Functional fiber-based composite foam and method of making

Abstract

The application provides a functional fiber-based composite foam material and a preparation method thereof, and belongs to the technical field of inorganic fiber composite materials. The preparation method comprises the following steps: providing a basalt fiber-based foam base; providing an impregnating solution in the form of a solution and containing monolayer MXene nanosheets; contacting the basalt fiber-based foam base with the impregnating solution containing monolayer MXene nanosheets, so that the basalt fiber-based foam base is impregnated with the impregnating solution containing monolayer MXene nanosheets; and drying the obtained composite foam loaded with MXene nanosheets, to obtain the functional fiber-based composite foam material with a density of 9-15 mg / cm 3 The method is prepared at low temperature and has low energy consumption. A layered rigid framework composed of flexible fiber chains and rigid sheet-shaped MXene is constructed. The prepared composite foam material has the characteristics of good mechanical properties, low density, compressibility and resilience, excellent sound absorption and heat insulation performance, and high specific shielding effectiveness.

Description

Technical Field

[0001] This invention relates to the field of inorganic fiber composite materials technology, and in particular to a functional fiber-based composite foam material and its preparation method. Background Technology

[0002] Inorganic fiber composite foam materials have gained increasing attention in the fields of sound absorption and noise reduction, and thermal insulation due to their excellent strength and temperature resistance, low thermal conductivity, fire resistance, moisture resistance, corrosion resistance, and low cost. However, as people's expectations for inorganic fiber-based acoustic and thermal insulation materials increase, traditional sound-absorbing and thermal insulation materials have long suffered from poor broadband sound absorption performance, low low-frequency absorption, low thermal insulation efficiency, and large size and thickness. Single-function materials can no longer meet people's needs. Therefore, the research and development of green, lightweight, multifunctional, and high-performance fiber-based sound-absorbing and thermal insulation materials is of great significance for mitigating noise pollution and protecting human health.

[0003] In recent years, many researchers have attempted to improve the sound absorption capacity of materials through internal and structural design. Among them, the most representative structural designs include gradient structures, layered network structures, spiral porous structures, and honeycomb structures. Kim designed a composite sound-absorbing structure made of spiral fiber thin layers and carbon fiber (KimB-S, ChoS-J, MinD-k, et al. Experimental study for improving sound absorption of a composite helical-shaped porous structure using carbon fiber[J]. CompositeStructures, 2016, 145: 242-247). By rolling long thin layers into a spiral shape to form a spiral sound-absorbing material, its acoustic performance was studied. The results showed that the composite spiral sound absorber coated with carbon fiber had better sound absorption performance than the fiber layer, especially at low frequencies. However, structural design plays an important role in addressing the poor broadband sound absorption effect (especially poor low-frequency sound absorption performance) and poor thermal insulation performance of current sound-absorbing and heat-insulating materials on the market. However, due to limitations in preparation technology, cost, and multifunctional applications, most sound-absorbing and heat-insulating structural design materials are still immature. In most cases, research focuses more on improving the internal structure of sound-absorbing and heat-insulating materials.

[0004] Basalt fiber, hailed as a "green industrial material of the 21st century," is primarily composed of SiO2 and Al2O3. It possesses outstanding high modulus, high strength, good temperature resistance, excellent chemical stability, sound absorption, and electrical insulation properties, making it a promising low-cost, high-performance sound-absorbing and heat-insulating material with broad application prospects in sound absorption, heat insulation, and thermal insulation fields. However, there are few reports on the preparation of foam materials using basalt fiber as a raw material. Furthermore, due to the surface tension of the liquid during the basalt fiber production process, the surface of the basalt fiber is relatively smooth. This can prevent basalt fiber-based foam materials from fully utilizing the mechanical properties of basalt fiber, resulting in deteriorated mechanical properties. It can also lead to larger internal pore sizes in basalt fiber-based foam materials, resulting in defects such as low sound absorption over a wide frequency range and poor thermal insulation. Summary of the Invention

[0005] This invention provides a functional fiber-based composite foam material and its preparation method that features excellent mechanical properties, low density, compressibility and resilience, superior sound absorption and heat insulation performance, high specific shielding effectiveness, low-temperature preparation and low energy consumption. This invention aims to solve the problems of poor mechanical properties, low sound absorption over a wide frequency range, poor heat insulation, large weight, limited functionality and lack of conductivity of existing fiber-based foam materials.

[0006] To achieve the above objectives, the present invention provides a method for preparing a functional fiber-based composite foam material, comprising: providing a basalt fiber-based foam matrix; providing an impregnation liquid containing monolayer MXene nanosheets in solution form; contacting the basalt fiber-based foam matrix with the impregnation liquid containing monolayer MXene nanosheets, such that the basalt fiber-based foam matrix is ​​impregnated by the impregnation liquid containing monolayer MXene nanosheets; and drying the impregnated composite foam loaded with MXene nanosheets to obtain the functional fiber-based composite foam material.

[0007] The above technical solution uses inorganic basalt fiber-based porous foam prepared by foam template method as the matrix and MXene nanosheets with excellent conductivity as the film-forming agent. By utilizing the low-temperature self-assembly characteristics of MXene nanosheets, a layered rigid framework composed of flexible fiber chains and rigid sheet-like MXene is constructed, which improves mechanical properties. The resulting functional fiber-based composite foam material has the characteristics of low density, compressibility and resilience, excellent sound absorption and heat insulation performance and high specific shielding efficiency, thus expanding the application field of basalt fiber-based composite foam materials.

