A flexible encapsulated aerogel composite and method of making the same

Abstract

The application provides a flexible encapsulated aerogel composite material and a preparation method thereof. The flexible encapsulated aerogel composite material uses titanium carbide as a conductive filler, uses carboxylated cellulose nanofiber as an aerogel skeleton, and uses a thermoplastic polyurethane / silicon wrapped ammonium polyphosphate composite material as an encapsulated outer layer. The flexible encapsulated aerogel composite material prepared by using the technical scheme has super-high electromagnetic shielding efficiency, can obviously reduce the fire risk of the aerogel, and reduce the release of heat and toxic smoke gas in the combustion process, so that the application of the flexible encapsulated aerogel composite material in wearable materials, home decoration, aerospace, electronic communication, transportation and the like is effectively widened.

Description

Technical Field

[0001] This invention relates to the fields of aerogel electromagnetic shielding and flame retardant technology, and in particular to a flexible encapsulated aerogel composite material and its preparation method. Background Technology

[0002] The generation, transmission, reception, processing, and storage of information all rely on electromagnetic waves as carriers. From highly integrated electronic products to the widespread application of automated control systems in various fields, these intelligent devices have made our lives easier. However, this has also brought about significant electromagnetic pollution. The increasing frequency and digitization of electronic devices, along with the increased energy density of interference signals, have further deteriorated the electromagnetic environment in confined spaces. Existing electromagnetic interference (EMI) shielding materials struggle to meet the requirements of being "thin, lightweight, strong, and wide." Furthermore, with the rapid development of flexible and wearable electronic products, corresponding EMI shielding materials, in addition to effective EMI shielding performance, should also be highly efficient, low-density (i.e., lightweight), have high thermal stability, considerable mechanical flexibility, and corrosion resistance.

[0003] Aerogels, hailed as "miracle materials of the 21st century," are ultralight and porous materials composed of ultra-high volume gaseous components and a three-dimensional solid matrix network, possessing a high specific surface area. This unique porous and loose structure endows aerogels with extremely low density, as well as extremely low thermal conductivity, large specific surface area, tunable thermal / electrical conductivity, and mechanical flexibility. Due to these outstanding properties, aerogels are expected to be "miracle materials that will change the world," and are used as thermal insulation materials, sound insulation materials, optical materials, catalyst supports, etc., showing significant application prospects in chemistry, optics, electronics, nuclear reactions, as well as aerospace, life sciences, transportation, clothing decoration, and construction.

[0004] Meanwhile, to broaden the application fields of aerogels, researchers have encapsulated them with polymer materials to improve their mechanical properties and weather resistance. However, most aerogels and their encapsulating polymer materials are extremely flammable, and combustion can cause significant personal injury and property damage. Improving the flame-retardant properties of encapsulated aerogels is crucial. Therefore, developing aerogel composite materials that combine electromagnetic shielding and flame-retardant properties is of great significance.

[0005] Currently, research on electromagnetic shielding and flame retardancy of encapsulated aerogels by scholars both domestically and internationally can be divided into two types. First, some studies only consider electromagnetic shielding performance. For example, Xin et al. prepared a composite aerogel of cellulose nanofibers / MXenes encapsulated with a silicon coating, achieving an electromagnetic shielding effectiveness of 39.5 dB. Huang et al. used trace amounts of hydroxyethyl cellulose as a gel and constructed an MXene aerogel with a stable, highly conductive network using a freeze-drying method, which was then encapsulated with silicone resin, ultimately achieving an electromagnetic shielding effectiveness of 74.5 dB. Second, some studies only investigate flame retardancy. Zhang et al. incorporated boron nitride (BNNS) and ammonium polyphosphate (APP) as flame retardants into polyvinyl alcohol (PVA) aerogel, improving its fire resistance. They further encapsulated the surface of the PVA-based aerogel with polydimethylsiloxane (PDMS) and hydrophobic SiO2, obtaining a micro / nano-scale rough structure with good chemical durability and self-cleaning ability. Compared to the original PVA aerogel, the peak exothermic rate and total exothermic rate of the prepared PVA-based composite aerogel were significantly reduced. Yang et al. encapsulated cellulose nanofiber aerogels with two-dimensional molybdenum disulfide. Combustion tests showed that the material exhibited good flame retardant properties, with a limiting oxygen index (LOI) of 34.7% and a total heat release of 0.4 MJ / m³. 2 The vertical burning test also showed excellent flame retardancy and self-extinguishing ability.

