High-swelling-degree hydrogel dressing and preparation method thereof

Abstract

The invention discloses a high-swelling-degree hydrogel dressing and a preparation method thereof, and relates to the technical field of sanitary materials. The prepared high-swelling-degree hydrogel dressing is prepared by taking natural polymer starch as a matrix and adding a self-made cross-linking agent and modified polyvinyl alcohol, the self-made cross-linking agent is prepared by reacting epoxy cardanol with a divinyl benzene polymer, the epoxy cardanol is prepared by reacting cardanol with epoxy chloropropane, and the modified polyvinyl alcohol is prepared by reacting the modified polyvinyl alcohol with a divinyl benzene polymer. The divinyl benzene polymer is prepared from chitosan, maleic anhydride and divinyl benzene through ternary polymerization, so that the dressing has high swelling degree, a wound is in a stable wet environment, and healing of the wound is promoted; the modified polyvinyl alcohol is prepared by mixing imidazole maleimide acid, polyvinyl alcohol and diethylene glycol monomethyl ether, and imidazole maleimide is prepared by reacting 2-(4-aminophenyl)-5-aminobenzimidazole and maleic anhydride, so that the moisturizing effect is enhanced, the healing of infected wounds is promoted, and meanwhile, the modified polyvinyl alcohol can cooperate with an antibacterial agent to achieve the antibacterial effect.

Description

Technical Field

[0001] The present invention relates to the technical field of sanitary materials, and particularly to a hydrogel dressing with high swelling degree and a preparation method thereof. Background Art

[0002] The skin is a barrier to maintain the stability of the internal environment and prevent the invasion of microorganisms. Due to reasons such as trauma, abrasion, burns, and skin ulcers, large-scale damage to the skin may occur. It is common knowledge that wounds are prone to infection, which is caused by the easy reproduction of pathogens such as Staphylococcus aureus, Candida, and Escherichia coli on the wounds. Infected wounds are not easy to heal, and are prone to fluid loss and cause various complications. Traditional dressings have a protective effect on the wound surface, but generally it is not considered that they have a promoting effect on wound healing. For example, if the granulation tissue is damaged when changing the dressing, it will instead delay the wound healing. The local application of antibiotics in gauze dressings leading to bacterial resistance makes it even more difficult for infected wounds to heal.

[0003] The hydrogel dressing is made by mixing and processing elastic polymer hydrogel, synthetic rubber, and viscous substances, and can be directly adhered to the wound site, having the effect of promoting wound healing. Therefore, the hydrogel dressing can be used to treat skin wounds caused by reasons such as trauma and surgery, and can also be used to treat diseases such as burns and scalds. The hydrogel dressing can protect the wound, provide a suitable environment for wound healing, and is easy to remove without causing harm to the newly generated tissue. The hydrogel dressing has been widely used in the treatment of various different wounds, especially having a significant effect on chronic refractory wounds. The water absorption, adhesion and other properties of the hydrogel dressing meet the basic requirements of an ideal dressing. However, it still has the disadvantage of low swelling degree. Therefore, the present invention studies and prepares a hydrogel dressing with high swelling degree. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a hydrogel dressing with high swelling degree and a preparation method thereof.

[0005] A technical solution proposed by the present invention to solve the above technical problem is: a hydrogel dressing with high swelling degree, which is prepared by using natural polymer starch as the matrix and adding a self-made crosslinking agent and modified polyvinyl alcohol; the self-made crosslinking agent is prepared by reacting epoxy cardanol with divinylbenzene polymer; the modified polyvinyl alcohol is prepared by mixing imidazole maleimide acid, polyvinyl alcohol, and diethylene glycol monomethyl ether; the starch is corn starch or wheat starch.

[0006] Preferably, it further includes an antibacterial agent and a solvent; the antibacterial agent is one of butanediamine, hexanediamine, octanediamine, decanediamine, or isophthalic acid; the solvent is deionized water.

