Rapidly prototypic, highly adhesive, and highly tensile self-healing hydrogels and their preparation methods

Abstract

This invention provides a rapidly formable, highly adhesive, and highly tensile self-healing hydrogel and its preparation method. The method first introduces double bonds by reacting glycidyl methacrylate with polyvinyl alcohol, and then introduces carboxyl groups by adding succinic anhydride, resulting in carboxylated methacryloyl polyvinyl alcohol. Glycyrrhizic acid is modified with 3-aminophenylboronic acid to obtain dipotassium glycyrrhizate with phenylboronic acid. This application utilizes the crosslinking of phenylboronic acid groups with hydroxyl groups and double bonds as the main forces, and hydrophilic-hydrophobic interactions (glycyrrhizic acid consists of one molecule of hydrophobic glycyrrhetinic acid and two molecules of hydrophilic glucuronic acid) as auxiliary forces, significantly shortening the gelation time and improving the mechanical properties of the hydrogel. Furthermore, the unique molecular structure of glycyrrhizic acid and the large number of hydroxyl groups in the system enable it to exhibit excellent adhesion to various substrates, and the hydrogel possesses good self-healing and tensile properties.

Description

Technical Field

[0001] This invention relates to the field of hydrogel materials technology, and in particular to a rapidly prototyping, highly adhesive, and highly tensile self-healing hydrogel and its preparation method. Background Technology

[0002] Self-healing hydrogels have become a research hotspot due to their excellent biocompatibility and structural recoverability under external forces, enabling them to dynamically adapt to complex wound microenvironments.

[0003] Glycyrrhizic acid (GA), a natural triterpenoid saponin, exhibits significant anti-inflammatory, antibacterial, and antiviral activities, and has great potential in promoting wound healing.

[0004] Currently, the use of glycyrrhizic acid can be broadly categorized into two types: First, leveraging the unique molecular structure of glycyrrhizic acid, metal ions are added to achieve self-assembly of the glycyrrhizic acid molecules, or its self-assembly behavior is controlled by temperature, using glycyrrhizic acid as a hydrogel framework. Second, primarily to exert its pharmaceutical activity, it is added to the hydrogel network, while simultaneously utilizing the structural properties of glycyrrhizic acid to assist in hydrogel formation.

[0005] Patent CN110585122A discloses an injectable natural triterpenoid antibacterial hydrogel and its preparation method. The invention discloses a hydrogel composed of a mixture of glycyrrhizic acid and pentacyclic or tetracyclic triterpenoid compounds as the gel molecules, using phosphate-buffered saline (PBS) as the gel solvent. It is prepared via a small molecule self-assembly mechanism utilizing the non-covalent bonds formed between the mixtures. However, hydrogels obtained solely through non-covalent bonds between small molecules exhibit poor mechanical properties.

[0006] Dynamic covalent bonds, especially borate ester bonds, have been widely incorporated into self-healing hydrogels due to their reversibility and pH responsiveness. However, borate ester hydrogels prepared by existing technologies generally have significant limitations: either insufficient self-healing properties and low modulus; or weak adhesion and stretchability, making it difficult to meet the mechanical properties and interfacial integration requirements of specific wound dressings for different wound environments.

[0007] In view of this, it is necessary to design a rapidly prototyping, highly adhesive, and highly tensile self-healing hydrogel and its preparation method to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to provide a rapidly formable, highly adhesive, and highly tensile self-healing hydrogel and its preparation method. This preparation method uses aminophenylboronic acid to modify glycyrrhizic acid, using the modified glycyrrhizic acid molecules as key crosslinking units or functional components, innovatively and efficiently introducing dynamic borate ester bonds into the hydrogel system.

[0009] This application achieves a wide range of controllable adjustments to the hydrogel modulus through precise control of reaction conditions. The unique molecular structure of glycyrrhizic acid and the large number of hydroxyl groups in the system enable it to exhibit excellent adhesion to various substrates. Furthermore, the presence of borate ester bonds allows for rapid rebuilding, giving the hydrogel good self-healing and tensile properties. This application selects highly biocompatible and biodegradable polyvinyl alcohol (PVA) as the main framework material for the hydrogel, ensuring the overall biocompatibility of the material.

