A superabsorbent hydrogel and a method for preparing the same

Abstract

The present application relates to the technical field of water-absorbing gel processing, and particularly relates to a high water-absorbing gel and a preparation method thereof, wherein the high water-absorbing gel comprises vegetable oil, a dispersing agent, 2-acryloyl butyl sulfonic acid, polyacrylamide, porous particles, a composite porous framework material, glycerol, sodium hydroxide, potassium persulfate, a crosslinking agent, sorbitol, sodium carbonate and water. In the present application, the porous particles and the composite porous framework material are introduced into the water-absorbing gel. The porous particles have good toughness, and their volume can expand and contract, thereby having greater water storage capacity, good water-absorbing capacity and water-absorbing amount. The composite porous framework material has sufficient water storage space, and can also limit the fixation of absorbed water, thereby inhibiting water loss, so that the surface of the high water-absorbing gel remains dry, and the growth of surface bacteria is avoided, thereby being more safe, sanitary and environmentally friendly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-absorbing hydrogel, in particular to a high water-absorbing hydrogel and a preparation method thereof. BACKGROUND

[0002] A hydrogel is a polymer material containing hydrophilic groups such as carboxyl, hydroxyl, amide and sulfonic acid in its structure, which can usually absorb water several times its own weight, and the water absorption capacity depends on the strength of the hydrogen bond formed between the hydrophilic groups and water molecules. Compared with traditional natural water-absorbing materials, the water-absorbing hydrogel has a three-dimensional network structure formed by physical crosslinking or chemical crosslinking, and exhibits good water retention performance. The hydrogen bond adsorption between the hydrophilic groups on the molecular chain and the water molecules has a much stronger force than the van der Waals force between the water molecules, and the water is not easy to lose at normal temperature and pressure. Therefore, it has a wide application prospect in the fields of medical treatment, agriculture, forestry, food, environmental protection and construction.

[0003] For example, the patent for invention with the announcement number CN106432611A discloses a chitosan quaternary ammonium salt grafted poly(acrylic acid-co-acrylamide) super water-absorbing hydrogel as well as a preparation method and application thereof. The super water-absorbing hydrogel is prepared by grafting copolymerization and crosslinking reaction under the action of an initiator and a crosslinking agent, using chitosan quaternary ammonium salt, acrylic acid and acrylamide as raw materials. The amount of chitosan quaternary ammonium salt is 6.5% to 75% of the total mass of acrylic acid and acrylamide; the amount of acrylamide is 10% to 70% of the total mass of acrylic acid and acrylamide. The chitosan quaternary ammonium salt grafted poly(acrylic acid-co-acrylamide) super water-absorbing hydrogel has excellent water absorption, salt water absorption, mechanical and antibacterial properties. However, although the acrylic acid in the water-absorbing hydrogel has good water absorption effect, the acidity is not easy to control, and when used in medical and health products such as breathing machines, it has great irritation to the human body. Moreover, after the water-absorbing hydrogel absorbs water, the absorbed water is easy to flow out of the hydrogel under the influence of the outside world, resulting in long-term moisture on the surface of the hydrogel, which is easy to breed bacteria, thereby being not conducive to the safe use of medical and health products. SUMMARY

[0004] In view of the problems existing in the prior art, the present application aims to provide a high water-absorbing hydrogel and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0006] A superabsorbent gel, comprising the following components by weight: 300-500 parts vegetable oil, 5-10 parts dispersant, 10-15 parts 2-acryloyloxybutylsulfonic acid, 50-80 parts polyacrylamide, 15-25 parts porous particles, 5-10 parts composite porous framework material, 20-26 parts glycerol, 1-3 parts sodium hydroxide, 0.1-0.6 parts potassium persulfate, 0.03-0.08 parts crosslinking agent, 0.1-0.5 parts sorbitol, 0.3-0.8 parts sodium carbonate, and 80-120 parts water.

[0007] As a further preferred embodiment of the present invention, the vegetable oil is at least one of castor oil, flaxseed oil, and sunflower seed oil;

[0008] The dispersant is either polyglycerol monostearate or polyglycerol monostearate;

[0009] The crosslinking agent is at least one of allyl methacrylate, ethylene glycol dimethacrylate, and ethylene glycol diacrylate.

