Coaxial structure aramid and cellulose aerogel fibers and methods of making the same

Abstract

The application provides a coaxial structure aramid and cellulose aerogel fiber and a preparation method thereof. The method is characterized in that: special outer-layer spinning dope and inner-layer spinning dope are injected into a coagulation bath by using a coaxial spinning mode at different extrusion speeds to perform wet spinning, and after coagulation and winding, the coaxial structure aramid and cellulose aerogel fiber is prepared by replacing the spinning dope in a solvent exchange liquid with different concentration gradients for a predetermined time, and finally washing and drying. The inner-layer fiber of the aerogel fiber has the characteristics of rich pores, ultra-low density and ultra-high specific surface area, and the outer-layer fiber has the excellent properties of dense surface, high temperature resistance, high strength and high modulus, and can better adapt to the application in harsh environments; the raw material cost is low, the process is simple, and the specific surface area, inner and outer diameters and pore structures are easy to control in the preparation process of the coaxial structure aerogel fiber.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preparation of porous aerogel fibers, in particular to a coaxial structure aramid and cellulose aerogel fiber and a preparation method thereof. BACKGROUND

[0002] Aerogel is a synthetic porous material derived from a gel, in which the liquid is replaced by gas, and the air content can be as high as 99.8%, so it has ultra-high porosity, ultra-low density, high specific surface area and excellent thermal insulation performance. At the same time, aerogel has a micro-nano porous three-dimensional structure, so aerogel has great potential application value in adsorption, filtration, catalysis, air purification and many other fields. If aerogel is combined with yarn to make aerogel fibers of different sizes and shapes, such aerogel fibers not only have high porosity and specific surface area, but also can endow the yarn with multifunctional applications, which will have high application value.

[0003] Aramid is a high-performance chemical fiber with high strength, light density, flexibility, good luster and stable chemical properties, which can be applied to various composite materials. Cellulose has many advantages such as wide source, green and renewable, good biocompatibility and many others. Cellulose aerogel has low density, high porosity, low cost and wide source of raw materials, and can be applied to air filtration, oil-water separation and other scenes, but its mechanical properties are insufficient, which limits its application.

[0004] Therefore, it is necessary to design a coaxial structure aramid and cellulose aerogel fiber and a preparation method thereof to solve the above problems. SUMMARY

[0005] In view of the defects of the prior art, the purpose of the present application is to provide a coaxial structure aramid and cellulose aerogel fiber and a preparation method thereof, which can better adapt to the application in harsh conditions by using a coaxial spinning method to inject the coagulation bath at different extrusion speeds for wet spinning to prepare a coaxial structure aramid and cellulose aerogel fiber with good thermal conductivity and good mechanical properties.

[0006] To achieve the above purpose, the present application provides a preparation method of a coaxial structure aramid and cellulose aerogel fiber, comprising the following steps:

[0007] S1, dissolving aramid fibers in an aprotic solvent in an alkaline environment to prepare an outer layer spinning stock solution;

[0008] The nanocellulose powder is placed in deionized water and treated by ultrasonic dispersion to prepare an inner layer spinning stock solution;

[0009] S2, the outer layer of the spinning dope and the inner layer of the spinning dope are injected into a coagulation bath through a coaxial spinning needle at different extrusion speeds respectively to perform wet spinning, and after coagulation for a predetermined time, a nanometer aramid fiber and nanometer cellulose coaxial structure gel fiber is prepared;

[0010] S3, after the nanometer aramid fiber and nanometer cellulose coaxial structure gel fiber is wound in the coagulation bath, it is sequentially immersed in a plurality of solvent exchange liquids with different concentration gradients for a predetermined time of replacement; the concentration of the solvent exchange liquid used for sequential immersion gradually decreases during replacement;

[0011] S4, after the nanometer aramid fiber and nanometer cellulose coaxial structure gel fiber treated by step S3 is washed to neutral, it is dried to prepare a coaxial structure aramid fiber and cellulose aerogel fiber.

[0012] Further, in step S1, the outer layer of the spinning dope includes the aramid fiber, the aprotic solvent, the alkaline substance and water; in the outer layer of the spinning dope, the mass fraction of the aramid fiber is 0.5-5wt%; the mass fraction of the aprotic solvent is 90-95wt%; the mass fraction of the alkaline substance is 2-4wt%; and the mass fraction of the water is 1-2wt%.