[0006] Currently, it remains a huge challenge to ensure that encapsulated aerogels possess both excellent electromagnetic shielding performance and high flame retardant properties. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a flexible encapsulated aerogel composite material and its preparation method. The method utilizes liquid encapsulation and vacuum-assisted impregnation technology to construct a flexible encapsulated aerogel composite material by using carboxylated cellulose nanofibers and titanium carbide aqueous solution to form an aerogel matrix, and using silicon-encapsulated ammonium polyphosphate flame retardant and thermoplastic polyurethane as encapsulation dispersion to improve the electromagnetic shielding and flame retardant properties of the aerogel.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a flexible encapsulated aerogel composite material, wherein the flexible encapsulated aerogel composite material uses titanium carbide as a conductive filler, carboxylated cellulose nanofibers as an aerogel skeleton, and thermoplastic polyurethane / silicone-encapsulated ammonium polyphosphate composite material as an encapsulation outer layer.

[0009] In a preferred embodiment, the flexible encapsulated aerogel composite material comprises, by weight, 25.0 parts of carboxylated cellulose nanofibers, 25.0 parts of an aqueous solution of titanium carbide at a concentration of 8-19 mg / g, 48.0 parts of thermoplastic polyurethane elastomer, and 12.0 parts of silicon-coated ammonium polyphosphate flame retardant.

[0010] This invention also provides a method for preparing a flexible encapsulated aerogel composite material, comprising the following steps: Step 1: Take hydrochloric acid, aluminum titanium carbide and lithium fluoride, heat in an oil bath at 35 degrees Celsius for 48 hours under magnetic stirring, wash the product with water until neutral, and obtain an aqueous solution of titanium carbide with a concentration of 8-19 mg / g after ultrasonic exfoliation. Step 2: Take 25.0 parts of an aqueous solution of titanium carbide with a concentration of 8-19 mg / mL into a three-necked flask, and sonicate for 30 minutes under ice bath conditions to separate the layers. Add 25.0 parts of carboxylated cellulose nanofibers and stir at room temperature for 2 hours. Step 3: Pour the well-mixed solution into a mold and freeze it at -25 degrees Celsius for 48 hours. Step 4: Place the frozen sample in a freeze dryer and freeze-dry it under vacuum at 10 MPa and -50 degrees Celsius for 48 hours to obtain carboxylated cellulose nanofibers / titanium carbide hybrid aerogel. Step 5: Take 48.0 parts of thermoplastic polyurethane into a three-necked flask, add 480.0 parts of N,N-dimethylformamide solution, heat and stir in an oil bath, and after the thermoplastic polyurethane is completely dissolved, add 12.0 parts of silicone-coated ammonium polyphosphate, continue stirring, and obtain a uniform thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion. Step 6: Using the carboxylated cellulose nanofiber / titanium carbide hybrid aerogel obtained in Step 4 as the matrix and the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion obtained in Step 5 as the encapsulation slurry, a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties is obtained by solution encapsulation and vacuum-assisted impregnation.

[0011] In a preferred embodiment, the stirring in step 5 specifically involves stirring the thermoplastic polyurethane and N,N-dimethylformamide solution at 80 degrees Celsius for 3 hours; then adding silicon-coated ammonium polyphosphate and stirring at 80 degrees Celsius for 1 hour.

[0012] In a preferred embodiment, step 6, solution encapsulation and vacuum-assisted impregnation, includes the following steps: Step 61: Place the carboxylated cellulose nanofibers / titanium carbide hybrid aerogel into a beaker, pour the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion into the beaker, and immerse it for several tens of seconds; Step 62: Take out the encapsulated aerogel from Step 1 and dry it in a vacuum drying oven to obtain a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties.

[0013] In a preferred embodiment, the immersion encapsulation time in step 1 is 90 seconds.

[0014] In a preferred embodiment, the vacuum drying in step 2 specifically refers to vacuum drying at 80 degrees Celsius for 48 hours.