[0007] Preferably, the epoxy cardanol is prepared by reacting cardanol with epichlorohydrin; the divinylbenzene polymer is prepared by the ternary polymerization of chitosan, maleic anhydride and divinylbenzene.

[0008] Preferably, the imidazole maleimide is prepared by reacting 2-(4-aminophenyl)-5-aminobenzimidazole with maleic anhydride.

[0009] Preferably, the preparation method of the highly swellable hydrogel dressing comprises the following specific steps:

[0010] S1. Mix epoxy cardanol, divinylbenzene polymer and acetone according to a mass ratio of 1:2-4, stir evenly and then heat up to 70-90 °C, dropwise add concentrated sulfuric acid with a mass 0.2-0.4 times that of epoxy cardanol at a rate of 1-3 ml / min, continue to react for 5-9 h, and perform rotary evaporation to obtain a self-made crosslinking agent;

[0011] S2. Mix imidazole maleimide acid, polyvinyl alcohol and diethylene glycol monomethyl ether according to a mass ratio of 2:8-12:1, stir evenly and heat up to 55-65 °C, and stir and react at 40-60 rpm for 8-12 h to obtain modified polyvinyl alcohol;

[0012] S3. Mix starch, modified polyvinyl alcohol and deionized water, stir evenly, adjust the pH to 7-12 with sodium hydroxide, heat up to 60-80 °C, keep warm for 10-20 min, add an antibacterial agent and the self-made crosslinking agent, continue to stir for 6-8 min, transfer to a mold, and keep warm for 4-6 h to obtain the highly swellable hydrogel dressing.

[0013] Preferably, in the above step S1, the preparation method of epoxy cardanol is as follows: Mix cardanol, epichlorohydrin and benzyltriethylammonium chloride according to a mass ratio of 1-1.2:1:0.02, heat up to 70-80 °C, stir and react at 200-400 rpm for 2-4 h, add a sodium hydroxide solution with a mass fraction of 30-38% and a mass 2-4 times that of cardanol, continue to react for 2-4 h, wash with deionized water 3-5 times, separate the liquid and perform vacuum distillation and suction filtration to obtain epoxy cardanol.

[0014] Preferably, in the above step S1, the preparation method of the divinylbenzene polymer is as follows: under an argon atmosphere, chitosan, p-toluenesulfonic acid monohydrate and formamide are mixed in a mass ratio of 1:1-1.02:100, and after stirring evenly, maleic anhydride with a mass 2.2-2.4 times that of chitosan is added. The temperature is raised to 55-65 °C and the reaction is carried out for 24 h. A divinylbenzene mixed solution with a mass 10-12 times that of chitosan is added dropwise at a rate of 1-3 ml / min. The mass ratio of dimethyl sulfoxide, divinylbenzene and 2,2'-azobisisobutyronitrile in the divinylbenzene mixed solution is 10:1-1.2:0.2. The temperature is raised to 68-72 °C and the reaction is continued for 10-12 h. It is exchanged with ethanol and deionized water for 3-5 times in sequence, and then freeze-dried at -20 to -40 °C to obtain the divinylbenzene polymer.

[0015] Preferably, in the above step S2, the preparation method of the imidazole maleimide acid is as follows: under a nitrogen atmosphere, maleic anhydride and N,N'-dimethylformamide are mixed in a mass ratio of 1:30-50, and after stirring evenly, the temperature is raised to 58-62 °C, and 2-(4-aminophenyl)-5-aminobenzimidazole with the same mass as aleic anhydride is added. The heat preservation reaction is carried out for 2-3 h, cooled to room temperature and filtered by suction, and washed with acetone for 3-5 times, and then dried in vacuum to obtain the imidazole maleimide acid.

[0016] Preferably, in the above step S3, the mass ratio of starch, modified polyvinyl alcohol, deionized water, antibacterial agent and self-made cross-linking agent is 10-20:6-8:40:1-3:4-6.