[0013] Further, in step S1, the mass fraction of the nanometer cellulose powder in the inner layer of the spinning dope is 0.1-1wt%.

[0014] Further, in step S2, the extrusion speed of the outer layer of the spinning dope for wet spinning is 10-20m / h; the extrusion speed of the inner layer of the spinning dope for wet spinning is 6-10m / h; and the predetermined time for coagulation is 30min-2h.

[0015] Further, in step S2, the concentration of the coagulation bath includes one or more of a weak alkaline solution with a concentration of 10-40wt%, an ethanol solution with a concentration of 25-40wt%, and an acetone solution with a concentration of 10-30wt%; the weak alkaline solution includes one or more of a calcium hydroxide solution and a calcium chloride solution.

[0016] Further, in step S3, the plurality of different concentration gradients is at least three; the solvent exchange liquid includes one or more of propanol, butanol and tert-butanol; the concentration of the solvent exchange liquid is 25-75wt%; and the predetermined time of replacement in the solvent exchange liquid is 4-6h.

[0017] Further, in step S4, the drying method includes freeze drying or carbon dioxide supercritical drying.

[0018] Further, in step S1, the aramid fiber includes para-aramid fiber or meta-aramid fiber; and the nanocellulose powder includes plant cellulose or bacterial cellulose.

[0019] Further, in step S1, the aprotic solvent includes one or more of acetonitrile, dimethylformamide, DMI, dimethyl sulfoxide, and hexamethylphosphoramide.

[0020] The application also provides a coaxial structure aramid and cellulose aerogel fiber prepared by the preparation method of the coaxial structure aramid and cellulose aerogel fiber.

[0021] The application has the following beneficial effects:

[0022] 1. The preparation method of the coaxial structure aramid and cellulose aerogel fiber provided by the application uses a special outer layer spinning dope and an inner layer spinning dope to perform wet spinning by using a coaxial spinning method and injecting into a coagulation bath at different extrusion speeds, and then performs solvent exchange liquid replacement at different concentration gradients for a predetermined time after coagulation and winding, and finally washes and dries to obtain the coaxial structure aramid and cellulose aerogel fiber with the inner layer fiber having the characteristics of rich hollow, ultra-low density, and ultra-high specific surface area, and the outer layer fiber having the characteristics of dense surface, high temperature resistance, and high strength. The raw material cost of the preparation method is low, the process is simple, and the specific surface area, inner and outer diameters, and pore structure are easy to control during the preparation of the coaxial structure aerogel fiber.

[0023] 2. The coaxial structure aramid and cellulose aerogel fiber provided by the application has good thermal conductivity and good mechanical properties, wherein the breaking strength ranges from 3 to 10 Mpa, and the thermal conductivity ranges from 5 to 25 mW / m·K, which effectively improves the usability of the nanocellulose aerogel fiber prepared in the prior art under the condition of strength, and the aerogel fiber prepared by the application can better adapt to the application under harsh conditions. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 The cross-sectional electron microscope image of the nanometer aramid in the coaxial structure aramid and cellulose aerogel fiber provided for Example 1.

[0025] Fig. 2 The cross-sectional electron microscope image of the nanometer fiber in the coaxial structure aramid and cellulose aerogel fiber provided for Example 1.

[0026] Fig. 3 The electron microscope image of the coaxial structure aramid and cellulose aerogel fiber provided in Example 1. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described in detail below with reference to the drawings and specific embodiments.

[0028] It should also be noted that, in order to avoid obscuring the present application with unnecessary details, only structures and / or processing steps closely related to the solutions of the present application are shown in the drawings, and other details not closely related to the present application are omitted.

[0029] In addition, it should also be noted that the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or equipment.

