrophobic modification. This process was repeated 3 times. Finally, the mixture was placed in an atmospheric pressure drying oven and heated to 80 °C at a rate of 5 °C / h. The mixture was then dried for 24 h to obtain aerogel needled fiberglass felt. The above-mentioned aerogel needled fiberglass mat was soaked in a 6wt% zinc borate solution for 12 hours, washed with deionized water to remove residual chemical reagents, and then dried at 110℃ for 1.5 hours to obtain modified needled fiberglass mat. The modified needle-punched fiberglass felt was placed between two 10mm thick poplar boards and hot-pressed with epoxy resin adhesive at a temperature of 120℃ and a pressure of 1.2MPa for 30 minutes to obtain an aerogel composite fiberglass needle-punched felt sound-absorbing board.

[0028] Comparative Example 1: The preparation method of porous nanofiber-silica sol includes the following steps: 15 mL of tetraethoxysilane, 30 mL of anhydrous ethanol and 5 mL of deionized water were stirred and mixed at room temperature for 10 min. 1 mol / L oxalic acid was added to adjust the pH to 2 to hydrolyze the tetraethoxysilane. Then 3-aminopropyltriethoxysilane was added and the mixture was stirred for another 10 min. After mixing, the porous polylactic acid nanofibers prepared in Example 1 were added to make the mass fraction of porous polylactic acid nanofibers 4%. The mixture was then ultrasonically dispersed to obtain a porous fiber-silica sol.

[0029] Comparative Example 2: The preparation method of reduced graphene oxide-silica sol includes the following steps: 220 μL of ethylenediamine was added to an aqueous solution of graphene oxide with a concentration of 2 mg / mL, sealed and heated at 90 °C for 12 h, excess impurities were washed 10 times with deionized water, and the mixture was freeze-dried for 48 h to obtain reduced graphene oxide aerogel. 15 mL of tetraethoxysilane, 30 mL of anhydrous ethanol, and 5 mL of deionized water were stirred together and stirred at room temperature for 10 min. The pH was adjusted to 2 by adding 1 mol / L oxalic acid to hydrolyze the tetraethoxysilane. Then, 3-aminopropyltriethoxysilane was added and the mixture was stirred for another 10 min. The mixture was then added to the above-mentioned reduced graphene oxide aerogel to make the mass fraction of reduced graphene oxide 3%, thus obtaining reduced graphene oxide-silica sol.

[0030] Compared with Example 4, Comparative Example 3 only replaced the porous fiber-reduced graphene oxide-silica sol prepared in Example 2 with the porous fiber-silica sol prepared in Comparative Example 1 by the same mass. The other components and preparation methods were completely the same as those in Example 4.

[0031] Compared with Example 4, Comparative Example 4 only replaced the porous fiber-reduced graphene oxide-silica sol prepared in Example 2 with the reduced graphene oxide-silica sol prepared in Comparative Example 2 in equal mass. The other components and preparation methods were completely the same as those in Example 4.

[0032] Compared with Example 4, Comparative Example 5 omits the step of soaking needle-punched fiberglass felt in an ethanol solution of methyltrimethoxysilane, and does not add hexamethyldisilazane. It only uses tert-butanol for solvent replacement. The remaining components and preparation methods are completely consistent with Example 4.

[0033] Compared with Example 4, Comparative Example 6 omits the step of soaking in zinc borate solution, while the remaining components and preparation methods are completely the same as those in Example 4.