[0008] According to the present invention, the impregnation holding time is 30-300 s; the concentration of the monolayer MXene nanosheets in the impregnation solution containing monolayer MXene nanosheets is 0.5-4 mg / L. Through the impregnation environment, the functional groups such as -OH and -COOH of the monolayer MXene nanosheets self-assemble with the basalt fiber-based foam matrix as a framework. During self-assembly, they also combine with the basalt fiber-based foam matrix through electrostatic interactions to form strong covalent bonds or hydrogen bonds, thereby improving the low density problem of the basalt fiber-based foam matrix, enhancing the mechanical properties of the obtained functional fiber-based composite foam material, and also endowing the functional fiber-based composite foam material with excellent electrical conductivity and electromagnetic shielding properties.

[0009] According to the present invention, the drying conditions for the composite foam loaded with Mxene nanosheets are: temperature 60-100℃, time 1-3h.

[0010] According to the present invention, an impregnation solution containing monolayer MXene nanosheets is prepared by the following steps: LiF is added to an HCl solution and stirred at a constant temperature. Then, Ti3AlC2 is added to the resulting hydrochloric acid / lithium fluoride mixed acid system to react. After the reaction is completed, the resulting mixed solution is washed with deionized water until neutral, and then concentrated with deionized water to obtain an impregnation solution containing monolayer MXene nanosheets. The obtained monolayer MXene nanosheets have good dispersibility, large particle size, thin thickness, and large specific surface area, exhibiting high surface activity, excellent conductivity, and chemical stability. Using them as a film-forming agent is beneficial for improving yield.

[0011] According to the present invention, the concentration of the HCl solution is 7-10 mol / L, and the mass ratio of Ti3AlC2 to LiF is 1:(1-2); the isothermal stirring conditions are: temperature 35-45℃, time 0.5-1h; the reaction conditions are: temperature 35-45℃, time 35-45h. Etching the atomic layers of the Ti3AlC2 layered material via hydrofluoric acid reaction forms a stable titanium carbide sheet structure without damaging the structure of the monolayer MXene nanosheets. Furthermore, due to the presence of hydrophilic hydroxyl groups and charge interaction, the exfoliated monolayer MXene nanosheets cannot re-aggregate, thus forming a stable monolayer MXene nanosheet dispersion system in water.

[0012] According to the present invention, the basalt fiber-based foam matrix is ​​prepared by the following steps:

[0013] (1) Basalt fiber is first calcined, and then the calcined basalt fiber is mixed with concentrated sulfuric acid and hydrogen peroxide solution to obtain acid-treated basalt fiber.

[0014] (2) After washing the acid-treated basalt fiber to neutral, dry it at 85-95℃ for 1.5-3h, then disperse it, and then filter and dehydrate it to obtain basalt fiber slurry.

[0015] (3) Mix basalt fiber slurry and polyvinyl alcohol fiber, and then mechanically stir to obtain mixed slurry A;

[0016] (4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at a rate of 1000-4000 rpm for 10-20 min to obtain mixed slurry B.

[0017] (5) Mix the mixed slurry B and the surfactant solution, and then mechanically foam to obtain a foam material preform;

[0018] (6) After drying the foam material preform at a temperature of 60-120℃ for 1-3 hours, a basalt fiber-based foam matrix is ​​obtained.

[0019] According to the present invention, the basalt fiber has a diameter of 8-15 μm and a length of 3-9 mm; the polyvinyl alcohol fiber has a diameter of 15-24 μm and a length of 2-6 mm.

[0020] According to the present invention, in step (1), the calcination treatment conditions are: temperature 350-430℃, time 1.5-3h; the ratio of basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution is 5g:(30-45)mL:(10-20)mL, the concentration of hydrogen peroxide solution is 25-40wt%, and the concentration of concentrated sulfuric acid is 2-5mol / L; the mixing treatment conditions are: temperature 60-90℃, time 1-2h.

[0021] According to the present invention, in step (2), the dispersing is carried out by a dispersing machine, the dispersion concentration of basalt fiber in the dispersing machine is 0.1-0.3wt%, and the dispersion time is 3-7min; the concentration of basalt fiber in the basalt fiber slurry is 5-15wt%.

[0022] According to the present invention, in step (3), the mass ratio of basalt fiber slurry to polyvinyl alcohol fiber is (50-95):(5-50); in step (4), the ratio of the oven-dry mass of fiber in mixed slurry A to the amount of sodium tetraborate decahydrate is 5g:(1-3)g.

[0023] According to the present invention, in step (5), the surfactant in the surfactant solution is sodium dodecyl sulfate with a mass fraction of 3-10 wt%; the ratio of mixed slurry B to surfactant is 1 L: (0.5-1) g; the mechanical foaming conditions are: speed 1000-4000 rpm, time 5-15 min.