[0030] A preparation method of a coaxial structure aramid and cellulose aerogel fiber, comprising the following steps:

[0031] S1, dissolving aramid fibers in an aprotic solvent in an alkaline environment to obtain an outer layer spinning dope;

[0032] The nanocellulose powder is placed in deionized water, and after ultrasonic dispersion treatment, an inner layer spinning dope is prepared;

[0033] The aramid fibers include para-aramid fibers or meta-aramid fibers; the nanocellulose powder includes plant cellulose or bacterial cellulose;

[0034] The aprotic solvent includes one or more of acetonitrile, dimethylformamide, DMI, dimethyl sulfoxide, and hexamethylphosphoramide;

[0035] In step S1, the outer layer spinning dope includes the aramid fibers, the aprotic solvent, the alkaline substance, and water; in the outer layer spinning dope, the mass fraction of the aramid fibers is 0.5-5wt%; the mass fraction of the aprotic solvent is 90-95wt%; the mass fraction of the alkaline substance is 2-4wt%; and the mass fraction of the water is 1-2wt%;

[0036] In step S1, in the inner layer spinning dope, the mass fraction of the nanocellulose powder is 0.1-1wt%;

[0037] S2, the outer layer spinning dope and the inner layer spinning dope are injected into a coagulation bath through a coaxial spinning needle at different extrusion speeds, respectively, to perform wet spinning at normal temperature and pressure, and after coagulation for 30min-2h, a nanometer aramid and nanometer cellulose coaxial structure gel fiber is prepared;

[0038] The coagulation bath concentration comprises one or more of a weak alkaline solution with a concentration of 10-40 wt%, an ethanol solution with a concentration of 25-40 wt%, and an acetone solution with a concentration of 10-30 wt%.

[0039] The weak alkaline solution comprises one or more of a barium hydroxide solution and a calcium chloride solution.

[0040] S3, after the nanometer aramid and nanocellulose coaxial structure gel fiber is wound in the coagulation bath, the coaxial structure gel fiber is sequentially immersed in a plurality of solvent exchange liquids with different concentration gradients for a predetermined time of replacement; the concentration of the solvent exchange liquid sequentially immersed in the replacement gradually decreases;

[0041] The solvent exchange liquid comprises one or more of propanol, butanol, and tert-butanol.

[0042] S4, after the nanometer aramid and nanocellulose coaxial structure gel fiber treated in step S3 is washed to neutral with deionized water and dried, a coaxial structure aramid and cellulose aerogel fiber is prepared.

[0043] The drying method comprises freeze drying or carbon dioxide supercritical drying; in the freeze drying, first, freezing at -40 DEG C for 12 hours, and then drying in a negative pressure dryer for 24-48 hours.

[0044] In this way, the coaxial structure aramid and cellulose aerogel fiber with the inner layer fiber having the characteristics of rich cavities, ultra-low density, and ultra-high specific surface area, and the outer layer fiber having the characteristics of dense surface, high temperature resistance, and high strength can be prepared by using low-cost raw materials and adopting a simple process. In addition, the specific surface area, inner and outer diameters, and pore structure of the coaxial structure aerogel fiber are easy to control during the preparation process. The coaxial structure aramid and cellulose aerogel fiber prepared by this method has high porosity, high specific surface area, ultra-low density, high temperature resistance, and other excellent properties, and thus has more advantages than ordinary fibers in the fields of temperature regulation, intelligent fibers, and air purification.

[0045] Specifically, in some embodiments of the present application, the extrusion speed of the outer layer spinning dope in step S2 is 10-20 m / h, and the extrusion speed of the inner layer spinning dope is 6-10 m / h.

[0046] Thus, the outer layer fiber has a larger diameter, and a faster extrusion speed is required to form the spinning dope. The different flow rates of the spinning dope are due to the different diameters of the inner and outer layer aerogel fibers, which results in the outer layer fiber requiring more spinning dope to form a dense network structure, while the inner layer forms a coaxial structure. In addition, wet spinning is used because the spinning dope needs to be quickly formed in the coagulation bath. If dry spinning is used, the desired fiber morphology cannot be obtained.

[0047] Specifically, in some embodiments of the present application, in step S3, the number of different concentration gradients is at least three; the concentration of the solvent exchange liquid is 25-75 wt%; and the predetermined time for replacement in the solvent exchange liquid is 4-6 h.

[0048] Thus, the pore structure of the fiber is improved.

[0049] The present application also provides a coaxial structure aramid and cellulose aerogel fiber prepared by the preparation method of the coaxial structure aramid and cellulose aerogel fiber.

[0050] Thus, the coaxial structure aramid and cellulose aerogel fiber prepared has good thermal conductivity and better mechanical properties, with a breaking strength in the range of 2-6 MPa and a thermal conductivity in the range of 10-35 mW / m·K. This effectively improves the usability of the nanocellulose aerogel fiber prepared in the prior art under strong force conditions, and the aerogel fiber prepared in the present application can better adapt to harsh conditions.

