Preparation method of aramid nanofiber / polyacrylonitrile composite aerogel microspheres
The preparation of aramid nanofiber/polyacrylonitrile composite aerogel microspheres through a novel emulsion phase separation method has solved the problems of low preparation efficiency and easy collapse of existing aramid nanofiber aerogel microspheres, achieving efficient preparation and structurally stable microspheres, providing convenient solutions for multi-field applications.
Patent Information
- Application Number
- CN202510376033.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-07-22
AI Technical Summary
The existing aramid nanofiber aerogel microsphere preparation process is inefficient, and the microspheres can be controlled and prepared with high requirements for instruments and equipment, and are prone to shrinking and collapse during drying.
A new emulsion phase separation method (one-pot method) is used to regulate the precursor concentration ratio and stirring conditions to prepare microspheres with adjustable size and dispersion, and avoid collapse by direct drying, which simplifies the preparation of chemical adsorption, special filtration and loading, new energy energy storage and catalyst support materials.
It improves the preparation efficiency, maintains the good dimensional morphology of the microsphere structure, simplifies the process flow, and is suitable for the application of chemical adsorption, special filtration and loading, new energy energy storage and catalyst support materials.
Smart Images
Figure CN120346750A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of aerogels, and particularly relates to a method for preparing aramid nanofiber / polyacrylonitrile composite aerogel microspheres. Background Art
[0002] As an advanced material, aramid gel microspheres have various potential applications, especially in the fields of environmental protection and materials science. Aramid nanofiber aerogel microspheres perform excellently in water purification. They can efficiently remove organic dye molecules in water, such as malachite green and methylene blue cationic dyes. These microspheres can still maintain high adsorption performance in dynamic and harsh chemical environments; in addition to water purification, aramid nanofiber aerogel microspheres also exhibit high adsorption capacity for various organic solvents, including tetrachloroethane, n-hexane, ethanol, etc. These microspheres have an adsorption capacity up to 40 - 130 times their own weight, and can be recycled at least 30 times by extrusion method, showing great potential in removing organic solvents; furthermore, through a one-step thermal-induced crosslinking strategy, aramid nanofiber aerogel microspheres obtain excellent compression and rebound characteristics. Even after 500 compression-release cycles at 50% strain, these microspheres can still maintain a spherical shape, indicating their excellent mechanical stability and durability, which gives them significant advantages in environmental remediation and other aspects; aramid gel microspheres have shown significant advantages in water purification, organic solvent adsorption, and environmental remediation materials. With the in-depth research and technological progress, these microspheres are expected to be applied in more fields and play a greater role.
[0003] The preparation of traditional aramid aerogel microspheres requires obtaining micro-droplets of the precursor first, then extruding the micro-droplets through a microfluidic channel, followed by a sol-gel transition in a coagulation bath to finally obtain wet gel microspheres, and finally obtaining aerogel microspheres through a special drying process. This process often has many problems, such as low efficiency in the preparation process, high requirements for instrument equipment for controllable preparation of microspheres, and easy shrinkage and collapse during the drying process. Summary of the Invention
[0004] In view of the technical problems existing in the background art, the present application provides a method for preparing aramid nanofiber / polyacrylonitrile composite aerogel microspheres, aiming to solve the problems of low efficiency in the preparation process of existing aramid nanofiber aerogel microspheres, high requirements for instrument equipment for controllable preparation of microspheres, and easy shrinkage and collapse during the drying process.
[0005] In a first aspect, the present application provides a method for preparing aramid nanofiber / polyacrylonitrile composite aerogel microspheres, which is characterized by comprising the following steps:
[0006] S1. Add para-aramid fibers into a first solvent, stir, and prepare an aramid nanofiber dispersion liquid;
[0007] S2. Add polyacrylonitrile to the second solvent and stir to prepare a polyacrylonitrile dispersion.
[0008] S3. Mix the aramid nanofiber dispersion and the polyacrylonitrile dispersion and stir to prepare an aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion.
[0009] S4. After centrifuging, filtering, washing, and drying the aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion, aramid nanofiber / polyacrylonitrile composite aerogel microspheres are obtained.
