Cellulose high-strength hydrogel material and preparation method thereof

Abstract

The invention discloses cellulose high-strength hydrogel and a preparation method thereof. According to the hydrogel, a cellulose material is taken as a raw material, and a multi-stage network structure formed by dissolved and regenerated nanofibers and micron fibers is spontaneously and tightly stacked by regulating and controlling cellulose regeneration environment conditions, so that the tensile strength and the compression strength of the hydrogel are remarkably improved. The preparation method comprises the following steps: dissolving a cellulose material in a green solvent system, injecting into a mold, pre-crosslinking in a high-temperature and low-humidity environment, and washing and regenerating to obtain the cellulose high-strength hydrogel. The prepared hydrogel has excellent mechanical properties and chemical stability, meanwhile, the raw materials are cheap and easy to obtain, exogenous chemical substances do not need to be added, and the hydrogel has good biocompatibility and environmental friendliness. The method is easy for large-scale production, and has wide application potential in the fields of biomedicine, environmental engineering, flexible electronic devices and the like.

Description

Technical Field

[0001] The invention belongs to the field of cellulose materials, and particularly relates to a cellulose high-strength hydrogel material and a preparation method thereof. Background Art

[0002] As a polymer material with a three-dimensional network structure, hydrogel has shown broad application prospects in the fields of biomedicine and environmental engineering due to its high water absorption, biocompatibility and adjustable physical and chemical properties. Traditional hydrogels such as polyacrylamide generally have the problem of insufficient mechanical properties and are prone to structural collapse under mechanical loads such as tension and compression, which seriously limits their application in complex working conditions. In order to improve the mechanical strength, existing technologies mostly use the introduction of synthetic polymers (such as polyurethane), inorganic nanofillers (such as clay, SiO 2 ), but these methods often rely on chemical cross-linking agents or complex modification steps, resulting in reduced biodegradability of materials, increased costs, and the possible introduction of potentially toxic substances.

[0003] In recent years, hydrogels based on natural cellulose have attracted much attention due to their renewability and environmental friendliness. As the most abundant biomass resource in nature, cellulose has abundant hydroxyl groups between its molecular chains that can form a physical cross-linked network through hydrogen bonding, and has the potential to construct high-strength hydrogels. However, the mechanical properties of existing cellulose hydrogels are still difficult to meet actual needs. The main reason is that its network structure is loose and the interfacial bonding force between micron-sized fibers is weak. For example, the cellulose hydrogel disclosed in CN119019714A is prepared by dissolution in an alkaline solution system, emulsification treatment and ethanol vapor regeneration. Although the use of chemical cross-linking agents is avoided, the processing process is complicated and its tensile strength is generally lower than 1MPa; CN115819799A adopts a strategy of partially dissolving longitudinally arranged hemp fibers. Although the process flow is simplified, the improvement of mechanical properties is limited, and the skeleton formed by the fiber arrangement also sacrifices the tensile ability of the hydrogel and reduces its toughness. In addition, some studies have introduced ionic cross-linking (such as Ca 2+ ) enhances the mechanical properties, but sacrifices the all-natural properties of the material and may affect its biocompatibility. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a cellulose high-strength hydrogel material with excellent mechanical strength, so as to solve the problems of low mechanical strength and poor structural stability of existing cellulose hydrogel materials; another purpose of the present invention is to provide a method for preparing the cellulose high-strength hydrogel material, which does not require exogenous additives and has a simple preparation process.

[0005] Technical solution: The high-strength cellulose hydrogel material of the present invention is composed of cellulose, and its structure is a micro-nano fiber multi-level network structure, with cross-linking densification between its own micro-fibers and regenerated nano-fibers.

[0006] Preferably, the high-strength cellulose hydrogel is isotropic, with a tensile strength of 2.10 - 28.05 MPa, an elongation at break of 72.75 - 204.0%; a compressive strength of 42.38 - 83.21 MPa, a compressive strain of 78.50 - 90.09%, and the water content of the hydrogel is 67.0% - 86.0%.

