Preparation method of crystal-free pomegranate-shaped nanocellulose

Abstract

The invention provides a preparation method of crystal-free pomegranate-shaped nanocellulose, which comprises the following steps: dissolving cellulose in a specific solvent to form a cellulose solution with the concentration of 0.001-15wt%, then adding a hydrophobic modifier into the cellulose solution, carrying out hydrophobic modification on the cellulose in the dissolved state to obtain a hydrophobic cellulose solution, and then adding the hydrophobic modifier into the hydrophobic cellulose solution to obtain the crystal-free pomegranate-shaped nanocellulose. Mixing and diffusing the hydrophobic cellulose solution and an anti-solvent to enable the hydrophobic cellulose to be self-assembled through Van der Waals force to form primary particles, reassembling the primary particles due to high surface energy to form amorphous pomegranate-shaped nano-cellulose, obtaining suspension of the amorphous pomegranate-shaped nano-cellulose, and finally completely removing the specific solvent and the hydrophobic modifier to obtain the amorphous pomegranate-shaped nano-cellulose. And drying to obtain the crystal-free pomegranate-shaped nano cellulose. According to the invention, dissolution, hydrophobic modification and regeneration of cellulose are innovatively combined for the first time, and the crystal-free pomegranate-shaped nano cellulose with a novel bionic pomegranate-shaped structure is prepared.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanocellulose, and particularly relates to a preparation method of amorphous pomegranate-shaped nanocellulose. Background Art

[0002] As a new type of bio-based nanomaterial, nanocellulose has shown great application potential in the fields of composite materials, biomedicine, flexible electronics, energy storage, etc. in recent years due to its high specific surface area, biodegradability, excellent mechanical properties and surface modifiability. However, traditional nanocellulose (such as rod-shaped nanocellulose CNC and fibrous nanocellulose CNF) still faces many technical bottlenecks in practical applications: 1. Structural singularity limitation: Existing nanocellulose mostly has a fibrous or rod-shaped structure, and its functional application is limited by insufficient morphological uniformity. Especially when loading functional nanoparticles, agglomeration is likely to occur, resulting in low interfacial bonding strength and uneven stress distribution of the composite material. 2. Complex preparation process: Traditional methods need to extract nanocellulose through steps such as strong acid hydrolysis or high-pressure homogenization, with high energy consumption and easy environmental pollution. 3. High crystallinity: Traditional rod-shaped nanocellulose and fibrous nanocellulose have relatively high crystallinity, resulting in poor interfacial compatibility of the materials.

[0003] Pomegranate-shaped materials are a new type of material with a biomimetic pomegranate structure. Due to their unique structure, pomegranate-shaped materials have attracted much attention in the fields of catalytic carriers, intelligent sensing, etc. Pomegranate-shaped materials mainly have the following advantages: it helps to separate the inclusions from the external environment, can effectively prevent the agglomeration of inclusions, improve the structural stability, or provide a buffering effect to improve the impact resistance and anti-swelling property of inclusions; pomegranate-shaped materials have a relatively large specific surface area, which can provide a large number of interfaces or active sites; it solves the problem of incompatibility between interfaces, etc. Pomegranate-shaped nanomaterials have significant advantages in the uses such as functional material encapsulation, material stability and dispersion. Summary of the Invention