[0010] In the technical solution of the embodiment of the present application, the aramid nanofiber / polyacrylonitrile composite aerogel microspheres are prepared by a novel emulsion phase separation (one-pot method). By adjusting the concentration ratio of the precursor solution and the stirring conditions, the size and dispersibility of the microspheres can be controlled. Moreover, during the drying process, direct drying can be carried out, and the microsphere structure can still maintain a good size and morphology without collapsing, eliminating the need for a freeze-drying process. This preparation method is convenient and highly efficient, providing ideas for the preparation of chemical adsorption, special filtration and loading, new energy energy storage, and catalyst support materials.
[0011] In some embodiments, in step S1, the concentration of the aramid nanofiber dispersion is 0.8 - 1.2%; in step S2, the concentration of the polyacrylonitrile dispersion is 10 - 14%; in step S3, the stirring speed is 500 - 1500 r / min; and the stirring time is 1.8 - 2.2 h.
[0012] In this embodiment, by mixing aramid nanofiber dispersions and polyacrylonitrile dispersions with specific concentrations under specific stirring conditions, aramid nanofiber / polyacrylonitrile composite aerogel microspheres with different sizes and dispersibilities can be prepared.
[0013] In some embodiments, in step S3, the volume ratio of the aramid nanofiber dispersion to the polyacrylonitrile dispersion is 1:3 - 3:1.
[0014] In some embodiments, in step S4, the drying temperature is 25 - 85°C.
[0015] In this embodiment, the aramid nanofiber / polyacrylonitrile composite aerogel microspheres can be directly dried, and the microsphere structure can still maintain a good size and morphology without collapsing.
[0016] In some embodiments, in step S1, the first solvent is a mixed solution of dimethyl sulfoxide and potassium hydroxide; and the stirring time is 5 - 7 days.
[0017] In this embodiment, aramid fiber can be dissolved in dimethyl sulfoxide (DMSO) under alkaline conditions to form an aramid nanofiber dispersion, and the aramid nanofibers are fully dissolved by stirring.
[0018] In some embodiments, in step S2, the second solvent is DMSO; the stirring time is 5.5 - 6.5 h.
[0019] In this embodiment, polyacrylonitrile can be dissolved in DMSO to form a dispersion, and polyacrylonitrile is fully dissolved by stirring.
[0020] In some embodiments, in step S1, the mass ratio of aramid fiber to potassium hydroxide is 0.5:1 - 2.5:1.
[0021] In this embodiment, aramid fiber can be dissolved under alkaline conditions to obtain an aramid nanofiber dispersion.
[0022] In a second aspect, the present application provides an aramid nanofiber / polyacrylonitrile composite aerogel microsphere, which is characterized in that it is prepared by using the preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microsphere according to any one of claims 1 - 9, and the particle size of the microsphere is 10 - 30 μm.
[0023] In the technical solutions of the embodiments of the present application, the microspheres with uniform size provide ideas for the preparation of materials for chemical adsorption, special filtration and loading, new energy energy storage, and catalyst support.
[0024] The above description is only an overview of the technical solutions of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically given below. Description of the Drawings
[0025] In order to more clearly illustrate the technical solutions of the present application, the drawings used in the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0026] Figure 1 It is a schematic diagram of the preparation process for preparing aramid nanofiber / polyacrylonitrile composite aerogel microspheres in Example 1.
[0027] Figure 2 It is SEM images of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Example 1 at different magnifications.
[0028] Figure 3SEM images of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 2-3 and Comparative Examples 1-2.
[0029] Figure 4 SEM images of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 4-5 and Comparative Examples 3-4.
[0030] Figure 5 SEM images of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 6-7 and Comparative Examples 5-6. Detailed Description of the Invention
[0031] The embodiments of the technical solutions of the present application will be described in detail below. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.
[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms "including" and "having" and any variations thereof used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0033] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.
