Preparation method of chitosan-based super absorbent material with antibacterial function and application of chitosan-based super absorbent material in sanitary napkins

Abstract

The invention relates to the field of preparation of polymer absorbent materials, in particular to a preparation method of a chitosan-based super absorbent material with an antibacterial function, the prepared super absorbent material comprises three layers, the upper surface and the lower surface are plant fiber highly breathable layers, and the middle is chitosan-based super absorbent microspheres with the antibacterial function; the plant fiber high-permeability layer is obtained by electrostatic spinning of kapok fiber, bamboo fiber, modified montmorillonite and polyvinyl alcohol, the super absorbent microspheres are gel materials obtained by polycondensation crosslinking of chitosan and acrylic acid and composite crosslinking of alginic acid, and the prepared super absorbent microspheres are high in deformation resistance and uniform and smooth in surface. The water absorption capacity of the super absorbent material is 410 g / g or above, the simulated blood absorption capacity is 35 g / g or above, and the super absorbent material has the advantages of being good in air permeability, high in water absorption and good in antibacterial activity.

Description

Technical Field

[0001] The present invention relates to the field of preparation of superabsorbent polymers, and particularly to a preparation method of a chitosan-based superabsorbent material with antibacterial function. Background Art

[0002] Superabsorbent materials are a new type of functional polymer materials, with a structure of moderately crosslinked three-dimensional network, which can absorb 10 - 1000 times its own mass of water, brine and physiological fluids. In the mid-1970s, Japan carried out research on preparing superabsorbent materials from cellulose, and obtained products in the form of flakes, powders and filaments. In the 1980s, crosslinking treatment of various alkylene oxides with radiation was proposed to synthesize non-ionic superabsorbent materials with a water absorption capacity of 2000 times, thus opening the door to non-ionic superabsorbent materials. As one of the three major raw materials (starch, cellulose and synthetic polymers) for synthesizing superabsorbent materials, cellulose has rich reserves, can be continuously regenerated, is inexpensive, has many advantages itself, is easy to be chemically modified, and can reduce environmental pollution. Therefore, how to make full use of the world's cellulose resources, especially the rich cellulose resources in China, to research and develop various types of superabsorbent materials with low price and high quality is of great significance.

[0003] Chitosan is a natural polymer material that forms hydrogels and contains different types of polysaccharide sulfates. There are a large number of hydroxyl and amino active groups in the molecular structure of chitosan. Different chitosan derivatives can be obtained through various methods. Among them, the synthesis of hybrid polymer hydrogels by combining chitosan with synthetic polymers can combine the advantages of both chitosan and synthetic polymers to improve the performance of the hydrogels. It can not only retain the mechanical strength of the matrix of artificial synthetic polymer materials, but also have good biocompatibility of natural polymer materials. However, due to the disadvantages of pure chitosan film dressings such as poor mechanical properties, large brittleness and poor water resistance. And after absorbing liquid, the air permeability will become worse.

[0004] Chinese Patent with Publication No. CN106963973B discloses a chitosan composite dressing and its preparation method, and discloses the composite dressing, including a chitosan dressing layer, a medical absorbent layer, a waterproof layer, and a medical tape adhesive layer. The waterproof layer covers the medical tape adhesive layer, and the medical absorbent layer is located between the chitosan dressing layer and the waterproof layer. The chitosan dressing layer is provided with air holes. The chitosan dressing layer, the medical absorbent layer and the waterproof layer have the same shape and area. A layer of release paper is covered on the chitosan dressing layer, and the area is the same as that of the medical tape adhesive layer. The air holes on the chitosan dressing layer and the medical absorbent layer can ensure high permeability of moisture and air, and avoid the phenomenon of wound turning white and swelling. Although the composite dressing is provided with air holes, when the dressing absorbs a large amount of water, the moisture will block the air holes, which will seriously affect the air permeability of the dressing.

[0005] The Chinese patent with the publication number CN118531519B discloses a superabsorbent fiber for diaper core layer materials and its production process. The patent discloses a superabsorbent fiber for diaper core layer materials, which includes the following raw materials in parts by weight: 70 - 90 parts of sodium acrylate solution, 20 - 45 parts of polyacrylamide microspheres, 2 - 10 parts of modified 2-hydroxyethyl methacrylate, 10 - 30 parts of polyvinyl alcohol solution, 0.5 - 5 parts of initiator, and 1 - 5 parts of crosslinking agent; the polyacrylamide microspheres are polyacrylamide microspheres prepared by inverse suspension polymerization; the modified 2-hydroxyethyl methacrylate is 2-hydroxyethyl methacrylate grafted with oxidized multi-walled carbon nanotubes. In the present invention, the addition of polyacrylamide microspheres and modified 2-hydroxyethyl methacrylate improves the water absorption rate, salt tolerance, and fracture toughness of the superabsorbent fiber. Although this patent solves the water absorption problem and anti-fracture property of cellulose, it does not solve the air permeability problem and antibacterial problem in the superabsorbent state.

[0006] Therefore, designing a superabsorbent material with good air permeability and certain antibacterial function is still an urgent problem to be solved at present. Summary of the Invention

[0007] In order to solve the above problems, the purpose of the present invention is to provide a preparation method of a superabsorbent material based on chitosan with antibacterial function, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial choice or create conditions.

