Bamboo fiber medical sponge and preparation method and application thereof

Abstract

The invention relates to the field of medical sponge materials, and particularly discloses a bamboo fiber medical sponge and a preparation method and application thereof.The preparation method comprises the following steps that bamboo fibers are firstly subjected to alkalization treatment and sulfonation treatment to prepare sulfoacid ester; the preparation method comprises the following steps: firstly, carrying out acid etching on glass fibers, and modifying the glass fibers with an amino silane coupling agent to obtain aminated glass fibers; the surface of the aminated glass fiber is coated with a nano-hydroxyapatite / chitosan composite material, and reinforced fiber is prepared; the preparation method comprises the following steps: dissolving sulfoacid ester in water, adding reinforced fibers, standing, uniformly stirring, adding a polyurethane prepolymer, mixing, adding acid, stirring, standing, carrying out alkali washing, and carrying out heat treatment to obtain the bamboo fiber medical sponge. The invention further discloses the bamboo fiber medical sponge prepared by the preparation method and application of the bamboo fiber medical sponge in vacuum sealing drainage treatment. The medical sponge suitable for vacuum sealing drainage treatment has the advantages of being not hardened when dried and good in mechanical property.

Description

Technical Field

[0001] The present application relates to the field of medical sponge materials, and more specifically, to a bamboo fiber medical sponge and its preparation method and application. Background Art

[0002] In the modern medical field, the treatment of open wounds has always been a key issue of clinical concern. Since open wounds are directly exposed to the external environment, they are prone to bacterial infection, which affects the healing process and may even cause serious systemic complications. Therefore, effective treatment means are needed to promote wound healing and reduce the risk of infection.

[0003] As an advanced wound treatment method, the vacuum sealing drainage (VSD) treatment technology has been widely used in the treatment of various open wounds in recent years. By covering the wound with a dressing having a drainage function and connecting a negative pressure device to continuously or intermittently apply negative pressure, this technology can timely remove the exudates and necrotic tissues of the wound, promote blood circulation, accelerate the growth of granulation tissue, and significantly improve the treatment effect of open wounds.

[0004] In the vacuum sealing drainage treatment, the performance of the drainage material plays a key role. At present, the commonly used drainage material is polyvinyl alcohol sponge. The polyvinyl alcohol sponge has good liquid absorption ability, can effectively absorb the wound exudate, keep the wound in a relatively clean environment, and at the same time it also has a certain molding stability, can better fit the shape of the wound, and provide a stable treatment environment for the wound, so it is widely used clinically.

[0005] However, the polyvinyl alcohol sponge also has obvious limitations in actual application. Under negative pressure, the sponge dressing will gradually lose water and harden. When the treatment enters the later stage, the friction between the hardened sponge dressing and the wound or the surrounding skin increases, which is likely to cause secondary damage to the wound and the skin, not only delaying the wound healing time but also greatly increasing the pain of the patient.

[0006] In order to overcome the hardening problem of the polyvinyl alcohol sponge in the dry state, the existing solutions include coating the surface of the sponge to increase flexibility, or adding a moisturizing agent to delay the hardening speed of the sponge. However, the above methods have limited effects and cannot fundamentally solve the problem of water loss and hardening of polyvinyl alcohol in a negative pressure environment.

[0007] Therefore, it is of great significance to develop a medical sponge suitable for vacuum sealing drainage treatment. Summary of the Invention

[0008] In order to provide a medical sponge suitable for vacuum sealing drainage treatment, which does not harden when dry and has good mechanical properties, the present application provides a bamboo fiber medical sponge and its preparation method and application.

[0009] In a first aspect, the present application provides a method for preparing a bamboo fiber medical sponge, adopting the following technical solutions: A method for preparing a bamboo fiber medical sponge, comprising the following steps: S1. First, the bamboo fiber is alkalized to form alkali fiber, and then sulfonated to obtain xanthate ester. S2. First, the glass fiber is acid-etched and then modified with an amino-silane coupling agent to obtain amino-functionalized glass fiber. S3. A nano-hydroxyapatite / chitosan composite material is coated on the surface of the amino-functionalized glass fiber to obtain reinforced fiber. S4. The xanthate ester is dissolved in water, then the reinforced fiber is added, and after standing, it is stirred evenly, then a polyurethane prepolymer is added and mixed, then acid is added and stirred, then left standing, and then alkali-washed and heat-treated to obtain a bamboo fiber medical sponge.

[0010] By adopting the above technical solutions, in the present application, first, the bamboo fiber is alkali-washed. During the process, the alkali solution ionizes part of the hydroxyl groups in the cellulose molecule, destroys the hydrogen bonds between the cellulose molecular chains, increases the reaction activity of the cellulose, and then sulfonation reaction occurs to generate xanthate ester. The formation of xanthate ester improves the hydrophilicity and solubility of cellulose. Then it is dissolved in water to form a viscose system. Then, amino-functionalized glass fiber coated with a nano-hydroxyapatite / chitosan composite material and a polyurethane prepolymer are added. Under acidic conditions, the xanthate ester is regenerated into cellulose and the residual chemical reagents are removed by alkali-washing. Moreover, under the conditions of the polyurethane prepolymer and solvent water, the isocyanate in the polyurethane prepolymer reacts based on the combination with water to form a foam structure, obtaining a sponge structure with high porosity. Finally, through heat treatment, it promotes the rearrangement and crystallization of cellulose molecules and at the same time realizes the curing of polyurethane to form a stable bamboo fiber medical sponge.