[0010] As a further preferred embodiment of the present invention, the method for preparing the porous particles is as follows:

[0011] 1) Dissolve konjac glucomannan and ferrous sulfate in deionized water, then add an aqueous solution of disodium ethylenediaminetetraacetate (EDTA), and control the molar ratio of EDTA to ferrous sulfate to be (0.03-0.08):1. Prepare an aqueous solution of 40-50 wt% ammonia, slowly add it dropwise to the above solution while stirring vigorously until the pH value is 8.0-8.5. Continue stirring for 1-2 hours and then let it stand for 2-5 hours to age, thus obtaining a mixed solution.

[0012] 2) Add carbon fiber to the mixed solution, disperse it evenly, then add sodium carbonate, stir thoroughly, and let it stand at room temperature for 30-50 minutes. Then heat it to 80-85℃ and keep it at that temperature for 40-70 minutes. Then place it at 3-6℃ and let it stand overnight. Then soak it in hydrochloric acid solution for 2-3 days, then soak it in ultrapure water for 1-2 days. After freeze drying, pulverize and grind it to obtain porous particles.

[0013] As a further preferred embodiment of the present invention, in step 1), the ratio of the amount of konjac glucomannan, ferrous sulfate and deionized water is (1-3) g: (2-6) g: (60-100) mL;

[0014] The concentration of the aqueous solution of disodium ethylenediaminetetraacetate is 0.1–0.3 mol / L.

[0015] As a further preferred embodiment of the present invention, in step 2), the ratio of the mixed solution, carbon fiber, and sodium carbonate is (50-80) mL: (1-3) g: (5-8) g;

[0016] The concentration of the hydrochloric acid solution is 0.1–0.2 mol / L.

[0017] As a further preferred embodiment of the present invention, the method for preparing the composite porous framework material is as follows:

[0018] 1) Add polyvinyl alcohol to deionized water, place it in an oil bath under magnetic stirring, heat and stir until the polyvinyl alcohol is completely dissolved, let it stand to room temperature, freeze it in a -4 to -10℃ refrigerator for 12 to 15 hours, and then freeze-dry it for 24 to 30 hours to obtain a porous polyvinyl alcohol framework.

[0019] 2) Boron elemental powder was completely dispersed in a 70-75 wt% ethanol solution under stirring. Then, polyether P123 was added and mixed well. Acetic acid and hydrogen peroxide were then added and stirred thoroughly to obtain a mixture. The mixture was then transferred to an ice-water bath and ultrasonically exfoliated with a probe at 500-600 W for 3-5 h, and ultrasonically exfoliated with a water bath at 200-260 W for 1-3 h. After centrifugation at 3000-5000 r / min for 10-20 min, the supernatant was centrifuged at 12000-18000 r / min for 30-50 min. The obtained product was dried to obtain boron nanosheets.

[0020] 3) Add boron nanosheets to an ethanol solution with a concentration of 75-80wt%, and disperse them evenly by ultrasonication to obtain a suspension. Place the polyvinyl alcohol porous framework in the suspension, evacuate to 10-80Pa and maintain for 20-50min, then connect to the atmosphere for 10-20min. Repeat the operation 3-6 times. After centrifuging the product, wash it repeatedly with deionized water and dry it to obtain the composite porous framework material.

[0021] As a further preferred embodiment of the present invention, in step 1), the ratio of polyvinyl alcohol to deionized water is (3-6) g: (100-130) mL;

[0022] The temperature of the oil bath is 110–120°C.

[0023] As a further preferred embodiment of the present invention, in step 2), the ratio of boron elemental powder, ethanol solution, polyether P123, acetic acid, and hydrogen peroxide is (100-300) mg: (100-300) mL: (500-600) mg: (380-400) mg: (3-5) mL;

[0024] The concentration of hydrogen peroxide is 30–32 wt%.

[0025] As a further preferred embodiment of the present invention, in step 3), the ratio of boron nanosheets, ethanol solution and polyvinyl alcohol porous framework is (300-500) mg: (100-150) mL: (2-6) g.

[0026] A method for preparing a superabsorbent gel specifically includes the following steps:

[0027] 1) In a reactor equipped with a condenser and a stirring device, add vegetable oil and dispersant, heat to 50-75°C, mix well, and then add porous particles to obtain material A. Then dissolve 2-acryloyloxybutylsulfonic acid in water equivalent to 70-80% of the total amount, add sodium hydroxide and polyacrylamide to obtain material B.