[0015] Compared with existing technologies, the present invention has the following advantages: the flexible encapsulated aerogel composite material exhibits good interfacial compatibility, high thermal stability, excellent electromagnetic shielding performance, and superior fire safety. Furthermore, through comprehensive comparison of test data, the results show that the aerogel exhibits optimal electromagnetic shielding and flame retardant properties when the concentration of the titanium carbide aqueous solution used is 19 mg / g. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a cone calorimeter test of a flexible encapsulated aerogel composite material according to a preferred embodiment of the present invention; wherein (a) heat release rate; (b) total heat release; (c) smoke release rate; (d) total smoke release; (e) CO release rate; (f) CO2 release rate; Figure 2 The following are schematic diagrams of electromagnetic shielding effectiveness testing of flexible encapsulated aerogel composite materials according to a preferred embodiment of the present invention: (a) Electromagnetic shielding dot plot in the X-band; (b) Electromagnetic shielding bar chart in the X-band; (c) Electromagnetic shielding dot plot in the K-band; (d) Electromagnetic shielding bar chart in the K-band. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0020] Table 1 Formulation of flexible encapsulated aerogel composite materials CNF 50.00 0.00 0.00 0.00 CNF / TPU 50.00 0.00 60.00 0.00 CNF / TPU / SiAPP 50.00 0.00 48.00 12.00 CNF-MXene8 / TPU / SiAPP 25.00 25.00 48.00 12.00 CNF-MXene11 / TPU / SiAPP 25.00 25.00 48.00 12.00 CNF-MXene19 / TPU / SiAPP 25.00 25.00 48.00 12.00 Note: CNF stands for carboxylated cellulose nanofibers, TPU stands for thermoplastic polyurethane; SiAPP stands for silicon-coated ammonium polyphosphate flame retardant; MXene refers to titanium carbide aqueous solution, and MXene8 refers to titanium carbide aqueous solution with a concentration of 8 mg / g.

[0021] A flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties, wherein the composite material uses titanium carbide as a conductive filler, carboxylated cellulose nanofibers as an aerogel skeleton, and thermoplastic polyurethane / silicone-coated ammonium polyphosphate composite material as an encapsulation outer layer. By mass parts, the carboxylated cellulose nanofibers are 25.0 parts, the aqueous solution of titanium carbide with a concentration of 8-19 mg / g is 25.0 parts, the thermoplastic polyurethane elastomer is 48.0 parts, and the silicon-coated ammonium polyphosphate flame retardant is 12.0 parts.

[0022] The concentration of the titanium carbide aqueous solution in the carboxylated cellulose nanofibers / titanium carbide aerogel is 8–19 mg / g; The mass ratio of the carboxylated cellulose nanofibers / titanium carbide aerogel is 1:1.

[0023] Example 1: A flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties, wherein a titanium carbide aqueous solution and a carboxylated cellulose nanofiber / titanium carbide hybrid aerogel composite material are prepared according to the following steps: (1) Add 20.00 ml of hydrochloric acid, 1.00 part of carbon aluminum titanium and 1.56 part of lithium fluoride to a plastic centrifuge tube, heat in an oil bath at 35 degrees Celsius for 48 hours under magnetic stirring, wash the product with water until neutral, and obtain an aqueous solution of titanium carbide with a concentration of 8 mg / g after ultrasonic peeling.

[0024] (2) Take 25.0 parts of titanium carbide aqueous solution with a concentration of 8 mg / mL in a three-necked flask, and ultrasonically stir for 30 minutes under ice bath conditions to separate the layers. Add 25.0 parts of carboxylated cellulose nanofibers and stir at room temperature for 2 hours.

[0025] (3) Pour the uniformly mixed solution into the mold and freeze it in the refrigerator at -25 degrees Celsius for 48 hours.

[0026] (4) The frozen sample was placed in a freeze dryer and vacuum freeze-dried at 10 MPa and -50 degrees Celsius for 48 hours to obtain carboxylated cellulose nanofiber / titanium carbide hybrid aerogel.