[0007] The preparation method of the high-strength cellulose hydrogel of the present invention includes the following steps:

[0008] (1) Dissolve the cellulose material in a cellulose solvent system;

[0009] (2) Cross-link and shape it in an environment with a temperature of 25°C - 150°C and a humidity less than or equal to 40%;

[0010] (3) After washing the formed sample with water, the high-strength cellulose hydrogel is obtained.

[0011] Further preferably, the cellulose material is pulverized before being dissolved in step (1).

[0012] Preferably, the cellulose material in step (1) is natural cellulose or cellulose containing plant fibers obtained by post-processing.

[0013] Preferably, the natural cellulose includes wood fiber, cotton fiber, bamboo fiber, and hemp fiber; the cellulose containing plant fibers obtained by post-processing includes paper, cellulose powder, and wood powder.

[0014] Preferably, the mass fraction of the cellulose material in the system in step (1) is 1.5% - 12%.

[0015] Preferably, the cellulose solvent system in step (1) is at least one of a lithium chloride / N,N-dimethylacetamide solution, an alkali / urea mixed solution, an N-methylmorpholine-N-oxide solution, and an ionic solution.

[0016] Preferably, a mold is used in the shaping process of step (2).

[0017] Further preferably, the mold includes various required shapes, including cylindrical, cubic, strip-shaped, and sheet-shaped.

[0018] Further preferably, the mold material includes glass, stainless steel, or engineering plastic.

[0019] Preferably, the cross-linking and shaping time in step (2) is not less than 2 h.

[0020] Further preferably, the environment described in step (2) is an oven.

[0021] Preferably, after obtaining the cellulose high-strength hydrogel in step (3), it is immersed and stored in an aqueous solution.

[0022] Further preferably, the aqueous solution required for soaking contains alcohols, and the mass percentage concentration range is 1% - 20%.

[0023] Further preferably, the alcohols include ethanol and isopropanol.

[0024] The present invention is a regenerated cellulose hydrogel material with high strength prepared by dissolving a cellulose material in a cellulose green solvent system and then inducing molding under specific environmental conditions. By innovatively regulating the microenvironmental conditions during cellulose regeneration, the present invention realizes the in-situ tight cross-linking of nano-scale regenerated fibers and original micro-fibers, constructs a cellulose network with a micro-nano multi-level structure, and significantly improves its mechanical properties while maintaining the environmental friendliness of the material.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: By introducing a pre-gelatinization step under specific environmental conditions, the cellulose high-strength hydrogel material prepared in the present invention enables the cellulose regeneration process to efficiently and spontaneously form a tight and uniform multi-level network structure, significantly improving the mechanical properties such as the tensile and compressive strengths of the hydrogel. The tensile stress is increased to 2.10 - 28.05 MPa, and compared with ordinary regenerated cellulose hydrogels, the strength is increased by 2.2 - 30 times; the compressive stress is increased to 42.38 - 83.21 Mpa, and compared with ordinary regenerated cellulose hydrogels, the strength is increased by 2.4 - 4.7 times, enabling it to meet the requirements of high-strength application scenarios. Secondly, the hydrogel uses cellulose as a raw material and does not require the addition of exogenous chemical substances. It not only has good chemical stability but also excellent biocompatibility, and can be safely applied in the biomedical field, such as tissue engineering and drug delivery. In addition, the green solvent system used in the preparation process of the present invention avoids the use of toxic chemical substances, conforming to the concepts of green chemistry and sustainable development. In summary, the present invention not only provides a cellulose hydrogel with high mechanical properties but also provides a green, economical and easy-to-scale-up preparation method, having important scientific significance and practical value. Description of the Drawings

[0026] Figure 1 It is a physical diagram of the prepared cellulose high-strength hydrogel material; A is a physical diagram of the cellulose high-strength hydrogel material prepared in Example 1; B is a physical diagram of the cellulose high-strength hydrogel material prepared in Example 2.