[0034] In order to solve the problems of low efficiency in the preparation process of existing aerogel microspheres, high requirements for instrument equipment in the controllable preparation of microspheres, and easy shrinkage and collapse during the drying process, the present application provides a preparation method for aramid nanofiber / polyacrylonitrile composite aerogel microspheres. The aramid nanofiber / polyacrylonitrile composite aerogel microspheres are prepared by a novel emulsion phase separation (one-pot method), and the size and dispersibility of the microspheres can be regulated by controlling the concentration ratio of the precursor solution and the stirring conditions. Moreover, the microspheres can be directly dried in the drying process, and the microsphere structure still maintains a good size and morphology without collapse, and no freeze-drying process is required. This preparation method is convenient and highly efficient, providing ideas for the preparation of chemical adsorption, special filtration and loading, new energy energy storage, and catalyst support materials.
[0035] The present application provides a preparation method for aramid nanofiber / polyacrylonitrile composite aerogel microspheres, which is characterized by comprising the following steps:
[0036] S1. Add para-aramid fibers into the first solvent and stir to prepare an aramid nanofiber dispersion;
[0037] S2. Add polyacrylonitrile into the second solvent and stir to prepare a polyacrylonitrile dispersion;
[0038] S3. Mix the aramid nanofiber dispersion and the polyacrylonitrile dispersion and stir to prepare an aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion;
[0039] S4. After centrifuging, filtering, washing and drying the aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion, aramid nanofiber / polyacrylonitrile composite aerogel microspheres are obtained.
[0040] In the technical solution of the embodiment of the present application, the aramid nanofiber / polyacrylonitrile composite aerogel microspheres are prepared by a novel emulsion phase separation (one-pot method). The size and dispersibility of the microspheres can be regulated by controlling the concentration ratio of the precursor solution and the stirring conditions. And during the drying process, it can be directly dried, and the microsphere structure still maintains a good size and morphology without collapsing, and a freeze-drying process is not required. This preparation method is convenient and highly efficient, providing ideas for the preparation of chemical adsorption, special filtration and loading, new energy energy storage and catalyst support materials.
[0041] Further, in some embodiments, in step S1, the concentration of the aramid nanofiber dispersion is 0.8-1.2%; in step S2, the concentration of the polyacrylonitrile dispersion is 10-14%; in step S3, the stirring speed is 500-1500 r / min; the stirring time is 1.8-2.2 h.
[0042] In the technical solution of the embodiment of the present application, by mixing aramid nanofiber dispersions and polyacrylonitrile dispersions with specific concentrations under specific stirring conditions, aramid nanofiber / polyacrylonitrile composite aerogel microspheres with different sizes and dispersibilities can be prepared.
[0043] Further, in some embodiments, in step S3, the volume ratio of the aramid nanofiber dispersion to the polyacrylonitrile dispersion is 1:3-3:1.
[0044] Further, in some embodiments, in step S4, the drying temperature is 25-85°C.
[0045] In the technical solution of the embodiment of the present application, the aramid nanofiber / polyacrylonitrile composite aerogel microspheres can be directly dried, and the microsphere structure still maintains a good size and morphology without collapsing.
[0046] Further, in some embodiments, in step S1, the first solvent is a mixed solution of dimethyl sulfoxide and potassium hydroxide; the stirring time is 5 to 7 days.
[0047] In the technical solution of the embodiment of the present application, in an alkaline environment, aramid fiber can be dissolved in dimethyl sulfoxide to form an aramid nanofiber dispersion, and the aramid nanofibers are fully dissolved by stirring.
[0048] Further, in some embodiments, in step S2, the second solvent is DMSO; the stirring time is 5.5 to 6.5 h.
[0049] In the technical solution of the embodiment of the present application, polyacrylonitrile can be dissolved in DMSO to form a dispersion, and polyacrylonitrile is fully dissolved by stirring.
[0050] Further, in some embodiments, in step S1, the mass ratio of aramid fiber to potassium hydroxide is 0.5:1 to 2.5:1.
[0051] In the technical solution of the embodiment of the present application, aramid fiber can be dissolved under alkaline conditions to obtain an aramid nanofiber dispersion.
[0052] Second, the embodiment of the present application provides an aramid nanofiber / polyacrylonitrile composite aerogel microsphere, which is characterized in that it is prepared by using the preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microsphere according to any one of claims 1 to 9, and the particle size of the microsphere is 10 to 30 μm.