[0051] The preparation method of the coaxial structure aramid and cellulose aerogel fiber provided by the present application will be described in detail below in conjunction with examples:

[0052] Example 1

[0053] The present embodiment provides a coaxial structure aramid and cellulose aerogel fiber and a preparation method thereof, which specifically comprises the following steps:

[0054] S1, dissolving para-aramid fibers in dimethyl sulfoxide (DMSO) solvent in an alkaline environment to prepare an outer layer spinning dope;

[0055] Plant cellulose powder is placed in deionized water and treated by ultrasonic dispersion to prepare an inner layer spinning dope;

[0056] In step S1, the outer layer spinning dope includes para-aramid fibers, the DMSO solvent, sodium hydroxide, and water; the mass fraction of para-aramid fibers in the outer layer spinning dope is 0.5 wt%; the mass fraction of the DMSO solvent is 95 wt%; the mass fraction of sodium hydroxide is 3 wt%; and the mass fraction of water is 1.5 wt%;

[0057] The mass fraction of the plant cellulose powder in the inner layer spinning dope is 0.5wt%;

[0058] S2, the outer layer spinning dope and the inner layer spinning dope are injected into the coagulation bath of the calcium chloride solution with a concentration of 25wt% through the coaxial spinning needle at different extrusion speeds, wet spinning is carried out at normal temperature and pressure, and after coagulation for 1h, the nanometer aramid and nanometer cellulose coaxial structure gel fiber is prepared;

[0059] In step S2, the extrusion speed of the outer layer spinning dope for wet spinning is 15m / h, and the extrusion speed of the inner layer spinning dope for wet spinning is 6m / h;

[0060] S3, after the nanometer aramid and nanometer cellulose coaxial structure gel fiber is wound in the coagulation bath, it is immersed in the solvent exchange solution of tert-butyl alcohol-water solution with a concentration of 75wt%, 50wt% and 25wt% respectively for 4h;

[0061] S4, after the nanometer aramid and nanometer cellulose coaxial structure gel fiber treated in step S3 is washed to neutral with deionized water, it is freeze-dried to prepare the coaxial structure aramid and cellulose aerogel fiber. During freeze-drying, first freeze at-40℃ for 12h, and then dry in the freeze dryer for 36h.

[0062] The SEM image of the cross-section porous structure of the coaxial structure aramid and cellulose aerogel fiber prepared in this example is shown in Figs. 1-3 As can be seen from the SEM image, the outer layer of the coaxial structure aramid and cellulose aerogel fiber produced by wet spinning is a dense network structure, and the inner layer is a three-dimensional network structure. These network structures form connection points, which are connected to each other and connected into a lamellar structure. The outer layer of this lamellar structure can effectively improve the mechanical properties of the aerogel fiber, and the dense structure of the aerogel fiber limits the internal air circulation, so it has good thermal management.

[0063] Finally, the coaxial structure aramid and cellulose aerogel fiber prepared in this example is tested, and the results show that its breaking strength is 5Mpa, and the thermal conductivity coefficient is 35mW / m·K, which proves the results of the electron microscope.

[0064] Examples 2-4

[0065] Examples 2-4 each provide a coaxial structure aramid and cellulose aerogel fiber and a method of making the same, which differ from Example 1 in that the mass of aramid fiber used in step S1 is different: in Example 2, the mass fraction of aramid fiber used in the outer layer spinning dope is 1 wt%; in Example 3, the mass fraction of aramid fiber used in the outer layer spinning dope is 1.5 wt%; and in Example 4, the mass fraction of aramid fiber used in the outer layer spinning dope is 2 wt%. The remaining steps and parameters are consistent with Example 1 and will not be repeated here.

[0066] Finally, the coaxial structure aramid and cellulose aerogel fibers prepared in Examples 2-3 are each tested, which shows that the breaking strength of the coaxial structure aramid and cellulose aerogel fiber prepared in Example 2 is 10 Mpa, and the thermal conductivity is 30 mW / m·K; the breaking strength of the coaxial structure aramid and cellulose aerogel fiber prepared in Example 3 is 15 Mpa, and the thermal conductivity is 25 mW / m·K; and the breaking strength of the coaxial structure aramid and cellulose aerogel fiber prepared in Example 4 is 5 Mpa, and the thermal conductivity is 20 mW / m·K.

