Preparation method of jute fiber silica aerogel material

Abstract

The application relates to a preparation method of a jute fiber silica aerogel material, which comprises the following steps: mixing and stirring a silicon sol solution containing jute fibers and polyethylene glycol, adjusting the pH to be acidic and stirring, adding polyvinyl alcohol and uniformly mixing, adjusting the pH to be neutral and stirring, precooling, and freeze-drying to obtain the jute fiber silica aerogel. Compared with the prior art, the preparation process is simple, raw materials are cheap, the cost is lower, batch production can be realized, and the jute fiber silica aerogel has great application prospect in the civil field.

Description

Technical Field

[0001] This invention belongs to the field of silica aerogel technology and relates to a method for preparing jute fiber silica aerogel material. Background Technology

[0002] Silica nanoporous materials are highly dispersed solid materials composed of silica nanoparticles aggregated into a three-dimensional network structure. Because the sizes of the nodes and pores are at the nanoscale, these materials possess many unique properties. Silica aerogels, as a representative example of nanoporous materials, exhibit high porosity (85%–95%, reaching up to 99.8%) and high specific surface area (1000 m² / m³). 2 Low density (0.03~0.20g / cm³) 3 With its unique properties such as low sound transmission rate (100 m / s), high visible light transmittance, and low refractive index, silica aerogel has a wide range of applications in thermal insulation, high-efficiency adsorption, and catalytic support. With the further development of nanotechnology, researchers are working to prepare materials with superior thermal insulation properties. Currently, silica aerogel is a widely used thermal insulation material. In the past decade, the preparation and application of silica aerogel have received considerable attention. Extensive research has been conducted considering various factors affecting aerogel performance, such as the selection of precursors, catalysts, aging techniques, and drying techniques. However, due to the inherent fragility of silica aerogel, its structural framework is prone to collapse, leading to surface cracking. Furthermore, the complexity and high cost of conventional aerogel preparation processes remain significant challenges. These shortcomings severely affect the application of silica aerogel in various fields.

[0003] Currently, in optimizing the preparation process of silica aerogels, silica aerogels prepared using tetraethyl orthosilicate as the silicon source exhibit excellent performance. However, due to their high cost, they are not suitable for widespread application in the civilian sector. Deionized water and silica sol are inexpensive, and most silica aerogel preparation methods use water glass as the silicon source. N-dimethylformamide (DCCA) is added as a desiccant to reduce shrinkage, avoiding solvent substitution. The resulting silica aerogels have relatively good performance, but because the solvent used is ethanol, which has a relatively high preparation cost, it is not suitable for civilian production. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing jute fiber silica aerogel materials that can improve the mechanical properties of silica aerogels and reduce research costs. This method eliminates the need for tedious solvent replacement work during the preparation process, and the preparation process is simple and easy to operate, greatly reducing costs and making it easier to develop a high-performance silica aerogel, thereby reducing manual labor and improving the success rate of experiments.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing jute fiber silica aerogel includes: mixing and stirring a silica sol solution containing jute fiber with polyethylene glycol (PEG), adjusting the pH to acidic and stirring, adding polyvinyl alcohol (PVA) and mixing evenly, adjusting the pH to neutral and stirring, pre-cooling, and freeze-drying to obtain jute fiber silica aerogel.

[0007] This invention compares fiber-reinforced aerogels made with varying fiber content with pure aerogels, and further compares them with aerogels containing different amounts of jute fiber to determine the fiber-reinforced aerogel with optimal performance. The advantage of this invention compared to other patented inventions lies in introducing jute as a plant fiber into the silica sol solution. Based on a two-step acid-base method, the fiber is uniformly introduced into the micro-molecular framework of silica during hydrolysis and polymerization, forming hydrogen bonds with the Si-O bonds on the gel surface without disrupting its own structure. The resulting jute fiber silica aerogel possesses a rich nanoporous structure, high porosity, and large specific surface area, exhibiting the superior thermal insulation properties of silica aerogels. The mechanical properties of the silica aerogel are further enhanced by the jute fiber framework. Compared to traditional methods, this preparation method is simpler, eliminates the need for ethanol, and is more cost-effective. The entire preparation process is simple and time-saving, making it more widely applicable in aerogel manufacturing processes.

[0008] Furthermore, in the silica sol solution containing jute fiber, the mass fraction of water is 70-72%, the mass fraction of silica sol is 28-30%, and the remainder is jute fiber.

[0009] Preferably, the mass fraction of jute fiber in the silica sol solution containing jute fiber is 3%.