[0053] In the technical solution of the embodiment of the present application, the microspheres with uniform size provide ideas for the preparation of chemical adsorption, special filtration and loading, new energy energy storage and catalyst support materials.
[0054] The following lists some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present application and cannot be understood as a limitation to the present application. For those without specific techniques or conditions mentioned in the embodiments, they shall be carried out according to the techniques or conditions described in the literature in the field or according to the product specifications. Those reagents or instruments without indicating the manufacturer can be obtained as conventional products through commercial purchase.
[0055] Example 1
[0056] This embodiment provides a preparation method of an aramid nanofiber / polyacrylonitrile composite aerogel microsphere, as Figure 1 shown, which specifically includes the following steps:
[0057] (1) Weigh 1.0 g of potassium hydroxide and dissolve it in 100 ml of dimethyl sulfoxide solution. Then weigh 1.0 g of para-aramid fiber and add it to the mixed solvent, and stir for 6 days to prepare an aramid nanofiber dispersion.
[0058] (2) Weigh 12 g of polyacrylonitrile and add it to 100 ml of DMSO, and stir for 6 hours to prepare a polyacrylonitrile dispersion.
[0059] (3) Take 50 ml of aramid nanofiber dispersion and 50 ml of polyacrylonitrile dispersion respectively, mix the two, and stir at a speed of 1000 r / min for 2 hours to prepare an aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion.
[0060] (4) Centrifuge the prepared aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion in a centrifuge, then filter and wash it, and then place it in an oven at 80 °C for drying to obtain aramid nanofiber / polyacrylonitrile composite aerogel microspheres.
[0061] The SEM image of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in this example is as Figure 2 shown.
[0062] From Figure 2 the SEM image in it, it can be seen that the spherical structure of the prepared aramid nanofiber / polyacrylonitrile composite aerogel microspheres is regular and the spherical roundness is relatively unified. The microspheres are relatively independent and have no contact with each other, and the surface is relatively smooth. Among them, the particle size of the microspheres is 10 - 30 μm, and the diameter distribution is relatively uniform.
[0063] Examples 2 - 3 and Comparative Examples 1 - 2
[0064] Examples 2 - 3 and Comparative Examples 1 - 2 respectively provide a method for preparing aramid nanofiber / polyacrylonitrile composite aerogel microspheres. Compared with Example 1, the difference is that the addition amount of para-aramid fiber is different, as shown in Table 1 specifically. Other steps are substantially the same as those in Example 1 and will not be elaborated here.
[0065] Table 1 The addition amount of para-aramid fiber in Examples 2 - 3 and Comparative Examples 1 - 2
[0066] Example / Comparative Example Example 2 Example 3 Comparative Example 1 Comparative Example 2 Weight (g) 0.8 1.2 0.5 1.5
[0067] The SEM images of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 2 - 3 and Comparative Examples 1 - 2 are as Figure 3 shown.
[0068] The particle sizes of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 2 - 3 and Comparative Examples 1 - 2 are shown in Table 2.
[0069] Table 2 Particle sizes of the microspheres in Examples 2-3 and Comparative Examples 1-2
[0070] Example / Comparative Example Example 2 Example 3 Comparative Example 1 Comparative Example 2 Particle Size (μm) 10～30 15～30 25～40 20～50
[0071] From Figure 3 the SEM images in
[0072] and the data in Table 2, it can be seen that the morphology and particle sizes of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 2-3 are close to those in Example 1. In Comparative Example 1, the addition amount of para-aramid fiber is too small, which enhances the interaction and adhesion between the microspheres, resulting in obvious agglomeration and dense contact between the microspheres. In Comparative Example 2, the addition amount of para-aramid is too large, and the excessive aramid hinders the uniform shrinkage of the microspheres during the curing process, resulting in a decrease in the roundness of the microspheres and the uniformity of the particle sizes. At the same time, the SEM images show that the microspheres are closely arranged and the independence is weakened, indicating that the excessive aramid fiber leads to an abnormal increase in the crosslinking density, and finally it is difficult to obtain discrete spherical particles. The addition amount of para-aramid fiber needs to be controlled within a specific range to balance the morphological integrity and dispersibility of the microspheres and avoid structural defects caused by unbalanced ratios.