[0004] In view of the deficiencies of traditional nanocellulose, the present invention combines the advantages of the biomimetic structure of pomegranate-shaped materials and provides a preparation method of amorphous pomegranate-shaped nanocellulose. In this method, cellulose is dissolved into a molecular chain dispersion state, and then hydrophobic modification is carried out on it. Hydrophobic functional groups are introduced into the cellulose molecular chain structure to obtain hydrophobic cellulose, weakening the strong hydrogen bond interaction within and between cellulose molecules. Then an anti-solvent is added to enable the hydrophobic cellulose to self-assemble into primary particles through van der Waals forces. The high surface energy of the primary particles prompts them to aggregate to reduce the total energy, and finally amorphous pomegranate-shaped nanocellulose is assembled. The prepared amorphous pomegranate-shaped nanocellulose is determined to have an obvious pomegranate-shaped structure and is amorphous, with uniform size and high yield, and the preparation method is simple, green and low-cost.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for preparing amorphous pomegranate-shaped nanocellulose, characterized in that the method is: first dissolve the cellulose-containing raw material in a specific solvent to form a cellulose solution with a concentration of 0.001 wt%-15 wt%, then add a hydrophobic modifier to the cellulose solution, and after hydrophobic modification of the dissolved cellulose, a hydrophobic cellulose solution is obtained. Then, the hydrophobic cellulose solution is mixed and diffused with an anti-solvent to precipitate the hydrophobically modified cellulose, obtaining a suspension of amorphous pomegranate-shaped nanocellulose. Finally, the suspension is washed with an anti-solvent until the solvent for dissolving cellulose and the hydrophobic modifier are completely removed, and after drying, amorphous pomegranate-shaped nanocellulose is obtained; The specific solvent is a solvent capable of dissolving cellulose; The hydrophobic modifier is a modifier capable of introducing hydrophobic chlorine-containing functional groups into the cellulose structure; The anti-solvent is a solvent that does not dissolve cellulose but is miscible with the specific solvent; The concentration of the hydrophobic cellulose solution is 0.001 wt%-15 wt%.

[0006] Preferably, before adding the hydrophobic modifier, the cellulose solution is centrifuged at 5000 r / min for purification, and the supernatant is taken as the purified cellulose solution, and then the hydrophobic modifier is added to hydrophobically modify the dissolved cellulose.

[0007] Preferably, the specific solvent is one or a mixture of two or more of 1-butyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium chloride, LiCl / N,N-dimethylacetamide (DMAc) / water, LiBr / DMAc, sodium hydroxide / urea / water, sodium hydroxide / thiourea / water, and sodium hydroxide / thiourea / urea / water.

[0008] Preferably, the hydrophobic modifier is a chlorinated modifier, specifically thionyl chloride, phosphorus oxychloride, or p-toluenesulfonyl chloride.

[0009] Preferably, the anti-solvent is one or a mixture of two or more of water, alcohols, ketones, esters, ethers, aromatic hydrocarbons, and alkane solvents.

[0010] Preferably, the mixing and diffusion is direct addition of an anti-solvent and stirring diffusion or dialysis diffusion. When mixing and diffusing, methods such as stirring and heating can be adopted to enhance the mixing efficiency.

[0011] Preferably, the obtained amorphous pomegranate-shaped nanocellulose is used as a cellulose-containing raw material and is dissolved again in a specific solvent to form a hydrophobic cellulose solution with a concentration of 0.001 wt% - 15 wt%. Then, the hydrophobic cellulose solution is mixed with an anti-solvent and diffused to precipitate the hydrophobically modified cellulose, obtaining a suspension of amorphous pomegranate-shaped nanocellulose. The suspension of amorphous pomegranate-shaped nanocellulose is washed with an anti-solvent or precipitated by dialysis to completely remove the solvent for dissolving cellulose and the hydrophobic modifier, and after drying, amorphous pomegranate-shaped nanocellulose is obtained.

[0012] The present invention has the following advantages compared with the prior art: 1. The present invention adopts an unpublished cellulose dissolution-hydrophobic modification-regeneration combined method. First, it is dissolved into cellulose molecular chains, then hydrophobic modification is carried out. Subsequently, amorphous pomegranate-shaped nanocellulose is successfully prepared by self-assembly of hydrophobically modified cellulose in a dispersed state through van der Waals forces, and there is only this morphology, with uniform size and narrow particle size distribution.

[0013] 2. When the present invention hydrophobically modifies cellulose, it is carried out in a dissolved state (homogeneous system). The modified hydrophobic cellulose solution is also in a dispersed state, which is beneficial to the subsequent preparation of amorphous pomegranate-shaped nanocellulose, and the prepared pomegranate-shaped nanocellulose has a special amorphous structure.