[0024] This invention also provides a functional fiber-based composite foam material, which is prepared by the aforementioned method for preparing functional fiber-based composite foam materials, and has a density of 9-15 mg / cm³. 3 The aforementioned functional fiber-based composite foam materials exhibit excellent sound absorption and heat insulation properties, as well as superior electromagnetic shielding and absorption characteristics. They can be applied in aerospace, military engineering, artificial intelligence, rail transportation, and construction, serving as sound-absorbing, heat-insulating, and electromagnetic protection materials. In specific examples, they can be used as interlayer materials in ships, aircraft, and / or vessels.

[0025] Based on this, the present invention also provides the use of basalt fiber-based composite foam material containing monolayer MXene nanosheets in the preparation of sound-absorbing materials, heat-insulating materials and / or electromagnetic protection materials, wherein the composite foam material is prepared by the aforementioned method for preparing functional fiber-based composite foam material.

[0026] The functional fiber-based composite foam material and its preparation method provided by this invention achieve the following:

[0027] Beneficial effects:

[0028] (1) This invention uses basalt fiber-based foam as the matrix and single-layer MXene nanosheets as the impregnation film-forming agent. By using the impregnation method and the low-temperature self-assembly characteristics of MXene nanosheets, a layered rigid framework composed of flexible fiber chains and rigid sheet-like MXene nanosheets is constructed, resulting in a functional fiber-based composite foam material with an internal fiber-membrane layered network structure. The unique skeleton fiber-membrane layered network structure further reduces the internal pore size of the composite foam material and complicates the pore structure, increasing the tortuous path of sound energy and heat energy propagation within it, improving mechanical properties, and enabling the composite foam material to obtain excellent airflow resistance and increased tortuosity of sound wave propagation, thereby exhibiting a smaller viscous characteristic length, internal reflection and interface damping, and excellent sound and heat energy dissipation.

[0029] (2) The MXene nanosheets on the functional fiber-based composite foam material of the present invention are firmly assembled and not easily detached. The introduction of MXene nanosheets effectively enhances the conductivity and mechanical properties of the basalt fiber-based foam matrix, while the basalt fiber-based foam matrix maintains its porous structure, flexibility, and resilience. This composite foam material has the characteristics of excellent mechanical properties, low density, compressibility and resilience, excellent sound absorption and heat insulation performance, and high specific shielding effectiveness. It realizes multiple functions such as sound absorption, heat insulation, and electromagnetic shielding, and solves the defects of current basalt fiber-based foam materials, such as electrical insulation, non-conductivity, and single function.

[0030] (3) In this invention, a simple and easy solution impregnation method is used to combine the flexibility and excellent sound absorption and heat insulation properties of basalt fiber with the high electromagnetic shielding efficiency of MXene nanosheets to prepare a composite foam material with enhanced sound absorption and heat insulation properties and high electromagnetic shielding efficiency. The preparation method is simple and easy to implement, the process is pollution-free and energy-efficient, and structural control can be achieved at low temperature conditions. It is green and environmentally friendly, expands the application of basalt fiber in the fields of sound absorption, heat insulation and electromagnetic shielding, and solves the problems of poor mechanical properties, wide-band low sound absorption, large weight, poor heat insulation and single function and lack of conductivity of current basalt fiber-based sound absorption and heat insulation materials. It is suitable for large-scale industrial production. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 SEM images of the functional fiber-based composite foam materials prepared in Examples 1, 3, 5 and the control group: a-control group, b-Example 3, c-Example 1, d-Example 5;

[0033] Figure 2 The mechanical properties of the functional fiber-based composite foam materials prepared in Examples 1, 3, 5 and the control group are shown in the figure.

[0034] Figure 3 The diagram shows the sound absorption performance of the functional fiber-based composite foam materials prepared in Examples 1, 3, 5, and the control group.

[0035] Figure 4 The electromagnetic shielding performance diagrams are for the functional fiber-based composite foam materials prepared in Examples 1, 3, 5, and the control group. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 also within the scope of protection of the present invention.

[0037] The following examples use conventional instruments and equipment in the art. Unless otherwise specified, the experimental materials and reagents used in the following examples are commercially available and conform to conventional specifications in the art. Any techniques or conditions not specifically described in the following examples can be performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0038] It should be noted that, in this invention and the following embodiments, unless otherwise specified, concentration, ratio, etc. are all weight concentration, weight ratio, etc., "%" all represent weight percentage, and "parts" all represent weight parts. These are common writing habits used by those skilled in the art, and therefore will not be repeated in this invention.

[0039] In a specific embodiment, the preparation method of the functional fiber-based composite foam material of the present invention includes the following steps:

[0040] (1) Preparation of basalt fiber-based foam matrix:

[0041] (1.1) Basalt fibers are first calcined in a muffle furnace at 350-430℃ for 1.5-3h. After calcination, the basalt fibers are then mixed with concentrated sulfuric acid and hydrogen peroxide solution at 60-90℃ for 1-2h to obtain acid-treated basalt fibers. The ratio of the above basalt fibers, concentrated sulfuric acid and hydrogen peroxide solution is 5g:(30-45)mL:(10-20)mL, the concentration of hydrogen peroxide solution is 25-40wt%, and the concentration of concentrated sulfuric acid is 2-5mol / L.