[0073] Examples 4-5 and Comparative Examples 3-4
[0074] Examples 4-5 and Comparative Examples 3-4 respectively provide an aramid nanofiber / polyacrylonitrile composite aerogel microsphere. Compared with Example 1, the difference lies in the different addition amounts of polyacrylonitrile, as shown in Table 2 specifically. Other steps are substantially the same as those in Example 1 and will not be elaborated here.
[0075] Example / Comparative Example Example 4 Example 5 Comparative Example 3 Comparative Example 4 Weight (g) 10 14 8 16
[0076] The SEM images of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 4-5 and Comparative Examples 3-4 are as Figure 4 shown.
[0077] The particle sizes of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 4-5 and Comparative Examples 3-4 are shown in Table 3.
[0078] Table 3 Particle sizes of the microspheres in Examples 4-5 and Comparative Examples 3-4
[0079] Example / Comparative Example Example 4 Example 5 Comparative Example 3 Comparative Example 4 Particle Size (μm) 10～30 15～30 10～50 10～50
[0080] From Figure 4From the SEM images in and the data in Table 3, it can be seen that the morphology and particle size of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 4-5 are close to those in Example 1; in Comparative Example 3, the addition amount of polyacrylonitrile is too small, and the insufficient crosslinking density leads to a decrease in the microsphere skeleton strength. Although the reduction of PAN may decrease the solution viscosity, the excessive exposure of ANF enhances the van der Waals force between particles, and finally still triggers the local agglomeration effect. In Comparative Example 4, the addition amount of polyacrylonitrile is too large, and the excessive PAN will change the phase separation behavior of the precursor solution. The SEM images show that the microspheres are closely packed and there are abnormal particles (such as ellipsoids or dumbbell shapes). It is speculated that the excessive PAN causes an imbalance in the solvent-nonsolvent exchange rate, uneven shrinkage during the curing process, and the residual unreacted PAN molecules may act as physical crosslinking points to exacerbate the adhesion between microspheres. As a result, the particle size distribution range of the microspheres increases, the size uniformity of the microsphere diameter is relatively weakened, and the microspheres still show an agglomeration effect. The PAN content directly affects the morphological integrity and dispersibility of the composite microspheres by regulating the crosslinking density, phase separation kinetics, and interfacial interaction.
[0081] Examples 6-7 and Comparative Examples 5-6
[0082] Examples 6-7 and Comparative Examples 5-6 respectively provide an aramid nanofiber / polyacrylonitrile composite aerogel microsphere. Compared with Example 1, the difference lies in that the stirring speed in step (3) is different, as shown in Table 3 specifically. The other steps are substantially the same as those in Example 1 and will not be elaborated here.
[0083] Table 3 Stirring speed in step (3) of Examples 6-7 and Comparative Examples 5-6
[0084] Example / Comparative Example Example 6 Example 7 Comparative Example 5 Comparative Example 6 Speed (r / min) 500 1500 300 2000
[0085] The SEM images of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 6-7 and Comparative Examples 5-6 are as Figure 5 shown.
[0086] The particle sizes of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres prepared in Examples 6-7 and Comparative Examples 5-6 are shown in Table 4.