[0011] In the present application, the addition of the polyurethane prepolymer in combination with water can not only form a foaming system, but also polyurethane, as a polymer elastomer, plays the role of a flexible skeleton in the sponge structure. Even in the state of negative pressure water loss, polyurethane can still maintain a certain flexibility, avoiding the hardening of the sponge. Moreover, in the present application, the sponge matrix is based on bamboo fiber. Bamboo fiber has good air permeability and hygroscopicity, and also has a natural antibacterial and bacteriostatic function, making it more suitable for use as a medical sponge for negative pressure closed drainage treatment. The addition of the reinforced fiber significantly improves the mechanical properties of the bamboo fiber sponge. Moreover, a chemical bonding effect is formed between the amino-functionalized glass fiber and the nano-hydroxyapatite / chitosan composite material, and the unsulfonated part of the bamboo fiber can also form a chemical bonding effect with the reinforced fiber. Coupled with the physical cross-linking effect between the generated polyurethane and cellulose, the interfacial bonding force inside the whole sponge is enhanced, avoiding the phenomenon of fragmentation and adhesion, and the prepared bamboo fiber sponge has better mechanical properties.

[0012] In addition, the glass fiber in this application is added after being modified and coated with a nano-hydroxyapatite / chitosan composite material. On the one hand, chitosan has good hygroscopicity and can retain moisture to a certain extent, preventing the sponge from drying out completely and hardening. Moreover, hydroxyapatite also has a certain hygroscopicity. When compounded with chitosan, it can play a more long-lasting hygroscopic role. And it has good biocompatibility. Its addition combines mechanical strength and a bio-functional coating, significantly improving the performance of the glass fiber. When coated on the surface of the glass fiber, its granular form enhances the roughness of the glass fiber, which is more conducive to the physical entanglement between glass fibers and between glass fibers and bamboo fibers. Together with the subsequent polyurethane macromolecular cross-linked network structure, the entanglement between fibers can be fixed. While alleviating fiber slippage or looseness, its elasticity allows relative movement of the fibers within a certain range, making the sponge material have better flexibility while enhancing the bonding force between fibers and further preventing it from breaking and sticking.

[0013] Finally, the medical sponge prepared in this application has certain antibacterial properties, and also has hygroscopicity and air permeability. It will not harden when dry, has good mechanical properties, will not break and stick, and has excellent comprehensive performance, and is particularly suitable for vacuum sealing drainage treatment.

[0014] Optionally, the nano-hydroxyapatite / chitosan composite material is prepared by the following method: 1), Mix chitosan and sodium alginate and dissolve them in an acetic acid solution and stir to obtain a chitosan mixed solution; 2), Mix the chitosan mixed solution with a phosphoric acid solution to obtain a mixed solution, then drop the mixed solution into a calcium hydroxide suspension while stirring, react at 40 - 60 °C, and adjust the pH value to 8.5 - 10, and react for 2 - 4 h; 3), After the reaction, let it stand for 15 - 20 h, then filter and wash with water until neutral, and then freeze-dry to obtain the nano-hydroxyapatite / chitosan composite material.

[0015] By adopting the above technical solution, in the present application, sodium alginate and chitosan are blended and then co-precipitated. Specifically, when the mixed solution is dropped into the calcium hydroxide suspension, calcium hydroxide provides calcium ions, and under the pH condition, the calcium ions combine with phosphate ions to form hydroxyapatite, so that chitosan and hydroxyapatite are co-precipitated and separated out in an alkaline environment. At the same time, hydroxyapatite particles are formed in the chitosan mixed solution and are loaded in the pore structure of chitosan due to the wrapping and adsorption of chitosan, realizing the loading and slow release of nano-hydroxyapatite, not only providing mechanical support but also realizing the slow release of moisturizing factors. The addition of sodium alginate forms a complex with chitosan through electrostatic interaction, enhancing the mechanical strength and stability of the composite material. Moreover, it can also prevent the aggregation of hydroxyapatite nanoparticles through electrostatic repulsion and promote their uniform dispersion in the chitosan matrix, improving the performance of the composite material.

[0016] Optionally, when preparing the nano-hydroxyapatite / chitosan composite material, the freeze-drying parameters in step 3) are as follows: First, pre-freeze at -40 - (-60)°C for 2 - 3 h, then dry at -50 - (-70)°C and a vacuum degree of 10 - 20 Pa for 12 - 13 h, then dry and treat at -10 - (-5)°C and a vacuum degree of 3 - 5 Pa for 1 - 2 h, and then treat at 20 - 40°C and a vacuum degree of 10 - 20 Pa for 6 - 10 h.

[0017] By adopting the above technical solution, first, pre-freezing treatment is carried out at a low temperature, and the water is quickly frozen into ice crystals. The low temperature helps to form fine and uniformly distributed ice crystals, which become the basis of the pore structure in the subsequent drying process. The temperature in the first drying stage is lower than that in the pre-freezing stage, and the surface water sublimes first, resulting in the formation of a closely arranged structure on the surface of the composite material, forming a pore structure with a dense exterior and a loose interior. Then, secondary drying is carried out to remove the residual water, and the water is completely removed in the final drying stage to fix the pore structure. Finally, the pore structure with a dense exterior and a loose interior is more conducive to improving the comprehensive performance of the sponge material.