[0028] 2) Dissolve the crosslinking agent, potassium persulfate, and sorbitol in the remaining water to obtain material C;

[0029] 3) Add materials B and C to material A in sequence, then add the composite porous framework material, mix and stir thoroughly, and react for 1-3 hours. During the reaction, add glycerol and sodium carbonate dropwise. Filter the obtained product to remove the vegetable oil, wash repeatedly with ethanol, and dry until the water content is 10-20%.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] In this invention, a porous polyvinyl alcohol framework with a porous structure is prepared by freeze-drying technology. Then, boron is treated by ultrasonic-assisted liquid-phase exfoliation to obtain boron nanosheets. These boron nanosheets are then adsorbed into the porous polyvinyl alcohol framework using a vacuum impregnation method, resulting in a composite porous framework material. This composite porous framework material possesses a porous structure that allows for rapid water absorption under capillary action, and the ample porous space provides sufficient storage for the adsorbed water. Furthermore, the boron nanosheets adsorbed within the framework form a multi-layered structure through stacking and intercalation, effectively increasing the... The roughness of the framework wall increases the frictional resistance between water and the framework wall, making water flow difficult. At the same time, some boron nanosheets will accumulate on the pore walls of the composite porous framework material, reducing the pore size. When water enters the interior of the composite porous framework material along the pore walls, it will agglomerate in the large space inside to form large water droplets. At this time, because the pore size of the pore walls is small, the large water droplets inside cannot flow out along the pore walls, thus confining the large water droplets and making it difficult for the adsorbed water to be lost. This helps to keep the surface of the hydrogel dry and avoids the growth of surface bacteria.

[0032] To improve the water absorption capacity and amount of water absorbed by the hydrogel, this invention uses konjac glucomannan as a raw material, and in situ loads ferric hydroxide into the network structure of the konjac glucomannan gel. At the same time, pore-forming treatment is performed, and carbon fibers with good toughness are introduced to form porous particles with an interconnected three-dimensional porous network structure. The introduced carbon fibers are cross-linked with the network structure, which not only helps to increase the stability of the network structure, but also makes the network structure more tough and can expand and contract better, thus having a greater water storage capacity.

[0033] In this invention, porous particles and composite porous framework materials are introduced into the hydrogel. The porous particles have good toughness and their volume can expand and contract, thus having a greater water storage capacity and excellent water absorption capacity and amount. The composite porous framework material, while having sufficient water storage space, can also play a role in confining and fixing the adsorbed water, inhibiting water loss. This keeps the surface of the superabsorbent gel dry, avoids the growth of surface bacteria, and is therefore safer, more hygienic and environmentally friendly. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In this embodiment of the invention, the vegetable oil is castor oil; the dispersant is polyglycerol monostearate; and the crosslinking agent is allyl methacrylate.

[0036] Example 1

[0037] A superabsorbent gel comprising the following components by weight: 300 parts vegetable oil, 5 parts dispersant, 10 parts 2-acryloyloxybutylsulfonic acid, 50 parts polyacrylamide, 15 parts porous particles, 5 parts composite porous framework material, 20 parts glycerol, 1 part sodium hydroxide, 0.1 part potassium persulfate, 0.03 parts crosslinking agent, 0.1 part sorbitol, 0.3 parts sodium carbonate, and 80 parts water;

[0038] The preparation method of this superabsorbent gel specifically includes the following steps:

[0039] 1) In a reactor equipped with a condenser and a stirring device, add vegetable oil and dispersant, heat to 50°C, mix well, and then add porous particles to obtain material A. Then dissolve 2-acryloyloxybutylsulfonic acid in water equivalent to 70% of the total amount, add sodium hydroxide and polyacrylamide to obtain material B.

[0040] 2) Dissolve the crosslinking agent, potassium persulfate, and sorbitol in the remaining water to obtain material C;

[0041] 3) Add materials B and C to material A in sequence, then add the composite porous framework material, mix thoroughly and stir for 1 hour. During the reaction, add glycerol and sodium carbonate dropwise. Filter the obtained product to remove the vegetable oil, wash repeatedly with ethanol and dry until the water content is 10%.