[0087] Table 4 Particle sizes of the microspheres in Examples 6-7 and Comparative Examples 5-6
[0088] Example / Comparative Example Example 6 Example 7 Comparative Example 5 Comparative Example 6 Particle Size (μm) 10～30 10～30 10～50 10～50
[0089] From Figure 5 the SEM images in and the data in Table 4, it can be seen that when the stirring speed of the prepared aramid nanofiber / polyacrylonitrile composite aerogel microspheres is 500-1500 r / min, the dispersibility and size uniformity of the microspheres are relatively good; from Figure 4From the SEM images of Comparative Examples 5 to 6, it can be seen that when the stirring rate is too fast, the roundness of the microspheres is reduced relative to that of Example 1, the diameter distribution range is expanded, the uniformity is reduced, and the high-speed stirring also causes the microspheres to agglomerate significantly, which may be attributed to the excessive interference of high-speed stirring with the electrostatic force between the two components. The strong shear force generated may destroy the electrostatic balance between ANF and PAN, resulting in a weakening of the interfacial bonding force. Excessive energy input may accelerate the exchange rate between the solvent and the non-solvent, causing uneven local phase separation, forming non-spherical particles, and causing the effect of the formed microspheres to deteriorate; when the stirring speed is too slow, the reaction rate of the two may be slow, resulting in uneven dispersion of ANF and PAN, an increase in the local concentration gradient in the precursor solution, and a difference in reaction rate; insufficient shear force reduces the stability of the emulsion droplets, and the solvent evaporation rate and the cross-linking rate during the curing process do not match, resulting in uneven shrinkage or incomplete formation of the microspheres. It will also significantly reduce the dispersibility and structural uniformity of the microspheres, a wide particle size distribution, and an increase in surface defects. The stirring rate significantly affects the morphological uniformity and dispersibility of the composite microspheres by regulating the shear strength, phase separation kinetics and interfacial interaction.
[0090] In summary, the present application provides a method for preparing aramid nanofiber / polyacrylonitrile composite aerogel microspheres. Aramid nanofiber / polyacrylonitrile composite aerogel microspheres are obtained by mixing an aramid nanofiber dispersion with a polyacrylonitrile dispersion under certain stirring conditions. The aramid nanofiber / polyacrylonitrile composite aerogel microspheres are prepared by a new emulsion phase separation (one-pot method), and the size and dispersibility of the microspheres can be regulated by regulating the precursor concentration ratio and stirring conditions, and the drying process can be directly dried, and the microsphere structure still maintains a good size morphology without collapse, and does not require a freeze-drying process. The preparation method is convenient and highly efficient, and provides ideas for the preparation of chemical adsorption, special filtration and loading, new energy storage and catalyst support materials.
[0091] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.
Claims
1. A preparation method of aramid nanofiber / polyacrylonitrile composite aerogel microspheres, characterized in that, It includes the following steps: S1. Add para-aramid fiber into the first solvent, stir to prepare an aramid nanofiber dispersion; S2. Add polyacrylonitrile into the second solvent, stir to prepare a polyacrylonitrile dispersion; S3. Mix the aramid nanofiber dispersion and the polyacrylonitrile dispersion, stir to prepare an aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion; S4. After centrifuging, filtering, washing and drying the aramid nanofiber / polyacrylonitrile composite aerogel microsphere emulsion, obtain aramid nanofiber / polyacrylonitrile composite aerogel microspheres.
2. The preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 1, wherein, In step S1, the concentration of the aramid nanofiber dispersion is 0.8 - 1.2%.
3. The preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 1, characterized in that In step S2, the concentration of the polyacrylonitrile dispersion is 10 - 14%.
4. The preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 1, wherein, In step S3, the stirring speed is 500 - 1500 r / min; the stirring time is 1.8 - 2.2 h.
5. The preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 1, wherein, In step S3, the volume ratio of the aramid nanofiber dispersion to the polyacrylonitrile dispersion is 1:3 - 3:
1.
6. The aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 1, characterized in that, In step S4, the drying temperature is 25 - 85 °C.
7. The preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 1, characterized in that, In step S1, the first solvent is a mixed solution of dimethyl sulfoxide and potassium hydroxide; the stirring time is 5 - 7 days.
8. The preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 1, wherein, In step S2, the second solvent is DMSO; the stirring time is 5.5 - 6.5 h.
9. The preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to claim 8, characterized in that, The mass ratio of the aramid fiber to potassium hydroxide is 0.5:1 - 2.5:
1.
10. An aramid nanofiber / polyacrylonitrile composite aerogel microsphere, characterized in that, Prepared by the preparation method of the aramid nanofiber / polyacrylonitrile composite aerogel microspheres according to any one of claims 1 - 9, the particle size of the microspheres is 10 - 30 μm.