[0034] Performance testing Strength performance: Compression tests were conducted on the composite porous materials using an AI-7000-NGD servo multifunctional material testing machine. The sound-absorbing panels prepared in Examples 4-7 and Comparative Examples 3-6 were subjected to a compression test with a strain of 70% at a speed of 30 mm / min under an action of 50 kgf, and the mechanical strength was determined. The test results are shown in Table 1. Thermal conductivity: A Netzsch HFM 436 thermal conductivity analyzer was used. This equipment requires the tested material to be 300×300mm in size, and its testing principle is based on the steady-state plate method. The sound-absorbing panels prepared in Examples 4-7 and Comparative Examples 3-6 were placed between two plates at different temperatures, one plate maintained at a higher temperature and the other at a lower temperature, thus creating a constant temperature gradient across the test sample. The heat flow of the test sample and the temperature difference across the sample are accurately captured by heat flow meters and temperature sensors embedded in the plates, and the thermal conductivity of the test sample is calculated. The formula for calculating thermal conductivity is as follows: ; Where Q is the heat flow through the test sample; d is the thickness of the test sample; and A is the area through which the heat passes. The temperature difference is represented by the two sides of the sample; the test results are shown in Table 1. Sound absorption coefficient: The sound absorption performance of the sound-absorbing panels prepared in Examples 4-7 and Comparative Examples 3-6 was tested in the range of 100-6000Hz using a four-channel digital signal acquisition system and impedance tubes with diameters of 100mm and 30mm. The tests were repeated three times and the average value was taken. The sound absorption coefficient at different frequency ranges reflects the strength of the sound absorption performance; the test results are shown in Table 1. Flame retardant performance test: Limiting oxygen index test. According to the GB5454-85 test standard, the sound-absorbing panels prepared in Examples 4-7 and Comparative Examples 3-6 were vertically clamped on the sample holder. In an upward flow of oxygen and nitrogen gas, the upper end of the sample was ignited. By observing the combustion characteristics in gas streams with different oxygen concentrations, the minimum percentage of oxygen required to maintain the combustion of the sample can be measured, which is the limiting oxygen index. The test results are shown in Table 1. Mass moisture absorption rate: The moisture absorption rate of the samples was tested using a constant temperature and humidity chamber and an electronic balance to study the moisture absorption performance of the samples. The specific operation was as follows: The sound-absorbing boards prepared in Examples 4-7 and Comparative Examples 3-6 were dried to constant weight, weighed, and the mass before moisture absorption was recorded. Then, they were placed in a temperature and humidity controlled chamber and kept in a chamber with a temperature of (50±2)℃, a relative humidity of (95±3)%, and air circulation for 96 hours. After that, the sample box was sealed and taken out, cooled to room temperature, weighed, and the mass of the sample after moisture absorption was recorded. The mass moisture absorption rate was calculated according to the following formula: ; Where: W is the mass moisture absorption rate, %; m1 is the mass of the dried sample, in g; m2 is the mass of the sample after moisture absorption, in g; the test results are shown in Table 1; Table 1: Statistical table of performance test data of sound-absorbing panels prepared in Examples 4-7 and Comparative Examples 3-6

[0035] As shown in Table 1, the aerogel composite fiberglass needle-punched felt sound-absorbing board prepared by this invention has excellent sound absorption performance, especially improving the absorption efficiency of low-frequency noise. It also has high thermal insulation and flame retardancy, excellent hydrophobicity and moisture resistance, and high compressive strength. In Comparative Example 3, the aerogel prepared without the addition of reduced graphene oxide resulted in a decrease in the thermal insulation performance of the sound-absorbing board. In Comparative Example 4, the aerogel prepared without the addition of porous fibers resulted in the lowest compressive strength and the worst sound absorption performance. In Comparative Example 5, the modification step of silane coupling agent was omitted, resulting in a sharp increase in the moisture absorption rate of the sound-absorbing board. In Comparative Example 6, the step of impregnation with zinc borate solution was omitted, resulting in a significant decrease in the flame retardant performance of the sound-absorbing board.