[0018] Optionally, when preparing the nano-hydroxyapatite / chitosan composite material, In step 1), the mass concentration of the acetic acid solution is 10 - 20%, and the added mass ratio of chitosan to the acetic acid solution is 1:(3 - 5), and the added mass ratio of chitosan and sodium alginate is 1:(0.1 - 0.2); In step 2), the concentration of the phosphoric acid solution is 0.1 - 0.5 mol / L, and the volume ratio of the chitosan mixed solution to the phosphoric acid solution is 1:(1 - 3), and the feeding ratio of phosphoric acid to calcium hydroxide is 1:(1.5 - 2).

[0019] Optionally, the specific operation of step S2 is as follows: The glass fiber is first treated in a sulfuric acid solution with a concentration of 0.5 - 2 mol / L at a treatment temperature of 60 - 70 °C for 10 - 20 min, then washed with water and dried. Then, the treated glass fiber is mixed and impregnated with glycine, γ-aminopropyltriethoxysilane, and water according to a mass ratio of 1:(0.2 - 0.3):(0.3 - 0.5):(4 - 6). The impregnation temperature is 50 - 60 °C, and the impregnation time is 4 - 6 h. After the impregnation treatment, the amino-functionalized glass fiber is obtained.

[0020] By adopting the above technical solution, when compounding with the nano-hydroxyapatite / chitosan composite material after the above amino-functionalization treatment, the amino groups on the glass fiber surface can form chemical bonds with the amino and hydroxyl groups in the composite material, thereby enhancing the bonding force between the two, and being more conducive to improving the mechanical properties and anti-hardening properties of the sponge material.

[0021] Optionally, the specific operation of step S3 is as follows: The nano-hydroxyapatite / chitosan composite material is mixed with water, then polyethylene glycol and carboxymethyl cellulose are added, and then genipin is added and stirred to prepare a spraying solution. Then, the spraying solution is sprayed on the amino-functionalized glass fiber, and then dried at 50 - 60 °C to obtain the reinforced fiber.

[0022] Optionally, in step S3, the added mass ratio of the nano-hydroxyapatite / chitosan composite material to water is 1:(3 - 4), the added mass ratio of polyethylene glycol to carboxymethyl cellulose is 1:(1.5 - 1.8), and the addition amount of polyethylene glycol is 10 - 20 wt% of the nano-hydroxyapatite / chitosan composite material, the addition amount of genipin is 1 - 3 wt% of the nano-hydroxyapatite / chitosan composite material, and the added mass ratio of the spraying solution to the amino-functionalized glass fiber is 1:(3 - 4).

[0023] By adopting the above technical solution, since polyethylene glycol and carboxymethyl cellulose are viscous after being dissolved in water, and with the cross-linking effect of genipin, the amino functional groups of the amino-functionalized glass fiber and the amino functional groups on chitosan form cross-links, realizing a firm combination between the composite material and the amino-functionalized glass fiber, being more conducive to forming entanglement with bamboo fiber, and finally obtaining a sponge that will not break and adhere.

[0024] Optionally, the specific operation of step S4 is as follows: The xanthate is dissolved in 6 - 8 mass times of water, then the reinforced fiber is added, and the addition amount of the reinforced fiber is 5 - 10 wt% of the xanthate. After standing for 10 - 12 h, the polyurethane prepolymer is added with stirring, and the addition amount of the polyurethane prepolymer is 10 - 15 wt% of the addition amount of the xanthate. Then, an acid is added to adjust the pH to 4.5 - 6, and after reacting for 30 - 40 min, an alkali is added to neutralize it. Then, it is filtered and treated at 60 - 70 °C for 4 - 6 h to obtain the bamboo fiber medical sponge.

[0025] Optionally, the specific operation of step S1 is as follows: First, place the bamboo fiber in a sodium hydroxide solution with a mass concentration of 3 - 8 wt%, the impregnation temperature is 30 - 40 °C, and the impregnation time is 1 - 2 h. Then, filter to obtain alkali cellulose. Then, react the alkali cellulose with carbon disulfide for 1 - 2 h under a vacuum of 40 - 50 Pa to form xanthate ester. The added mass ratio of bamboo fiber to carbon disulfide is 1:(0.3 - 0.4).

[0026] By adopting the above technical solution, in the sodium hydroxide solution, some hydroxyl groups in the cellulose of the bamboo fiber are ionized to form alkali cellulose, which weakens the hydrogen bonds between the cellulose molecular chains and increases the reactivity of the molecular chains. Then, under vacuum conditions, carbon disulfide reacts with alkali cellulose to carry out a sulfonation reaction, converting some hydroxyl groups in the cellulose molecule into xanthate ester groups, increasing the hydrophilicity and solubility of the cellulose. Then, it dissolves in water to form a viscose system. Subsequently, when standing, the xanthate ester undergoes an intermolecular crosslinking reaction to form a certain network structure, and forms a macromolecular network structure with the reinforcing fiber and polyurethane through physical entanglement and chemical action. Finally, after adding acid, the xanthate ester is neutralized by the acid to regenerate cellulose, promoting the rearrangement of cellulose to form a stable bamboo sponge structure.