[0010] Preferably, in the silica sol solution before the jute fibers are added, the mass fraction of water is 71% and the mass fraction of silica sol is 29%.

[0011] Furthermore, the mass ratio of water to silica sol is 1-1.25:2.5, preferably 1:2.5.

[0012] Furthermore, in the silica sol solution containing jute fibers, the mass fraction of jute fibers is 1.5%-6%, preferably 3%.

[0013] Furthermore, the amount of polyethylene glycol added is 1 g / (0.07-0.3) g jute fiber.

[0014] Furthermore, the pH is adjusted to acidic using hydrochloric acid, with an endpoint pH of 2-3. Preferably, the mass fraction of hydrochloric acid in the jute fiber silica sol solution is 6-8%, more preferably 6%.

[0015] Furthermore, the amount of polyvinyl alcohol added is 1g / (0.07~0.3)g jute fiber.

[0016] Furthermore, the pH is adjusted to neutral using ammonia water, with the final pH being 6-8. Preferably, the mass fraction of ammonia water dissolved in the jute fiber silica sol solution is 1.2-1.4%, more preferably 1.3%.

[0017] Furthermore, the precooling conditions include: a precooling temperature of -20°C and a precooling time of 4-8 hours, preferably 8 hours.

[0018] Furthermore, the freeze-drying conditions include: a freeze-drying temperature of -61.5℃ to -30℃, a freeze-drying time of 40-48h, and a vacuum degree of 12.9Pa-13.2Pa.

[0019] Furthermore, the freeze-drying conditions include: a freeze-drying temperature of -61.2℃, a freeze-drying time of 48h, and a vacuum degree of 13.2Pa.

[0020] Compared with the prior art, the present invention has the following characteristics:

[0021] 1) The jute fiber introduced in this invention is added to the preparation process of aerogel. Compared with pure aerogel, jute fiber silica aerogel has good mechanical properties, as well as good porosity and thermal insulation.

[0022] 2) This invention employs a two-step acid-base catalytic method. During preparation, the silica aerogel remains in equilibrium between hydrolysis and polymerization reactions. Therefore, pH significantly affects the hydrolysis-polymerization reaction. Adding hydrochloric acid makes the solution acidic, increasing the hydrolysis rate while simultaneously slowing the polymerization rate. When the hydrolysis rate exceeds the polymerization rate, a structure with small pore size and low cross-linking density is formed within the solution. After the hydrolysis reaction is complete, ammonia is added, making the solution alkaline. In this case, the polymerization rate exceeds the hydrolysis rate, and polymerization occurs immediately after hydrolysis. This polymerization reaction forms a structure with large pore size and high density, resulting in a porous aerogel.

[0023] 3) The preparation process of this invention is simple, the raw materials are inexpensive, the cost is lower, and it can be mass-produced, which has great application prospects in the civilian field. Attached Figure Description

[0024] Figure 1 , Figure 6 This is a flowchart illustrating the preparation process of a jute fiber silica aerogel according to the present invention.

[0025] Figure 2 The images show the front, side, and bottom (from left to right) of the jute fiber silica aerogel prepared in Experiment Example 1.

[0026] Figure 3 The images show the front, side, and bottom (from left to right) of the jute fiber silica aerogel prepared in Experiment Example 2.

[0027] Figure 4 The images show the front, side, and bottom (from left to right) of the jute fiber silica aerogel prepared in Experiment Example 3.

[0028] Figure 5 The images show the front, side, and bottom (from left to right) of the jute fiber silica aerogel prepared in Experiment Example 4.

[0029] Figure 7 Line graph showing the mechanical properties of the jute fiber silica aerogel prepared in Experiment Example 2. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] A method for preparing jute fiber silica aerogel includes: using low-cost, high-performance industrial silica sol (silicon content 30±1%, pH=9.4) as the silicon source and deionized water as the solvent, a silica solution is formed by reacting the industrial silica sol with deionized water and a small amount of jute; hydrochloric acid and ammonia are added sequentially to the aqueous solution; and under the lubricating effect of PEG and the adhesive effect of PVA, a two-step acid-base process is used to initially form a plant fiber silica sol mainly composed of jute. The jute fiber silica sol solution is then placed in a freezer at -20 degrees Celsius to obtain jute fiber silica gel. The jute fiber silica gel is then freeze-dried for 48 hours to obtain jute fiber silica aerogel.