[0042] (1.2) After washing the acid-treated basalt fibers to neutral, dry them at 85-95℃ for 1.5-3h, and then disperse them using a disintegration machine. The dispersion concentration of basalt fibers in the disintegration machine is 0.1-0.3wt%, and the dispersion time is 3-7min. Then filter and dehydrate to obtain basalt fiber slurry with a basalt fiber concentration of 5-15wt%.

[0043] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of (50-95):(5-50) and mechanically stirred to obtain mixed slurry A.

[0044] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at a rate of 1000-4000 rpm for 10-20 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g:(1-3) g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0045] (1.5) Mix the mixed slurry B with a surfactant solution of 3-10 wt%, and then mechanically foam it at a rate of 1000-4000 rpm for 5-15 min. After foaming is completed, transfer the foam slurry to a molding device to filter water to obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: (0.5-1) g.

[0046] (1.6) After drying the foam material preform at a temperature of 60-120℃ for 1-3 hours, a basalt fiber-based foam matrix is ​​obtained.

[0047] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: LiF was added to an HCl solution with a concentration of 7-10 mol / L and stirred at a constant temperature of 35-45℃ for 0.5-1h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:(1-2). The reaction was carried out at a temperature of 35-45℃ for 35-45h. After the reaction was completed, the mixed solution obtained from the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0048] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix is ​​immersed in an impregnation solution containing monolayer MXene nanosheets with a concentration of 0.5-4 mg / L for 30-300 s, so that the MXene nanosheets are uniformly distributed in the fiber pores and undergo self-assembly. Then, the composite foam uniformly loaded with MXene nanosheets is dried in an oven at a temperature of 60-100℃ for 1-3 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0049] The present invention will be further described in detail below with reference to embodiments. However, it should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0050] Example 1:

[0051] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0052] (1) Preparation of basalt fiber-based foam matrix:

[0053] (1.1) The basalt fiber was first calcined in a muffle furnace at 350℃ for 2 hours. The calcined basalt fiber was then fed into a concentrated sulfuric acid and hydrogen peroxide solution and mixed at 60℃ for 1 hour to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:35mL:15mL, the concentration of hydrogen peroxide solution was 30wt%, and the concentration of concentrated sulfuric acid was 3mol / L.

[0054] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 90°C for 2 hours and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.2 wt%, and the dispersion time was 5 min. Then, the basalt fiber slurry with a basalt fiber concentration of 10 wt% was obtained by filtration and dehydration.

[0055] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 50:50 and mechanically stirred to obtain mixed slurry A.

[0056] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 2000 rpm for 10 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 1.73 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0057] (1.5) Mix the mixed slurry B with a surfactant solution of 5 wt% by mass, and then mechanically foam it at a rate of 1000 rpm for 10 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 0.2 g.

[0058] (1.6) After drying the foam material preform at 60℃ for 3 hours, basalt fiber-based foam matrix is ​​obtained.

[0059] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of 7mol / L HCl solution and stirred at 35℃ for 1h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:1. The reaction was carried out at 35℃ for 40h. After the reaction was completed, the mixed solution obtained by the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0060] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets with a concentration of 1 mg / L and the immersion was maintained for 100 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 60 ℃ for 3 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0061] Example 2:

[0062] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0063] (1) Preparation of basalt fiber-based foam matrix:

[0064] (1.1) The basalt fiber was first calcined in a muffle furnace at 430℃ for 1.5h. The calcined basalt fiber was then fed into a concentrated sulfuric acid and hydrogen peroxide solution and mixed at 90℃ for 1h to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:45mL:20mL, the concentration of hydrogen peroxide solution was 25wt%, and the concentration of concentrated sulfuric acid was 2mol / L.

[0065] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 95°C for 1.5 hours and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.3 wt%, and the dispersion time was 7 minutes. Then, the basalt fiber slurry with a basalt fiber concentration of 15 wt% was obtained by filtration and dehydration.

[0066] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 90:10 and mechanically stirred to obtain mixed slurry A.

[0067] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 4000 rpm for 10 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 2.8 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0068] (1.5) Mix the mixed slurry B with a surfactant solution of 10 wt%, and then mechanically foam it at a rate of 4000 rpm for 5 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 1 g.

[0069] (1.6) After drying the foam material preform at 120℃ for 1 hour, a basalt fiber-based foam matrix is ​​obtained.

[0070] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of 10mol / L HCl solution and stirred at 45℃ for 0.5h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:2. The reaction was carried out at 45℃ for 35h. After the reaction was completed, the mixed solution obtained by the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0071] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets at a concentration of 0.5 mg / L for 300 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 100 ℃ for 1 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0072] Example 3:

[0073] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0074] (1) Preparation of basalt fiber-based foam matrix:

[0075] (1.1) The basalt fiber was first calcined in a muffle furnace at 350℃ for 2 hours. The calcined basalt fiber was then fed into a concentrated sulfuric acid and hydrogen peroxide solution and mixed at 90℃ for 1 hour to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:35mL:15mL, the concentration of hydrogen peroxide solution was 30wt%, and the concentration of concentrated sulfuric acid was 3mol / L.

[0076] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 90°C for 2 hours and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.2 wt%, and the dispersion time was 5 min. Then, the basalt fiber slurry with a basalt fiber concentration of 10 wt% was obtained by filtration and dehydration.