[0027] In a second aspect, the present application provides a bamboo fiber medical sponge, adopting the following technical solution: A bamboo fiber medical sponge is prepared by the above preparation method.

[0028] By adopting the above technical solution, the bamboo fiber medical sponge prepared by the preparation method in the present application has good hygroscopicity and air permeability. More importantly, it has good anti-hardening performance and mechanical properties, will not break and adhere, and is suitable for negative pressure closed drainage treatment.

[0029] In a third aspect, the present application provides an application of a bamboo fiber medical sponge, adopting the following technical solution: The application of the bamboo fiber medical sponge in negative pressure closed drainage treatment.

[0030] In summary, the present application has the following beneficial effects: 1. The addition of the polyurethane prepolymer in the present application in combination with water can not only form a foaming system, but also the polyurethane, as a high molecular elastomer, plays a role of a flexible skeleton in the sponge structure. Even in the state of losing water under negative pressure, the polyurethane can still maintain a certain flexibility, avoiding the sponge from hardening. Moreover, the sponge matrix in the present application is based on bamboo fiber, which has good air permeability and hygroscopicity, and also has a natural antibacterial and bacteriostatic function, making it more suitable for the medical sponge for negative pressure closed drainage treatment; 2. The addition of reinforcing fibers in this application significantly improves the mechanical properties of bamboo fiber sponges. Moreover, a chemical bonding interaction is formed between the aminated glass fibers and the nano-hydroxyapatite / chitosan composite material, and the unsulfonated part of the bamboo fibers can also form a chemical bonding interaction with the reinforcing fibers. Coupled with the physical cross-linking interaction between the generated polyurethane and cellulose, the interfacial bonding force inside the sponge as a whole is enhanced, avoiding the phenomenon of fragmentation and adhesion. The prepared bamboo fiber sponge has better mechanical properties. Detailed implementation manners

[0031] The following further elaborates on this application in conjunction with examples. It should be specifically noted that: for those not specifying specific conditions in the following examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. Except for special instructions, the raw materials used in the following examples can all be sourced from ordinary commercial sales.

[0032] In the following examples, the polyurethane prepolymer is the terminal isocyanate group polyurethane prepolymer from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., with the model number 103837-45-2.

[0033] The following preparation examples are for the preparation of nano-hydroxyapatite / chitosan composite materials Preparation Example 1 A preparation method for a nano-hydroxyapatite / chitosan composite material includes the following steps: 1). Mix chitosan and sodium alginate and dissolve them in an acetic acid solution with a mass concentration of 15% and stir to obtain a chitosan mixed solution. The added mass ratio of chitosan to the acetic acid solution is 1:4, and the added mass ratio of chitosan to sodium alginate is 1:0.2; 2). Dilute phosphoric acid to form a phosphoric acid solution with a concentration of 0.3 mol / L, then mix the chitosan mixed solution and the phosphoric acid solution in a volume ratio of 1:2 to obtain a mixed solution, and then drop the mixed solution into a calcium hydroxide suspension while stirring, react at 50 °C, and adjust the pH value to 9, react for 3 h, and the feeding ratio of phosphoric acid to calcium hydroxide is 1:1.8; 3). After the reaction, let it stand for 18 h, then filter and wash with water until neutral, and then freeze-dry to obtain the nano-hydroxyapatite / chitosan composite material.

[0034] The freeze-drying parameters in step 3) are: First, pre-freeze at -50 °C for 2.5 h, then dry at -60 °C and a vacuum degree of 15 Pa for 12.5 h, then dry and process at -8 °C and a vacuum degree of 4 Pa for 1.5 h, and then process at 30 °C and a vacuum degree of 15 Pa for 8 h.

[0035] Preparation Example 2 A preparation method for a nano-hydroxyapatite / chitosan composite material includes the following steps: 1), Mix chitosan and sodium alginate and dissolve them in acetic acid solution with a mass concentration of 10% and stir to obtain a chitosan mixed solution. The added mass ratio of chitosan to acetic acid solution is 1:3, and the added mass ratio of chitosan to sodium alginate is 1:0.1; 2), Dilute phosphoric acid to form a phosphoric acid solution with a concentration of 0.1 mol / L. Then mix the chitosan mixed solution and the phosphoric acid solution according to a volume ratio of 1:1 to obtain a mixed solution. Then drop the mixed solution into a calcium hydroxide suspension while stirring, react at 40 °C, and adjust the pH value to 8.5, react for 4 h, and the feeding ratio of phosphoric acid to calcium hydroxide is 1:1.5; 3), After the reaction is completed, let it stand for 15 h, then filter and wash with water until neutral, and then freeze-dry to obtain a nano-hydroxyapatite / chitosan composite material.

[0036] The freeze-drying parameters in step 3) are: First, pre-freeze at -40 °C for 3 h, then dry at -50 °C and a vacuum degree of 10 Pa for 13 h, then dry and treat at -10 °C and a vacuum degree of 3 Pa for 2 h, and then treat at 20 °C and a vacuum degree of 10 Pa for 10 h.