[0067] Comparative Examples 1-2

[0068] Comparative Examples 1-2 each provide a method of making a coaxial structure aramid and cellulose aerogel fiber, which differs from Example 1 in that the mass of aramid fiber used in step S1 is different: in Comparative Example 2, the mass fraction of aramid fiber used in the outer layer spinning dope is 0.1 wt%; and in Comparative Example 2, the mass fraction of aramid fiber used in the outer layer spinning dope is 8 wt%. The remaining steps and parameters are consistent with Example 1 and will not be repeated here.

[0069] Finally, the coaxial structure aramid and cellulose aerogel fibers prepared in Comparative Examples 1-2 are each tested, which shows that the breaking strength of the coaxial structure aramid and cellulose aerogel fiber prepared in Comparative Example 1 is 1 Mpa, and the thermal conductivity is 40 mW / m·K; and the coaxial structure aramid and cellulose aerogel fiber prepared in Comparative Example 2 cannot be spun due to high viscosity.

[0070] Comparative Examples 3-4

[0071] Comparative Examples 3-4 each provide a method of making a coaxial structure aramid and cellulose aerogel fiber, which differs from Example 1 in that the mass of nanocellulose powder used in step S1 is different: in Comparative Example 3, the mass fraction of nanocellulose powder used in the inner layer spinning dope is 0.01 wt%; and in Comparative Example 4, the mass fraction of nanocellulose powder used in the inner layer spinning dope is 4 wt%. The remaining steps and parameters are consistent with Example 1 and will not be repeated here.

[0072] Finally, the coaxial structure aramid and cellulose aerogel fibers prepared by Comparative Examples 3-4 were tested, and the results showed that the breaking strength of the coaxial structure aramid and cellulose aerogel fibers prepared by Comparative Example 3 was 4 MPa, and the thermal conductivity was 5 mW / m·K; the cellulose solution in Comparative Example 4 was not easy to disperse due to too high concentration, and the hydroxyl groups would agglomerate, which was not conducive to subsequent spinning.

[0073] The process parameters and performance test results in the examples and comparative examples are shown in Table 1.

[0074] Table 1 Process parameters and performance test results in Examples 1-4 and Comparative Examples 1-4

[0075]

[0076] Comparative Examples 1-4 and Comparative Examples 1-2 showed that when the content of aramid fiber was too low, although it had no effect on the thermal conductivity of the coaxial structure aramid and cellulose aerogel fibers, the strength of the fiber was not very good. This was because the fiber surface had more holes, the density was smaller, there were fewer entanglement points between the nanometer aramid inside the fiber, and the fiber orientation degree was lower. When subjected to external stretching, the fiber was prone to deformation and breakage. When the content of aramid fiber was too high, it was also not conducive to the formation of the strength of the coaxial structure aramid and cellulose aerogel fibers. This was because when the content of aramid fiber exceeded 5 wt% of the total mass of aramid fiber and aprotic solvent in the alkaline environment, the fiber could not be spun due to its viscosity. Comparative Examples 1 and Comparative Examples 3-4 showed that when the content of nanocellulose powder was too low, it would affect the increase of the thermal conductivity of the coaxial structure aramid and cellulose aerogel fibers. This was because the cellulose concentration was reduced, which would affect the formation of the inner structure and the network structure, thereby affecting the content of the still air in the fiber, and thus leading to a decrease in the warmth retention performance.

[0077] Therefore, only when the parameters are controlled within a predetermined range, can the coaxial structure aramid and cellulose aerogel fibers with good thermal conductivity and better mechanical properties be prepared.