[0032] Specifically, the following steps are included:

[0033] Using industrial silica sol, deionized water, and jute fiber as the silicon source and precursor, a mixed solution was obtained. Polyethylene glycol 20000 (PEG) was added to the mixed solution, and the mixture was stirred thoroughly. Then, hydrochloric acid was added as an acidity regulator to obtain an acidic jute-based plant fiber silica sol. After adding hydrochloric acid, the solution became acidic, and the hydrolysis rate was greater than the polymerization rate. Polyvinyl alcohol (PVA) was added to the acidic jute-based plant fiber silica sol, followed by ammonia, to obtain an alkaline jute-based plant fiber silica sol. At this point, the solution was alkaline, and the polymerization rate was greater than the hydrolysis rate. Using a two-step acid-base method, the jute-based plant fiber silica sol was frozen for 8 hours to obtain a jute-based plant fiber silica gel. This gel was then freeze-dried for 48 hours to obtain jute fiber silica aerogel. By introducing jute-based plant fibers as the internal framework of the aerogel, supporting the aerogel while leveraging the superior sound absorption and heat insulation properties of plant fibers, along with their good damping performance, light weight, and high specific strength and modulus, the jute-based silica fiber aerogel maintains excellent heat insulation performance and, to some extent, mitigates the aerogel's inherent fragility, significantly improving its mechanical properties. This invention uses inexpensive industrial silica sol as the silicon source and deionized water as the solvent to replace organic solvents, greatly reducing costs and simplifying the operation, thus producing an aerogel with a porous structure.

[0034] More specifically, such as Figure 1 , Figure 6 As shown, it includes the following steps:

[0035] 1) Under stirring conditions, industrial silica sol and deionized water are mixed to form a mixed solution: jute fiber (small pieces) is added to the mixed solution and then placed on a magnetic stirrer and stirred continuously for 2 minutes to obtain a mixed solution of plant fiber silica sol with jute as the main component.

[0036] 2) Jute fiber silica aerogel material and its preparation method: Under stirring conditions, polyethylene glycol (PEG) is added to the silica sol mixture containing jute plant fiber obtained in step 1). The amount of polyethylene glycol 20000 (PEG) is controlled at 1g, mainly to ensure that the jute can be fully stirred in the solution.

[0037] 3) Add hydrochloric acid (5% concentration) to the silica sol mixture obtained in step 2) slowly until the pH value of the solution reaches about 2-3. Then stir for 15 minutes to obtain an acidic plant fiber silica sol mainly composed of jute.

[0038] 4) Slowly add polyvinyl alcohol to the acidic jute fiber silica sol obtained in step 3). The amount of polyvinyl alcohol should be controlled at 1g. During the addition process, the polyvinyl alcohol should be added to the solvent slowly to prevent clumping after rapid addition. Then stir for 10 minutes.

[0039] 5) Add ammonia (5% concentration) dropwise to the jute fiber silica sol obtained in step 4) until the pH value reaches 6-8 as detected by pH test paper. Then stir for 30 minutes to obtain an alkaline jute fiber silica sol.

[0040] 6) After freezing the alkaline jute fiber silica sol obtained in step 5) in a freezer for 8 hours, jute fiber silica gel is obtained.

[0041] 7) Place the jute fiber silica gel obtained in step 6) into a freeze dryer and freeze dry for 48 hours to obtain fiber aerogel by freeze drying.

[0042] The following embodiments are implemented based on the above-described technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0043] In the following examples, the industrial silica sol was industrial grade, produced by Hubei Zhenghe Tiancheng Technology Co., Ltd., with a silica content of 30±1wt%, a sodium oxide content of 0.24wt%, and a pH of 9.45. Its viscosity was 4.5, specific gravity (25°) was 1.204, and particle size was 9.8nm. Deionized water was purchased from China Resources Yibao Co., Ltd., using a two-stage reverse osmosis process. Hydrochloric acid was 1mol / L, of superior purity, produced by National Chemical Reagent Co., Ltd. Ammonia water was 5% concentration, of superior purity, produced by National Chemical Reagent Co., Ltd. Polyvinyl alcohol (PVA) was analytical grade, produced by Jinzhou Yaston Building Materials Technology Co., Ltd. Polyethylene glycol 20000 (PEG) was analytical grade, produced by Shanghai Yi'en Chemical Technology Co., Ltd. Jute fiber was industrial grade, manufactured by Taizhou Ke'en Environmental Protection Technology Co., Ltd. The magnetic stirrer was model MS-H280-Pro1, manufactured by Dalong Xingchuang Experimental Instrument Co., Ltd. The freezer is model DW-25W147, manufactured by Aucma Co., Ltd. The freeze dryer is model SCIENTZ-10N, manufactured by Ningbo Xinzhi Biotechnology Co., Ltd. The stirring temperature is room temperature.