[0027] A flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties, wherein the aerogel composite material with encapsulation structure is prepared according to the following steps: (5) Take 48.0 parts of thermoplastic polyurethane into a three-necked flask, add 480.0 parts of N,N-dimethylformamide solution, stir in an oil bath at 80 degrees Celsius for 3 hours, and after the thermoplastic polyurethane is completely dissolved, add 12.0 parts of silicon-coated ammonium polyphosphate, stir at 80 degrees Celsius for 1 hour to obtain a uniform thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion.

[0028] (6) Place the carboxylated cellulose nanofibers / titanium carbide hybrid aerogel obtained in step (4) into a beaker, and pour the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion obtained in step (5) into the beaker as an encapsulation slurry, so that the aerogel is immersed for 90 seconds.

[0029] (7) Take out the encapsulated aerogel and put it into a vacuum drying oven at 80 degrees Celsius for 48 hours to obtain a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties.

[0030] Example 2: A flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties, wherein a titanium carbide aqueous solution and a carboxylated cellulose nanofiber / titanium carbide hybrid aerogel composite material are prepared according to the following steps: (1) Add 20.00 ml of hydrochloric acid, 1.00 part of carbon aluminum titanium, and 1.56 part of lithium fluoride to a plastic centrifuge tube. Heat in an oil bath at 35 degrees Celsius for 48 hours with magnetic stirring. Wash the product with water until neutral. After ultrasonic peeling, obtain an aqueous solution of titanium carbide with a concentration of 11 mg / g.

[0031] (2) Take 25.0 parts of titanium carbide aqueous solution with a concentration of 11 mg / mL in a three-necked flask, and ultrasonically stir for 30 minutes under ice bath conditions to separate the layers. Add 25.0 parts of carboxylated cellulose nanofibers and stir at room temperature for 2 hours.

[0032] (3) Pour the uniformly mixed solution into the mold and freeze it in the refrigerator at -25 degrees Celsius for 48 hours.

[0033] (4) The frozen sample was placed in a freeze dryer and vacuum freeze-dried at 10 MPa and -50 degrees Celsius for 48 hours to obtain carboxylated cellulose nanofiber / titanium carbide hybrid aerogel.

[0034] A flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties, wherein the aerogel composite material with encapsulation structure is prepared according to the following steps: (5) Take 48.0 parts of thermoplastic polyurethane into a three-necked flask, add 480.0 parts of N,N-dimethylformamide solution, stir in an oil bath at 80 degrees Celsius for 3 hours, and after the thermoplastic polyurethane is completely dissolved, add 12.0 parts of silicon-coated ammonium polyphosphate, stir at 80 degrees Celsius for 1 hour to obtain a uniform thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion.

[0035] (6) Place the carboxylated cellulose nanofibers / titanium carbide hybrid aerogel obtained in step (4) into a beaker, and pour the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion obtained in step (5) into the beaker as an encapsulation slurry, so that the aerogel is immersed for 90 seconds.

[0036] (7) Take out the encapsulated aerogel and put it into a vacuum drying oven at 80 degrees Celsius for 48 hours to obtain a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties.

[0037] Example 3: A flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties, wherein a titanium carbide aqueous solution and a carboxylated cellulose nanofiber / titanium carbide hybrid aerogel composite material are prepared according to the following steps: (1) Add 20.00 ml of hydrochloric acid, 1.00 part of carbon aluminum titanium, and 1.56 part of lithium fluoride to a plastic centrifuge tube. Heat in an oil bath at 35 degrees Celsius for 48 hours with magnetic stirring. Wash the product with water until neutral. After ultrasonic peeling, obtain an aqueous solution of titanium carbide with a concentration of 19 mg / g.

[0038] (2) Take 25.0 parts of titanium carbide aqueous solution with a concentration of 19 mg / mL in a three-necked flask, and ultrasonically stir for 30 minutes under ice bath conditions to separate the layers. Add 25.0 parts of carboxylated cellulose nanofibers and stir at room temperature for 2 hours.

[0039] (3) Pour the uniformly mixed solution into the mold and freeze it in the refrigerator at -25 degrees Celsius for 48 hours.

[0040] (4) The frozen sample was placed in a freeze dryer and vacuum freeze-dried at 10 MPa and -50 degrees Celsius for 48 hours to obtain carboxylated cellulose nanofiber / titanium carbide hybrid aerogel.