[0017] Preferably, the highly swellable hydrogel dressing prepared by the preparation method of the highly swellable hydrogel dressing may further add a traditional Chinese medicine extract accounting for 18-20% of the total mass of the highly swellable hydrogel dressing; the traditional Chinese medicine extract is one or more of aloe extract, ginseng extract, astragalus extract, bletilla striata extract, polygonum cuspidatum extract, notoginseng extract, lithospermum erythrorhizon extract, mint extract and turmeric extract.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0019] The highly swellable hydrogel dressing prepared by the present invention is prepared by using natural polymer starch as the matrix and adding a self-made cross-linking agent and modified polyvinyl alcohol;

[0020] The self-made cross-linking agent is prepared by the reaction of epoxy cardanol and divinylbenzene polymer. Epoxy cardanol is prepared by the reaction of cardanol and epichlorohydrin. Divinylbenzene polymer is prepared by the ternary polymerization of chitosan, maleic anhydride and divinylbenzene. Chitosan grafts maleic anhydride to form a graft copolymer, and then divinylbenzene is added for copolymerization reaction to form a polymer with a highly active ternary system. Then it reacts with epoxy cardanol to form a self-made cross-linking agent with an adsorption and cross-linking structure. Adding it to starch makes the dressing have a high swelling degree, keeps the wound in a stable moist environment, and promotes wound healing.

[0021] The modified polyvinyl alcohol is prepared by mixing imidazole maleimide acid, polyvinyl alcohol and diethylene glycol monomethyl ether. Imidazole maleimide is prepared by the reaction of 2-(4-aminophenyl)-5-aminobenzimidazole and maleic anhydride. Imidazole maleimide acid, polyvinyl alcohol and diethylene glycol monomethyl ether form a modified polyvinyl alcohol with a cross-linking structure and adsorption ability, which can enhance moisturizing and promote the healing of infected wounds, and can cooperate with antibacterial agents for antibacterial effects at the same time. Specific embodiments

[0022] The present invention will be specifically described below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention according to the above content of the present invention. Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art.

[0023] In order to more clearly illustrate the method provided by the present invention, it is described in detail through the following examples. The test methods for each index of the highly anti-fouling hot-melt marking material prepared in the examples and comparative examples are as follows:

[0024] Secondary swelling rate: The highly swelling hydrogel dressings prepared in the examples and comparative examples absorb deionized water at 25°C, and the weight is measured before and after the water absorption balance to calculate the secondary swelling rate;

[0025] Secondary swelling rate = (weight of the hydrogel dressing after water absorption - dry weight of the hydrogel dressing before water absorption) / dry weight of the hydrogel dressing before water absorption × 100%.

[0026] Antibacterial property: The highly swelling hydrogel dressings prepared in the examples and comparative examples are tested with reference to FZ / T01021.

[0027] Wound healing experiment: Male Wistar rats were used as experimental animals. The observation points were 5, 10, and 15 days. The back of the rats was depilated with sodium sulfide with a mass fraction of 8%. After 24 hours, the rats were anesthetized and scalded with hot water at 80°C for 15 s to cause deep second-degree burns on the skin. After the injury, 5 mL of normal saline was administered intraperitoneally. The high-swelling hydrogel dressings prepared in the examples and comparative examples were respectively covered on the wound surface, and then medical gauze was covered on the wound surface as a control group. The wound healing rate was calculated at the observation time points:

[0028] Wound healing rate = (original wound area - unhealed wound area) / original wound area.

[0029] Example 1

[0030] In this example, the preparation method of the high-swelling hydrogel dressing is as follows:

[0031] S1. Cardanol, epichlorohydrin, and benzyltriethylammonium chloride were mixed at a mass ratio of 1:1:0.02, heated to 70°C, and stirred and reacted at 200 rpm for 2 h. A sodium hydroxide solution with a mass fraction of 30-38% twice the mass of cardanol was added, and the reaction continued for 2 h. It was washed 3 times with deionized water, separated by liquid separation, distilled under reduced pressure, and filtered to obtain epoxidized cardanol. Under an argon atmosphere, chitosan, p-toluenesulfonic acid monohydrate, and formamide were mixed at a mass ratio of 1:1:100, stirred evenly, and then 2.2 times the mass of maleic anhydride of chitosan was added. The temperature was raised to 55°C and the reaction was carried out for 24 h. A divinylbenzene mixture 10 times the mass of chitosan was added dropwise at a rate of 1 ml / min. The mass ratio of dimethyl sulfoxide, divinylbenzene, and 2,2'-azobisisobutyronitrile in the divinylbenzene mixture was 10:1:0.2. The temperature was raised to 68°C and the reaction continued for 10 h. It was exchanged 3 times with ethanol and deionized water in turn, and freeze-dried at -20°C to obtain a divinylbenzene polymer. Epoxidized cardanol, divinylbenzene polymer, and acetone were mixed at a mass ratio of 1:2, stirred evenly, heated to 70°C, and concentrated sulfuric acid 0.2 times the mass of epoxidized cardanol was added dropwise at a rate of 1 ml / min. The reaction continued for 5 h, and rotary evaporation was carried out to obtain a self-made cross-linking agent;

[0032] S2. Under a nitrogen atmosphere, maleic anhydride and N,N'-dimethylformamide were mixed at a mass ratio of 1:30-50, stirred evenly, heated to 58°C, and 2-(4-aminophenyl)-5-aminobenzimidazole with the same mass as maleic anhydride was added. The reaction was carried out under insulation for 2 h, cooled to room temperature, filtered, and washed 3 times with acetone, and then vacuum dried to obtain imidazole maleimide acid. Imidazole maleimide acid, polyvinyl alcohol, and diethylene glycol monomethyl ether were mixed at a mass ratio of 2:8:1, stirred evenly, heated to 55°C, and stirred and reacted at 40 rpm for 8 h to obtain modified polyvinyl alcohol;

[0033] S3. Mix starch, modified polyvinyl alcohol and deionized water, stir evenly, adjust the pH to 7 with sodium hydroxide, heat up to 60 °C, keep warm for 10 min, add an antibacterial agent and a self-made crosslinking agent. The mass ratio of starch, modified polyvinyl alcohol, deionized water, antibacterial agent and self-made crosslinking agent is 10:6:40:1:4. Continue stirring for 6 min, transfer to a mold, keep warm for 4 h to obtain a high-swelling hydrogel dressing.

[0034] Example 2

[0035] In this example, the preparation method of the high-swelling hydrogel dressing is as follows:

[0036] S1. Mix cardanol, epichlorohydrin and benzyltriethylammonium chloride in a mass ratio of 1.1:1:0.02, heat up to 75 °C, stir and react at 300 rpm for 3 h, add a sodium hydroxide solution with a mass fraction of 30-38% which is 3 times the mass of cardanol, continue to react for 3 h, wash 4 times with deionized water, separate the liquid and carry out reduced pressure distillation and suction filtration to obtain epoxy cardanol; Under an argon atmosphere, mix chitosan, p-toluenesulfonic acid monohydrate and formamide in a mass ratio of 1:1.01:100, stir evenly and then add maleic anhydride which is 2.3 times the mass of chitosan, heat up to 60 °C, react for 24 h, and dropwise add a divinylbenzene mixed solution which is 11 times the mass of chitosan at a rate of 2 ml / min. The mass ratio of dimethyl sulfoxide, divinylbenzene and 2,2'-azobisisobutyronitrile in the divinylbenzene mixed solution is 10:1.1:0.2, heat up to 70 °C, continue to react for 11 h, exchange 4 times with ethanol and deionized water in sequence, and place in a -30 °C freeze dryer to obtain a divinylbenzene polymer; Mix epoxy cardanol, divinylbenzene polymer and acetone in a mass ratio of 1:3, stir evenly and then heat up to 80 °C, dropwise add concentrated sulfuric acid which is 0.3 times the mass of epoxy cardanol at a rate of 2 ml / min, continue to react for 7 h, and carry out rotary evaporation to obtain a self-made crosslinking agent;