[0044] Example 1:

[0045] A method for preparing jute fiber silica aerogel, comprising the following steps:

[0046] Pour 10 ml of industrial silica sol into measuring cup #1, then pour 25 ml of deionized water into measuring cup #2, ensuring a deionized water to industrial silica sol ratio of 1:2.5. Next, take approximately 0.07 g of jute fiber, about 1.5% of the aerogel's mass. Pour the solutions from both measuring cups, along with the jute, into a solvent cup to form a jute-based plant fiber silica sol solution.

[0047] Then add 1g of polyethylene glycol (PEG) to the solution. Place the plant fiber silica sol solution, mainly jute, on a magnetic turntable, put in a magnetic rotor, and stir the solution at a speed of 430 rpm to allow the jute to fully dissolve in the solution at room temperature. Stir for 15 minutes.

[0048] Add approximately 2.5 ml of hydrochloric acid, and measure the pH value using pH paper to ensure it is approximately 2-3. The jute-based plant fiber silica sol solution will immediately undergo hydrolysis, and the solution will quickly turn milky white. Since industrial silica sol is an alkaline solution, the polymerization rate is lower than the hydrolysis rate at this point, resulting in a low-crosslinking, small-pore, and low-density network structure within the solution. Stir the solution for 15 minutes.

[0049] Add 1g of polyvinyl alcohol (PVA) as a binder. Then continue stirring at 430 rpm for 15 minutes until the PVA is fully dissolved. Add 0.5ml of ammonia water, and adjust the pH to approximately 6-8 using pH paper to accelerate the polymerization reaction. At this point, the polymerization rate in the solution is greater than the hydrolysis rate, and a high-density network structure with large pores will form inside the solution. After stirring for 30 minutes, a silica solution of plant fiber, mainly jute, is obtained. Impurities are clearly visible in the solution, mainly jute fiber, and the solution is light white.

[0050] The obtained jute-based plant fiber silica solution was frozen in a freezer at -20°C for 6 hours to obtain a jute-based plant fiber silica gel, which was a white solid at this stage. The jute-based plant fiber silica gel was then placed in a freeze dryer. After turning on the freeze dryer and ensuring the internal temperature was -20°C, the jute-based plant fiber silica gel was placed inside and freeze-dried for 48 hours. The vacuum degree was 13.2 Pa, the internal temperature was -61.2°C, and the sample temperature was -29.9°C, thus successfully preparing jute fiber silica aerogel.

[0051] like Figure 2As shown, the jute-based plant fiber aerogel prepared in Example 1, with a jute fiber content of 0.07g, has an appearance color similar to that of pure aerogel, both being white. A small amount of jute fiber is attached to the surface of the aerogel. The mechanical properties measured show that the highest compressive strength, approximately 0.18 MPa, is found at 80% strain. The compressive strength of pure aerogel at 80% strain is approximately 0.14 MPa, representing an increase of 0.04 MPa.

[0052] Example 2:

[0053] A method for preparing jute fiber silica aerogel, comprising the following steps:

[0054] Pour 10 ml of industrial silica sol into measuring cup #1, then pour 25 ml of deionized water into measuring cup #2, ensuring a deionized water to industrial silica sol ratio of 1:2.5. Next, take approximately 0.15 g of jute fiber, about 3% of the aerogel's mass. Pour the solutions from both measuring cups, along with the jute, into a solvent cup to form a jute-based plant fiber silica sol solution.

[0055] Then add 1g of polyethylene glycol (PEG) to the solution. Place the plant fiber silica sol solution, mainly jute, on a magnetic turntable, put in a magnetic rotor, and stir the solution at a speed of 440 rpm to fully dissolve the jute in the solution at room temperature for 15 minutes.

[0056] Add approximately 2.7 ml of hydrochloric acid, and measure the pH value using pH paper to ensure it is approximately 2-3. The jute-based plant fiber silica sol solution will immediately undergo hydrolysis, and the solution will quickly turn milky white. Since industrial silica sol is an alkaline solution, the polymerization rate is lower than the hydrolysis rate at this point, resulting in a network structure with low cross-linking, small pore size, and low density. Stir the solution for 15 minutes.