[0008] The superabsorbent material provided by the present invention includes three layers. The upper and lower surfaces are plant fiber highly breathable layers, and the middle is superabsorbent microspheres based on chitosan with antibacterial function. The plant fiber highly breathable layer is obtained by electrospinning kapok fiber, bamboo fiber, modified montmorillonite, and polyvinyl alcohol. The superabsorbent microspheres are gel materials obtained by polycondensation crosslinking of chitosan and acrylic acid and then composite crosslinking with alginic acid; Among them, the preparation method of the plant fiber highly breathable layer is specifically as follows: S1. Cut the kapok fiber with a high-speed shearer, perform surface treatment on the kapok fiber with 2% NaOH aqueous solution for 5 - 10 minutes, then wash it with deionized water until neutral to obtain kapok fiber fragments, put them into a beater for beating treatment, and then add vinyltrimethoxysilane, stir evenly to obtain kapok pulp for standby; The addition amount of vinyltrimethoxysilane is 0.1 - 0.3 parts per 100 parts of kapok pulp; the conditions for the stirring reaction are: stirring speed 800 - 1000 rpm, time 2 - 3 hours; S2. Cut the bamboo fiber with a high-speed shearer, put it into a beater for beating treatment, and then add kapok pulp, stir evenly to obtain plant fiber pulp; put the plant fiber pulp liquid into a high-pressure homogenizer for homogenization treatment to obtain a plant cellulose solution; Among them, the mass ratio of kapok fiber to bamboo fiber is 1:8 - 10; S3. Polyvinyl alcohol and deionized water are stirred and heated at 80 °C for 80 - 120 min until completely dissolved. Modified montmorillonite is added and stirred for 30 - 50 min to uniformly disperse the modified montmorillonite into the polyvinyl alcohol solution, obtaining a polymer solution; The mass ratio of the described modified montmorillonite to polyvinyl alcohol is 1:3 - 5; the mass fraction of the described polyvinyl alcohol is 12 - 18%; S4. The polymer solution and the plant cellulose solution are mixed according to a mass ratio of 1:(2 - 3), and then electrospinning is carried out to obtain a highly breathable plant fiber layer; After the kapok fiber is treated with 2% NaOH aqueous solution and vinyltrimethoxysilane, the kapok fiber shows stronger hydrophobicity. The NaOH treatment helps to provide more effective binding opportunities for silane molecules. The coating of silane will make the fiber surface more hydrophobic, reduce the water contact angle, and thus enhance the hydrophobicity. And the highly breathable plant fiber layer made of the hydrophobic kapok fiber, polymer solution, and bamboo fiber has a higher porosity and stronger breathability due to the hydrophilic-hydrophobic design.

[0009] The preparation method of the described modified montmorillonite is specifically as follows: Montmorillonite with a diameter of about 1 μm is selected. The montmorillonite is added to deionized water, and dilute hydrochloric acid is added and stirred evenly to fully disperse the montmorillonite in the dilute hydrochloric acid solution. The temperature is raised to 60 °C, octadecyltrimethylammonium chloride is added, and it is fully stirred and reacted for 1 - 2 hours to obtain a suspension of montmorillonite. Then it is centrifuged at a speed of 3500 rpm and washed 2 - 3 times with deionized water to remove hydrochloric acid and octadecyltrimethylammonium chloride, and then centrifuged. The solid mixture at the bottom is taken out. At this time, the interlayer spacing of the montmorillonite is enlarged due to the action of the quaternary ammonium salt; The solid mixture at the bottom is added to deionized water, and then the pH is adjusted to 6.3 - 6.5 with sodium carbonate or citric acid. Glycine is added and reacted for 1 - 2 hours to make the surface of the montmorillonite carry negative charges. After completion, it is filtered, dried, and ground to obtain the modified montmorillonite. The mass ratio of the described octadecyltrimethylammonium chloride to montmorillonite is 1:6 - 8; the mass ratio of the described glycine to montmorillonite is 1:10.

[0010] Glycine is fixed on the montmorillonite layer through ionic bonds and hydrogen bonds, further resulting in an enlarged interlayer spacing. After treatment, the hydrophilicity of the modified montmorillonite decreases, the hydrophobicity increases, and the interlayer spacing increases.

[0011] The described electrospinning parameters are: voltage is 30 kV, receiving distance is 10 cm, flow rate is 1 mL / h; the environmental temperature and humidity are 25 °C and 40% - 60% respectively.

[0012] The upper and lower surface layers of the superabsorbent material with a three-layer structure are made of a plant fiber highly breathable layer composed of modified montmorillonite, plant fibers, and polyvinyl alcohol solution, which is mainly used for air and water permeability; the middle layer is a superabsorbent layer, mainly for adsorbing and enriching liquids.

[0013] Because kapok fiber is a renewable natural cellulose, the cross-section of the fiber is oval or round, with a hollow structure, and the hollowness rate is as high as 80% - 90%. The cell wall is relatively thin, about 0.5 - 2.0μm, and the cross-section of the fiber wall shows micropores. After modification, the contact angle with water is as high as 160°, with very significant hydrophobic and oleophilic characteristics. Therefore, kapok fiber has a certain resistance to water. However, due to the too-high hollowness rate of kapok fiber, its too-loose structure is not conducive to water control. How to process the fiber and utilize the special hollow structure and oleophilic and hydrophobic characteristics of kapok fiber to make it have a significant breathable effect in the overall superabsorbent environment is the key problem to be solved first.

[0014] First, kapok fiber and bamboo fiber can be processed into plant fibers through electrospinning technology. Both kapok fiber and bamboo fiber have a large number of hollow structures. After the polyvinyl alcohol solution containing oleophilic montmorillonite is compounded with them, the oleophilic montmorillonite fills the pores between the electrospun fibers, ensuring that the fiber specific surface area and porosity are both excellent, and can improve the mechanical properties of the fiber and its adsorption performance. This structure not only improves the adsorption property of the fiber itself but also increases the liquid phase and air fluxes after the fiber forms a film. This is because the fiber structure is isotropic in the two-dimensional direction, that is, the fibers are randomly oriented in the plane, and it has a rich and tortuous three-dimensional space channel inside, which provides a flow path for air. Kapok fiber has very significant hydrophobic and oleophilic characteristics, while bamboo fiber contains a large number of hydroxyl groups inside, which can form hydrogen bonds with water molecules, so it has a particularly strong water absorption property and the characteristics of rapid moisture absorption and quick drying. Polyvinyl alcohol also contains a large number of hydroxyl groups, which can combine with water molecules to form a hydrophilic environment. The organic combination of the three makes the prepared plant fiber highly breathable layer contain both hydrophobic groups and hydrophilic groups. Such a structural setting enables part of the highly breathable layer to effectively absorb water through hydrophilic groups and introduce it into the superabsorbent layer, while the surface of the other part of the hydrophobic groups is not occupied by water molecules due to water resistance and interacts with the oleophilic modified montmorillonite to form a rich and tortuous three-dimensional space channel inside, which provides a flow path for air, realizing high breathability. Even after high water absorption, the breathable pores of the material still have effective breathability on the surface layer due to the hydrophobic property.