[0037] Preparation Example 3 A preparation method of a nano-hydroxyapatite / chitosan composite material, comprising the following steps: 1), Mix chitosan and sodium alginate and dissolve them in acetic acid solution with a mass concentration of 20% and stir to obtain a chitosan mixed solution. The added mass ratio of chitosan to acetic acid solution is 1:5, and the added mass ratio of chitosan to sodium alginate is 1:0.2; 2), Dilute phosphoric acid to form a phosphoric acid solution with a concentration of 0.5 mol / L. Then mix the chitosan mixed solution and the phosphoric acid solution according to a volume ratio of 1:3 to obtain a mixed solution. Then drop the mixed solution into a calcium hydroxide suspension while stirring, react at 60 °C, and adjust the pH value to 10, react for 2 h, and the feeding ratio of phosphoric acid to calcium hydroxide is 1:2; 3), After the reaction is completed, let it stand for 20 h, then filter and wash with water until neutral, and then freeze-dry to obtain a nano-hydroxyapatite / chitosan composite material.

[0038] The freeze-drying parameters in step 3) are: First, pre-freeze at -60 °C for 2 h, then dry at (-70) °C and a vacuum degree of 20 Pa for 12 h, then dry and treat at (-5) °C and a vacuum degree of 5 Pa for 1 h, and then treat at 40 °C and a vacuum degree of 20 Pa for 6 h.

[0039] Preparation Example 4 A preparation method of a nano-hydroxyapatite / chitosan composite material is carried out according to the method in Preparation Example 1, the difference is that the freeze-drying parameters in step 3) are: First, pre-freeze at -50°C for 2.5 h, then dry at -60°C and a vacuum degree of 15 Pa for 12.5 h, and then treat at 30°C and a vacuum degree of 15 Pa for 8 h.

[0040] Example 1 A preparation method of a bamboo fiber medical sponge, comprising the following steps: S1. First, immerse bamboo fibers (with a length of 5 - 10 cm and a diameter of 10 - 20 μm) in a sodium hydroxide solution with a mass concentration of 5 wt%, the sodium hydroxide solution covering the bamboo fibers, the immersion temperature being 35°C and the immersion time being 1.5 h. Then, filter to obtain alkali cellulose, and then react the alkali cellulose with carbon disulfide at a vacuum degree of 45 Pa for 1.5 h to form xanthate ester, the added mass ratio of bamboo fiber to carbon disulfide being 1:0.3; S2. First, treat glass fibers (with a diameter of 8 - 12 μm and a length of 5 - 10 mm) in a sulfuric acid solution with a concentration of 1 mol / L, the sulfuric acid solution covering the glass fibers, the treatment temperature being 65°C and the treatment time being 15 min. Then, wash with water and dry, and then mix and immerse the treated glass fibers with glycine, γ-aminopropyltriethoxysilane and water according to a mass ratio of 1:0.2:0.4:5, the immersion temperature being 55°C and the immersion time being 5 h. After immersion treatment, filter and dry to obtain amino-functionalized glass fibers; S3. Mix the nano-hydroxyapatite / chitosan composite material prepared in Preparation Example 1 with water, then add polyethylene glycol and carboxymethyl cellulose, and then add genipin and stir to obtain a spraying solution. Then, spray the spraying solution on the amino-functionalized glass fibers, and then dry at 55°C to obtain reinforced fibers; The added mass ratio of the nano-hydroxyapatite / chitosan composite material to water is 1:3.5, the added mass ratio of polyethylene glycol to carboxymethyl cellulose is 1:1.6, and the addition amount of polyethylene glycol is 15 wt% of the nano-hydroxyapatite / chitosan composite material, the addition amount of genipin is 5 wt% of the nano-hydroxyapatite / chitosan composite material, and the added mass ratio of the spraying solution to the amino-functionalized glass fibers is 1:3.5; S4. Dissolve the xanthate ester in 7 times the mass of water, then add the reinforced fibers, the addition amount of the reinforced fibers being 8 wt% of the xanthate ester. Let stand for 11 h, then stir and add a polyurethane prepolymer, the addition amount of the polyurethane prepolymer being 12 wt% of the addition amount of the xanthate ester. Then, add hydrochloric acid to adjust the pH to 5, react for 35 min, then add alkali to neutrality, and then filter and treat at 65°C for 5 h to obtain the bamboo fiber medical sponge.