[0042] The method for preparing porous particles is as follows:

[0043] 1) Dissolve 1g of konjac glucomannan and 2g of ferrous sulfate in 60mL of deionized water, then add a 0.1mol / L aqueous solution of disodium ethylenediaminetetraacetate, and control the molar ratio of disodium ethylenediaminetetraacetate to ferrous sulfate to be 0.03:1. Prepare a 40wt% ammonia solution, slowly add it dropwise to the above solution while stirring vigorously until the pH value is 8.0. Continue stirring for 1h and let it stand for 2h to age, and obtain a mixed solution.

[0044] 2) Add 1g of carbon fiber to 50mL of mixed solution, disperse it evenly, then add 5g of sodium carbonate, stir thoroughly, let stand at room temperature for 30min, then heat to 80℃ and keep warm for 40min, then place at 3℃ and stand overnight, then soak in 0.1mol / L hydrochloric acid solution for 2d, then soak in ultrapure water for 1d, freeze dry and then pulverize and grind to obtain porous particles.

[0045] The preparation method of the composite porous framework material is as follows:

[0046] 1) Add 3g of polyvinyl alcohol to 100mL of deionized water, place it in an oil bath with magnetic stirring, heat and stir at 110℃ until the polyvinyl alcohol is completely dissolved, let it stand to room temperature, freeze it in a -4℃ refrigerator for 12h, and then freeze-dry it for 24h to obtain a porous polyvinyl alcohol framework.

[0047] 2) 100 mg of boron powder was completely dispersed in 100 mL of 70 wt% ethanol solution under stirring. Then, 500 mg of polyether P123 was added and mixed well. Then, 380 mg of acetic acid and 3 mL of 30 wt% hydrogen peroxide were added and stirred thoroughly to obtain a mixture. The mixture was then transferred to an ice-water bath and ultrasonically exfoliated at 500 W for 3 h and ultrasonically exfoliated in a water bath at 200 W for 1 h. After centrifugation at 3000 r / min for 10 min, the supernatant was centrifuged at 12000 r / min for 30 min. The obtained product was dried to obtain boron nanosheets.

[0048] 3) Add 300 mg of boron nanosheets to 100 mL of 75 wt% ethanol solution, and disperse evenly by ultrasonication to obtain a suspension. Place 2 g of polyvinyl alcohol porous framework in the suspension, evacuate to 10 Pa and maintain for 20 min, then connect to the atmosphere for 10 min. Repeat the operation 3 times. After centrifuging the product, wash it repeatedly with deionized water and dry it to obtain the composite porous framework material.

[0049] Example 2

[0050] A superabsorbent gel comprising the following components by weight: 400 parts vegetable oil, 8 parts dispersant, 12 parts 2-acryloyloxybutylsulfonic acid, 70 parts polyacrylamide, 20 parts porous particles, 7 parts composite porous framework material, 23 parts glycerol, 2 parts sodium hydroxide, 0.5 parts potassium persulfate, 0.05 parts crosslinking agent, 0.3 parts sorbitol, 0.5 parts sodium carbonate, and 100 parts water;

[0051] The preparation method of this superabsorbent gel specifically includes the following steps:

[0052] 1) In a reactor equipped with a condenser and a stirring device, add vegetable oil and dispersant, heat to 65°C, mix well, and then add porous particles to obtain material A. Then dissolve 2-acryloyloxybutylsulfonic acid in water equivalent to 75% of the total amount, add sodium hydroxide and polyacrylamide to obtain material B.

[0053] 2) Dissolve the crosslinking agent, potassium persulfate, and sorbitol in the remaining water to obtain material C;

[0054] 3) Add materials B and C to material A in sequence, then add the composite porous framework material, mix thoroughly and stir for 2 hours. During the reaction, add glycerol and sodium carbonate dropwise. Filter the obtained product to remove the vegetable oil, wash repeatedly with ethanol and dry until the water content is 15%.

[0055] The method for preparing porous particles is as follows:

[0056] 1) Dissolve 2g of konjac glucomannan and 5g of ferrous sulfate in 80mL of deionized water, then add a 0.2mol / L aqueous solution of disodium ethylenediaminetetraacetate, and control the molar ratio of disodium ethylenediaminetetraacetate to ferrous sulfate to be 0.05:1. Prepare a 45wt% ammonia solution, slowly add it dropwise to the above solution while stirring vigorously until the pH value is 8.5. Continue stirring for 1.5h and then let it stand for 3h to age, to obtain a mixed solution.