[0010] To achieve the above-mentioned objectives, this invention provides a method for preparing a rapidly prototyping, highly adhesive, and highly tensile self-healing hydrogel, comprising the following steps:

[0011] S1, Preparation of carboxylated methacryloyl polyvinyl alcohol: Polyvinyl alcohol was completely dissolved in a reaction vessel containing an organic solvent, and then a catalyst was added; subsequently, a glycidyl methacrylate solution was added, and the reaction was carried out for 5-10 hours. Then, a succinic anhydride solution was added, and the reaction was continued for another 5-10 hours. After the reaction was completed, the pH of the reaction solution was adjusted to 7-9; then, acetone was used for precipitation, and after filtration, the precipitate was dialyzed for 48-72 hours. Finally, the dialysate was frozen and freeze-dried to obtain carboxylated methacryloyl polyvinyl alcohol.

[0012] S2, Preparation of dipotassium glycyrrhizate phenylboronic acid: Dipotassium glycyrrhizate was completely dissolved in dimethyl sulfoxide, followed by the addition of N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 3-aminophenylboronic acid. The reaction was carried out at 25-35℃ for 20-48 h. Then, the reaction solution was dialyzed for 48-72 h, and the dialysate was filtered and freeze-dried to obtain dipotassium glycyrrhizate phenylboronic acid.

[0013] S3, the carboxylated methacrylamide polyvinyl alcohol prepared in step S1 is prepared into a solution A with a concentration of 10%~12%, and the dipotassium glycyrrhizate prepared in step S2 is prepared into a solution B with a concentration of 6%~10%. The solutions A and B are extruded and mixed using a dual-tube syringe to obtain a rapidly moldable, highly adhesive, and highly tensile self-healing hydrogel.

[0014] As a further improvement of the present invention, in step S1, the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.064-0.1).

[0015] As a further improvement of the present invention, when the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.064-0.0652), the degree of substitution of the double bonds in the obtained carboxylated methacryloyl polyvinyl alcohol is 0.007~0.01; when the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.096-0.1), the degree of substitution of the double bonds in the obtained carboxylated methacryloyl polyvinyl alcohol is 0.018~0.021.

[0016] As a further improvement of the present invention, in step S2, the molar ratio of the carboxyl group on dipotassium glycyrrhizate to the amino group on 3-aminophenylboronic acid is 3:(1.25~1.3).

[0017] As a further improvement of the present invention, in step S1, the mass ratio of succinic anhydride to polyvinyl alcohol is (1~4):10.

[0018] As a further improvement of the present invention, in step S1, the organic solvent is one of dimethyl sulfoxide, DMF, and chloroform.

[0019] As a further improvement of the present invention, in step S1, the catalyst is p-dimethylaminopyridine, and the mass ratio of p-dimethylaminopyridine to polyvinyl alcohol is (0.1~0.15):5.

[0020] As a further improvement of the present invention, in step S1, the pH of the solution is adjusted by adding sodium bicarbonate solution dropwise to the reaction system.

[0021] The present invention also provides a rapidly formable strong adhesion and high tensile self-healing hydrogel, wherein the adhesive strength of the rapidly formable strong adhesion and high tensile self-healing hydrogel reaches 20~65kPa and the tensile strain reaches 300~1050%.

[0022] The beneficial effects of the present invention are:

[0023] 1. This invention provides a method for preparing a rapidly formable, highly adhesive, and highly tensile self-healing hydrogel. This method utilizes the cross-linking of phenylboronic acid groups with hydroxyl groups and double bonds as the primary forces, and hydrophilic-hydrophobic interactions (glycyrrhizic acid consists of one molecule of hydrophobic glycyrrhetinic acid and two molecules of hydrophilic glucuronic acid) as auxiliary forces, significantly shortening gelation time and improving the mechanical properties of the hydrogel. Specifically, aminophenylboronic acid modifies glycyrrhizic acid, and the dynamic borate ester bonds endow the hydrogel with rapid and efficient self-healing capabilities. After physical damage or cutting, the hydrogel structure can quickly rebuild and restore its integrity, extending its service life and maintaining its barrier and functional properties, significantly outperforming existing glycyrrhizic acid or borate ester hydrogels with poor self-healing performance and slow recovery.

[0024] 2. This invention achieves a wide range of controllable adjustments to the hydrogel modulus by precisely controlling the degree of double bond substitution in modified polyvinyl alcohol. This characteristic allows the hydrogel prepared by this invention to flexibly adapt to the specific mechanical properties (softness and hardness) of dressings for different locations (such as joint movement zones and static zones) and wounds of different depths, overcoming the limitations of existing technologies where the hydrogel modulus is singular or uncontrollable.

