Lyocell fiber-based medical bio-hydrogel dressing and preparation method thereof

Abstract

The application discloses a lyocell fiber-based medical bio-hydrogel dressing and a preparation method thereof, and belongs to the technical field of medical materials. The medical bio-hydrogel dressing is prepared by performing pretreatment on lyocell fibers by using a deep eutectic solvent, and then performing alkalization and etherification to introduce hydrophilic groups for hydrophilic modification. The medical bio-hydrogel dressing is a self-supporting material, effectively maintains the original morphology and most of the mechanical properties of the lyocell fibers, can be directly used as a dressing, is more convenient to use, has stronger environmental adaptability, has good water absorption, water retention and biocompatibility, and has a wide application prospect in the field of medical dressings. Meanwhile, the lyocell fibers are hydrophilically modified by a simple method, the problem of low reactivity of the lyocell fibers is effectively solved, the alkalization and etherification difficulty is reduced, the reaction efficiency is improved, the cost is reduced, the raw materials are green and environmentally friendly, and the industrial application is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of medical dressing materials, and particularly relates to a lyocell fiber-based medical bio-hydrogel dressing and a preparation method thereof. Background Art

[0002] Lyocell fiber is a regenerated cellulose fiber made from natural cellulose, typically produced through the N-methylmorpholine-N-oxide (NMMO) solvent spinning process. This renewable raw material boasts a solvent recovery rate exceeding 99.5%, and the production process produces no harmful byproducts, making it environmentally friendly. Lyocell fiber exhibits exceptional mechanical properties, with dry strength approaching that of polyester (approximately 35 cN / tex) and wet strength retention reaching 85%, far exceeding that of traditional viscose. Lyocell fiber also exhibits excellent biocompatibility, with its cellulose structure exhibiting high affinity for human tissue. It is biodegradable, with its degradation products being non-toxic. Furthermore, the specific surface area of ​​Lyocell nanofiber membranes is orders of magnitude higher than that of traditional gauze, making it particularly advantageous for medical functionalization. Therefore, Lyocell fiber holds great potential for the preparation of medical dressings. However, its high crystallinity (approximately 40%-60%) and dense molecular chain arrangement result in insufficient hydrophilicity, resulting in a water absorption rate of only 1.5-2 times its weight. In addition, the fibrillation properties of lyocell fibers (i.e., the fiber surface is easily split into microfibers) further reduce its moisture absorption stability, limiting its application in fields such as wound care. Therefore, there is an urgent need for methods that can combine the strong comprehensive performance of lyocell with the characteristics of good water-absorbent dressings.

[0003] To meet the water absorption requirements of medical dressings made from lyocell fibers, lyocell fibers need to be hydrophilically modified. However, due to the unique polyhydroxy chemical structure of lyocell fibers and their physical form, which forms a tightly entangled structure, their overall reactivity is relatively low. Currently, common methods for treating lyocell fibers to gelate generally include chemical oxidation, graft copolymerization, and surface coating, but these methods all have certain problems. For chemical oxidation, the fibers are typically post-treated with oxidants such as N-oxyl compounds and sodium hypochlorite to introduce hydrophilic groups such as carboxyl groups. However, this process is complex, requires multiple reactions, is costly, consumes a lot of energy, places a high environmental burden, and increases wastewater treatment costs. Furthermore, the degree of oxidation during the reaction is difficult to control, which can easily lead to a decrease in fiber strength. For example, after carboxymethylation, strength loss can reach 30%, and residual sodium hypochlorite can cause wound irritation or allergic reactions. For graft copolymerization, hydrophilic monomers such as acrylic acid and methacrylic acid are typically grafted onto the fiber surface through free radical polymerization. However, this method requires the use of initiators (such as persulfates) and organic solvents, which imposes a high environmental load and results in low organic solvent recovery rates. Surface coating methods typically coat the fiber surface with hydrophilic polymers such as chitosan and polyvinyl alcohol. However, this method suffers from weak adhesion to the fiber, making it easily detachable after washing. Furthermore, uneven coating thickness leads to unstable water absorption. When coating thickness deviation exceeds a certain value, water absorption stability deteriorates. Summary of the Invention