[0057] 2) Add 2g of carbon fiber to 70mL of mixed solution, disperse it evenly, then add 6g of sodium carbonate, stir thoroughly, let stand at room temperature for 40min, then heat to 82℃ and keep warm for 60min, then place at 5℃ and stand overnight, then soak in 0.2mol / L hydrochloric acid solution for 3d, then soak in ultrapure water for 2d, freeze dry and then pulverize and grind to obtain porous particles.

[0058] The preparation method of the composite porous framework material is as follows:

[0059] 1) Add 5g of polyvinyl alcohol to 120mL of deionized water, place it in an oil bath with magnetic stirring, heat and stir at 115℃ until the polyvinyl alcohol is completely dissolved, let it stand to room temperature, freeze it in a -8℃ refrigerator for 13h, and then freeze-dry it for 28h to obtain a porous polyvinyl alcohol framework.

[0060] 2) 200 mg of boron powder was completely dispersed in 200 mL of 72 wt% ethanol solution under stirring. Then, 550 mg of polyether P123 was added and mixed well. Then, 390 mg of acetic acid and 4 mL of 31 wt% hydrogen peroxide were added and stirred thoroughly to obtain a mixture. The mixture was then transferred to an ice-water bath and ultrasonically exfoliated at 550 W for 4 h and ultrasonically exfoliated in a water bath at 230 W for 2 h. After centrifugation at 4000 r / min for 15 min, the supernatant was centrifuged at 16000 r / min for 40 min. The obtained product was dried to obtain boron nanosheets.

[0061] 3) Add 400 mg of boron nanosheets to 130 mL of 78 wt% ethanol solution, and disperse evenly by ultrasonication to obtain a suspension. Place 5 g of polyvinyl alcohol porous framework in the suspension, evacuate to 50 Pa and maintain for 35 min, then connect to the atmosphere for 15 min. Repeat the operation 5 times. After centrifuging the product, wash it repeatedly with deionized water and dry it to obtain the composite porous framework material.

[0062] Example 3

[0063] A superabsorbent gel comprising the following components by weight: 500 parts vegetable oil, 10 parts dispersant, 15 parts 2-acryloyloxybutylsulfonic acid, 80 parts polyacrylamide, 25 parts porous particles, 10 parts composite porous framework material, 26 parts glycerol, 3 parts sodium hydroxide, 0.6 parts potassium persulfate, 0.08 parts crosslinking agent, 0.5 parts sorbitol, 0.8 parts sodium carbonate, and 120 parts water;

[0064] The preparation method of this superabsorbent gel specifically includes the following steps:

[0065] 1) In a reactor equipped with a condenser and a stirring device, add vegetable oil and dispersant, heat to 75°C, mix well, and then add porous particles to obtain material A. Then dissolve 2-acryloyloxybutylsulfonic acid in water equivalent to 80% of the total amount, add sodium hydroxide and polyacrylamide to obtain material B.

[0066] 2) Dissolve the crosslinking agent, potassium persulfate, and sorbitol in the remaining water to obtain material C;

[0067] 3) Add materials B and C to material A in sequence, then add the composite porous framework material, mix thoroughly and stir for 3 hours. During the reaction, add glycerol and sodium carbonate dropwise. Filter the obtained product to remove the vegetable oil, wash repeatedly with ethanol and dry until the water content is 20%.

[0068] The method for preparing porous particles is as follows:

[0069] 1) Dissolve 3g of konjac glucomannan and 6g of ferrous sulfate in 100mL of deionized water, then add a 0.3mol / L solution of disodium ethylenediaminetetraacetate, and control the molar ratio of disodium ethylenediaminetetraacetate to ferrous sulfate to be 0.08:1. Prepare a 50wt% ammonia solution, slowly add it dropwise to the above solution while stirring vigorously until the pH value is 8.5. Continue stirring for 2 hours and then let it stand for 5 hours to age, to obtain a mixed solution.

[0070] 2) Add 3g of carbon fiber to 80mL of mixed solution, disperse it evenly, then add 8g of sodium carbonate, stir thoroughly, let stand at room temperature for 50min, then heat to 85℃ and keep warm for 70min, then place at 6℃ and stand overnight, then soak in 0.2mol / L hydrochloric acid solution for 3d, then soak in ultrapure water for 2d, freeze dry and then pulverize and grind to obtain porous particles.