[0014] 3. The present invention uses a green, simple, safe, low-energy-consuming and high-efficiency method to prepare amorphous pomegranate-shaped nanocellulose.

[0015] 4. The raw materials used in the present invention are cellulose-containing raw materials, with wide raw material sources and low raw material requirements.

[0016] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0017] Figure 1 It is the X-ray diffraction spectrum of the amorphous pomegranate-shaped nanocellulose prepared from the cellulose chloride solution in Example 1 of the present invention.

[0018] Figure 2 It is the scanning electron micrograph of the amorphous pomegranate-shaped nanocellulose prepared in Example 2 of the present invention.

[0019] Figure 3 It is the scanning electron micrograph of the amorphous pomegranate-shaped nanocellulose prepared in Example 3 of the present invention.

[0020] Figure 4 It is the scanning electron micrograph of the amorphous pomegranate-shaped nanocellulose prepared in Example 4 of the present invention.

[0021] Figure 5This is the scanning electron microscope image of the amorphous pomegranate-shaped nanocellulose prepared in Example 5 of the present invention.

[0022] Figure 6 This is the scanning electron microscope image of the nanocellulose prepared in Comparative Example 1 of the present invention. Detailed implementation manners

[0023] Example 1 This example discloses a preparation method of amorphous pomegranate-shaped nanocellulose, and the method includes: Disperse microcrystalline cellulose into DMAc, and vigorously stir the mixture at 110 °C for 1 h to obtain an activated cellulose suspension. After the suspension is cooled, filter and wash it with deionized water, and dry it to obtain activated cellulose.

[0024] Disperse the activated cellulose into a 9 wt% LiCl / DMAc solution, vigorously stir it at 125 °C for 2.5 h, and then stir it at room temperature (25 °C) for 12 h to obtain a dissolution solution. Centrifuge the dissolution solution at 11000 r / min for 20 min to separate the insoluble components and obtain a 1.5 wt% cellulose dissolution solution in the upper layer. Under the conditions of 80 °C, condensation reflux, and nitrogen protection, add a hydrophobic modifier thionyl chloride (SOCl 2 )(SOCl 2 (the molar ratio of SOCl to the cellulose anhydroglucose unit is 10:1) to the cellulose dissolution solution, and maintain the above conditions to stir and react for 4 h to obtain a cellulose chloride solution (cellulose chloride is a hydrophobic cellulose). Load the cellulose chloride solution into a dialysis bag for precipitation, dialyze it with deionized water at 30 °C for 48 h, and change the deionized water regularly until LiCl and DMAc are completely removed, and dry it to obtain amorphous pomegranate-shaped nanocellulose chloride.

[0025] The X-ray diffraction spectrum of the amorphous pomegranate-shaped nanocellulose prepared in this example is as Figure 1 shown. A weak and broad signal is observed, and no crystalline peak signal is observed, confirming the amorphous structural characteristics of the pomegranate-shaped nanocellulose chloride.

[0026] Example 2 This example discloses a preparation method of amorphous pomegranate-shaped nanocellulose, and the method includes: Disperse microcrystalline cellulose into DMAc, and vigorously stir the mixture at 110 °C for 1 h to obtain an activated cellulose suspension. After the suspension is cooled, filter and wash it with deionized water, and dry it to obtain activated cellulose.

[0027] Disperse the activated cellulose into a 9 wt% LiCl / DMAc solution, and vigorously stir the mixture at 125 °C for 2.5 h. Subsequently, stir it at room temperature (25 °C) for 12 h to obtain a dissolution solution. Centrifuge the dissolution solution at 11,000 r / min for 20 min to separate the insoluble components and obtain a 1.5 wt% cellulose dissolution solution in the upper layer. Under the conditions of 80 °C, condensation reflux, and nitrogen protection, add thionyl chloride (SOCl 2 )(SOCl 2 to the cellulose dissolution solution (the molar ratio of SOCl 2 to the anhydroglucose unit of cellulose is 10:1), and maintain the above conditions to stir and react for 4 h to obtain a cellulose chloride solution. While stirring at a speed of 500 r / min, slowly drop the cellulose chloride solution into 2 L of deionized water to precipitate the cellulose chloride, obtaining a suspension of amorphous pomegranate-shaped nanocellulose chloride. Then, use deionized water as an antisolvent to filter and wash the suspension of amorphous pomegranate-shaped nanocellulose chloride to remove LiCl and SOCl

[0028] to obtain amorphous pomegranate-shaped nanocellulose chloride.