[0027] Figure 2Scanning electron microscope image of the liquid nitrogen brittle fracture cross-section of the cellulose high-strength hydrogel film material prepared in Example 1;

[0028] Figure 3 Scanning electron microscope image of the cross-section of the cellulose high-strength hydrogel film material prepared in Example 1 after stretching;

[0029] Figure 4 Tensile mechanical property curve graph of the hydrogel film materials prepared in Example 1 and Comparative Example 1;

[0030] Figure 5 Compressive mechanical property curve graph of the hydrogel bulk materials prepared in Example 2 and Comparative Example 2. Detailed implementation mode

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0032] Example 1

[0033] The preparation method of the cellulose high-strength hydrogel material in Example 1 is as follows:

[0034] (1) Soak 14.58 g of dry cotton fibers in 350 g of DMAc solution, place them in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0035] (2) Take it out and let it stand for 7 days to obtain a transparent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet-shaped polypropylene mold, and place it in a 60 °C oven and expose it to hot air for shaping;

[0036] (3) Take it out after 5 days, wash it with water, and soak it in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0037] The obtained cellulose high-strength hydrogel film is as shown in Figure 1 A. The thickness of the hydrogel film is 170 μm, the tensile strength reaches 28.05 MPa, the tensile strain is 90.52%, and the water content is 71.7%. See the tensile stress-strain curve graph of the hydrogel film in Figure 4 , compared with the ordinary cellulose hydrogel film in Comparative Example 1, the strength is increased by about 30 times.

[0038] Figure 2 Scanning electron microscope image of the liquid nitrogen brittle fracture cross-section of the cellulose high-strength hydrogel material prepared in Example 1 and the enlarged detail image, and the internal fibers show a closely stacked state; Figure 3 Scanning electron microscope image of its cross-section after stretching, the micron fibers are tightly connected to the regenerated nanofiber matrix, which not only greatly improves the cross-linking density, but also makes the micron fibers wrap in the matrix to form a network skeleton, significantly improving the tensile strength of the hydrogel.

[0039] Example 2

[0040] (1) Soak 14.58 g of dry cotton fibers in 350 g of DMAc solution, place them in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0041] (2) Take out and let stand for 7 days to obtain a transparent liquid gel sample, pour it into a 5 cm × 3 cm × 3 cm rectangular polypropylene mold, and place it in a 60 °C oven and expose it to hot air for shaping;

[0042] (3) Take out after 48 h, wash with water, and soak in an aqueous solution to obtain a cellulose high-strength hydrogel block.

[0043] The obtained cellulose high-strength hydrogel block is shown in Figure 1 Figure B. Its compressive strength reaches 83.21 MPa, the compressive strain is 90.09%, and the water content is 84.5%. See the compressive stress-strain curve diagram of the hydrogel block in Figure 5 , compared with the ordinary cellulose hydrogel block prepared in Comparative Example 2, the compressive strength is increased by about 4.7 times.

[0044] Example 3

[0045] (1) Soak 14.58 g of dry cotton fibers in 350 g of DMAc solution, place them in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0046] (2) Take out and let stand for 24 h to obtain a semi-transparent liquid gel sample, take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet-shaped polypropylene mold, and place it in a 60 °C oven and expose it to hot air for shaping;

[0047] (3) Take out after 12 h, wash with water, and soak in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0048] The obtained cellulose high-strength hydrogel film has a thickness of 380 μm, a tensile strength of 14.72 MPa, a tensile strain of 125.6%, and a water content of 78.3%.

[0049] Example 4

[0050] (1) Soak 14.58 g of dry cotton fibers in 350 g of DMAc solution, that is, the raw material mass fraction is 4%, place them in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0051] (2) Take it out and let it stand for 60 h to obtain a translucent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet glass mold, and place it in an oven at 60 °C and expose it to hot air for shaping;

[0052] (3) Take it out after 24 h, wash it with water, and soak it in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0053] The obtained cellulose high-strength hydrogel film has a thickness of 250 μm, a tensile strength of 21.21 MPa, a tensile strain of 189.9%, and a water content of 76.7%.