[0004] The purpose of the present invention is to provide a lyocell fiber-based medical bio-hydrogel dressing and a preparation method thereof. The obtained medical bio-hydrogel dressing maintains the main structural integrity of the lyocell fiber and can be used directly as a dressing. It is more convenient to use and has stronger environmental adaptability. At the same time, it also has good water absorption, water retention and biocompatibility, and has broad application prospects in the field of medical dressings.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] Provided is a lyocell fiber-based medical bio-hydrogel dressing, which is prepared by pretreating lyocell fiber with a deep eutectic solvent, followed by alkalization and etherification to introduce hydrophilic groups for hydrophilic modification.

[0007] According to the above scheme, the water absorption rate of the hydrogel dressing is 1280~4670%, preferably 1600~4670%, and more preferably 2000~4670%; the volume expansion rate is 1320~4335%, preferably 1680~4335%, and more preferably 2000~4335%.

[0008] According to the above scheme, the deep eutectic solvent includes a hydrogen bond acceptor and a hydrogen bond donor, and the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 0.1-1:1.

[0009] Preferably, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 0.1-0.7:1.

[0010] Preferably, the hydrogen bond acceptor is one of choline chloride and urea; the hydrogen bond donor is one of glycerol, ethanol, chloroacetic acid, citric acid, and sorbitol.

[0011] According to the above scheme, the etherifying agent used in the etherification is chloroacetic acid.

[0012] Provided is a method for preparing the above-mentioned lyocell fiber-based medical bio-hydrogel dressing, comprising the following steps:

[0013] 1) Mixing lyocell fiber and deep eutectic solvent (DES) at 50-70°C and letting it stand for 2-10 minutes to allow the fiber surface to swell or partially dissolve, thereby obtaining pretreated lyocell fiber;

[0014] 2) adding a sodium hydroxide solution to the pretreated lyocell fiber obtained in step 1) to perform an alkalization treatment to ionize the hydroxyl groups on the fiber and enhance the activity of the hydroxyl groups; wherein the solvent in the sodium hydroxide solution is a mixture of ethanol and water;

[0015] 3) adding chloroacetic acid as an etherifying agent to the mixed solution obtained in step 2) and performing an etherification reaction at a temperature of 40-85° C. to introduce hydrophilic groups such as carboxymethyl groups, and then post-processing to obtain a lyocell fiber-based medical bio-hydrogel dressing.

[0016] The present invention firstly pre-treats the lyocell fiber by using a reactive deep eutectic solvent under suitable process conditions. On the one hand, the deep eutectic solvent brings the reactants into the fiber structure in the form of hydrogen bonds, interrupting the intermolecular and intramolecular hydrogen bonds inside the fiber, so that the surface of the lyocell fiber is reasonably swollen or slightly dissolved, forming a porous structure, opening up a smoother penetration and diffusion path, and providing more active sites for subsequent alkalization reactions. On the other hand, the presence of the deep eutectic solvent in the fiber further activates the reactive active sites of the fiber, promoting subsequent alkalization and etherification reactions to occur more efficiently.

[0017] After pretreatment, alkalization and etherification are carried out to introduce hydrophilic groups into the fiber, wherein sodium hydroxide reacts with the hydroxyl groups exposed on the fiber surface to form sodium cellulose (-O - Na + ), which "activates hydroxyl groups." Ethanol, as a polar solvent, reduces the surface tension of water, promoting the penetration of NaOH into the fiber micropores. This avoids the strength loss caused by excessive fiber swelling in traditional aqueous solutions and prevents the binding of water with subsequent products. Finally, the activated sodium cellulose undergoes a nucleophilic substitution reaction with chloroacetic acid (ClCH2COOH) to produce sodium carboxymethyl cellulose (CMC-Na), resulting in a lyocell fiber-based medical biohydrogel dressing.