[0037] S2. Under a nitrogen atmosphere, mix maleic anhydride and N,N'-dimethylformamide in a mass ratio of 1:40, stir evenly and then heat up to 60 °C, add 2-(4-aminophenyl)-5-aminobenzimidazole with the same mass as maleic anhydride, keep warm and react for 2.5 h, cool to room temperature and carry out suction filtration, and wash 4 times with acetone, and dry under vacuum to obtain imidazole maleimide acid; Mix imidazole maleimide acid, polyvinyl alcohol and diethylene glycol monomethyl ether in a mass ratio of 2:10:1, stir evenly and heat up to 60 °C, stir and react at 50 rpm for 10 h to obtain modified polyvinyl alcohol;

[0038] S3. Mix starch, modified polyvinyl alcohol, and deionized water. After stirring evenly, adjust the pH to 10 with sodium hydroxide, heat up to 70 °C, keep warm for 15 min, add an antibacterial agent and a self-made crosslinking agent. The mass ratio of starch, modified polyvinyl alcohol, deionized water, antibacterial agent, and self-made crosslinking agent is 15:7:40:2:5. Continue stirring for 7 min, transfer to a mold, and keep warm for 5 h to obtain a high-swelling hydrogel dressing.

[0039] Example 3

[0040] In this example, the preparation method of the high-swelling hydrogel dressing is as follows:

[0041] S1. Mix cardanol, epichlorohydrin, and benzyltriethylammonium chloride in a mass ratio of 1.2:1:0.02. Heat up to 80 °C and stir and react at 400 rpm for 4 h. Add a sodium hydroxide solution with a mass fraction of 38% that is 4 times the mass of cardanol, and continue to react for 4 h. Wash 5 times with deionized water, separate the liquid, perform vacuum distillation and suction filtration to obtain epoxy cardanol; under an argon atmosphere, mix chitosan, p-toluenesulfonic acid monohydrate, and formamide in a mass ratio of 1:1.02:100. After stirring evenly, add maleic anhydride that is 2.4 times the mass of chitosan, heat up to 65 °C, and react for 24 h. Dropwise add a divinylbenzene mixed solution that is 12 times the mass of chitosan at a rate of 3 ml / min. The mass ratio of dimethyl sulfoxide, divinylbenzene, and 2,2'-azobisisobutyronitrile in the divinylbenzene mixed solution is 10:1.2:0.2. Heat up to 72 °C and continue to react for 12 h. Exchange 5 times with ethanol and deionized water in sequence, and place in a -40 °C freeze dryer to obtain a divinylbenzene polymer; mix epoxy cardanol, divinylbenzene polymer, and acetone in a mass ratio of 1:4. After stirring evenly, heat up to 90 °C and dropwise add concentrated sulfuric acid that is 0.4 times the mass of epoxy cardanol at a rate of 3 ml / min, and continue to react for 9 h. Perform rotary evaporation to obtain a self-made crosslinking agent;

[0042] S2. Under a nitrogen atmosphere, mix maleic anhydride and N,N'-dimethylformamide in a mass ratio of 1:50. After stirring evenly, heat up to 62 °C, add 2-(4-aminophenyl)-5-aminobenzimidazole with the same mass as maleic anhydride, keep warm and react for 3 h, cool to room temperature and perform suction filtration, and wash 5 times with acetone, then perform vacuum drying to obtain imidazole maleimide acid; mix imidazole maleimide acid, polyvinyl alcohol, and diethylene glycol monomethyl ether in a mass ratio of 2:12:1. Stir evenly and heat up to 65 °C, and stir and react at 60 rpm for 12 h to obtain modified polyvinyl alcohol;

[0043] S3. Mix starch, modified polyvinyl alcohol and deionized water, stir evenly, adjust the pH to 12 with sodium hydroxide, heat up to 80 °C, keep warm for 20 min, add an antibacterial agent and a self-made cross-linking agent. The mass ratio of starch, modified polyvinyl alcohol, deionized water, antibacterial agent and self-made cross-linking agent is 20:8:40:3:6. Continue stirring for 8 min, transfer to a mold, and keep warm for 6 h to obtain a high-swelling hydrogel dressing.