[0054] Example 5

[0055] (1) Immerse 14.58 g of dry cotton fibers in 350 g of DMAc solution, place it in an environment at 165 °C for full activation for 1 h, cool it down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0056] (2) Take it out and let it stand for 7 days to obtain a transparent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet polypropylene mold, and place it in an oven at 60 °C and expose it to hot air for shaping;

[0057] (3) Take it out after 7 days, wash it with water, and soak it in a 5% mass fraction ethanol aqueous solution to obtain a cellulose high-strength hydrogel material.

[0058] The obtained cellulose high-strength hydrogel film has a thickness of 144 μm, a tensile strength of 26.26 MPa, a tensile strain of 72.75%, and a water content of 67.0%.

[0059] Example 6

[0060] (1) Immerse 14.58 g of dry cotton fibers in 350 g of DMAc solution, place it in an environment at 165 °C for full activation for 1 h, cool it down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0061] (2) Take it out and let it stand for 7 days to obtain a translucent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet glass mold, and place it in an oven at 25 °C for shaping;

[0062] (3) Take it out after 2 h, wash it with water, and soak it in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0063] The obtained cellulose high-strength hydrogel film has a thickness of 1050 μm, a tensile strength of 2.17 MPa, a tensile strain of 204.0%, and a water content of 86.0%.

[0064] Example 7

[0065] (1) Soak 14.58 g of dry cotton fibers in 350 g of DMAc solution, place them in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0066] (2) Take it out and let it stand for 7 days to obtain a transparent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet glass mold, and place it in an oven at 150 °C and expose it to hot air for shaping;

[0067] (3) Take it out after 2 h, wash it with water, and soak it in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0068] The obtained cellulose high-strength hydrogel film has a thickness of 425 μm, a tensile strength of 4.46 MPa, a tensile strain of 116.5%, and a moisture content of 82.4%.

[0069] Example 8

[0070] (1) Crush 7.14 g of dry wood fibers and soak them in 350 g of DMAc solution, that is, the raw material mass fraction is 2%, place them in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0071] (2) Take it out and let it stand for 24 h to obtain a semi-transparent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet glass mold, and place it in an oven at 60 °C and expose it to hot air for shaping;

[0072] (3) Take it out after 6 h, wash it with water, and soak it in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0073] The obtained cellulose high-strength hydrogel film has a thickness of 340 μm, a tensile strength of 5.16 MPa, a tensile strain of 95.34%, and a moisture content of 81.4%.

[0074] Example 9

[0075] (1) Take 100 g of 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and heat it to 90 °C. Crush 11.1 g of dry bamboo and hemp mixed fibers and soak them in [Bmim]Cl liquid, that is, the raw material mass fraction is 10%, and place them in an environment of 90 °C and stir to dissolve fully for 4 h;

[0076] (2) Obtain a semi-transparent liquid sample. Take 36 g and pour it into a 20 cm × 20 cm × 1 cm layered glass mold, and place it in an oven at 60 °C and expose it to hot air for shaping;

[0077] (3) Take it out after 24 h, wash it with water, and soak it in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0078] The thickness of the obtained cellulose high-strength hydrogel film is 212 μm, the tensile strength reaches 7.65 MPa, the tensile strain is 86.9%, and the water content is 81.0%.

[0079] Example 10

[0080] (1) Soak 38.89 g of dry wood powder in 350 g of DMAc solution, that is, the raw material mass fraction is 10%, place it in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0081] (2) Take it out and let it stand for 60 h to obtain a semi-transparent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet glass mold, and place it in an 80 °C oven and expose it to hot air for shaping;

[0082] (3) Take it out after 4 h, wash it with water, and soak it in an ethanol aqueous solution with a mass fraction of 5% to obtain a cellulose high-strength hydrogel material.