[0018] According to the above scheme, in step 1), the deep eutectic solvent comprises a hydrogen bond acceptor and a hydrogen bond donor, and the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 0.1-1:1.

[0019] Preferably, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 0.1-0.7:1.

[0020] Preferably, the hydrogen bond acceptor is one of choline chloride and urea; the hydrogen bond donor is one of glycerol, ethanol, chloroacetic acid, citric acid, and sorbitol.

[0021] According to the above scheme, in step 1), the deep eutectic solvent is prepared by mixing a hydrogen bond acceptor and a hydrogen bond donor, and completely dissolving them to form a transparent homogeneous phase. Preferably, the dissolution temperature is 50-70°C.

[0022] According to the above scheme, in step 1), the mass volume ratio of lyocell fiber and deep eutectic solvent is 1 g:4-6 mL.

[0023] According to the above scheme, in step 2), the concentration of the sodium hydroxide solution is 20-40 g / L; and the volume ratio of ethanol to water in the solvent is 3-5:1.

[0024] According to the above scheme, in step 2), the alkalization treatment time is 20-120 min, preferably 20-80 min.

[0025] According to the above scheme, in step 2), the mass volume ratio of lyocell fiber and sodium hydroxide solution is 1g:50-200ml.

[0026] According to the above scheme, in step 3), the etherification reaction temperature is 60-80°C.

[0027] According to the above scheme, in step 3), the mass ratio of lyocell fiber to etherifying agent is 1-2:1.

[0028] According to the above scheme, in step 3), the etherification reaction time is 2-6 hours, preferably 2-5 hours, and more preferably 3.5-4.5 hours.

[0029] According to the above scheme, in step 3), the post-treatment process is: the etherified lyocell fiber is deeply rinsed with ethanol for multiple times, and then air-dried at room temperature to a constant weight to obtain the lyocell fiber-based medical bio-hydrogel dressing.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. The present invention provides a lyocell fiber-based medical biological hydrogel dressing, which is a fiber self-supporting material that maintains the main structural integrity of the lyocell fiber, effectively maintains the original morphology and most of the mechanical properties of the lyocell fiber, and can be used directly as a dressing without relying on other carrier materials for compounding like hydrogel powder. It is more convenient to use and has stronger environmental adaptability. At the same time, the obtained hydrogel dressing also has good water absorption, water retention and biocompatibility, and has broad application prospects in the field of medical dressings.

[0032] 2. The present invention provides a preparation method of a lyocell fiber-based medical bio-hydrogel dressing. First, the lyocell fiber is pretreated by using a reactive deep eutectic solvent under suitable process conditions, so that the lyocell fiber undergoes surface swelling and partial dissolution while ensuring its original morphology and most of its mechanical properties, thereby constructing a porous structure and helping to introduce hydrophilic groups during subsequent alkalization and etherification, effectively improving the reaction efficiency of subsequent alkalization and etherification, and thus significantly improving its water absorption performance. The present invention realizes the hydrophilic modification of the lyocell fiber through a simple method, effectively solves the problem of low reaction activity of the lyocell fiber, reduces the difficulty of alkalization and etherification, and still obtains good hydrophilic properties at a shorter alkalization time and etherification time and a lower etherification temperature, thereby improving reaction efficiency and reducing costs. The raw materials are green and environmentally friendly, and are conducive to industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The deep eutectic solvent prepared in step 1) of Example 1 ( Figure 1 a) Prepare the deep eutectic solvent obtained by step 1) of Example 14 ( Figure 1 b) Thermogravimetric analysis diagram.

[0034] Figure 2 This is a comparison chart of infrared tests of the deep eutectic solvent prepared in step 1) of Example 1, the deep eutectic solvent prepared in step 1) of Example 14, chloroacetic acid crystals, and choline chloride crystals.