[0028] Add 1.0 g of the dried amorphous pomegranate-shaped nanocellulose obtained to 60 mL of DMAc, and stir until the amorphous pomegranate-shaped nanocellulose chloride is completely dissolved in DMAc. Centrifuge the dissolution solution at 11,000 r / min for 20 min to separate the insoluble components and obtain a 0.75 wt% cellulose chloride solution dissolved in DMAc. Take 40 mL of the 1.75 wt% cellulose chloride solution and place it in a dialysis bag to precipitate the cellulose chloride. Dialyze it with deionized water at 30 °C for 48 h, and regularly change the deionized water until DMAc is completely removed. After drying, obtain the product. Perform a scanning electron microscope on the prepared product. As Figure 2 shown, it can be seen from the figure that the morphology of the product is amorphous pomegranate-shaped, the particle size is uniform, and there is no cellulose with other morphologies generated.

[0029] In this example, redissolving and precipitating the amorphous pomegranate-shaped nanocellulose chloride aims to make the morphology of the prepared amorphous pomegranate-shaped nanocellulose particles better and remove impurities more thoroughly.

[0030] Example 3 This example discloses a preparation method of amorphous pomegranate-shaped nanocellulose, and the method includes: Disperse microcrystalline cellulose in DMAc, and vigorously stir the mixture at 110 °C for 1 h to obtain an activated cellulose suspension. After the suspension is cooled, filter and wash it with deionized water by suction, and dry it to obtain activated cellulose. Disperse the activated cellulose in a 9 wt% LiCl / DMAc solution, and vigorously stir the mixture at 125 °C for 2.5 h, and then stir it at room temperature (25 °C) for 12 h to obtain a dissolution solution. Centrifuge the dissolution solution at 11000 r / min for 20 min to separate the insoluble components to obtain a 1.5 wt% cellulose dissolution solution in the upper layer. Under the conditions of 80 °C, condensation reflux, and nitrogen protection, add thionyl chloride (SOCl 2 )(SOCl 2 with a molar ratio of 10:1 to the anhydroglucose unit of cellulose) to the cellulose dissolution solution, and maintain the above conditions and stir and react for 4 h to obtain a cellulose chloride solution. Under stirring at a speed of 500 r / min, slowly drop the cellulose chloride solution into 2 L of deionized water to precipitate the cellulose chloride to obtain a suspension of amorphous pomegranate-like nanocellulose chloride. Then, filter and wash the suspension of amorphous pomegranate-like nanocellulose chloride with deionized water as an anti-solvent to remove LiCl and SOCl 2 , and dry it to obtain amorphous pomegranate-like nanocellulose chloride.

[0031] Add 1.0 g of the dried amorphous pomegranate-like nanocellulose obtained to 60 mL of DMAc, and stir until the amorphous pomegranate-like nanocellulose chloride is completely dissolved in DMAc. Centrifuge the dissolution solution at 10000 r / min for 10 min to separate the insoluble components to obtain a 1.75 wt% cellulose chloride solution dissolved in DMAc. Take 10 mL of the cellulose chloride / DMAc solution and transfer it to a dialysis bag, and stir and dialyze it with deionized water for 3 d until DMAc is removed. Centrifuge and separate the precipitate at 11000 r / min for 8 min, and dry it to obtain amorphous pomegranate-like nanocellulose (as shown in Figure 3 ).