[0077] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 70:30 and mechanically stirred to obtain mixed slurry A.

[0078] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 4000 rpm for 10 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 1.73 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0079] (1.5) Mix the mixed slurry B with a surfactant solution of 5 wt% by mass, and then mechanically foam it at a rate of 4000 rpm for 15 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 0.2 g.

[0080] (1.6) After drying the foam material preform at 95℃ for 2 hours, basalt fiber-based foam matrix is ​​obtained.

[0081] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of 9mol / L HCl solution and stirred at 40℃ for 1h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:1.6. The reaction was carried out at 35℃ for 40h. After the reaction was completed, the mixed solution obtained by the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0082] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets with a concentration of 1 mg / L and the immersion was maintained for 120 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 70 ℃ for 2 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0083] Example 4:

[0084] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0085] (1) Preparation of basalt fiber-based foam matrix:

[0086] (1.1) The basalt fiber was first calcined in a muffle furnace at 380℃ for 2.5h. The calcined basalt fiber was then fed into concentrated sulfuric acid and hydrogen peroxide solution and mixed at 85℃ for 1.5h to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:40mL:15mL, the concentration of hydrogen peroxide solution was 35wt%, and the concentration of concentrated sulfuric acid was 4mol / L.

[0087] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 90°C for 2.5 h and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.2 wt%, and the dispersion time was 5 min. Then, the basalt fiber slurry with a basalt fiber concentration of 12.5 wt% was obtained by filtration and dehydration.

[0088] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 60:40 and mechanically stirred to obtain mixed slurry A.

[0089] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 3500 rpm for 15 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 2.2 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0090] (1.5) Mix the mixed slurry B with a surfactant solution of 7 wt% by mass, and then mechanically foam it at a rate of 2500 rpm for 10 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 0.7 g.

[0091] (1.6) After drying the foam material preform at 100℃ for 2.5h, basalt fiber-based foam matrix is ​​obtained.

[0092] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of HCl solution with a concentration of 8mol / L and stirred at a constant temperature of 40℃ for 0.5h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:1.5. The reaction was carried out at a temperature of 40℃ for 40h. After the reaction was completed, the mixed solution obtained from the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0093] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets at a concentration of 3 mg / L for 200 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 80 ℃ for 2 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0094] Example 5:

[0095] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0096] (1) Preparation of basalt fiber-based foam matrix:

[0097] (1.1) The basalt fiber was first calcined in a muffle furnace at 350℃ for 2 hours. The calcined basalt fiber was then fed into a concentrated sulfuric acid and hydrogen peroxide solution and mixed at 90℃ for 1 hour to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:35mL:15mL, the concentration of hydrogen peroxide solution was 30wt%, and the concentration of concentrated sulfuric acid was 3mol / L.

[0098] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 90°C for 2 hours and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.2 wt%, and the dispersion time was 5 min. Then, the basalt fiber slurry with a basalt fiber concentration of 10 wt% was obtained by filtration and dehydration.

[0099] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 70:30 and mechanically stirred to obtain mixed slurry A.

[0100] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 4000 rpm for 10 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 1.73 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0101] (1.5) Mix the mixed slurry B with a surfactant solution of 5 wt% by mass, and then mechanically foam it at a rate of 4000 rpm for 15 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 0.2 g.

[0102] (1.6) After drying the foam material preform at 95℃ for 2 hours, basalt fiber-based foam matrix is ​​obtained.

[0103] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of 9mol / L HCl solution and stirred at 40℃ for 1h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:1.6. The reaction was carried out at 35℃ for 40h. After the reaction was completed, the mixed solution obtained by the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0104] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets at a concentration of 2.5 mg / L for 150 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 70 °C for 2 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0105] The functional fiber-based composite foam material prepared in this embodiment was characterized for its properties, and its density was 10.1 mg / cm³. 3 .

[0106] Example 6:

[0107] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0108] (1) Preparation of basalt fiber-based foam matrix:

[0109] (1.1) The basalt fiber was first calcined in a muffle furnace at 350℃ for 2 hours. The calcined basalt fiber was then fed into a concentrated sulfuric acid and hydrogen peroxide solution and mixed at 60℃ for 1 hour to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:35mL:15mL, the concentration of hydrogen peroxide solution was 30wt%, and the concentration of concentrated sulfuric acid was 3mol / L.

[0110] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 90°C for 2 hours and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.2 wt%, and the dispersion time was 5 min. Then, the basalt fiber slurry with a basalt fiber concentration of 10 wt% was obtained by filtration and dehydration.

[0111] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 50:50 and mechanically stirred to obtain mixed slurry A.

[0112] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 4000 rpm for 10 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 1.73 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0113] (1.5) Mix the mixed slurry B with a surfactant solution of 5 wt% by mass, and then mechanically foam it at a rate of 2000 rpm for 15 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 0.2 g.

[0114] (1.6) After drying the foam material preform at 100℃ for 2 hours, basalt fiber-based foam matrix is ​​obtained.