[0015] It is generally believed that due to the blockage of the pore structure, when the piezoresistance suddenly increases, it enters an unsteady state. At this time, when the pores between fibers are small, air molecules in the tube bypass one fiber and may hit another fiber, resulting in a serious decrease in air permeability. At the same time, its water absorption performance will also decrease due to the increase in piezoresistance. Therefore, how to achieve a high coefficient and low air resistance has always been a key scientific problem to be solved in the regulation of fiber structures. If the water absorption layer is a simple fiber layer, although the diameter of electrospun fibers is mostly in the nanometer range, the high specific surface area brought by this structural feature enables the material to exhibit high air permeability at low gram weights. However, nanofibers often exhibit the characteristic of dense packing, making it difficult to improve the porosity of electrospun fiber materials. When kapok fibers are used and oleophilic montmorillonite is introduced into the fibers, this problem can be well solved. This is mainly because the kapok fiber structure has a relatively large fiber diameter and a hollowness rate of more than 90%, which significantly improves the porosity. However, if only a single kapok fiber structure is used, it is difficult to make it have good water permeability, and the water absorption is very poor. At this time, by compounding a polymer solution containing oleophilic montmorillonite and bamboo fibers, the problem of water absorption and water permeability can be solved. At this time, the polymer solution can make the pore diameter smaller, and the microsphere structure of oleophilic montmorillonite has a large number of rich and tortuous three-dimensional space channels inside, significantly improving the air permeability. Therefore, such a fiber structure not only has a small diameter, but also can achieve a high porosity depending on the small pore diameter of the microspheres. And the hollow structures between them will be closely packed by the polymer with microsphere channels, forming countless fine micropores. Therefore, without reducing the porosity, there are a large number of rich and tortuous three-dimensional space channels inside the fiber structure.

[0016] Furthermore, the high water absorption microspheres are gel materials obtained by condensing and crosslinking chitosan and acrylic acid under the action of a catalyst, and then compounding and crosslinking alginic acid, including the following raw materials: acrylic acid; water, chitosan, chitosan oligosaccharide, 2,2 - azobis(2 - methylpropionamidine) dihydrochloride; 1 - hydroxycyclohexyl phenyl ketone; alginic acid; glutaraldehyde and lubricant. The specific preparation method is as follows: S01, weigh the following raw materials by weight: 15 - 20 parts of acrylic acid, 60 - 75 parts of water, 2 - 6 parts of chitosan, 1 - 3 parts of chitosan oligosaccharide, and add 2,2 - azobis(2 - methylpropionamidine) dihydrochloride; 1 - hydroxycyclohexyl phenyl ketone to obtain a mixed solution; S02, place the mixed solution at 40 - 80 °C for polymerization cross - linking reaction, and cool to obtain a polymerized liquid material system; Through chemical grafting and physical cross - linking, a copolymer of chitosan / chitosan oligosaccharide - grafted polyacrylic acid is formed, which has a three - dimensional network structure.

[0017] The 2,2 - azobis(2 - methylpropionamidine) dihydrochloride is 2 to 5 per ten thousand of the total material mass; the 1 - hydroxycyclohexyl phenyl ketone is 2 to 5 per ten thousand of the total material mass; the chitosan oligosaccharide is a chitosan oligosaccharide with a number - average molecular weight of 1200 - 3400; S03, Add alginic acid and glutaraldehyde to the polymer solution material system. After quickly stirring for 3 - 5 minutes until uniform, let it stand for 5 - 10 hours to form a viscous material system; heat the material to 75 - 95 °C and keep it warm for 8 - 12 hours to form a hard and brittle hydrogel material.

[0018] S04, Add a lubricant to the hard and brittle hydrogel material, stir at high speed for 30 - 50 minutes to break it, heat it to 95 - 110 °C and dry it to hard and dry particles, and finally grind it into 60 - 100 - mesh particles to obtain superabsorbent microspheres.

[0019] The alginic acid is 1.5 - 2 times the mass of chitosan, and the glutaraldehyde is 65 - 85% of the mass of chitosan; the lubricant is composed of ammonia water, polyethylene glycol, glycerol and aziridine. The mass ratio of ammonia water, polyethylene glycol, glycerol, aziridine to the gel material is 150 - 300:5 - 15:0.2 - 0.6:0.01 - 0.03:100; the mass fraction of ammonia water is 10 - 15%.

[0020] Using acrylic acid, chitosan, and oligosaccharide as raw materials, under the action of a catalyst, through polycondensation cross - linking, a copolymer of chitosan / chitosan oligosaccharide - grafted polyacrylic acid is formed by chemical grafting and physical cross - linking. Then, through the cross - linker glutaraldehyde, the hyaluronic acid continues to cross - link with the copolymer to obtain superabsorbent gel microparticles. Finally, through the action of a lubricant, superabsorbent microspheres are obtained; it is a type of polyelectrolyte with a certain cross - linked structure. It repels each other in water, promoting the swelling of the polymer. At the same time, due to the difference in ion concentration inside and outside, an osmotic pressure is generated, causing a large amount of water to enter the interior of the hydrogel; while the cross - linked structure of the polymer restricts its swelling, making the polymer after water absorption have a certain mechanical strength. The balance of these two factors determines the water absorption capacity. Chitosan and oligosaccharide cellulose are high - molecular polysaccharides containing multiple hydroxyl groups. Due to the hydrophilicity of the hydroxyl groups, natural cellulose itself has a certain water absorption and moisture absorption capacity. However, its highly crystalline structure makes most of the hydroxyl groups in a hydrogen - bond association state, restricting this water absorption capacity. Therefore, when preparing cellulose - based superabsorbent materials, first, this crystalline structure should be destroyed as much as possible. Then, through chemical reaction methods such as graft copolymerization and cross - linking, hydrophilic groups such as carboxyl groups and hydroxyl groups are grafted onto the cellulose macromolecules, and through appropriate cross - linking to ensure the gel strength after water absorption. Chitosan - based superabsorbent materials are synthesized to form macromolecules with a cross - linked network structure.

[0021] Finally, a superabsorbent material with a three-layer structure is prepared. The upper and lower surface layers are 0.5-1.0 mm plant fiber highly breathable layers, and the middle layer is 1-2 mm superabsorbent microspheres based on chitosan with antibacterial function.

[0022] Since the surface layer is prepared by electrospinning a hydrophilic material prepared from hydrophilic fibers and a hydrophobic structure prepared from hydrophobic fibers, the surface is soft and breathable, and the water permeability is good. By introducing hydroxyl and carboxyl groups on the polymer chain, crosslinking polysaccharides with ionic groups, adding inorganic particles, etc. in the middle layer, the electrostatic repulsion and internal and external osmotic pressure can be increased, endowing the superabsorbent material with better liquid absorption capacity. With a fabric as the substrate, a porous structure gel is loaded into the breathable layer to obtain a superabsorbent material with good forming ability and strong water absorption ability, and the absorption capacity of the superabsorbent material for saline or viscous liquids is improved by increasing the anionic electrostatic repulsion and internal and external osmotic pressure in the system.