[0041] A flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties, wherein the aerogel composite material with encapsulation structure is prepared according to the following steps: (5) Take 48.0 parts of thermoplastic polyurethane into a three-necked flask, add 480.0 parts of N,N-dimethylformamide solution, stir in an oil bath at 80 degrees Celsius for 3 hours, and after the thermoplastic polyurethane is completely dissolved, add 12.0 parts of silicon-coated ammonium polyphosphate, stir at 80 degrees Celsius for 1 hour to obtain a uniform thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion.

[0042] (6) Place the carboxylated cellulose nanofibers / titanium carbide hybrid aerogel obtained in step (4) into a beaker, and pour the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion obtained in step (5) into the beaker as an encapsulation slurry, so that the aerogel is immersed for 90 seconds.

[0043] (7) Take out the encapsulated aerogel and put it into a vacuum drying oven at 80 degrees Celsius for 48 hours to obtain a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties.

[0044] Comparative Example 1: Take 25.0 parts of carboxylated cellulose nanofibers and stir at room temperature for 2 hours. Pour the homogeneous solution into a mold and freeze it at -25 degrees Celsius for 48 hours. Place the frozen sample in a freeze dryer and freeze-dry it under vacuum at 10 MPa and -50 degrees Celsius for 48 hours to obtain carboxylated cellulose nanofiber aerogel.

[0045] Comparative Example 2: Take 25.0 parts of carboxylated cellulose nanofibers and stir at room temperature for 2 hours. Pour the homogeneous solution into a mold and freeze at -25°C for 48 hours. Place the frozen sample in a freeze dryer and freeze-dry under vacuum at 10 MPa and -50°C for 48 hours to obtain carboxylated cellulose nanofiber aerogel. Take 60.0 parts of thermoplastic polyurethane in a three-necked flask, add 600.0 parts of N,N-dimethylformamide solution, and stir in an oil bath at 80°C for 3 hours to obtain a homogeneous thermoplastic polyurethane solution. Place the carboxylated cellulose nanofiber aerogel into a beaker, and pour the thermoplastic polyurethane solution as an encapsulation slurry into the beaker, immersing the aerogel for 90 seconds. Remove the encapsulated aerogel and place it in a vacuum drying oven at 80°C for 48 hours to obtain a carboxylated cellulose nanofiber aerogel composite material encapsulated with thermoplastic polyurethane.

[0046] Comparative Example 3: Take 25.0 parts of carboxylated cellulose nanofibers and stir at room temperature for 2 hours. Pour the uniformly mixed solution into a mold and freeze at -25°C for 48 hours. Place the frozen sample in a freeze dryer and freeze-dry under vacuum at 10 MPa and -50°C for 48 hours to obtain carboxylated cellulose nanofiber aerogel. Take 48.0 parts of thermoplastic polyurethane in a three-necked flask, add 480.0 parts of N,N-dimethylformamide solution, and stir in an oil bath at 80°C for 3 hours. After the thermoplastic polyurethane is completely dissolved, add 12.0 parts of silicone-coated ammonium polyphosphate and stir at 80°C for 1 hour to obtain a uniform thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion. Place the carboxylated cellulose nanofiber aerogel into a beaker, and pour the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion as an encapsulation slurry into the beaker, immersing the aerogel for 90 seconds. The encapsulated aerogel was removed and placed in a vacuum drying oven at 80 degrees Celsius for 48 hours to obtain a carboxylated cellulose nanofiber aerogel composite material with thermoplastic polyurethane / silicone encapsulation of ammonium polyphosphate.

[0047] The carboxylated cellulose nanofiber aerogels and aerogel composites obtained in Examples 1, 2, 3 and Comparative Examples 1, 2, 3 were subjected to combustion tests in a cone burner. The experimental results are shown in Table 2.

[0048] Table 2. Cone calorimeter test data of a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties at a heat flux density of 35 kW / m².

[0049] Notes: TTI is the sample ignition time; PHRR is the peak heat release rate; THR is the total heat release; PSPR is the peak smoke release rate; TSR is the total smoke release; PCOPR is the peak CO generation rate; PCO2PR is the peak CO2 generation rate.