[0078] In summary, the preparation method of the coaxial structure aramid and cellulose aerogel fiber provided by the application is to inject special outer layer spinning dope and inner layer spinning dope into a coagulation bath by using coaxial spinning at different extrusion speeds, and then perform wet spinning, coagulation and winding, and then replace in solvent exchange liquid with different concentration gradients for a predetermined time, and finally wash and dry to obtain the coaxial structure aramid and cellulose aerogel fiber with the inner layer fiber having the characteristics of rich hollow, ultra-low density, and ultra-high specific surface area, and the outer layer fiber having the characteristics of dense surface, high temperature resistance, and high strength; the raw material cost of the preparation method is low, the process is simple, and the specific surface area, inner and outer diameters, and pore structure are easy to control during the preparation of the coaxial structure aerogel fiber. The coaxial structure aramid and cellulose aerogel fiber prepared by the application has good thermal conductivity and good mechanical properties, wherein the breaking strength range is 2-6 Mpa, and the thermal conductivity range is 15-35 mW / m·K, which effectively improves the usability of the prepared nanocellulose aerogel fiber under the strength condition in the prior art, and the prepared aerogel fiber can better adapt to the application under harsh conditions.

[0079] The above examples are only used to illustrate the technical solutions of the application and not to limit the application. Although the application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the application.

Claims

1. A method for preparing coaxial aramid and cellulose aerogel fibers, characterized in that, Includes the following steps: S1. Aramid fibers are dissolved in an aprotic solvent in an alkaline environment to prepare an outer spinning solution; the outer spinning solution includes aramid fibers, an aprotic solvent, an alkaline substance, and water; in the outer spinning solution, the mass fraction of the aramid fibers is 0.5-5 wt%; the mass fraction of the aprotic solvent is 90-95 wt%; and the mass fraction of the alkaline substance is 2-4 wt%. Nanocellulose powder was placed in deionized water and then ultrasonically dispersed to obtain the inner spinning solution. S2. The outer spinning solution and the inner spinning solution are injected into a coagulation bath at different extrusion speeds through a coaxial spinning needle for wet spinning. After coagulation for a predetermined time, nano-aramid and nano-cellulose coaxial structure gel fibers are obtained; the coagulation bath is a calcium chloride solution. S3. After the nano-aramid and nano-cellulose coaxial structure gel fiber is wound in the coagulation bath, it is sequentially immersed in several solvent exchange solutions with different concentration gradients for a predetermined time for replacement; during the replacement, the concentration of the solvent exchange solution used for sequential immersion gradually decreases; S4. After washing the nano-aramid and nano-cellulose coaxial structured gel fibers treated in step S3 until neutral, dry them to obtain coaxial structured aramid and cellulose aerogel fibers.

2. The method for preparing coaxial aramid and cellulose aerogel fibers according to claim 1, characterized in that: In step S1, the mass fraction of the deionized water is 1~2wt%.

3. The method for preparing coaxial aramid and cellulose aerogel fibers according to claim 1, characterized in that: In step S1, the mass fraction of the nanocellulose powder in the inner spinning solution is 0.1~1wt%.

4. The method for preparing coaxial aramid and cellulose aerogel fibers according to claim 1, characterized in that: In step S2, the extrusion speed for wet spinning of the outer spinning solution is 10~20m / h; the extrusion speed for wet spinning of the inner spinning solution is 6~10m / h; and the predetermined time for solidification is 30min~2h.

5. The method for preparing coaxial aramid and cellulose aerogel fibers according to claim 1, characterized in that: In step S3, there are at least three different concentration gradients; the solvent exchange liquid includes one or more of propanol, butanol, and tert-butanol; the concentration of the solvent exchange liquid is 25-75 wt%; and the predetermined replacement time in the solvent exchange liquid is 4-6 hours.

6. The method for preparing coaxial aramid and cellulose aerogel fibers according to claim 1, characterized in that: In step S4, the drying method includes freeze drying or supercritical carbon dioxide drying.

7. The method for preparing coaxial aramid and cellulose aerogel fibers according to claim 2, characterized in that: In step S1, the aramid fiber includes para-aramid fiber or meta-aramid fiber; the nanocellulose powder includes plant cellulose or bacterial cellulose.

8. The method for preparing coaxial aramid and cellulose aerogel fibers according to claim 2, characterized in that: In step S1, the aprotic solvent includes one or more of acetonitrile, dimethylformamide, DMI, dimethyl sulfoxide, and hexamethylphosphoric triamine.

9. A coaxial aramid and cellulose aerogel fiber, characterized in that: The coaxial aramid and cellulose aerogel fibers are prepared according to the preparation method of any one of claims 1 to 8; the outer layer of the coaxial aramid and cellulose aerogel fibers is a dense network structure, and the inner layer is a three-dimensional network structure.

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