[0023] The finally prepared superabsorbent material based on chitosan with antibacterial function can be used as a medical dressing or in sanitary napkins.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The present invention provides a superabsorbent gel particle. Using acrylic acid, chitosan, and oligosaccharides as raw materials, under the action of a catalyst, through polycondensation crosslinking, a copolymer of chitosan / chitosan oligosaccharide-grafted polyacrylic acid is formed by chemical grafting and physical crosslinking. Then, through a crosslinking agent glutaraldehyde, hyaluronic acid continues to crosslink with the copolymer to obtain superabsorbent gel particles. Finally, through the action of a lubricant, a superabsorbent microsphere material is obtained; the prepared superabsorbent microspheres have strong anti-deformation ability, a uniform and smooth surface, and the swelling behavior, degradation, and mechanical properties of the superabsorbent microspheres can be adjusted by adjusting the raw material ratio.

[0025] 2) The present invention also provides a plant fiber highly breathable layer, which includes hydrophobic kapok fibers, hydrophilic bamboo fibers, and a polymer containing oleophilic montmorillonite is further compounded to obtain a highly breathable plant fiber; the organic combination of the three makes the prepared plant fiber highly breathable layer contain both hydrophobic groups and hydrophilic groups. Such a structural setting makes the air permeability of the surface layer still effective due to the hydrophobic property of the air holes after the material absorbs water. Therefore, such a fiber structure not only has a smaller diameter of the fiber structure, but also can achieve a high porosity depending on the small pore diameter of the microspheres. And the hollow structures between them will be closely packed by the polymer with microsphere channels, forming countless fine micropores. Therefore, without reducing the porosity, due to the microsphere structure of oleophilic montmorillonite inside the fiber structure, there are a large number of rich and tortuous three-dimensional space channels inside, significantly improving the air permeability.

[0026] 3) The three-layer superabsorbent material provided by this invention is composed of biomaterials that are non-toxic to the human body and have excellent compatibility and safety. It has a water absorption capacity of over 400g / g and an absorption capacity of over 35g / g of simulated blood. It is not only breathable, antibacterial, highly absorbent, uniformly distributed, and has good air permeability, but also uses natural, non-toxic, and environmentally friendly raw materials. It can be used in medical dressings and sanitary napkins and has promising application and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 , Preparation flow chart of super absorbent microspheres DETAILED DESCRIPTION Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application. Example 1 A method for preparing a chitosan-based super absorbent material with antibacterial function, first preparing a plant fiber high breathable layer, specifically: 50 parts of kapok fiber were chopped with a high-speed shearing machine, and the kapok fiber was surface-treated with a 2% NaOH aqueous solution for 5 minutes. The kapok fiber was then washed with deionized water until neutral to obtain kapok fiber shreds, which were then placed in a pulper for pulping. 0.05 parts of vinyltrimethoxysilane were added, and the mixture was stirred at a stirring speed of 800 rpm for 2 hours. The kapok pulp was stirred evenly to obtain a kapok pulp for later use. 400 parts of bamboo fiber were chopped with a high-speed shearing machine, and the mixture was placed in a pulper for pulping. The kapok pulp was then added and stirred evenly to obtain a plant fiber pulp. The plant fiber pulp was placed in a high-pressure homogenizer for homogenization to obtain a plant cellulose solution. Furthermore, the preparation method of modified montmorillonite is specifically as follows: montmorillonite with a diameter of about 1 μm is selected, 80 parts of montmorillonite is added to 80 parts of deionized water, 3 parts of dilute hydrochloric acid is added and stirred evenly to fully disperse the montmorillonite in the dilute hydrochloric acid solution, the temperature is raised to 60°C, 10 parts of octadecyltrimethylammonium chloride are added, the mixture is fully stirred, and the reaction is carried out for 1 to 2 hours to obtain a montmorillonite suspension, which is then centrifuged at a speed of 3500 rpm, washed with deionized water 2 to 3 times to remove the hydrochloric acid and excess octadecyltrimethylammonium chloride, centrifuged, and the solid mixture at the bottom is removed. At this time, the interlayer spacing of the montmorillonite is expanded by the action of the quaternary ammonium salt; Add the solid mixture at the bottom to 50 parts of deionized water, then adjust the pH to 6.3 with sodium carbonate or citric acid, add 8 parts of glycine, and react for 2 hours to make the surface of montmorillonite carry negative charges. After completion, filter, dry, and grind to obtain modified montmorillonite; Stir and heat 120 parts of polyvinyl alcohol and 1000 parts of deionized water at 80 °C for 120 min until completely dissolved, add 40 parts of modified montmorillonite, and stir for 40 min to uniformly disperse the modified montmorillonite into the polyvinyl alcohol solution to obtain a polymer solution; Finally, at a voltage of 30 kV, a receiving distance of 10 cm, and a flow rate of 1 mL / h; under environmental temperature and humidity of 25 °C and 40% respectively, mix 100 parts of the polymer solution and 300 parts of the plant cellulose solution, and then perform electrospinning to obtain a highly breathable plant fiber layer.

[0028] Furthermore, to prepare superabsorbent microspheres, the raw materials include acrylic acid; water, chitosan, chitosan oligosaccharide, 2,2 - azobis(2 - methylpropionamidine) dihydrochloride, 1 - hydroxycyclohexyl phenyl ketone, alginic acid, glutaraldehyde, and a lubricant; The specific preparation method is as follows: Weigh by weight: 15 parts of acrylic acid, 60 parts of water, 6 parts of chitosan, 1 part of chitosan oligosaccharide, add 0.02 parts of 2,2 - azobis(2 - methylpropionamidine) dihydrochloride; 0.02 parts of 1 - hydroxycyclohexyl phenyl ketone to obtain a mixed solution; Place it at 60 °C for a polymerization cross - linking reaction for 4 hours, cool to obtain a polymerized liquid material system; Add 12 parts of alginic acid and 5.1 parts of glutaraldehyde to the polymerized liquid material system, quickly stir for 5 minutes until uniform, then let it stand for 8 hours to form a viscous material system; Heat the material to 75 °C and keep it warm for 10 hours to form a brittle hydrogel material; Mix 150 parts of 15% ammonia water, 10 parts of polyethylene glycol, 0.3 parts of glycerol, and 0.02 parts of aziridine to obtain a lubricant; Take 100 parts of the brittle hydrogel material, add the lubricant, stir at high speed for 50 minutes to break it, heat up to 100 °C and dry it to hard and dry particles, and finally grind it to 60 - 100 - mesh particles to obtain superabsorbent microspheres.

[0029] Finally, the preparation of the antibacterial - functional chitosan - based superabsorbent material is a three - layer - structured superabsorbent material. The upper and lower surface layers are 0.5 - mm plant fiber highly breathable layers, and the middle layer is 2 - mm antibacterial - functional chitosan - based superabsorbent microspheres.