[0071] The preparation method of the composite porous framework material is as follows:

[0072] 1) Add 6g of polyvinyl alcohol to 130mL of deionized water, place it in an oil bath with magnetic stirring, heat and stir at 120℃ until the polyvinyl alcohol is completely dissolved, let it stand to room temperature, freeze it in a -10℃ refrigerator for 15h, and then freeze-dry it for 30h to obtain a porous polyvinyl alcohol framework.

[0073] 2) 300 mg of boron powder was completely dispersed in 300 mL of 75 wt% ethanol solution under stirring. Then, 600 mg of polyether P123 was added and mixed well. Then, 400 mg of acetic acid and 5 mL of 32 wt% hydrogen peroxide were added and stirred thoroughly to obtain a mixture. The mixture was then transferred to an ice-water bath and ultrasonically exfoliated with a probe at 600 W for 5 h and ultrasonically exfoliated with a water bath at 260 W for 3 h. After centrifugation at 5000 r / min for 20 min, the supernatant was centrifuged at 18000 r / min for 50 min. The obtained product was dried to obtain boron nanosheets.

[0074] 3) Add 500 mg of boron nanosheets to 150 mL of 80 wt% ethanol solution, and disperse evenly by ultrasonication to obtain a suspension. Place 6 g of polyvinyl alcohol porous framework in the suspension, evacuate to 80 Pa and maintain for 50 min, then connect to the atmosphere for 20 min. Repeat the operation 6 times. After centrifuging the product, wash it repeatedly with deionized water and dry it to obtain the composite porous framework material.

[0075] Comparative Example 1: This comparative example is basically the same as Example 1, except that it does not contain porous particles and composite porous framework materials.

[0076] Comparative Example 2: This comparative example is basically the same as Example 1, except that it does not contain porous particles.

[0077] Comparative Example 3: This comparative example is basically the same as Example 1, except that carbon fiber is not contained in the preparation of the porous particles.

[0078] Comparative Example 4: This comparative example is basically the same as Example 1, except that it does not contain composite porous skeleton material.

[0079] Comparative Example 5: This comparative example is basically the same as Example 1, except that step 2 is omitted in the preparation of the composite porous framework material.

[0080] Test experiment:

[0081] The hydrogel samples provided in Examples 1-3 and Comparative Examples 1-5 were soaked in deionized water for 2 hours. After being taken out, their water absorption ratio was measured. Then, they were placed at room temperature for 48 hours, and their water retention rate and surface dryness were measured. The results are shown in Table 1.

[0082] Table 1

[0083]

[0084] As can be seen from the table above, the absorbent gel of this invention has excellent water absorption capacity and amount, and the absorbed water is not easily lost, so that the gel surface can be kept dry, avoiding the growth of surface bacteria, thus making it safer, more hygienic and environmentally friendly.

[0085] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A superabsorbent gel, characterized in that, The superabsorbent polymer comprises the following components by weight: 300-500 parts vegetable oil, 5-10 parts dispersant, 10-15 parts 2-acryloyloxybutylsulfonic acid, 50-80 parts polyacrylamide, 15-25 parts porous particles, 5-10 parts composite porous framework material, 20-26 parts glycerol, 1-3 parts sodium hydroxide, 0.1-0.6 parts potassium persulfate, 0.03-0.08 parts crosslinking agent, 0.1-0.5 parts sorbitol, 0.3-0.8 parts sodium carbonate, and 80-120 parts water; The porous particles are prepared as follows: 1) Dissolve konjac glucomannan and ferrous sulfate in deionized water, then add an aqueous solution of disodium ethylenediaminetetraacetate (EDTA), and control the molar ratio of EDTA to ferrous sulfate to be (0.03-0.08):

1. Prepare an aqueous solution of 40-50 wt% ammonia, slowly add it dropwise to the above solution while stirring vigorously until the pH value is 8.0-8.