[0032] Example 4 This example discloses a preparation method of amorphous pomegranate-like nanocellulose, and the method includes: Disperse bamboo cellulose into 91 g of DMAc, and vigorously stir the mixture at 110 °C for 1 h to obtain an activated cellulose suspension. After the suspension cools, add 9 g of LiCl to it to prepare a 9 wt% LiCl / DMAc solution. Heat the mixture to 125 °C and vigorously stir it for 2.5 h, and then stir it at room temperature (25 °C) for 12 h to obtain a dissolution solution. Centrifuge the dissolution solution at 11000 r / min for 20 min to separate the insoluble components and obtain a 1.5 wt% cellulose dissolution solution in the upper layer. Under the conditions of 80 °C, condensing reflux, and nitrogen protection, add thionyl chloride (SOCl 2 )(SOCl 2 with a molar ratio of 10:1 to the cellulose anhydroglucose unit) to the cellulose dissolution solution, and maintain the above conditions to stir and react for 4 h to obtain a cellulose chloride solution. Stir the cellulose chloride solution at a speed of 500 r / min and slowly drip it into 2 L of deionized water to precipitate the cellulose chloride, obtaining a suspension of amorphous pomegranate-shaped nanocellulose chloride. Then, use deionized water as an anti-solvent to filter and wash the suspension of amorphous pomegranate-shaped nanocellulose chloride to remove LiCl and SOCl 2 , and dry it to obtain amorphous pomegranate-shaped nanocellulose chloride.

[0033] Add 0.5 g of the dried amorphous pomegranate-shaped nanocellulose to 100 mL of DMAc, and stir for 1 h until the amorphous pomegranate-shaped nanocellulose chloride is completely dissolved in DMAc. Centrifuge the dissolution solution at 10000 r / min for 10 min to separate the insoluble components and obtain a 0.5 wt% cellulose chloride solution dissolved in DMAc. Take 5 mL of the cellulose chloride / DMAc solution in a 100 mL tall beaker, stir the solution with a magnetic stirrer at a rotation speed of 300 r / min, and at the same time use a peristaltic pump to drip deionized water into the solution along the wall of the beaker at a dripping rate of 5 mL / min, with a total of 60 mL added, to precipitate the cellulose chloride and obtain a suspension of pomegranate-shaped nanocellulose; centrifuge and separate the precipitate at 11000 r / min for 8 min, wash the precipitate with deionized water until DMAc is removed, and dry it to obtain amorphous pomegranate-shaped nanocellulose (as Figure 4 shown).

[0034] Example 5 This example discloses a preparation method of amorphous pomegranate-shaped nanocellulose, and the method includes: Disperse microcrystalline cellulose into 91 g of DMAc, and vigorously stir the mixture at 110 °C for 1 h to obtain an activated cellulose suspension. After the suspension cools, add 9 g of LiCl to it to prepare a 9 wt% LiCl / DMAc solution, and heat up to 125 °C and vigorously stir the mixture for 2.5 h. Then stir at room temperature (25 °C) for 12 h to obtain a dissolution solution. Centrifuge the dissolution solution at 11000 r / min for 20 min to separate the insoluble components and obtain a 1.5 wt% cellulose dissolution solution in the upper layer. Under the conditions of 80 °C, reflux condensation, and nitrogen protection, add thionyl chloride (SOCl 2 )(SOCl 2 to the cellulose dissolution solution with a molar ratio of 10:1 to the dehydrated glucose unit of cellulose), and maintain the above conditions and stir and react for 4 h to obtain a cellulose chloride solution. While stirring at a speed of 500 r / min, slowly drop the cellulose chloride solution into 2 L of deionized water to precipitate the cellulose chloride and obtain a suspension of amorphous pomegranate-shaped nanocellulose chloride. Then use deionized water as an antisolvent to filter and wash the suspension of amorphous pomegranate-shaped nanocellulose chloride to remove the excessive LiCl and SOCl 2 , and dry to obtain amorphous pomegranate-shaped nanocellulose chloride.