[0030] Example 2 A preparation method of an antibacterial - functional chitosan - based superabsorbent material. First, prepare a plant fiber highly breathable layer, specifically: 50 parts of kapok fiber were chopped with a high-speed shearing machine, and the kapok fiber was surface-treated with a 2% NaOH aqueous solution for 5 minutes. Then, the kapok fiber was washed with deionized water until neutral to obtain kapok fiber crumbs, which were placed in a pulper for pulping. 0.15 parts of vinyltrimethoxysilane were added, and the mixture was stirred at a stirring speed of 1000 rpm for 2 hours to obtain kapok pulp for standby use; 500 parts of bamboo fiber were chopped with a high-speed shearing machine, and the mixture was placed in a pulper for pulping. Then, the kapok pulp was added and stirred to obtain plant fiber pulp; the plant fiber pulp was placed in a high-pressure homogenizer for homogenization to obtain a plant cellulose solution; Furthermore, the preparation method of modified montmorillonite is specifically as follows: Select montmorillonite with a diameter of about 1 μm, add 80 parts of montmorillonite to 80 parts of deionized water, add 3 parts of dilute hydrochloric acid and stir evenly to fully disperse the montmorillonite in the dilute hydrochloric acid solution, raise the temperature to 60°C, add 12 parts of octadecyltrimethylammonium chloride, stir well, and react for 2 hours to obtain a montmorillonite suspension, then centrifuge at 3500 rpm, wash three times with deionized water to remove hydrochloric acid and excess octadecyltrimethylammonium chloride, centrifuge, and remove the solid mixture at the bottom. At this time, the interlayer spacing of the montmorillonite is expanded by the action of the quaternary ammonium salt; The solid mixture at the bottom was added with 50 parts of deionized water, and then the pH was adjusted to 6.4 with sodium carbonate or citric acid. 8 parts of glycine was added and reacted for 2 hours to make the surface of the montmorillonite negatively charged. After completion, the mixture was filtered, dried, and ground to obtain modified montmorillonite. 150 parts of polyvinyl alcohol and 1000 parts of deionized water were stirred and heated at 80°C for 120 minutes until completely dissolved. 30 parts of modified montmorillonite was added and stirred for 50 minutes to evenly disperse the modified montmorillonite in the polyvinyl alcohol solution to obtain a polymer solution. Finally, at a voltage of 30 kV, a receiving distance of 10 cm, a flow rate of 1 mL / h, and an ambient temperature and humidity of 25°C and 40% respectively, 100 parts of polymer solution and 200 parts of plant cellulose solution were mixed and then electrospun to obtain a highly breathable plant fiber layer.

[0031] Furthermore, highly absorbent microspheres are prepared, comprising the following raw materials: acrylic acid; water, chitosan, chitosan oligosaccharide, 2,2-azobis(2-methylpropylamidine) dihydrochloride, 1-hydroxycyclohexylphenyl ketone, alginic acid, glutaraldehyde, and a lubricant; and the specific preparation method is as follows: Weigh 20 parts of acrylic acid, 75 parts of water, 2 parts of chitosan, and 3 parts of chitosan oligosaccharide, add 0.03 parts of 2,2-azobis(2-methylpropylamidine) dihydrochloride, and 0.02 parts of 1-hydroxycyclohexylphenyl ketone to obtain a mixed solution; place the mixture at 80°C for 4 hours for polymerization and cross-linking reaction, and cool to obtain a polymer solution material system; add 4 parts of alginic acid and 1.3 parts of glutaraldehyde to the polymer solution material system, stir rapidly for 3 minutes to uniformly mix, and let it stand for 5 hours to form a viscous material system; heat the material to 80°C and keep it warm for 12 hours to form a hard and brittle hydrogel material; A lubricant is prepared by mixing and stirring 300 parts of 10% ammonia water, 15 parts of polyethylene glycol, 0.2 parts of glycerol and 0.03 parts of aziridine; the lubricant is added to 100 parts of hard and brittle hydrogel material, and the material is stirred at high speed for 50 minutes to break it up, and then the material is dried to dry and hard particles at 110°C, and finally ground into 60-100 mesh particles to obtain highly absorbent microspheres.

[0032] Finally, the high water-absorbent material with antibacterial function and chitosan-based structure is a three-layer structure of high water-absorbent material, the upper and lower surface layers are 0.5mm plant fiber high breathable layers, and the middle layer is 1.2mm high water-absorbent microspheres with antibacterial function and chitosan-based structure.

[0033] Example 3 A method for preparing a chitosan-based super absorbent material with antibacterial function, first preparing a plant fiber high breathable layer, specifically: 50 parts of kapok fiber were chopped with a high-speed shearing machine, and the kapok fiber was surface-treated with a 2% NaOH aqueous solution for 5 minutes. The kapok fiber was then washed with deionized water until neutral to obtain kapok fiber shreds, which were then placed in a pulper for pulping. 0.1 parts of vinyltrimethoxysilane were added, and the mixture was stirred at a stirring speed of 9000 rpm for 3 hours to obtain kapok pulp for standby use. 450 parts of bamboo fiber were chopped with a high-speed shearing machine, and pulped in a pulper. The kapok pulp was then added and stirred to obtain plant fiber pulp. The plant fiber pulp was homogenized in a high-pressure homogenizer to obtain a plant cellulose solution. Furthermore, the preparation method of modified montmorillonite is specifically as follows: Select montmorillonite with a diameter of about 1 μm, add 80 parts of montmorillonite to 80 parts of deionized water, add 3 parts of dilute hydrochloric acid and stir evenly to fully disperse the montmorillonite in the dilute hydrochloric acid solution, raise the temperature to 60°C, add 10 parts of octadecyltrimethylammonium chloride, stir well, and react for 2 hours to obtain a montmorillonite suspension, then centrifuge at 3500 rpm, wash three times with deionized water to remove hydrochloric acid and excess octadecyltrimethylammonium chloride, centrifuge, and remove the solid mixture at the bottom. At this time, the interlayer spacing of the montmorillonite is expanded by the action of the quaternary ammonium salt; Add the solid mixture at the bottom to 50 parts of deionized water, adjust the pH to 6.5 with sodium carbonate or citric acid, add 8 parts of glycine, and react for 2 hours to make the surface of montmorillonite carry negative charges. After completion, filter, dry, and grind to obtain modified montmorillonite; Stir and heat 180 parts of polyvinyl alcohol and 1000 parts of deionized water at 80 °C for 120 min until completely dissolved, add 45 parts of modified montmorillonite, and stir for 50 min to uniformly disperse the modified montmorillonite into the polyvinyl alcohol solution to obtain a polymer solution; Finally, at a voltage of 30 kV, a receiving distance of 10 cm, and a flow rate of 1 mL / h; under environmental temperature and humidity of 25 °C and 40% respectively, mix 100 parts of the polymer solution and 300 parts of the plant cellulose solution, and then perform electrospinning to obtain a highly breathable plant fiber layer.