5. Continue stirring for 1-2 hours and then let it stand for 2-5 hours to age, thus obtaining a mixed solution. 2) Add carbon fiber to the mixed solution, disperse it evenly, then add sodium carbonate, stir thoroughly, let it stand at room temperature for 30-50 minutes, then heat it to 80-85℃ and keep it at that temperature for 40-70 minutes, then place it at 3-6℃ and let it stand overnight, then soak it in hydrochloric acid solution for 2-3 days, then soak it in ultrapure water for 1-2 days, freeze dry it, and then pulverize and grind it to obtain porous particles; The preparation method of the composite porous framework material is as follows: 1) Add polyvinyl alcohol to deionized water, place it in an oil bath under magnetic stirring, heat and stir until the polyvinyl alcohol is completely dissolved, let it stand to room temperature, freeze it in a -4 to -10℃ refrigerator for 12 to 15 hours, and then freeze-dry it for 24 to 30 hours to obtain a porous polyvinyl alcohol framework. 2) Boron elemental powder was completely dispersed in a 70-75 wt% ethanol solution under stirring. Then, polyether P123 was added and mixed well. Acetic acid and hydrogen peroxide were then added and stirred thoroughly to obtain a mixture. The mixture was then transferred to an ice-water bath and ultrasonically exfoliated with a probe at 500-600 W for 3-5 h, and ultrasonically exfoliated with a water bath at 200-260 W for 1-3 h. After centrifugation at 3000-5000 r / min for 10-20 min, the supernatant was centrifuged at 12000-18000 r / min for 30-50 min. The obtained product was dried to obtain boron nanosheets. 3) Add boron nanosheets to an ethanol solution with a concentration of 75-80wt%, and disperse them evenly by ultrasonication to obtain a suspension. Place the polyvinyl alcohol porous framework in the suspension, evacuate to 10-80Pa and maintain for 20-50min, then connect to the atmosphere for 10-20min. Repeat the operation 3-6 times. After centrifuging the product, wash it repeatedly with deionized water and dry it to obtain the composite porous framework material.

2. The superabsorbent gel according to claim 1, characterized in that, The vegetable oil is at least one of castor oil, flaxseed oil, and sunflower seed oil; The dispersant is either polyglycerol monostearate or polyglycerol monostearate; The crosslinking agent is at least one of allyl methacrylate, ethylene glycol dimethacrylate, and ethylene glycol diacrylate.

3. The superabsorbent polymer according to claim 1, characterized in that, In step 1), the ratio of konjac glucomannan, ferrous sulfate, and deionized water is (1-3) g: (2-6) g: (60-100) mL; The concentration of the aqueous solution of disodium ethylenediaminetetraacetate is 0.1–0.3 mol / L.

4. The superabsorbent gel according to claim 1, characterized in that, In step 2), the ratio of the mixed solution, carbon fiber, and sodium carbonate is (50-80) mL: (1-3) g: (5-8) g; The concentration of the hydrochloric acid solution is 0.1–0.2 mol / L.

5. The superabsorbent polymer according to claim 1, characterized in that, In step 1), the ratio of polyvinyl alcohol to deionized water is (3-6) g: (100-130) mL; The temperature of the oil bath is 110–120°C.

6. The superabsorbent gel according to claim 1, characterized in that, In step 2), the ratio of boron powder, ethanol solution, polyether P123, acetic acid, and hydrogen peroxide is (100-300) mg: (100-300) mL: (500-600) mg: (380-400) mg: (3-5) mL; The concentration of hydrogen peroxide is 30–32 wt%.

7. The superabsorbent polymer according to claim 1, characterized in that, In step 3), the ratio of boron nanosheets, ethanol solution, and polyvinyl alcohol porous framework is (300-500) mg: (100-150) mL: (2-6) g.

8. A method for preparing a superabsorbent gel according to any one of claims 1-7, characterized in that, Specifically, the steps include the following: 1) In a reactor equipped with a condenser and a stirring device, add vegetable oil and dispersant, heat to 50-75°C, mix well, and then add porous particles to obtain material A. Then dissolve 2-acryloyloxybutylsulfonic acid in water equivalent to 70-80% of the total amount, add sodium hydroxide and polyacrylamide to obtain material B. 2) Dissolve the crosslinking agent, potassium persulfate, and sorbitol in the remaining water to obtain material C; 3) Add materials B and C to material A in sequence, then add the composite porous framework material, mix and stir thoroughly, and react for 1-3 hours. During the reaction, add glycerol and sodium carbonate dropwise. Filter the obtained product to remove the vegetable oil, wash repeatedly with ethanol, and dry until the water content is 10-20%.

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