[0041] Example 2 A preparation method of a bamboo fiber medical sponge, comprising the following steps: S1. First, immerse bamboo fibers in a sodium hydroxide solution with a mass concentration of 3 wt%, ensuring that the sodium hydroxide solution covers the bamboo fibers. The immersion temperature is 30 °C and the immersion time is 2 h. Then, filter to obtain alkali cellulose. Next, react the alkali cellulose with carbon disulfide for 2 h under a vacuum of 40 Pa to form xanthate ester. The mass ratio of bamboo fibers to carbon disulfide added is 1:0.3. S2. First, treat glass fibers in a sulfuric acid solution with a concentration of 0.5 mol / L, ensuring that the sulfuric acid solution covers the glass fibers. The treatment temperature is 60 °C and the treatment time is 20 min. Then, wash with water and dry. Next, mix and immerse the treated glass fibers with glycine, γ-aminopropyltriethoxysilane, and water in a mass ratio of 1:0.2:0.3:4. The immersion temperature is 50 °C and the immersion time is 6 h. After the immersion treatment, filter and dry to obtain amino-functionalized glass fibers. S3. Mix the nano-hydroxyapatite / chitosan composite material prepared in Preparation Example 2 with water, then add polyethylene glycol and carboxymethyl cellulose, and then add genipin and stir to obtain a spraying solution. Then, spray the spraying solution on the amino-functionalized glass fibers and dry at 50 °C to obtain reinforced fibers. The mass ratio of the nano-hydroxyapatite / chitosan composite material to water added is 1:3. The mass ratio of polyethylene glycol to carboxymethyl cellulose added is 1:1.5. The addition amount of polyethylene glycol is 10 wt% of the nano-hydroxyapatite / chitosan composite material. The addition amount of genipin is 1 wt% of the nano-hydroxyapatite / chitosan composite material. The mass ratio of the spraying solution to the amino-functionalized glass fibers added is 1:3. S4. Dissolve the xanthate ester in 6 times its mass of water, then add the reinforced fibers. The addition amount of the reinforced fibers is 5 wt% of the xanthate ester. Let it stand for 10 h, then stir and add a polyurethane prepolymer. The addition amount of the polyurethane prepolymer is 10 wt% of the addition amount of the xanthate ester. Then, add hydrochloric acid to adjust the pH to 4.5. After reacting for 30 min, add alkali to neutralize, then filter and treat at 60 °C for 6 h to obtain a bamboo fiber medical sponge.

[0042] Example 3 A preparation method of a bamboo fiber medical sponge, comprising the following steps: S1. First, immerse bamboo fibers in a sodium hydroxide solution with a mass concentration of 8 wt%, ensuring that the sodium hydroxide solution covers the bamboo fibers. The immersion temperature is 40 °C and the immersion time is 1 h. Then, filter to obtain alkali cellulose. Next, react the alkali cellulose with carbon disulfide at a vacuum of 50 Pa for 1 h to form xanthate ester. The mass ratio of bamboo fibers to carbon disulfide added is 1:0.4. S2. First, treat glass fibers in a sulfuric acid solution with a concentration of 2 mol / L, ensuring that the sulfuric acid solution covers the glass fibers. The treatment temperature is 70 °C and the treatment time is 10 min. Then, wash with water and dry. Next, mix and immerse the treated glass fibers with glycine, γ-aminopropyltriethoxysilane, and water in a mass ratio of 1:0.3:0.5:6. The immersion temperature is 60 °C and the immersion time is 4 h. After immersion treatment, filter and dry to obtain amino-functionalized glass fibers. S3. Mix the nano-hydroxyapatite / chitosan composite material prepared in Preparation Example 3 with water, then add polyethylene glycol and carboxymethyl cellulose. Next, add genipin and stir to obtain a spraying solution. Then, spray the spraying solution on the amino-functionalized glass fibers and dry at 60 °C to obtain reinforced fibers. The mass ratio of the nano-hydroxyapatite / chitosan composite material to water added is 1:4. The mass ratio of polyethylene glycol to carboxymethyl cellulose added is 1:1.8. Moreover, the addition amount of polyethylene glycol is 20 wt% of the nano-hydroxyapatite / chitosan composite material, and the addition amount of genipin is 3 wt% of the nano-hydroxyapatite / chitosan composite material. Also, the mass ratio of the spraying solution to the amino-functionalized glass fibers added is 1:4. S4. Dissolve the xanthate ester in 8 times its mass of water, then add the reinforced fibers. The addition amount of the reinforced fibers is 10 wt% of the xanthate ester. Let it stand for 12 h, then stir and add the polyurethane prepolymer. The addition amount of the polyurethane prepolymer is 15 wt% of the addition amount of the xanthate ester. Then, add hydrochloric acid to adjust the pH to 6. After reacting for 40 min, add alkali to neutralize. Then, filter and treat at 70 °C for 4 h to obtain a bamboo fiber medical sponge.

[0043] Example 4 A method for preparing a bamboo fiber medical sponge is carried out according to the method in Example 1, with the difference that the nano-hydroxyapatite / chitosan composite material in step S3 is the nano-hydroxyapatite / chitosan composite material prepared in Preparation Example 4.

[0044] Example 5 A method for preparing a bamboo fiber medical sponge is carried out according to the method in Example 1, with the difference that glycine is not added in step S2.

[0045] Example 6 A method for preparing a bamboo fiber medical sponge is carried out according to the method in Example 1, with the difference that genipin is not added in step S3.

[0046] Comparative Example 1 A preparation method of bamboo fiber medical sponge is carried out according to the method in Example 1, except that the operation in step S1 is not carried out. In step S4, bamboo fibers are directly added and dispersed in water, and then reinforcing fibers are added. The remaining operations are the same as those in Example 1.

[0047] Comparative Example 2 A preparation method of bamboo fiber medical sponge is carried out according to the method in Example 1, except that the operation in step S2 is not carried out. In step S4, the reinforcing fibers are replaced with amino-functionalized glass fibers and nano-hydroxyapatite / chitosan composites in a ratio of 1:15.