[0083] The thickness of the obtained cellulose high-strength hydrogel film is 770 μm, the tensile strength reaches 6.79 MPa, the tensile strain is 118.6%, and the water content is 81.7%.

[0084] Example 11

[0085] (1) Soak 14.58 g of dry cotton fibers in 350 g of DMAc solution, place it in an environment of 165 °C for full activation for 1 h, cool down to 105 °C, and add 35 g of LiCl and stir to dissolve for 3 h;

[0086] (2) Take it out and let it stand for 60 h to obtain a semi-transparent liquid gel sample. Take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet polypropylene mold, and place it in a 60 °C oven and expose it to hot air for shaping;

[0087] (3) Take it out after 2 h, wash it with water, and soak it in an aqueous solution to obtain a cellulose high-strength hydrogel material.

[0088] The thickness of the obtained cellulose high-strength hydrogel film is 890 μm, the tensile strength reaches 3.86 MPa, the tensile strain is 161.7%, and the water content is 85.7%.

[0089] Example 12:

[0090] (1) Soak 9.28 g of dry cellulose powder in 300 g of NaOH / urea aqueous solution pre-cooled at -12 °C for 2 h, that is, the raw material mass fraction is 3%, and place it in an environment of -12 °C and stir to dissolve for 4 h;

[0091] (2) Obtain a translucent liquid sample, take 70 g and pour it into a cubic polypropylene mold with dimensions of 10 cm × 10 cm × 3 cm, and place it in an oven at 60 °C to be shaped by exposure to hot air;

[0092] (3) After 24 h, take it out, wash it with water, and soak it in an aqueous isopropanol solution with a mass fraction of 10% to obtain a cellulose high-strength hydrogel material.

[0093] The obtained cellulose high-strength hydrogel block has a compressive strength of 42.38 MPa, a compressive strain of 78.50%, and a water content of 78.2%.

[0094] Examples 13 - 19

[0095] The preparation methods of Examples 13 - 19 are as follows:

[0096] (1) Dissolve the cellulose material in a cellulose solvent system;

[0097] (2) Crosslink and shape at a certain temperature and humidity;

[0098] (3) After washing the shaped sample with water, a cellulose high-strength hydrogel is obtained.

[0099] Among them, the specific cellulose material, cellulose solvent system, mass fraction of the cellulose material in the system, crosslinking and shaping temperature, crosslinking and shaping humidity, and crosslinking and shaping time are shown in the following table:

[0100]

[0101] Comparative Example 1

[0102] The rest are the same as in Example 1, except that:

[0103] After the sample stands for 60 h, take 36 g and evenly coat it on the surface of a 20 cm × 20 cm sheet glass mold, without any treatment, and directly immerse it in water for regeneration to obtain a hydrogel film.

[0104] The obtained hydrogel film has a thickness of 1150 μm, a tensile strength of 0.96 MPa, a tensile strain of 64.11%, and a water content of 89.2%. For the tensile stress-strain curve of the hydrogel film, see Figure 4 .

[0105] Comparative Example 2

[0106] The rest are the same as in Example 2, except that:

[0107] After the sample stands for 7 days, pour it into a cuboid polypropylene mold with dimensions of 5 cm × 3 cm × 3 cm, without any treatment, and directly immerse it in water for regeneration to obtain a hydrogel block.

[0108] The compressive strength of the obtained hydrogel block reaches 17.62 MPa, the compressive strain is 74.71%, and the water content is 86.7%. See the tensile stress-strain curve of the hydrogel block in Figure 5 .

[0109] Comparative Examples 3-6

[0110] The preparation methods of Comparative Examples 3-6 are the same as those of Example 13 in other respects, except for whether to wash with water, different temperatures or different humidities. The specific preparation method is as follows:

[0111] (1) Dissolve the cellulose material in the cellulose solvent system;

[0112] (2) Crosslink and shape at a certain temperature and humidity;

[0113] (3) After the formed sample is washed or not washed with water, a cellulose hydrogel is obtained.