[0034] Furthermore, prepare superabsorbent microspheres, including the following raw materials: acrylic acid; water, chitosan, chitosan oligosaccharide, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 1-hydroxycyclohexyl phenyl ketone, alginic acid, glutaraldehyde, and lubricant; The specific preparation method is as follows: Weigh by weight: 18 parts of acrylic acid, 70 parts of water, 4 parts of chitosan, 2 parts of chitosan oligosaccharide, add 0.29 parts of 2,2'-azobis(2-methylpropionamidine) dihydrochloride; 0.3 parts of 1-hydroxycyclohexyl phenyl ketone to obtain a mixed solution; Place it at 40 - 80 °C for 4 hours of polymerization cross-linking reaction, cool to obtain a polymerized liquid material system; Add 6 parts of alginic acid and 2.8 parts of glutaraldehyde to the polymerized liquid material system, quickly stir for 4 minutes to make it uniform, and then let it stand for 8 hours to form a viscous material system; Heat the material to 95 °C and keep it warm for 10 hours to form a brittle hydrogel material; Mix 150 parts of 12% ammonia water, 10 parts of polyethylene glycol, 0.3 parts of glycerol, and 0.02 parts of aziridine to obtain a lubricant; Take 100 parts of the brittle hydrogel material, add the lubricant, stir at high speed for 50 minutes to break it, heat up to 100 °C and dry it to dry and hard particles, and finally grind it to 60 - 100 mesh particles to obtain superabsorbent microspheres.

[0035] Finally, the superabsorbent material with antibacterial function based on chitosan is a three-layer superabsorbent material. The upper and lower surface layers are 1.0 mm plant fiber highly breathable layers, and the middle layer is 1.5 mm superabsorbent microspheres with antibacterial function based on chitosan.

[0036] Comparative Example 1; When preparing the plant fiber highly breathable layer, neither kapok fiber nor modified montmorillonite is added, and only polyvinyl alcohol and bamboo fiber are used in equal amounts for substitution, and the others are the same as in Example 1; Comparative Example 2; When preparing the plant fiber highly breathable layer, cotton pulp is used to replace kapok pulp in equal amounts, and montmorillonite is used to replace modified montmorillonite in equal amounts, and the others are the same as in Example 1; Comparative Example 3: When preparing the superabsorbent microspheres, chitosan and oligosaccharides were not added, and the polycondensed acrylic acid was directly cross-linked with alginic acid through glutaraldehyde, and the others were the same as in Example 1; Comparative Example 4: When preparing the highly breathable plant fiber layer, cotton pulp was used to replace kapok pulp in equal amounts, and montmorillonite was used to replace modified montmorillonite in equal amounts. When preparing the superabsorbent microspheres, chitosan and oligosaccharides were not added, and the polycondensed acrylic acid was directly cross-linked with alginic acid through glutaraldehyde, and the others were the same as in Example 1; Comparative Example 5: A certain brand of sanitary napkin purchased on the market.

[0037] Test data and result analysis 1. Air permeability: According to the provisions of GB / T 5453-1997, the air permeability of the prepared superabsorbent material with antibacterial function based on chitosan was tested. The test samples of Examples 1-3 and Comparative Examples 1-5 were pre-conditioned in a standard atmospheric environment with a temperature of 20 °C and a relative humidity of 65%. The test area was set to 20 cm 2 , the pressure drop was set to 100 Pa, and different positions were randomly selected for testing. Each group of samples was tested 10 times and the values were recorded, and the average air permeability of the test samples was calculated, as shown in Table 1; The test samples of Examples 1-3 and Comparative Examples 1-5 were placed in water, evenly absorbed 100 g of water, and then the test samples were taken out, and the excess water on the surface was blotted with a paper towel. Different positions were randomly selected for testing. Each group of samples was tested 10 times and the values were recorded, and the average air permeability of the test samples after water absorption was calculated, as shown in Table 1.

[0038] Table 1 Test of air permeability of superabsorbent materials

[0039] As can be seen from Table 1, Examples 1-3 have excellent air permeability before and after water absorption. This is because the plant fibers on the surface layer of Examples 1-3 are made of hydrophilic and hydrophobic fibers. When not absorbing water, both types of fibers have good air permeability. However, when the fibers absorb water, these two types of fibers exhibit different hydrophilic and hydrophobic properties. Due to the presence of hydrophobic fibers, the air pores of these fibers will not expand due to water absorption, resulting in a decrease in pore size or an increase in resistance, or even being completely blocked, which significantly reduces the air permeability. The bamboo fibers and polyvinyl alcohol in Comparative Example 1 are both hydrophilic materials. After absorbing water, they are filled with water, resulting in a significant decrease in air permeability. In Comparative Examples 2 and 4, when hydrophilic cotton pulp is used instead of hydrophobic kapok pulp, the porosity becomes smaller. In the case of increasing water content, its air permeability will inevitably decrease sharply. Moreover, in Comparative Examples 2 and 4, hydrophilic montmorillonite is filled. After montmorillonite absorbs water, its originally tiny interlayer spacing is occupied by water molecules, further weakening its air permeability. For Examples 1-3, in addition to the air pores reserved due to the hydrophobicity of the hydrophobic kapok fibers, more importantly, montmorillonite with oleophilicity and an expanded interlayer spacing is further superimposed. It has a rich and tortuous three-dimensional space channel inside, which provides a flow path for air. The kapok fibers have very obvious hydrophobic and oleophilic characteristics. The bamboo fibers contain a large number of hydroxyl groups inside, which can form hydrogen bonds with water molecules, so they have a particularly strong water absorption capacity and the characteristics of rapid moisture absorption and quick drying. Polyvinyl alcohol also contains a large number of hydroxyl groups, which can combine with water molecules to form a hydrophilic environment. The organic combination of the three makes the prepared plant fiber high air permeability layer contain both hydrophobic groups and hydrophilic groups. Such a structural setting enables part of the high air permeability layer to effectively absorb water through hydrophilic groups and conduct it into the high water absorption layer, while the surface of the other part of the hydrophobic groups is not occupied by water molecules due to water resistance and interacts with the oleophilic modified montmorillonite to form a rich and tortuous three-dimensional space channel inside, which provides a flow path for air, achieving high air permeability. Even after high water absorption, due to the hydrophobic property of the air pores of this material, the air permeability of the surface layer remains effective. The air permeability is also related to the high water absorption microspheres in the middle to a certain extent. The mechanical strength of the high water absorption microspheres obtained by polycondensation physical cross-linking and chemical cross-linking is significantly improved. They are not easily broken after water absorption, and the gaps between the microspheres will be larger than those after fragmentation. Therefore, it will also be helpful for air permeability.