[0035] Figure 3 This is a scanning electron microscope (SEM) image of the lyocell fiber-based medical biohydrogel dressing prepared in Example 2 ( Figure 3 a and 3b) and scanning electron microscopy (SEM) images of untreated lyocell fibers ( Figure 3 c and 3d). DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] Example 1

[0038] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing, comprising the following steps:

[0039] 1) Choline chloride and chloroacetic acid were mixed in a molar ratio of 2:3 and stirred at 60°C until completely dissolved to form a transparent homogeneous deep eutectic solvent (DES) as a fiber treatment agent.

[0040] 2) Pretreatment of lyocell fiber: 1 g of lyocell fiber was mixed evenly with 5.8 ml of the DES obtained in step 1) at 55°C and allowed to stand for 4 minutes to allow the fiber surface to swell or partially dissolve, thereby obtaining pretreated lyocell fiber.

[0041] 3) Alkalization treatment: a sodium hydroxide-alcohol-water mixed solution containing 3 g of sodium hydroxide, 20 ml of deionized water and 80 ml of anhydrous ethanol was added to the pretreated lyocell fiber obtained in step 2), and the alkalization treatment was carried out at room temperature for 60 minutes.

[0042] 4) Etherification: Add 1 g of chloroacetic acid to step 3) and carry out etherification reaction at 80°C for 4 hours.

[0043] 5) Post-processing and storage: The etherified fibers are rinsed deeply with ethanol several times, and then air-dried at room temperature to a constant weight to obtain the lyocell fiber-based medical bio-hydrogel dressing. The dressing is then sealed at room temperature and stored for later use after the air is removed.

[0044] Example 2

[0045] A method for preparing a lyocell fiber-based medical bio-hydrogel dressing is provided. Except that the etherification treatment conditions in step 4) are changed to etherification reaction at 70° C. for 4 hours, the remaining steps and conditions are the same as those in Example 1.

[0046] Example 3

[0047] A method for preparing a lyocell fiber-based medical bio-hydrogel dressing is provided. Except that the etherification treatment conditions in step 4) are changed to etherification reaction at 60° C. for 4 hours, the remaining steps and conditions are the same as those in Example 1.

[0048] Example 4

[0049] A method for preparing a lyocell fiber-based medical bio-hydrogel dressing is provided. Except that the etherification treatment conditions in step 4) are changed to etherification reaction at 50° C. for 4 hours, the remaining steps and conditions are the same as those in Example 1.

[0050] Example 5

[0051] A method for preparing a lyocell fiber-based medical bio-hydrogel dressing is provided. Except that the etherification treatment conditions in step 4) are changed to etherification reaction at 40° C. for 4 hours, the remaining steps and conditions are the same as those in Example 1.

[0052] Example 6

[0053] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing, comprising the following steps: except that the etherification treatment conditions in step 4) are changed to etherification reaction at 70° C. for 5 hours, the remaining steps and conditions are the same as those in Example 2.

[0054] Example 7

[0055] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. The method comprises the following steps and conditions: performing the etherification reaction at 70° C. for 3 h in step 4; and the following steps and conditions are the same as those in Example 2.

[0056] Example 8

[0057] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. The method comprises the following steps and conditions: performing the etherification reaction at 70° C. for 2 h in step 4; and the following steps and conditions are the same as those in Example 2.

[0058] Example 9

[0059] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. The method comprises the following steps and conditions: the alkalization treatment in step 3 is performed at room temperature for 120 minutes; and the remaining steps and conditions are the same as those in Example 2.

[0060] Example 10

[0061] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. The method comprises the following steps and conditions: the alkalization treatment in step 3 is performed at room temperature for 100 minutes; and the remaining steps and conditions are the same as those in Example 2.

[0062] Example 11

[0063] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. The method comprises the following steps and conditions: the alkalization treatment in step 3 is performed at room temperature for 80 minutes; and the remaining steps and conditions are the same as those in Example 2.

[0064] Example 12

[0065] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. The method comprises the following steps and conditions: the alkalization treatment in step 3) is performed at room temperature for 40 minutes; and the remaining steps and conditions are the same as those in Example 2.