[0048] Comparative Example 3 A preparation method of bamboo fiber medical sponge is carried out according to the method in Example 1, except that step S2 is not carried out, and in step S3, the amino-functionalized glass fibers are replaced with glass fibers in equal amounts.

[0049] Comparative Example 4 A preparation method of bamboo fiber medical sponge is carried out according to the method in Example 1, except that in step S4, the polyurethane prepolymer is replaced with sodium sulfate in equal amounts.

[0050] Comparative Example 5 A preparation method of bamboo fiber medical sponge is carried out according to the method in Example 1, except that the treatments in steps S2 and S3 are not carried out, and in step S4, the reinforcing fibers are replaced with wood fibers in equal amounts.

[0051] Comparative Example 6 A preparation method of bamboo fiber medical sponge is carried out according to the method in Example 1, except that the treatments in steps S2 and S3 are not carried out, and in step S4, no reinforcing fibers are added.

[0052] Performance Detection 1. Negative pressure water loss without hardening The bamboo fiber medical sponge samples prepared in the examples and comparative examples are cut into round sheet samples with a diameter of 50 mm and a thickness of 5 mm. Then, at room temperature, the round sheet samples are directly immersed in physiological saline to make them fully saturated with water absorption. Then, a vacuum dryer is used to apply a negative pressure of -80 kPa to the samples. After continuously applying for 30 min, the hardness change is measured, and the hardness change rate of the samples before and after the negative pressure treatment is statistically analyzed to detect their hardness change. The detection results are shown in Table 1 below.

[0053] Table 1: Referring to the detection results in Table 1 above, in Examples 1-3, sulfonation treatment was used to improve the hydrophilicity and solubility of bamboo fibers, enhance the moisture absorption capacity, while the nano-hydroxyapatite / chitosan composite material provided good moisture retention performance and biocompatibility. The polyurethane prepolymer and water formed a foaming system that played a role of a flexible skeleton in the sponge structure, preventing hardening due to water loss. The sponge prepared in the examples of this application had a small change in hardness under negative pressure drying, making it more suitable for negative pressure closed drainage treatment.

[0054] Referring again to the detection results of Example 1 and Example 4, during the preparation of the nano-hydroxyapatite / chitosan composite material, when the freeze-drying parameters changed, it had an impact on the pore structure of the composite material and the change rate of its negative pressure hardness. Combining with the detection results of Example 5, when amino-modified glass fibers were prepared in Example 5 and glycine was not added, the modification effect was weakened, the interfacial bonding force decreased, affecting the anti-hardening performance of the final sponge. Combining with the detection results of Example 6, when genipin was not added during the preparation of the reinforcing fibers, the cross-linking effect between the nano-hydroxyapatite / chitosan composite material and the amino-modified glass fibers was weakened, the interfacial bonding force decreased, and the anti-hardening performance also decreased.

[0055] Combining with the detection results of Example 1 and Comparative Example 1, when bamboo fibers were directly applied without sulfonation treatment, their anti-hardening performance decreased. Combining with Comparative Example 2, when glass fibers were not amino-modified and not adhesively compounded with the composite material and were directly added and mixed, the interfacial bonding force was poor, and no rough structure was formed, the overlap and entanglement between fibers decreased, and the anti-hardening performance was weak. In Comparative Example 3, when unmodified glass fibers were used, the interfacial bonding force was weak and the anti-hardening performance was weak. In Comparative Example 4, when sodium sulfate was used as the pore-forming agent for the bamboo fiber matrix, the flexible skeleton function of polyurethane was lost, and the anti-hardening performance was significantly reduced. In Comparative Example 5, no reinforcing fibers were added, but wood fibers were used as the reinforcing fibers, and the anti-hardening performance was significantly reduced. In Comparative Example 6, no reinforcing fibers were added, and the internal structural strength was insufficient, and the anti-hardening performance was weak.

[0056] 2. Mechanical Property Testing Tear Resistance Strength: The tear resistance strength was detected using a universal testing machine. The sample size was dumbbell-shaped (width 15 mm, total length 100 mm), and the tensile speed was 100 mm / min. Compression Resilience: The sample was placed in a compression tester, a 50% compression deformation was applied, the pressure was released after 30 s, and the recovery height was recorded. Liquid Absorption Capacity: The sample was completely immersed in physiological saline, and the liquid absorption capacity was recorded. The detection results are shown in Table 2 below.

[0057] Table 2: Referring to the test results in Table 2 above, the medical sponge in this application has good mechanical properties and liquid absorption properties. The tear resistance strength in the comparative examples is significantly weaker than that in Example 1, especially in Comparative Example 4 and Comparative Example 6. In the examples, through the synergistic effect of amino-functionalized glass fiber and nano-hydroxyapatite / chitosan composite, the interfacial bonding force between fibers is enhanced, and the tear resistance strength is improved. In Comparative Example 4, sodium sulfate is used to replace the polyurethane prepolymer, lacking an elastic cross-linked network structure, and the mechanical properties are significantly reduced; in the examples, the addition of nano-hydroxyapatite / chitosan composite improves the rigidity and support force of the material, and at the same time, the elastic network structure formed by the polyurethane prepolymer helps to disperse the compressive stress and promote recovery.