[0040] 2. Backflow volume test: Place the high water absorption material after absorbing deionized water for 1 hour at 25°C and 70% (relative humidity), and place a filter paper on its surface. Main testing instruments and materials: Standard briquette, medium-speed qualitative analysis filter paper (150mm×150mm). Testing solution: Standard synthetic test solution for permeability testing. Testing method: Refer to Appendix B of Standard GB / T3013-2013 to test the re-permeation amount of the test sample, and cut the test specimen. The size is 100mm×100mm. Each sample is tested 5 times and the average value is taken, as shown in Table 2. The calculation formula for the re-permeation amount is: G = G2 - G1 Where: G2—the mass of the filter paper after re-permeation, g; G1—the initial mass of the filter paper, g.

[0041] The re-permeation amount refers to the mass of the liquid that returns to the surface layer after passing through the test specimen and being absorbed by the absorbent material. The liquid penetration time is the time taken for the liquid to pass through the surface layer material, which is used to measure the speed of the material transferring the liquid.

[0042] Testing instrument: YG814D type liquid penetrometer Testing method: Refer to Standard GB / T24218.8-2010 to test the liquid penetration time on both sides of the sample respectively, as shown in Table 2.

[0043] Table 2 Permeability of superabsorbent materials

[0044] As can be seen from Table 2, the liquid penetration time of Examples 1-3 is less than that of the comparative examples, mainly because when the absorbent material contacts the hydrophilic surface, it shows strong hydrophilicity, and a large wetting driving force is generated between the hydrophobic surface and the hydrophilic surface, which promotes the easy transfer of the liquid to the absorbent material. However, when the liquid transfers from the hydrophilic surface, only the hydrophilicity of the absorbent material plays a role, generating a weak pressure difference, making it difficult for the liquid to transfer. Therefore, adding a certain amount of hydrophobic material not only does not affect the water permeability of the superabsorbent material, but instead promotes the liquid penetration time, making the liquid permeability better. After adding hydrophobic kapok fibers, the re-permeation amount also decreases to a certain extent. This is also because of the unidirectionality of its hydrophobicity, which increases the contact angle on the surface layer of the material, making the viscose fiber surface change from hydrophilic to water-repellent, while the contact between the bamboo fiber surface and the filter paper surface shows hydrophilicity. When the liquid penetrates, a wetting gradient effect is formed, resulting in unidirectional liquid conductivity, and thus the re-permeation amount decreases.

[0045] 3. Liquid absorption performance: Prepare superabsorbent material specimens of the same specification, weigh them, and record the mass as m0. Immerse the specimens in a container filled with water for 1 hour to allow the specimens to absorb water. Then take out the specimens, blot the excess water on the surface with a tissue, and weigh their wet weight, which is m. Calculate the water absorption capacity according to the following formula, as shown in Table 3; Water absorption capacity (g / g) = m - m0; m0—the dry weight of the test specimen, g; m—the wet weight of the test specimen, g.

[0046] Test its blood absorption ability in the same way, as shown in Table 3; Table 3 Liquid Absorption Ability

[0047] As can be seen from Table 3, the absorption abilities of Examples 1-3 for water and simulated blood are both very good. When the absorption object changes from water to high-viscosity blood, the absorption ability of Comparative Example 2 decreases significantly. This is because the cotton pulp and hydrophilic montmorillonite in the comparative example have a smaller porosity, which easily makes the absorption resistance larger. While the kapok fiber in the example has a high hollowness and porosity, and in addition, the large wetting driving force generated by hydrophobic and hydrophilic forms a pressure difference, which promotes the ability of the liquid to absorb high-viscosity liquids.

[0048] 4. Antibacterial Performance Prepare the superabsorbent materials of Examples 1-3 and Comparative Examples 1-5 into specimens of 2 cm × 2 cm, and use the ASTM E2149 method to investigate the antibacterial effects of the chitosan-based superabsorbent materials with antibacterial functions against two strains of Escherichia coli (E.coli) and Staphylococcus aureus (s.aureus). Inoculate the test strains on the test tube slant medium under sterile conditions respectively, place them in a constant temperature incubator at 37 °C for 20 hours. After the bacteria grow, add sterile distilled water, dissolve and shake to form a suspension of bacteria. Place the samples in flasks inoculated with Staphylococcus aureus and Escherichia coli respectively, and culture them at 37 °C for 24 hours. Observe the antibacterial situation, measure the diameter of the inhibition zone produced by each strain 3 times, repeat 3 times for each concentration, and take the average value. The results are shown in Table 4. Table 4 Bacteriostatic Ability

[0049] As can be seen from Table 5, the chitosan-based superabsorbent materials with antibacterial functions prepared in Examples 1-3 have obvious antibacterial effects against two strains of Escherichia coli (E.coli) and Staphylococcus aureus (s.aureus). Here, the main antibacterial components in the superabsorbent material are chitosan and oligosaccharides. Chitosan is chemically cross-linked on acrylic acid, and oligosaccharides are physically cross-linked and filled in the polymer, making its antibacterial activity effect persistent, stable and safe. At the same time, the antibacterial properties of bamboo fiber and kapok fiber are superimposed, making the antibacterial performance of this superabsorbent material more prominent and gentler.

[0050] In summary, it can be seen that the chitosan-based superabsorbent material with antibacterial functions prepared by the present invention has good breathability, antibacterial activity and water absorption, and its raw materials are environmentally friendly and low-toxic, having certain application prospects.

[0051] The above is only used to illustrate the technical solution of the present invention rather than to limit it. Any equivalent modifications and changes made by those of ordinary skill in the art to the technical solution of the present invention still fall within the scope covered by the present invention as long as they do not depart from the overall concept of the present invention.