[0115] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of 9mol / L HCl solution and stirred at 40℃ for 1h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:1.6. The reaction was carried out at 35℃ for 40h. After the reaction was completed, the mixed solution obtained by the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0116] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets at a concentration of 3 mg / L for 300 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 100 ℃ for 1 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0117] Example 7:

[0118] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0119] (1) Preparation of basalt fiber-based foam matrix:

[0120] (1.1) The basalt fiber was first calcined in a muffle furnace at 350℃ for 2 hours. The calcined basalt fiber was then fed into a concentrated sulfuric acid and hydrogen peroxide solution and mixed at 60℃ for 1 hour to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:35mL:15mL, the concentration of hydrogen peroxide solution was 30wt%, and the concentration of concentrated sulfuric acid was 3mol / L.

[0121] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 90°C for 2 hours and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.2 wt%, and the dispersion time was 5 min. Then, the basalt fiber slurry with a basalt fiber concentration of 10 wt% was obtained by filtration and dehydration.

[0122] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 70:30 and mechanically stirred to obtain mixed slurry A.

[0123] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 2000 rpm for 10 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 1.73 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0124] (1.5) Mix the mixed slurry B with a surfactant solution of 5 wt% by mass, and then mechanically foam it at a rate of 4000 rpm for 15 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 0.2 g.

[0125] (1.6) After drying the foam material preform at 95℃ for 2 hours, basalt fiber-based foam matrix is ​​obtained.

[0126] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of 9mol / L HCl solution and stirred at 40℃ for 1h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:1.6. The reaction was carried out at 35℃ for 40h. After the reaction was completed, the mixed solution obtained by the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0127] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets at a concentration of 2.5 mg / L for 60 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 60 °C for 2 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0128] Example 8:

[0129] A method for preparing a functional fiber-based composite foam material includes the following steps:

[0130] (1) Preparation of basalt fiber-based foam matrix:

[0131] (1.1) The basalt fiber was first calcined in a muffle furnace at 350℃ for 2 hours. The calcined basalt fiber was then fed into a concentrated sulfuric acid and hydrogen peroxide solution and mixed at 80℃ for 1 hour to obtain acid-treated basalt fiber. The ratio of the above basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution was 5g:35mL:15mL, the concentration of hydrogen peroxide solution was 30wt%, and the concentration of concentrated sulfuric acid was 3mol / L.

[0132] (1.2) After washing the acid-treated basalt fibers to neutral, they were dried at 90°C for 2 hours and then dispersed using a disintegrator. The dispersion concentration of basalt fibers in the disintegrator was 0.2 wt%, and the dispersion time was 5 min. Then, the basalt fiber slurry with a basalt fiber concentration of 10 wt% was obtained by filtration and dehydration.

[0133] (1.3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed in a mass ratio of 70:30 and mechanically stirred to obtain mixed slurry A.

[0134] (1.4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at 3000 rpm for 10 min to obtain mixed slurry B; the ratio of the oven-dry weight of fiber to the amount of sodium tetraborate decahydrate in the above mixed slurry A is 5 g: 1.73 g. The pH of the above mixed solution is adjusted using concentrated sulfuric acid with a concentration of 3 mol / L.

[0135] (1.5) Mix the mixed slurry B with a surfactant solution of 5 wt% by mass, and then mechanically foam it at a rate of 2000 rpm for 10 min. After foaming is completed, transfer the foam slurry to a molding device to filter water and obtain a foam material preform. The surfactant in the above surfactant solution is sodium dodecyl sulfate, and the ratio of mixed slurry B to surfactant is 1 L: 0.2 g.

[0136] (1.6) After drying the foam material preform at 80℃ for 2 hours, basalt fiber-based foam matrix is ​​obtained.

[0137] (2) Preparation of impregnation solution containing monolayer MXene nanosheets: 3.2g of LiF was added to 50mL of 9mol / L HCl solution and stirred at 40℃ for 1h. Then Ti3AlC2 was added to the obtained hydrochloric acid / lithium fluoride mixed acid system. The mass ratio of Ti3AlC2 to LiF was 1:1.6. The reaction was carried out at 35℃ for 40h. After the reaction was completed, the mixed solution obtained by the reaction was washed with deionized water until neutral to obtain an impregnation solution with a concentration of about 1wt%. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets.

[0138] (3) Preparation of functional fiber-based composite foam material: The basalt fiber-based foam matrix was immersed in an impregnation solution containing monolayer MXene nanosheets with a concentration of 3 mg / L and the immersion was maintained for 150 s, so that the MXene nanosheets were uniformly distributed in the fiber pores and self-assembled. Then the composite foam uniformly loaded with MXene nanosheets was dried in an oven at 80 ℃ for 1 h to obtain a functional fiber-based composite foam material with a layered network structure.

[0139] Experimental Example 1:

[0140] Microstructure of composite foam materials

[0141] Characterization methods: Functional fiber-based composite foam materials prepared in Examples 1, 3, and 5 were used as samples, with the basalt fiber-based foam matrix prepared in Example 5 serving as a control group. The morphology of the composite foam materials was observed using a scanning electron microscope (SEM) (Vega3SBH, TESCAN). The samples were sputter-coated with gold for 45 seconds at an accelerating voltage of 10 kV, and the surface morphology of their cross-sections was observed based on the SEM images. The results are as follows: Figure 1 As shown.