[0050] From Table 2 and Appendix Figure 1-2 It can be seen that in the comparative examples, the cellulose aerogel encapsulated in thermoplastic polyurethane releases a large amount of heat and toxic fumes when burned, with very little char residue. After adding silicon-encapsulated ammonium polyphosphate flame retardant (Shandong Chenxu Chemical Co., Ltd.), the heat release and smoke release of the thermoplastic polyurethane composite material decreased significantly. Furthermore, in Examples 1, 2, and 3, the addition of different concentrations of titanium carbide significantly improved the electromagnetic shielding and flame retardant properties. In summary, the higher the concentration of titanium carbide, the better the electromagnetic shielding effectiveness of the encapsulated aerogel composite material, while also significantly improving the flame retardant properties of the encapsulated aerogel.

[0051] The above is a detailed description of the present invention (a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties and its preparation method). Specific embodiments are used to illustrate the preparation and application of the present invention, helping to understand the method and core ideas of the invention. It is worth noting that those skilled in the art can make various modifications and improvements to the present invention without departing from its principles, and these modifications and improvements should also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a flexible encapsulated aerogel composite material, characterized in that... A flexible encapsulated aerogel composite material was prepared, wherein titanium carbide is used as a conductive filler, carboxylated cellulose nanofibers are used as an aerogel skeleton, and thermoplastic polyurethane / silicone-encapsulated ammonium polyphosphate composite material is used as the encapsulation outer layer; the preparation method includes the following steps: Step 1: Take hydrochloric acid, aluminum titanium carbide and lithium fluoride, heat in an oil bath at 35 degrees Celsius for 48 hours under magnetic stirring, wash the product with water until neutral, and obtain an aqueous solution of titanium carbide with a concentration of 8-19 mg / g after ultrasonic exfoliation. Step 2: Take 25.0 parts by weight of an aqueous solution of titanium carbide with a concentration of 8-19 mg / mL in a three-necked flask, and sonicate for 30 minutes under ice bath conditions to separate the layers. Add 25.0 parts by weight of carboxylated cellulose nanofibers and stir at room temperature for 2 hours. Step 3: Pour the well-mixed solution into a mold and freeze it at -25 degrees Celsius for 48 hours. Step 4: Place the frozen sample in a freeze dryer and freeze-dry it under vacuum at 10 Pa atm and -50 degrees Celsius for 48 hours to obtain carboxylated cellulose nanofibers / titanium carbide hybrid aerogel. Step 5: Take 48.0 parts by weight of thermoplastic polyurethane into a three-necked flask, add 480.0 parts by weight of N,N-dimethylformamide solution, heat and stir in an oil bath, and after the thermoplastic polyurethane is completely dissolved, add 12.0 parts by weight of silicon-coated ammonium polyphosphate, and continue stirring to obtain a uniform thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion. Step 6: Using the carboxylated cellulose nanofiber / titanium carbide hybrid aerogel obtained in Step 4 as the matrix and the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion obtained in Step 5 as the encapsulation slurry, a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties is obtained by solution encapsulation and vacuum-assisted impregnation. Step 6, the solution encapsulation and vacuum-assisted impregnation, includes the following steps: Step 61: Place the carboxylated cellulose nanofibers / titanium carbide hybrid aerogel into a beaker, pour the thermoplastic polyurethane / silicone-coated ammonium polyphosphate dispersion into the beaker, and immerse it for several tens of seconds; Step 62: Take out the encapsulated aerogel from Step 1 and dry it in a vacuum drying oven to obtain a flexible encapsulated aerogel composite material with electromagnetic shielding and flame retardant properties.

2. The method for preparing a flexible encapsulated aerogel composite material according to claim 1, characterized in that, The stirring described in step 5 specifically involves stirring thermoplastic polyurethane and N,N-dimethylformamide solution at 80 degrees Celsius for 3 hours; then adding silicon-coated ammonium polyphosphate and stirring at 80 degrees Celsius for 1 hour.

3. The method for preparing a flexible encapsulated aerogel composite material according to claim 1, characterized in that, The immersion time in step 61 is 90 seconds.

4. The method for preparing a flexible encapsulated aerogel composite material according to claim 1, characterized in that, The vacuum drying described in step 62 specifically involves vacuum drying at 80 degrees Celsius for 48 hours.

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