[0058] This specific embodiment is only an explanation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment that do not contribute creatively as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A method for preparing a bamboo fiber medical sponge, characterized in that: The following steps are involved: S1, firstly subjecting the bamboo fiber to an alkalization treatment to form an alkali fiber, and then subjecting the bamboo fiber to a sulfonation treatment to obtain a sulfonate; S2, firstly etching the glass fiber with acid and then modifying it with an aminosilane coupling agent to obtain an amino-modified glass fiber; S3, coating the surface of the amino glass fiber with a nano-hydroxyapatite / chitosan composite material to obtain a reinforcing fiber; S4, dissolving the sulfonate in water, then adding the reinforcing fiber, standing and stirring evenly, adding the polyurethane prepolymer to mix, then adding acid and stirring, standing, then alkali washing and heat treatment, to obtain a bamboo fiber medical sponge.

2. The method for preparing a bamboo fiber medical sponge according to claim 1, characterized in that: The nano-hydroxyapatite / chitosan composite material is prepared by the following method: 1) Mix chitosan and sodium alginate, dissolve in acetic acid solution and stir to prepare chitosan mixed solution; 2) Mix the chitosan mixed solution with the phosphoric acid solution to obtain a mixed solution, then add the mixed solution dropwise into the calcium hydroxide suspension while stirring, react at 40-60°C, adjust the pH value to 8.5-10, and react for 2-4 hours; 3) After the reaction is completed, the mixture is allowed to stand for 15-20 hours, filtered, washed with water until neutral, and then freeze-dried to obtain a nano-hydroxyapatite / chitosan composite material.

3. The method for preparing a bamboo fiber medical sponge according to claim 2, characterized in that: When preparing nano-hydroxyapatite / chitosan composite materials, the freeze-drying parameters in step 3) are: First, pre-freeze at -40-(-60)℃ for 2-3h, then dry at -50-(-70)℃ and vacuum degree of 10-20Pa for 12-13h, then dry at -10-(-5)℃ and vacuum degree of 3-5Pa for 1-2h, and then treat at 20-40℃ and vacuum degree of 10-20Pa for 6-10h.

4. The method for preparing a bamboo fiber medical sponge according to claim 2, characterized in that: When preparing nano-hydroxyapatite / chitosan composite materials, In step 1), the mass concentration of the acetic acid solution is 10-20%, and the mass ratio of chitosan to the acetic acid solution is 1:(3-5), and the mass ratio of chitosan to sodium alginate is 1:(0.1-0.2); In step 2), the concentration of the phosphoric acid solution is 0.1-0.5 mol / L, the volume ratio of the chitosan mixed solution to the phosphoric acid solution is 1:(1-3), and the feed ratio of phosphoric acid to calcium hydroxide is 1:(1.5-2).

5. The method for preparing a bamboo fiber medical sponge according to claim 1, characterized in that: The specific operations of step S2 are: The glass fiber is first treated in a sulfuric acid solution with a concentration of 0.5-2 mol / L, the treatment temperature is 60-70°C, the treatment time is 10-20 min, and then washed with water and dried. The treated glass fiber is then impregnated with a mixture of glycine, γ-aminopropyltriethoxysilane and water in a mass ratio of 1: (0.2-0.3): (0.3-0.5): (4-6) at a temperature of 50-60°C and a time of 4-6 h. After the impregnation treatment, the amino glass fiber is obtained.

6. The method for preparing a bamboo fiber medical sponge according to claim 1, characterized in that: The specific operations of step S3 are: The nano-hydroxyapatite / chitosan composite material is mixed with water, polyethylene glycol and carboxymethyl cellulose are added, and then genipin is added and stirred to obtain a spray liquid, and then the spray liquid is sprayed on the amino glass fiber, and then dried at 50-60°C to obtain the reinforcing fiber.

7. The method for preparing a bamboo fiber medical sponge according to claim 6, characterized in that: In step S3, the mass ratio of the nano-hydroxyapatite / chitosan composite material to water is 1:(3-4), the mass ratio of polyethylene glycol to carboxymethyl cellulose is 1:(1.5-1.8), the amount of polyethylene glycol added is 10-20wt% of the nano-hydroxyapatite / chitosan composite material, the amount of genipin added is 1-3wt% of the nano-hydroxyapatite / chitosan composite material, and the mass ratio of the spray liquid to the amino glass fiber is 1:(3-4).

8. The method for preparing a bamboo fiber medical sponge according to claim 1, characterized in that: The specific operations of step S4 are: The sulfonate is dissolved in 6-8 times the mass of water, and then reinforcing fiber is added, the reinforcing fiber addition amount is 5-10wt% of the sulfonate, and after standing for 10-12 hours, a polyurethane prepolymer is added with stirring, and the polyurethane prepolymer addition amount is 10-15wt% of the sulfonate, and then an acid is added to adjust the pH to 4.5-6, and after reacting for 30-40 minutes, a base is added to neutrality, and then filtered and treated at 60-70°C for 4-6 hours to obtain a bamboo fiber medical sponge.

9. A bamboo fiber medical sponge prepared by the preparation method as described in any one of claims 1 to 8.

10. Use of the bamboo fiber medical sponge as claimed in claim 9 in negative pressure sealing drainage treatment.

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