[0057] Add 1g of polyvinyl alcohol (PVA) as a binder. Then continue stirring at 440 rpm for 15 minutes until the PVA is fully dissolved. Add 0.5ml of ammonia water, and adjust the pH to approximately 6-8 using pH paper to accelerate the polymerization reaction. At this point, the polymerization rate in the solution is greater than the hydrolysis rate, and a high-density network structure with large pores will form inside the solution. After stirring for 45 minutes, a silica solution of plant fiber, mainly jute, is obtained. Impurities are clearly visible in the solution, mainly jute fiber, and the solution is light white.

[0058] The obtained jute-based plant fiber silica solution was frozen in a freezer at -20°C for 8 hours to obtain a jute-based plant fiber silica gel, which was a white solid at this stage. The jute-based plant fiber silica gel was then placed in a freeze dryer. After turning on the freeze dryer and ensuring the internal temperature was -20°C, the jute-based plant fiber silica gel was placed inside and freeze-dried for 48 hours. The vacuum degree was 13.0 Pa, the internal temperature was -60.9°C, and the sample temperature was -30.9°C, thus successfully preparing jute fiber silica aerogel.

[0059] like Figure 3 As shown, the jute-based plant fiber aerogel prepared in Example 2, with a jute fiber content of 0.15g, exhibits a lighter yellow color compared to pure aerogel. Jute fibers are clearly visible adhering to the aerogel surface. The mechanical properties measured show that the highest compressive strength, approximately 1.0 MPa, is achieved at 75% strain. In contrast, the compressive strength of pure aerogel at 75% strain is approximately 0.13 MPa, representing an 8-fold increase. Under these conditions, the increase in compressive strength is the highest (e.g., ...). Figure 7 (As shown). The plant fiber aerogel prepared with a jute fiber content of 0.15g and a mass fraction of 6% exhibited the best mechanical properties.

[0060] Example 3:

[0061] A method for preparing jute fiber silica aerogel, comprising the following steps:

[0062] Pour 10 ml of industrial silica sol into measuring cup #1, then pour 25 ml of deionized water into measuring cup #2, ensuring a deionized water to industrial silica sol ratio of 1:2.5. Next, take approximately 0.3 g of jute fiber, about 6% of the aerogel's mass. Pour the solutions from both measuring cups, along with the jute, into a solvent cup to form a jute-based plant fiber silica sol solution.

[0063] Then add 1g of polyethylene glycol (PEG) to the solution. Place the jute-based plant fiber silica sol solution on a magnetic turntable, put in a magnetic rotor, and stir the solution at a speed of 450 rpm to allow the jute to fully dissolve in the solution at room temperature. Stir for 15 minutes.

[0064] Add approximately 2.6 ml of hydrochloric acid, and measure the pH value using pH paper to ensure it is approximately 2-3. The jute-based plant fiber silica sol solution will immediately undergo hydrolysis, and the solution will quickly turn milky white. Since industrial silica sol is an alkaline solution, the polymerization rate is lower than the hydrolysis rate at this point, resulting in a low-crosslinking, small-pore, and low-density network structure within the solution. Stir the solution for 15 minutes.

[0065] Add 1g of polyvinyl alcohol (PVA) as a binder. Then continue stirring at 450 rpm for 15 minutes until the PVA is fully dissolved. Add 0.5ml of ammonia water, and adjust the pH to approximately 6-8 using pH paper to accelerate the polymerization reaction. At this point, the polymerization rate in the solution is greater than the hydrolysis rate, and a high-density network structure with large pores will form inside the solution. After stirring for 55 minutes, a silica solution of plant fiber, mainly jute, is obtained. Impurities are clearly visible in the solution, mainly jute fiber, and the solution is light white.

[0066] The obtained jute-based plant fiber silica solution was frozen in a freezer at -20°C for 8 hours to obtain a jute-based plant fiber silica gel, which was a white solid at this stage. The jute-based plant fiber silica gel was then placed in a freeze dryer. After turning on the freeze dryer and ensuring the internal temperature was -20°C, the jute-based plant fiber silica gel was placed inside and freeze-dried for 48 hours. The vacuum degree was 12.9 Pa, the internal temperature was -61.5°C, and the sample temperature was -30.2°C, thus successfully preparing jute fiber silica aerogel.

[0067] like Figure 4 As shown, the jute fiber aerogel prepared in Example 3, with a jute fiber content of 0.3g, exhibits a yellow color compared to pure aerogel. It is clearly visible that the jute fibers are attached to the aerogel surface. The mechanical properties measured show that the highest compressive strength, approximately 0.14 MPa, is achieved at 80% strain.