[0036] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing an aerogel composite glass fiber needle-punched felt sound-absorbing panel, characterized in that, It includes at least the following preparation steps: After being ultrasonically treated with a silane coupling agent solution, the needled fiberglass felt was immersed in a porous nanofiber-reduced graphene oxide-silica sol for vacuum impregnation. After gel aging, an alcohol solution of a hydrophobic modifier was added to perform hydrophobic modification and solvent replacement. After drying, aerogel needled fiberglass felt was obtained. The aerogel needled fiberglass felt was soaked in zinc borate solution, washed and dried to obtain modified needled fiberglass felt. The modified needle-punched fiberglass felt is placed between two plates and bonded together with an adhesive to obtain an aerogel composite fiberglass needle-punched felt sound-absorbing board.

2. The method for preparing an aerogel composite glass fiber needle-punched felt sound-absorbing board according to claim 1, characterized in that, The modified needle-punched glass fiber mat has a thickness of 3-20 mm and contains at least 30-55 wt% porous nanofiber-reduced graphene oxide-silica aerogel, 3-8 wt% zinc borate, 1-3 wt% silane coupling agent and 1-3 wt% hydrophobic modifier.

3. The method for preparing an aerogel composite glass fiber needle-punched felt sound-absorbing board according to claim 1, characterized in that, The preparation method of the porous fiber-reduced graphene oxide-silica sol includes the following steps: Ethylenediamine was added to an aqueous solution of graphene oxide, sealed and heated, washed and freeze-dried to obtain reduced graphene oxide aerogel. Tetraethoxysilane, anhydrous ethanol and deionized water were stirred and mixed, and the pH was adjusted to 2-3. Then 3-aminopropyltriethoxysilane was added, and the mixture was added to the reduced graphene oxide aerogel to obtain reduced graphene oxide-silica sol. Porous polylactic acid nanofibers were added to the reduced graphene oxide-silica sol and ultrasonically dispersed to obtain porous fiber-reduced graphene oxide-silica sol.

4. The method for preparing an aerogel composite glass fiber needle-punched felt sound-absorbing board according to claim 3, characterized in that, The volume ratio of the tetraethoxysilane, the anhydrous ethanol, and the deionized water is 0.5-2:1-5:0.1-1, and the content of the reduced graphene oxide in the reduced graphene oxide-silica sol is 1-3 wt%.

5. The method for preparing an aerogel composite fiberglass needle-punched felt sound-absorbing board according to claim 3, characterized in that, The content of porous polylactic acid nanofibers in the porous fiber-reduced graphene oxide-silica sol is 2-5 wt%.

6. The method for preparing an aerogel composite fiberglass needle-punched felt sound-absorbing board according to claim 1, characterized in that, The method for preparing the porous nanofibers includes the following steps: A non-solvent cyclohexane was introduced into a dichloromethane / dimethyl sulfoxide system, and polylactic acid was added to obtain a polylactic acid spinning solution. After spinning and grinding, porous nanofibers were obtained.

7. The method for preparing an aerogel composite fiberglass needle-punched felt sound-absorbing board according to claim 6, characterized in that, The porous nanofibers have a length of 0.1-1 mm, the polylactic acid content in the spinning solution is 8-12 wt%, and the mass ratio of dichloromethane, dimethyl sulfoxide, and cyclohexane is 7-9:1-2:

1.

8. The method for preparing an aerogel composite glass fiber needle-punched felt sound-absorbing board according to claim 1, characterized in that, The board material is poplar wood board or bamboo fiber board, the thickness of the board material is 5-10mm, and the adhesive is at least one of epoxy resin adhesive, water-based acrylic adhesive, phenolic adhesive or silica sol adhesive.

9. The method for preparing an aerogel composite glass fiber needle-punched felt sound-absorbing board according to claim 1, characterized in that, The silane coupling agent is one or a mixture of two of methyltrimethoxysilane or octadecyltrichlorosilane, the hydrophobic modifier is one or a mixture of several of the modifiers, including silane coupling agents, siloxane compounds or silazane compounds, and the alcohol solution is at least one of ethanol and tert-butanol.

10. An aerogel composite fiberglass needle-punched felt sound-absorbing board, characterized in that... It is prepared by the method described in any one of claims 1-9.

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