[0035] Add 1.0 g of the dried amorphous pomegranate-shaped nanocellulose obtained to 100 mL of DMAc, and stir for 1 h until the amorphous pomegranate-shaped nanocellulose chloride is completely dissolved in DMAc. Centrifuge the dissolution solution at 10000 r / min for 10 min to separate the insoluble components and obtain a 1 wt% cellulose chloride solution dissolved in DMAc. Take 5 mL of the cellulose chloride / DMAc solution in a 100 mL tall beaker, stir the solution with a magnetic stirrer at a rotation speed of 300 r / min, and at the same time use a peristaltic pump to drip deionized water into the solution along the cup wall at a dripping rate of 5 mL / min, with a total of 60 mL added, to precipitate the cellulose chloride and obtain a suspension of pomegranate-shaped nanocellulose; centrifuge and separate the precipitate with parameters of 11000 r / min and 8 min, and wash the precipitate with deionized water until DMAc is removed, and dry to obtain amorphous pomegranate-shaped nanocellulose (as shown in Figure 5 ).

[0036] In the above embodiments, the specific solvent can also be one or a mixture of two or more of 1-allyl-3-methylimidazolium chloride, LiCl / N,N-dimethylacetamide / water, LiBr / DMAc, sodium hydroxide / urea / water, sodium hydroxide / thiourea / water, and sodium hydroxide / thiourea / urea / water.

[0037] Acetyl chloride as the hydrophobic modifier can also be replaced by other chlorination modifiers, such as phosphorus oxychloride or p-toluenesulfonyl chloride.

[0038] The water used as the anti-solvent can also be replaced with one or a mixture of two or more of alcohols, ketones, esters, ethers, aromatic hydrocarbons, and alkane solvents.

[0039] Comparative Example 1 Microcrystalline cellulose was dispersed in 91 g of DMAc, and the mixture was vigorously stirred at 110 °C for 1 h to obtain an activated cellulose suspension. After the suspension was cooled, it was filtered and washed with deionized water and dried to obtain activated cellulose.

[0040] The activated cellulose was dispersed in a 9 wt% LiCl / DMAc solution, and the mixture was vigorously stirred at 125 °C for 2.5 h, and then stirred at room temperature (25 °C) for 12 h to obtain a solution. The solution was centrifuged at 11000 r / min for 20 min to separate the insoluble components to obtain a 1.5 wt% cellulose solution in the upper layer. The cellulose solution was taken in a 100 mL tall beaker, and the solution was stirred with a magnetic stirrer at a rotation speed of 300 r / min. At the same time, deionized water was dropped into the solution along the wall of the beaker at a dripping rate of 5 mL / min using a peristaltic pump, and a total of 60 mL was dropped to regenerate and precipitate the cellulose to obtain a suspension of spherical nanocellulose; the precipitate was centrifuged and separated at parameters of 11000 r / min and 8 min, and the precipitate was washed with deionized water until LiCl / DMAc was removed, and then dried to obtain nanocellulose.

[0041] Compared with Example 5, this comparative example only removed the step of modifying the cellulose solution with thionyl chloride. Figure 6 This is the scanning electron microscope image of the nanocellulose prepared in this comparative example. It can be seen from the figure that the white particle part is spherical nanocellulose, and there are also some cellulose with morphologies such as sheets and blocks, indicating that there are various morphologies of the regenerated cellulose in Comparative Example 1, and the size of the particulate cellulose is much smaller than that of the pomegranate-shaped nanocellulose. This shows that after hydrophobic modification of cellulose, hydrophobic functional groups are introduced onto the cellulose, weakening the strong hydrogen bond interaction within and between cellulose molecules. Then, an anti-solvent is added to enable the hydrophobic cellulose to self-assemble into primary particles through van der Waals forces. The high surface energy of the primary particles prompts them to aggregate to reduce the total energy, grow in size, and change in morphology, ultimately assembling into amorphous pomegranate-shaped nanocellulose, and only producing a product with the morphology of amorphous pomegranate-shaped nanocellulose.