[0114] Among them, the specific cellulose material, cellulose solvent system, mass fraction of cellulose material in the system, crosslinking and shaping temperature, crosslinking and shaping humidity, crosslinking and shaping time, and whether it is washed with water are shown in the following table:

[0115]

[0116] It can be seen that by comparing Example 13 and Comparative Example 3, it can be seen that if not washed with water, although the hydrogel formed by pre-gelation initially forms a tight cross-linked network structure, the complete regeneration process has not been achieved, resulting in the existence of liquid gel regions inside the cross-linked network, with many defects, a significant decrease in tensile stress, and the residual solvent inside the hydrogel also has an adverse effect on its mechanical properties; by comparing Example 13 and Comparative Examples 4-5, it can be seen that if the temperature is not in the range of 25°C - 150°C, the formed structure will be relatively loose or too dense due to the too slow or too rapid cross-linking process. The internal pores and other defects of the loose structure increase, and the overly dense structure is not conducive to the deformation of the hydrogel, both of which result in a decrease in the tensile strength of the obtained hydrogel; by comparing Example 13 and Comparative Example 6, it can be seen that if the humidity does not meet the requirement of being less than or equal to 40%, the high humidity environment has no significant effect on the solvent volatilization and cellulose regeneration process during pre-gelation, resulting in no obvious improvement in the mechanical properties of the hydrogel.

Claims

1. A high-strength cellulose hydrogel, characterized in that: The material is composed of cellulose and has a multi-level network structure of micro-nano fibers. The cross-linking and densification between the micron fibers themselves and the regenerated nano fibers is achieved.

2. The high-strength cellulose hydrogel according to claim 1, characterized in that: The high-strength cellulose hydrogel is isotropic, has a tensile strength of 2.10-28.05 MPa, an elongation at break of 72.75-204.0%, a compressive strength of 42.38-83.21 MPa, a compressive strain of 78.50-90.09%, and a water content of 67.0%-86.0%.

3. A method for preparing the high-strength cellulose hydrogel according to claim 1, characterized in that: The steps include: (1) dissolving a cellulose material in a cellulose solvent system; (2) Crosslinking and setting at a temperature of 25°C to 150°C and a humidity of 40% or less; (3) After the molded sample is washed with water, a high-strength cellulose hydrogel is obtained.

4. The method for preparing the high-strength cellulose hydrogel according to claim 3, characterized in that: The cellulose material in step (1) is natural cellulose or cellulose containing plant fibers obtained by post-processing.

5. The method for preparing the high-strength cellulose hydrogel according to claim 4, characterized in that: The natural cellulose includes wood fiber, cotton fiber, bamboo fiber, and hemp fiber; the cellulose containing plant fiber obtained by post-processing includes paper, cellulose powder, and wood powder.

6. The method for preparing the high-strength cellulose hydrogel according to claim 3, characterized in that: In step (1), the mass fraction of the cellulose material in the system is 1.5%-12%.

7. The method for preparing the high-strength cellulose hydrogel according to claim 3, characterized in that: In step (1), the cellulose solvent system is at least one of lithium chloride / NN dimethylacetamide solution, alkali / urea mixed solution, N-methylmorpholine-N-oxide solution, and ion solution.

8. The method for preparing the high-strength cellulose hydrogel according to claim 3, characterized in that: The shaping process in step (2) uses a mold.

9. The method for preparing the high-strength cellulose hydrogel according to claim 3, characterized in that: The cross-linking and shaping time in step (2) is not less than 2 hours.

10. The method for preparing the high-strength cellulose hydrogel according to claim 3, characterized in that: The high-strength cellulose hydrogel obtained in step (3) is then immersed in an aqueous solution for storage.

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