Claims

1. A preparation method of a chitosan-based superabsorbent material with antibacterial function, characterized in that The described chitosan-based superabsorbent material with antibacterial function comprises three layers. The upper and lower surfaces are plant fiber highly breathable layers, and the middle is superabsorbent microspheres based on chitosan with antibacterial function. The plant fiber highly breathable layer is prepared by electrospinning of kapok fiber, bamboo fiber, modified montmorillonite and polyvinyl alcohol. The superabsorbent microspheres are gel materials obtained by polycondensation cross-linking of chitosan and acrylic acid and then composite cross-linking with alginic acid.

2. The preparation method of the chitosan-based superabsorbent material with antibacterial function according to claim 1, characterized in that, Among them, the preparation method of the plant fiber highly breathable layer is specifically as follows: S1. Cut kapok fiber into pieces with a high-speed shearer, perform surface treatment on the kapok fiber with 2% NaOH aqueous solution for 5 - 10 minutes, then wash it with deionized water until neutral to obtain kapok fiber pieces, put them into a beater for beating treatment, and then add vinyltrimethoxysilane and stir evenly to obtain kapok pulp for standby; The addition amount of the vinyltrimethoxysilane is 0.1 - 0.3 parts per 100 parts of kapok pulp; the conditions for the stirring reaction are: stirring speed 800 - 1000 rpm, time 2 - 3 hours; S2. Cut bamboo fiber into pieces with a high-speed shearer, perform beating treatment in a beater, then add kapok pulp and stir evenly to obtain plant fiber pulp; put the plant fiber pulp liquid into a high-pressure homogenizer for homogenization treatment to obtain plant cellulose solution; Among them, the mass ratio of kapok fiber to bamboo fiber is 1:8 - 10; S3. Stir and heat polyvinyl alcohol and deionized water at 80°C for 80 - 120 min until completely dissolved, add modified montmorillonite, and stir for 30 - 50 min to make the modified montmorillonite evenly dispersed in the polyvinyl alcohol solution to obtain a polymer solution; The mass ratio of the modified montmorillonite to polyvinyl alcohol is 1:3 - 5; the mass fraction of the polyvinyl alcohol is 12 - 18%; S4. Mix the polymer solution and the plant cellulose solution according to the mass ratio of 1:(2 - 3), and then perform electrospinning to obtain the plant fiber highly breathable layer.

3. The preparation method of the chitosan-based superabsorbent material with antibacterial function according to claim 1, wherein The superabsorbent microspheres include the following raw materials: acrylic acid; water, chitosan, chitosan oligosaccharide, 2,2 - azobis(2 - methylpropionamidine) dihydrochloride, 1 - hydroxycyclohexyl phenyl ketone, alginic acid, glutaraldehyde and lubricant; its specific preparation method is as follows: S01. Weigh the following raw materials by weight: 15 - 20 parts of acrylic acid, 60 - 75 parts of water, 2 - 6 parts of chitosan, 1 - 3 parts of chitosan oligosaccharide, add 2,2 - azobis(2 - methylpropionamidine) dihydrochloride; 1 - hydroxycyclohexyl phenyl ketone to obtain a mixed solution; S02. Place the mixed solution at 40 - 80°C for polymerization cross-linking reaction, cool to obtain a polymerized liquid material system; S03. Add alginic acid and glutaraldehyde to the polymerized liquid material system, quickly stir for 3 - 5 minutes to make it uniform, then let it stand for 5 - 10 hours to form a viscous material system; heat the material to 75 - 95°C and keep it warm for 8 - 12 hours to form a hard and brittle hydrogel material; S04. Add a lubricant to the hard and brittle hydrogel material, stir at high speed for 30 - 50 minutes to break it, heat up to 95 - 110°C and dry it to dry and hard particles, and finally grind it to 60 - 100 mesh particles to obtain the superabsorbent microspheres.

4. The preparation method of the chitosan-based superabsorbent material with antibacterial function according to claim 3, characterized in that, The 2,2-azobis(2-methylpropylamidine) dihydrochloride accounts for 2 to 5 ten-thousandths of the total material mass; the 1-hydroxycyclohexylphenyl ketone accounts for 2 to 5 ten-thousandths of the total material mass; the chitosan oligosaccharide has a number average molecular weight of 1200-3400; the alginic acid accounts for 1.5 to 2 times the mass of the chitosan; and the glutaraldehyde accounts for 65 to 85% of the mass of the chitosan; and the lubricant is a mixture of ammonia water, polyethylene glycol, glycerol and aziridine, wherein the mass ratio of ammonia water, polyethylene glycol, glycerol, aziridine and gel material is 150 to 300:5 to 15:0.2 to 0.6:0.01 to 0.03:

100.

5. The preparation method of the chitosan-based superabsorbent material with antibacterial function according to claim 2, wherein, The preparation method of the modified montmorillonite is specifically as follows: Select montmorillonite with a diameter of about 1 μm, add the montmorillonite to deionized water, add dilute hydrochloric acid and stir evenly to fully disperse the montmorillonite in the dilute hydrochloric acid solution, heat to 60°C, add octadecyltrimethylammonium chloride, stir well, and react for 1 to 2 hours to obtain a montmorillonite suspension, then centrifuge at 3500 rpm, wash with deionized water 2 to 3 times to remove hydrochloric acid and octadecyltrimethylammonium chloride, centrifuge, and remove the solid mixture at the bottom. At this time, the interlayer spacing of the montmorillonite is expanded by the action of the quaternary ammonium salt; The solid mixture at the bottom is added with deionized water, and then the pH is adjusted to 6.3-6.5 with sodium carbonate or citric acid. Glycine is added and reacted for 1-2 hours to make the surface of the montmorillonite negatively charged. After completion, the modified montmorillonite is filtered, dried, and ground. The mass ratio of the octadecyltrimethylammonium chloride to the montmorillonite is 1:6-8; and the mass ratio of the glycine to the montmorillonite is 1:

10.

6. The preparation method of the chitosan-based superabsorbent material with antibacterial function according to claim 2, characterized in that, The electrospinning parameters are as follows: voltage of 30 kV, receiving distance of 10 cm, flow rate of 1 mL / h; ambient temperature and humidity of 25° C. and 40% to 60% respectively.

7. A superabsorbent material based on chitosan with antibacterial function, wherein the superabsorbent material based on chitosan with antibacterial function is prepared by the method according to any one of claims 1 to 6, and is characterized in that The high water-absorbing material with three-layer structure is prepared. The upper and lower surface layers are 0.5-1.0mm plant fiber high air permeability layers, and the middle layer is 1-2mm chitosan-based high water-absorbing microspheres with antibacterial function.

8. The superabsorbent material based on chitosan with antibacterial function according to claim 7, characterized in that, Application in preparing the water-absorbing layer of wound healing patches or sanitary napkins.

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