[0042] The above are only the preferred embodiments of the present invention and do not impose any limitation on the present invention. Any simple modification, change, and equivalent change made to the above embodiments according to the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing amorphous pomegranate-shaped nanocellulose, characterized in that: The method is: First, a cellulose-containing raw material is dissolved in a specific solvent to form a cellulose solution with a concentration of 0.001 wt%-15 wt%, and then a hydrophobic modifier is added to the cellulose solution to hydrophobically modify the dissolved cellulose to obtain a hydrophobic cellulose solution, and then the hydrophobic cellulose solution is mixed and diffused with an antisolvent to precipitate the hydrophobically modified cellulose, thereby obtaining a suspension of amorphous pomegranate-shaped nanocellulose; The suspension of the amorphous pomegranate-shaped nanocellulose is washed with an anti-solvent or dialyzed to completely remove the specific solvent and the hydrophobic modifier that dissolve the cellulose, and dried to obtain the amorphous pomegranate-shaped nanocellulose; The specific solvent is a solvent that can dissolve cellulose; The hydrophobic modifier is a modifier that can introduce hydrophobic chlorine-containing functional groups into the cellulose structure; The antisolvent is a solvent that does not dissolve cellulose but is miscible with the specific solvent; The concentration of the hydrophobic cellulose solution is 0.001 wt%-15 wt%.

2. The method for preparing amorphous pomegranate-shaped nanocellulose according to claim 1, characterized in that: Before adding the hydrophobic modifier, the cellulose solution is subjected to a centrifugal purification treatment at 5000 r / min, the supernatant is taken as the purified cellulose solution, and then the hydrophobic modifier is added to hydrophobically modify the dissolved cellulose.

3. A method for preparing amorphous pomegranate-shaped nanocellulose according to claim 1 or 2, characterized in that: The specific solvent is one or a mixture of two or more of 1-butyl-3-methylimidazole chloride, 1-allyl-3-methylimidazole chloride, LiCl / N,N-dimethylacetamide / water, LiBr / DMAc, sodium hydroxide / urea / water, sodium hydroxide / thiourea / water and sodium hydroxide / thiourea / urea / water.

4. A method for preparing amorphous pomegranate-shaped nanocellulose according to claim 1 or 2, characterized in that: The hydrophobic modifier is a chlorinated modifier.

5. The method for preparing amorphous pomegranate-shaped nanocellulose according to claim 4, characterized in that: The hydrophobic modifier is thionyl chloride, phosphorus oxychloride or p-toluenesulfonyl chloride.

6. The method for preparing amorphous pomegranate-shaped nanocellulose according to claim 1 or 2, characterized in that: The antisolvent is one or a mixture of two or more of water, alcohols, ketones, esters, ethers, aromatic hydrocarbons, and alkane solvents.

7. A method for preparing amorphous pomegranate-shaped nanocellulose according to claim 1 or 2, characterized in that: The mixed diffusion is direct addition of anti-solvent and stirring diffusion or dialysis diffusion.

8. The method for preparing amorphous pomegranate-shaped nanocellulose according to claim 1 or 2, characterized in that: During the mixed diffusion, stirring and heating methods can be adopted to enhance the mixing efficiency.

9. The method for preparing amorphous pomegranate-shaped nanocellulose according to claim 1 or 2, characterized in that: The obtained amorphous pomegranate-like nanocellulose is used as a cellulose-containing raw material, which is dissolved again in a specific solvent to form a hydrophobic cellulose solution with a concentration of 0.001 wt%-15 wt%, and then the hydrophobic cellulose solution is mixed and diffused with an antisolvent to precipitate hydrophobically modified cellulose, thereby obtaining a suspension of amorphous pomegranate-like nanocellulose. The suspension of amorphous pomegranate-like nanocellulose is washed with an antisolvent or dialyzed to completely remove the solvent that dissolves the cellulose and the hydrophobic modifier, and amorphous pomegranate-like nanocellulose can be obtained after drying.

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