[0142] Figure 1 SEM images of the functional fiber-based composite foam materials prepared in Examples 1, 3, 5, and the control group are shown. a-Control group, b-Example 3, c-Example 1, d-Example 5. The functional fiber-based composite foam material in Example 5 has the highest amount of MXene nanosheets loaded on it. Figure 1 As shown, increasing the concentration of MXene nanosheets in the impregnation solution or extending the impregnation time can increase the MXene nanosheet loading. With increasing MXene nanosheet loading, the pore size of the composite foam material gradually decreases. This is because the increased MXene nanosheet content leads to an increase in the number of MXene nanosheets self-assembling into films that cover the basalt fiber framework network, resulting in smaller internal pore sizes and a more complex structure. Simultaneously, the increased MXene nanosheet loading also increases the thickness of the MXene film in the composite foam material, leading to increased rigidity and the formation of a robust 3D porous network. This is beneficial for improving the mechanical properties and compression resilience of the composite foam material.

[0143] Experimental Example 2:

[0144] Mechanical property testing

[0145] Test Method: Functional fiber-based composite foam materials prepared in Examples 1, 3, and 5 were used as samples, with the basalt fiber-based foam matrix prepared in Example 5 serving as the control group. The samples were cut into 15mm × 20cm specimens. Compression tests and cyclic compression tests were performed on the composite foam materials using an AI-7000-NGD servo multifunctional material testing machine. Under a stress of 3000 kgf and a speed of 15 mm / min, compression tests were conducted on different composite foam materials with a strain of 50%, and the compressive strength was measured. Results are as follows: Figure 2 As shown.

[0146] Figure 2The mechanical properties of the functional fiber-based composite foam materials prepared in Examples 1, 3, 5 and the control group are shown in the figure. Figure 2 The results show that, under external load and 50% strain, the compressive strength of the functional fiber-based composite foam materials prepared by different methods gradually increases with the increase of MXene nanosheet concentration in the impregnation solution or the extension of impregnation time, exhibiting linear compressive stress.

[0147] Experimental Example 3:

[0148] Sound absorption performance test

[0149] Test Method: Functional fiber-based composite foam materials prepared in Examples 1, 3, and 5 were used as samples, with the basalt fiber-based foam matrix prepared in Example 5 serving as the control group. The sound absorption performance of the composite foam materials was tested in the 63-6300Hz range using mid-to-high frequency impedance tubes (SW422 and SW477). Referring to GB / T18696.2-2002 and ISO10534-2:2001 standards, the samples were made into cylinders with diameters of 29mm and 100mm. The sound absorption coefficient of the samples was determined using a four-channel digital signal acquisition system and the transfer function method. During the test, the samples were placed inside a rigid wall with a thickness of 1mm and a pore size of 3mm. The sample thickness was set, and the test was repeated three times, with the average value taken. Simultaneously, the noise reduction coefficient (NRC) was calculated to evaluate the sound absorption performance of the material; the NRC is the average of the sound absorption coefficients at 250, 500, 1000, and 2000Hz. Results are as follows: Figure 3 As shown.

[0150] Figure 3 The diagram shows the sound absorption performance of the functional fiber-based composite foam materials prepared in Examples 1, 3, 5, and the control group. Figure 3 The results showed that the sound absorption coefficient of the composite foam material increased with increasing frequency during sound absorption tests, exhibiting excellent sound absorption coefficients in the mid-to-high frequency range. Specifically, the NRC of the composite foam material prepared in Example 3 was 0.40, demonstrating lightweight yet excellent sound absorption performance; the NRC of the composite foam material prepared in Example 5 was 0.54, showing a significant increasing trend. This is because MXene nanosheets self-assembled into a film on the basalt fiber-based foam matrix, forming an internal layered fiber-film network structure that covered some of the large pores in the original structure, reducing the pore size. Furthermore, the pore size of the composite foam material decreased with increasing MXene nanosheet loading, increasing airflow resistance and making the propagation path of the incident wave more tortuous, thus generating more sound energy dissipation and enhancing sound absorption capacity.

[0151] Experimental Example 4:

[0152] Electromagnetic shielding performance test

[0153] Test Method: Functional fiber-based composite foam materials prepared in Examples 1, 3, and 5 were used as samples, with the basalt fiber-based foam matrix prepared in Example 5 serving as the control group. Samples were prepared using a paraffin solidification sectioning method. An appropriate amount of paraffin was melted into a clear liquid at 50°C. A slightly larger sample was placed in the melt and allowed to fully immerse for 5 minutes. After cooling for 30 minutes, the paraffin was completely solidified. The sample was then sliced ​​to the specified size of 10mm × 20mm × 2mm to obtain the specimen. Finally, the EMI shielding performance was analyzed in the frequency range of 8.2-12.4GHz (X-band) using the waveguide method with an Agilent PNA-N5244A vector network analyzer (USA). Results are as follows: Figure 4 As shown.

[0154] Figure 4 The electromagnetic shielding performance diagrams are shown for the functional fiber-based composite foam materials prepared in Examples 1, 3, 5, and the control group. Figure 4 The results show that as the concentration of MXene nanosheets in the impregnation solution gradually increases or the impregnation time is extended, the loading of MXene nanosheets increases, the conductive network formed inside the composite foam material becomes more complete, the propagation path of electromagnetic waves is extended, and its electromagnetic shielding value is significantly improved, thus significantly increasing the electromagnetic shielding performance.