[0068] Example 4:

[0069] The preparation method of pure silica aerogel is as follows:

[0070] Pour 10 ml of industrial silica sol into measuring cup #1, then pour 25 ml of deionized water into measuring cup #2, ensuring a deionized water to industrial silica sol ratio of 1:2.5. Combine the solutions from both measuring cups and pour them into a solvent cup to form a silica sol solution.

[0071] Then add 1g of polyethylene glycol (PEG) to the solution, place the silica sol solution on a magnetic turntable, put in the magnetic rotor, and stir the solution at a speed of 420 rpm to allow the jute to fully dissolve in the solution at room temperature for 15 minutes.

[0072] Add approximately 2.7 ml of hydrochloric acid, and measure the pH value using pH paper to ensure it is approximately 2-3. The silica sol solution will immediately undergo a hydrolysis reaction, quickly turning milky white. Since industrial silica sol is an alkaline solution, the polymerization rate is lower than the hydrolysis rate at this point, resulting in a network structure with low cross-linking, small pore size, and low density. Stir the solution for 15 minutes.

[0073] Add 1g of polyvinyl alcohol (PVA) as a binder. Then continue stirring at 440 rpm for 15 minutes until the PVA is fully dissolved. Add 0.5ml of ammonia water, and adjust the pH to approximately 6-8 using pH paper to accelerate the polymerization reaction. At this point, the polymerization rate in the solution is greater than the hydrolysis rate, and a high-density network structure with large pores will form inside the solution. After stirring for 30 minutes, a silica solution of plant fiber, mainly jute, is obtained. Impurities are clearly visible in the solution, mainly jute fiber, and the solution is light white.

[0074] The obtained silica solution was frozen in a freezer at -20°C for 4-8 hours to obtain silica gel, which was a white solid at this stage. The silica gel was then placed in a freeze dryer. After turning on the freeze dryer and ensuring the internal temperature was -20°C, the silica gel was placed inside and freeze-dried for 48 hours. The vacuum degree was 13.4 Pa, the internal temperature was -60.9°C, and the sample temperature was -29.6°C, thus successfully preparing pure silica aerogel.

[0075] like Figure 5 As shown, the pure aerogel prepared in Example 4 is pure white in color, and its compressive strength at 80% strain is approximately 0.14 MPa. Compared with the mechanical properties of silica aerogel with added jute fiber, the silica aerogel with added jute fiber clearly exhibits better mechanical properties.

[0076] In the above four examples, jute fiber silica aerogels prepared in Examples 1, 2, and 3 had jute fiber mass fractions of 1.5%, 3%, and 6%, respectively. In addition, a pure aerogel without jute fiber was prepared in Example 4. Comparing the jute fiber aerogel with the pure aerogel, the former has excellent thermal insulation function and better mechanical properties. At the same time, comparing jute fiber silica aerogels with different mass fractions, it was found that the jute fiber silica aerogel with a jute fiber mass fraction of 3% has the best mechanical properties, with mechanical properties enhanced by about 8 times, which greatly enhances the mechanical properties of the aerogel.

[0077] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing jute fiber silica aerogel, characterized in that, include: A silica sol solution containing jute fiber was mixed and stirred with polyethylene glycol, then the pH was adjusted to acidic and stirred. Polyvinyl alcohol was added and mixed evenly, then the pH was adjusted to neutral and stirred. The mixture was pre-cooled and freeze-dried to obtain jute fiber silica aerogel. In the silica sol solution containing jute fiber, the mass fraction of jute fiber is 3%; The mass ratio of water to silica sol is 1:2.5; The amount of polyethylene glycol added is 1g / 0.15g jute fiber; the amount of polyvinyl alcohol added is 1g / 0.15g jute fiber.

2. The method for preparing jute fiber silica aerogel according to claim 1, characterized in that, The pH was adjusted to acidic using hydrochloric acid, with the final pH being 2-3.

3. The method for preparing jute fiber silica aerogel according to claim 1, characterized in that, The pH was adjusted to neutral using ammonia, with the final pH being 6-8.

4. The method for preparing jute fiber silica aerogel according to claim 1, characterized in that, Pre-cooling conditions include: a pre-cooling temperature of -20℃ and a pre-cooling time of 4-8 hours.

5. The method for preparing jute fiber silica aerogel according to claim 1, characterized in that, The freeze-drying conditions include: freeze-drying temperature of -61.5℃ to -30℃, freeze-drying time of 40-48 h, and vacuum degree of 12.9Pa-13.2Pa.

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