[0044] Comparative Example 1

[0045] The preparation method of Comparative Example 1 is the same as that of Example 2. The difference between this high-swelling hydrogel dressing and Example 2 is that the self-made cross-linking agent is only prepared by reacting epoxy cashew phenol with divinylbenzene.

[0046] Comparative Example 2

[0047] The preparation method of Comparative Example 2 is the same as that of Example 2. The difference between this high-swelling hydrogel dressing and Example 2 is that the self-made cross-linking agent is only a divinylbenzene polymer.

[0048] Comparative Example 3

[0049] The preparation method of Comparative Example 3 is the same as that of Example 2. The difference between this high-swelling hydrogel dressing and Example 2 is that the modified polyvinyl alcohol only includes polyvinyl alcohol and diethylene glycol monomethyl ether.

[0050] Comparative Example 4

[0051] The preparation method of Comparative Example 4 is the same as that of Example 2. The difference between this high-swelling hydrogel dressing and Example 2 is that the modified polyvinyl alcohol only includes a mixture of imidazole maleimide acid and polyvinyl alcohol.

[0052] Effect Example

[0053] The following Table 1 shows the performance test results of the high-swelling hydrogel dressings prepared in the examples and comparative examples;

[0054] Table 1

[0055]

[0056] From the comparison of the performance data in Table 2, it can be seen that the high-swelling hydrogel dressing prepared by the present invention has excellent antibacterial properties, high swelling degree, and can promote wound healing;

[0057] From the comparison of the experimental data of Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2, it can be found that chitosan grafted with maleic anhydride forms a graft copolymer, and then divinylbenzene is added for copolymerization reaction to form a polymer with a highly active ternary system. Then, it reacts with epoxy cashew phenol to form a self-made cross-linking agent with an adsorption and cross-linking structure, which is added to starch to make the dressing have a high swelling degree, enabling the wound to be in a stable moist environment and promoting wound healing.

[0058] From the comparison of the experimental data of Example 1, Example 2, Example 3, Comparative Example 3, and Comparative Example 4, it can be found that imidazole maleimide acid, polyvinyl alcohol, and diethylene glycol monomethyl ether form a modified polyvinyl alcohol with a cross-linking structure and adsorption ability. While enhancing moisture retention and promoting the healing of infected wounds, it can also cooperate with antibacterial agents for antibacterial effects.

[0059] Obviously, the above embodiments are merely examples given for clearly explaining the embodiments of the present invention, rather than limitations on the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the embodiments here. And these obvious changes or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A high swelling hydrogel dressing, characterized in that: The invention is prepared by taking natural polymer starch as matrix, adding self-made cross-linking agent and modified polyvinyl alcohol; the self-made cross-linking agent is prepared by reacting epoxy cardanol with divinyl benzene polymer; the modified polyvinyl alcohol is prepared by mixing imidazole maleimide acid, polyvinyl alcohol and diethylene glycol monomethyl ether; the starch is corn starch or wheat starch.

2. A high swelling hydrogel dressing according to claim 1, characterized in that: It also includes an antibacterial agent and a solvent; the antibacterial agent is one of diamine, hexamethylenediamine, octanediamine, decanediamine or isophthalic acid; and the solvent is deionized water.

3. The high swelling hydrogel dressing according to claim 1, characterized in that: The epoxy cardanol is prepared by reacting cardanol with epichlorohydrin; and the divinylbenzene polymer is prepared by terpolymerization of chitosan, maleic anhydride and divinylbenzene.

4. The high swelling hydrogel dressing according to claim 1, characterized in that: The imidazole maleimide is prepared by reacting 2-(4-aminophenyl)-5-aminobenzimidazole with maleic anhydride.