[0066] Example 13

[0067] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. The method comprises the following steps and conditions: the alkalization treatment in step 3 is performed at room temperature for 20 minutes; and the remaining steps and conditions are the same as those in Example 2.

[0068] Example 14

[0069] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. Except for step 1) of mixing choline chloride and chloroacetic acid in a molar ratio of 3:7, the remaining steps and conditions are the same as those in Example 2.

[0070] Example 15

[0071] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. Except for step 1) of mixing choline chloride and chloroacetic acid in a molar ratio of 1:4, the remaining steps and conditions are the same as those in Example 2.

[0072] Example 16

[0073] Provided is a method for preparing a lyocell fiber-based medical bio-hydrogel dressing. Except for step 1) mixing choline chloride and chloroacetic acid in a molar ratio of 1:9, the remaining steps and conditions are the same as those in Example 2.

[0074] Example 17

[0075] Provided is a method for preparing a lyocell fiber-based hydrogel dressing. Except for step 1) mixing choline chloride and chloroacetic acid in a molar ratio of 1:1, the remaining steps and conditions are the same as those in Example 2.

[0076] Comparative Example 1

[0077] A method for preparing a lyocell fiber-based hydrogel dressing is provided. Except that the etherification treatment conditions in step 4) are changed to etherification reaction at 30° C. for 4 hours, the remaining steps and conditions are the same as those in Example 2.

[0078] Comparative Example 2

[0079] Provided is a method for preparing a lyocell fiber-based hydrogel dressing, comprising the following steps:

[0080] 1) Alkalization treatment: a sodium hydroxide-alcohol-water mixed solution containing 3.0 g sodium hydroxide, 20 ml deionized water and 80 ml anhydrous ethanol was added to 1 g of lyocell fiber, and the mixture was alkalized at room temperature for 60 min.

[0081] 2) Etherification treatment: Add 1 g of chloroacetic acid and carry out etherification reaction at 70°C for 4 hours.

[0082] 3) Post-processing and storage: The etherified fibers are rinsed deeply with ethanol several times, and then air-dried at room temperature to a constant weight to obtain a lyocell fiber-based hydrogel dressing. The dressing is then sealed at room temperature to remove air and set aside.

[0083] Comparative Example 3

[0084] A method for preparing a lyocell fiber-based hydrogel dressing is provided. Except that the etherification treatment condition in step 4) is to carry out the etherification reaction at 70° C. for 1 hour, the remaining steps and conditions are the same as those in Example 2.

[0085] The following are relevant tests:

[0086] 1) Thermogravimetric Analysis: The deep eutectic solvent prepared in step 1) of Example 1 and the deep eutectic solvent prepared in step 1) of Example 14 were subjected to TG thermogravimetric analysis to test their thermal stability. The equipment used was a HITACHI STA200, and the heating rate was 10°C / min. The TG and DTG temperature curves of the two samples were obtained, as shown in Figure 1. Figure 1 The results show that no obvious thermal decomposition occurs within 150°C, indicating a certain degree of thermal stability; this indicates that within the subsequent reaction temperature range, there is no obvious thermal decomposition of the deep eutectic solvent.

[0087] 2) Infrared characterization: The deep eutectic solvent prepared in step 1) of Example 1 was compared with the deep eutectic solvent prepared in step 1) of Example 14, as well as the constituent chloroacetic acid crystals and choline chloride crystals. Figure 2 The results show that, when comparing the O-stretching vibration peaks, the peak shape becomes significantly broader after the formation of a deep eutectic solvent compared to the constituent monomers. This is because hydrogen bonding reduces the O-H bond force constant and expands the distribution of vibrational energy levels, confirming the formation of hydrogen bonds. This further demonstrates that chloroacetic acid and choline chloride have successfully formed a deep eutectic solvent.