[0155] It should be noted that some detailed steps of the operation are not described in this invention, but are existing technologies known to those skilled in the art, and therefore will not be repeated here. Furthermore, in this invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible secondary ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. In this invention, not all possible combinations of the various technical features in each embodiment or implementation are described. As long as the combinations of these technical features do not contradict each other, the various technical features in each embodiment or implementation can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a functional fiber-based composite foam material, characterized in that, include: A basalt fiber-based foam matrix is ​​provided; An impregnation solution comprising monolayer MXene nanosheets is provided in solution form; The basalt fiber-based foam matrix is ​​brought into contact with the impregnation liquid containing monolayer MXene nanosheets, so that the basalt fiber-based foam matrix is ​​impregnated by the impregnation liquid containing monolayer MXene nanosheets; and, The composite foam loaded with Mxene nanosheets obtained by impregnation is dried to prepare a functional fiber-based composite foam material; The immersion holding time is 30-300 seconds; The concentration of the monolayer MXene nanosheets in the impregnation solution is 0.5-4 mg / L. The impregnation solution containing monolayer MXene nanosheets is prepared by the following steps: LiF was added to HCl solution and stirred at a constant temperature. Then Ti3AlC2 was added to the resulting hydrochloric acid / lithium fluoride mixed acid system to react. After the reaction was completed, the mixed solution obtained from the reaction was washed with deionized water until neutral. Then deionized water was added to concentrate the solution to obtain an impregnation solution containing monolayer MXene nanosheets. The basalt fiber-based foam matrix is ​​prepared through the following steps: (1) Basalt fiber is first calcined, and then the calcined basalt fiber is mixed with concentrated sulfuric acid and hydrogen peroxide solution to obtain acid-treated basalt fiber. (2) After washing the acid-treated basalt fiber to neutral, dry it at 85-95℃ for 1.5-3h, then disperse it, and then filter and dehydrate it to obtain basalt fiber slurry. (3) Basalt fiber slurry and polyvinyl alcohol fiber are mixed and mechanically stirred to obtain mixed slurry A; (4) Mix the mixed slurry A and sodium tetraborate decahydrate solution, adjust the pH of the resulting mixed solution to 10, and then mechanically stir at a rate of 1000-4000 rpm for 10-20 min to obtain mixed slurry B; (5) Mix the mixed slurry B and the surfactant solution, and then mechanically foam to obtain a foam material preform; (6) After drying the foam material preform at a temperature of 60-120℃ for 1-3 hours, a basalt fiber-based foam matrix is ​​obtained; The basalt fibers have a diameter of 8-15 μm and a length of 3-9 mm; the polyvinyl alcohol fibers have a diameter of 15-24 μm and a length of 2-6 mm.

2. The method for preparing the functional fiber-based composite foam material according to claim 1, characterized in that, The drying conditions for the composite foam loaded with Mxene nanosheets are: temperature 60-100℃, time 1-3h.

3. The method for preparing the functional fiber-based composite foam material according to claim 1, characterized in that, The concentration of the HCl solution is 7-10 mol / L, and the mass ratio of Ti3AlC2 to LiF is 1:(1-2); the constant temperature stirring conditions are: temperature 35-45℃, time 0.5-1h; the reaction conditions are: temperature 35-45℃, time 35-45h.

4. The method for preparing the functional fiber-based composite foam material according to claim 1, characterized in that, In step (1), the calcination conditions are: temperature 350-430℃, time 1.5-3h; the ratio of basalt fiber, concentrated sulfuric acid and hydrogen peroxide solution is 5g:(30-45)mL:(10-20)mL, the concentration of hydrogen peroxide solution is 25-40wt%, and the concentration of concentrated sulfuric acid is 2-5mol / L; the mixing conditions are: temperature 60-90℃, time 1-2h.

5. The method for preparing the functional fiber-based composite foam material according to claim 1, characterized in that, In step (2), the dispersing is carried out using a dispersing machine. The dispersion concentration of basalt fiber in the dispersing machine is 0.1-0.3wt%, and the dispersion time is 3-7min. The concentration of basalt fiber in the basalt fiber slurry is 5-15wt%.

6. The method for preparing the functional fiber-based composite foam material according to claim 1, characterized in that, In step (3), the mass ratio of basalt fiber slurry to polyvinyl alcohol fiber is (50-95):(5-50); in step (4), the ratio of the oven-dry mass of fiber in mixed slurry A to the amount of sodium tetraborate decahydrate is 5g:(1-3)g.

7. The method for preparing the functional fiber-based composite foam material according to claim 1, characterized in that, In step (5), the surfactant in the surfactant solution is sodium dodecyl sulfate, with a mass fraction of 3-10 wt%; the ratio of the mixed slurry B to the surfactant is 1 L:(0.5-1) g; the mechanical foaming conditions are: speed 1000-4000 rpm, time 5-15 min.

8. A functional fiber-based composite foam material, characterized in that, The functional fiber-based composite foam material is prepared by the method for preparing the functional fiber-based composite foam material according to any one of claims 1-7, and the density of the functional fiber-based composite foam material is 9-15 mg / cm³. 3 .

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