5. A method for preparing a high swelling hydrogel dressing as claimed in claim 1, characterized in that: The specific steps include: S1. Mix epoxy cardanol, divinylbenzene polymer and acetone in a mass ratio of 1:2-4, stir evenly and heat to 70-90°C, add concentrated sulfuric acid 0.2-0.4 times the mass of epoxy cardanol at a rate of 1-3 ml / min, continue the reaction for 5-9 hours, and rotary evaporate to obtain a homemade cross-linking agent; S2. imidazole maleimide acid, polyvinyl alcohol and diethylene glycol monomethyl ether were mixed in a mass ratio of 2:8 to 12:1, stirred evenly, heated to 55 to 65°C, and stirred at 40 to 60 rpm for 8 to 12 hours to obtain modified polyvinyl alcohol; S3. Mix starch, modified polyvinyl alcohol and deionized water, stir evenly, adjust the pH to 7-12 with sodium hydroxide, raise the temperature to 60-80℃, keep warm for 10-20 minutes, add antibacterial agent and homemade cross-linking agent, continue stirring for 6-8 minutes, transfer to a mold, keep warm for 4-6 hours, and obtain a high swelling hydrogel dressing.

6. The method for preparing a high swelling hydrogel dressing according to claim 5, characterized in that: In the above step S1., the preparation method of epoxy cardanol is: mixing cardanol, epichlorohydrin and benzyltriethylammonium chloride in a mass ratio of 1-1.2:1:0.02, heating to 70-80°C, stirring at 200-400rpm for reaction for 2-4h, adding a sodium hydroxide solution with a mass fraction of 30-38% which is 2-4 times the mass of cardanol, continuing the reaction for 2-4h, washing with deionized water 3-5 times, separating the liquids and distilling under reduced pressure, and filtering to obtain epoxy cardanol.

7. The method for preparing a high swelling hydrogel dressing according to claim 5, characterized in that: In the above step S1., the preparation method of the divinylbenzene polymer is: under an argon atmosphere, chitosan, p-toluenesulfonic acid monohydrate and formamide are mixed in a mass ratio of 1:1~1.02:100, and maleic anhydride is added in an amount of 2.2~2.4 times the mass of chitosan after stirring evenly, and the temperature is raised to 55~65°C, and the reaction is carried out for 24 hours. A divinylbenzene mixed solution in which the mass of chitosan is 10~12 times is added dropwise at a rate of 1~3 ml / min, wherein the mass ratio of dimethyl sulfoxide, divinylbenzene and 2,2′-azobisisobutyronitrile in the divinylbenzene mixed solution is 10:1~1.2:0.2, the temperature is raised to 68~72°C, the reaction is continued for 10~12 hours, and the mixture is exchanged with ethanol and deionized water 3~5 times in sequence, and freeze-dried at -20~-40°C to obtain a divinylbenzene polymer.

8. The method for preparing a high swelling hydrogel dressing according to claim 5, characterized in that: In the above step S2., the preparation method of imidazole maleimide acid is: under a nitrogen atmosphere, maleic anhydride and N, N'-dimethylformamide are mixed in a mass ratio of 1:30~50, stirred evenly and then heated to 58~62°C, and 2-(4-aminophenyl)-5-aminobenzimidazole of equal mass of allic anhydride is added, and the reaction is kept warm for 2~3h, cooled to room temperature, filtered, washed with acetone 3~5 times, and vacuum dried to obtain imidazole maleimide acid.

9. The method for preparing a high swelling hydrogel dressing according to claim 5, characterized in that: In the above step S3., the mass ratio of starch, modified polyvinyl alcohol, deionized water, antibacterial agent and homemade cross-linking agent is 10~20:6~8:40:1~3:4~6.

10. The method for preparing a high swelling hydrogel dressing according to claim 5, characterized in that: The high swelling hydrogel dressing prepared by the preparation method of the high swelling hydrogel dressing can also be added with 18-20% of the total mass of the high swelling hydrogel dressing Chinese herbal medicine extract; the Chinese herbal medicine extract is one or more of aloe extract, ginseng extract, astragalus extract, bletilla striata extract, knotweed extract, notoginseng extract, lithospermum officinale extract, mint extract and turmeric extract.

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