[0088] 3) Scanning electron microscopy (SEM) analysis:

[0089] Figure 3 (a) (b) are scanning electron microscope (SEM) images of the lyocell fiber-based medical biohydrogel dressing prepared in Example 2. Figure 3 (c) and (d) are scanning electron microscope (SEM) images of untreated Lyocell fibers. Observation and analysis reveal that, at a microscopic level, the fiber surface morphology and internal microfiber bundle arrangement remain well-ordered. This characteristic enables the fibers to effectively form a stable three-dimensional network support system during the construction of hydrogel dressings. Lyocell fibers treated with the present method maintain excellent water absorption while significantly preserving the structural integrity of the fiber backbone, thereby ensuring the product's excellent mechanical properties.

[0090] 4) Water absorption test:

[0091] Water absorption test method: take an appropriate amount of fiber, record the fiber mass as m0, use a fine iron cage as a carrier container, the cage mass is m 漏笼 , slowly add deionized water to the cage at a constant speed until the fibers are saturated, stop titration immediately, quickly absorb the remaining water droplets on the outer wall of the cage with filter paper, and record the total mass of the saturated water-absorbing gel-like fibers and the cage as m1. The water absorption rate W (Water Absorption) can be expressed as:

[0092] W=

[0093] Volume expansion ratio test method: This is carried out simultaneously with the water absorption test. The saturated water-absorbing fiber (in gel form) that has completed the water absorption test is used as the test sample. It is placed in a measuring cylinder filled with a certain volume of anhydrous ethanol (V0), ensuring that the fiber is completely immersed and evenly dispersed. The volume at this point is recorded as V1. The volume expansion ratio SR (Swelling Ratio) can be expressed as:

[0094] SR=

[0095] The water absorption rate and volume expansion rate of the hydrogel dressings obtained in the examples and comparative examples are specifically shown in Tables 1-4.

[0096] Table 1. Water absorption and volume expansion rate data of hydrogel dressings obtained in Examples 1-6 and Comparative Example 1

[0097]

[0098] It can be seen from Table 1 that after Example 2 was pretreated with a deep eutectic solvent, compared with Comparative Example 2 in which no deep eutectic solvent pretreatment was used, the water absorption rate of the hydrogel dressing obtained in Example 2 was increased by 192.20%, and the volume expansion rate was increased by 122.98%, and the water absorption performance was significantly improved. It can be seen from Examples 1-5 that when the etherification temperature was 40-80°C, the water absorption rate of the obtained hydrogel dressing was significantly higher than that of Comparative Example 2 which was not treated with a deep eutectic solvent, indicating that the temperature of the etherification reaction of the lyocell fiber can be reduced by the deep eutectic solvent pretreatment process. The present invention pre-treats and modifies the lyocell fiber through a deep eutectic solvent pretreatment process, improves the reaction microenvironment, reduces the difficulty of alkalization and etherification, thereby effectively improving the conversion rate of the etherification reaction of the lyocell fiber and significantly improving the hydrophilic properties of the lyocell fiber.

[0099] Table 2. Water absorption and volume expansion rate data of hydrogel dressings obtained in Examples 2, 6-8 and Comparative Example 2

[0100]

[0101] As shown in Table 2, in Examples 6, 2, 7-8, and Comparative Example 3, the etherification reaction time gradient ranged from 5 hours to 1 hour. In Comparative Example 2, the etherification time was 4 hours, the same as in Example 2, but without deep eutectic solvent pretreatment. The data in the table demonstrate that even with a 1-hour etherification time in Comparative Example 3, the resulting hydrogel dressing exhibited higher water absorption than the 4-hour etherification in Comparative Example 2. Furthermore, in Example 8, after the etherification time reached 2 hours, the resulting hydrogel dressing exhibited significantly higher water absorption and volume expansion than those in Comparative Example 2. This further demonstrates that the process of the present invention can accelerate the etherification process in a short period of time, significantly enhancing reaction activity and improving the hydrophilic properties of Lyocell fibers.

[0102] Table 3. Water absorption and volume expansion rate data of hydrogel dressings obtained in Examples 2, 9-13 and Comparative Example 2

[0103]

[0104] Table 3 shows that Examples 9-11, 2, and 12-13 used an alkalization treatment time gradient of 120 minutes to 20 minutes. Even with an alkalization time of 20 minutes (as in Example 13), the water absorption rate and volume expansion rate of the material were significantly higher than those of Comparative Example 2, which did not use a deep eutectic solvent. This experimental observation demonstrates that the deep eutectic solvent pretreatment process can significantly reduce the alkalization treatment time of Lyocell fiber, ensuring that the hydrophilicity of the resulting hydrogel dressing is effectively improved even with a reduced alkalization treatment time.

[0105] Table 4. Water absorption and volume expansion rate data of hydrogel dressings obtained in Examples 2, 14-17 and Comparative Example 2

[0106]

[0107] As can be seen from Table 4, changes in the molar ratio of hydrogen bond acceptors to hydrogen bond donors in the deep eutectic solvent will affect the water absorption rate and volume expansion rate of the hydrogel dressing. However, overall, when the molar ratio of hydrogen bond acceptors to hydrogen bond donors is in the range of 0.1-1:1, the hydrophilicity of the resulting hydrogel dressing is significantly higher than that of Comparative Example 2, which is not treated with a deep eutectic solvent.

[0108] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A lyocell fiber-based medical bio-hydrogel dressing, characterized in that: The medical bio-hydrogel dressing is a fiber self-supporting material that maintains the main structural integrity of the lyocell fiber. It is prepared by pre-treating the lyocell fiber with a deep eutectic solvent, then alkalizing and etherifying the lyocell fiber to introduce hydrophilic groups for hydrophilic modification. The water absorption rate of the medical biological hydrogel dressing is 3012.62-4670%; and the volume expansion rate is 2943.72-4335%.

2. The medical bio-hydrogel dressing according to claim 1, characterized in that: The deep eutectic solvent comprises a hydrogen bond acceptor and a hydrogen bond donor, and the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 0.1-1:

1.

3. The medical bio-hydrogel dressing according to claim 2, characterized in that: The hydrogen bond acceptor is one of choline chloride and urea; the hydrogen bond donor is one of glycerol, ethanol, chloroacetic acid, citric acid and sorbitol.

4. The medical bio-hydrogel dressing according to claim 1, characterized in that: The etherifying agent used in the etherification is chloroacetic acid.

5. A method for preparing the lyocell fiber-based medical bio-hydrogel dressing according to any one of claims 1 to 4, characterized in that: The steps include: 1) Evenly mix the lyocell fiber and the deep eutectic solvent at 50-70°C and let it stand for 2-10 minutes to allow the fiber surface to swell or partially dissolve, thereby obtaining the pretreated lyocell fiber; 2) adding sodium hydroxide solution to the pretreated lyocell fiber obtained in step 1) to perform alkalization treatment; Wherein the sodium hydroxide solution, the solvent is a mixture of ethanol and water; 3) adding chloroacetic acid as an etherifying agent to the alkalized mixed solution obtained in step 2) to carry out an etherification reaction at a temperature of 40-85° C., and then post-processing to obtain a lyocell fiber-based medical bio-hydrogel dressing.

6. The preparation method according to claim 5, characterized in that In the step 1), the mass volume ratio of the lyocell fiber to the deep eutectic solvent is 1 g:4-6 mL; in the step 2), the mass volume ratio of the lyocell fiber to the sodium hydroxide solution is 1 g:50-200 mL.

7. The preparation method according to claim 5, characterized in that In the step 3), the mass ratio of lyocell fiber to etherifying agent is 1-2:

1.

8. The preparation method according to claim 5, characterized in that In step 2), the concentration of the sodium hydroxide solution is 20-40 g / L; and the volume ratio of ethanol to water in the solvent of the sodium hydroxide solution is 3-5:

1.

9. The preparation method according to claim 5, characterized in that In the step 2), the alkalization treatment time is 20-120 minutes; in the step 3), the etherification reaction time is 2-6 hours.

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