[0025] 3. The hydrogel prepared by this invention has abundant hydroxyl groups, which endows the hydrogel with strong and durable adhesion to various biological tissues and material surfaces. It effectively solves the key problem of generally weak adhesion performance of existing glycyrrhizic acid composite hydrogels, ensuring stable adhesion of dressings to wound sites and preventing them from falling off.

[0026] 4. The hydrogel of the present invention uses polyvinyl alcohol (PVA), which has good biocompatibility and is biodegradable, as the main skeleton material. The system does not introduce harmful components, ensuring that the overall material is safe and harmless to the human body and meets the biosafety requirements of wound dressings.

[0027] 5. The present invention uses a dual-tube injection method for mixing, which is simple to operate and results in uniform solution mixing. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the synthesis process of carboxylated methacryloylpolyvinyl alcohol in this invention.

[0029] Figure 2 This is a schematic diagram of the synthesis process of dipotassium glycyrrhizate with phenylboronic acid in this invention.

[0030] Figure 3 The NMR spectra are for 3-aminophenylboronic acid (B), dipotassium glycyrrhizate (G), and dipotassium glycyrrhizate phenylboronic acid (GB) in Example 1 of this invention.

[0031] Figure 4 This is a diagram of the hydrogel self-healing process in Example 1.

[0032] Figure 5 The image shows the tensile properties test results of the hydrogel in Example 1.

[0033] Figure 6 The graph shows the adhesion performance test results of the hydrogel in Example 1.

[0034] Figure 7 The rheological properties-gel time diagrams are for the hydrogels of Examples 1-3, 5 and Comparative Example 1.

[0035] Figure 8 The rheological properties-shear thinning diagrams are for the hydrogels of Examples 1-3, 5 and Comparative Example 1.

[0036] Figure 9The rheological properties-oscillation strain diagrams are for the hydrogels of Examples 1-3, 5 and Comparative Example 1.

[0037] Figure 10 The rheological properties-alternating strain diagrams are for the hydrogels of Examples 1-3, 5 and Comparative Example 1.

[0038] Figure 11 The adhesion energy diagrams are for the hydrogels of Examples 1-2 and Examples 4-5.

[0039] Figure 12 The adhesion strength diagrams are for the hydrogels of Examples 1-2 and Examples 4-5.

[0040] Figure 13 The graph shows the compression properties of the hydrogels in Examples 1-2 and Example 5. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0043] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0044] Existing hydrogels generally have significant limitations: they may have insufficient self-healing properties or low modulus; or they may have weak adhesion and stretchability, making it difficult to meet the mechanical properties and interfacial integration requirements of specific wound dressings for different wound environments.

[0045] For example, some wounds require strong adhesion, while others do not. Diabetic wounds, for instance, require medication and must be biodegradable; otherwise, dressing changes could cause secondary damage. Conversely, some gels with too high a modulus can create gaps when in contact with the wound, hindering proper adhesion and thus impeding wound healing.

[0046] This invention achieves a wide range of controllable adjustments to the hydrogel modulus by precisely controlling the degree of double bond substitution in modified polyvinyl alcohol. This characteristic allows the hydrogel prepared by this invention to flexibly adapt to the specific mechanical properties (softness and hardness) of dressings for different locations (such as joint movement zones and static zones) and wounds of different depths, overcoming the limitations of existing technologies where the hydrogel modulus is singular or uncontrollable.

[0047] This invention provides a method for preparing a rapidly prototyping, highly adhesive, and highly tensile self-healing hydrogel, comprising the following steps:

[0048] S1, Preparation of carboxylated methacryloyl polyvinyl alcohol: Polyvinyl alcohol was completely dissolved in a reaction vessel containing an organic solvent, and then a catalyst was added; subsequently, a glycidyl methacrylate solution was added, and the reaction was carried out for 5-10 hours. Then, a succinic anhydride solution was added, and the reaction was continued for another 5-10 hours. After the reaction was completed, the pH of the solution was adjusted to 7-9; then, acetone was used for precipitation, and after filtration, the precipitate was dialyzed for 48-72 hours. Finally, the dialysate was frozen and freeze-dried to obtain carboxylated methacryloyl polyvinyl alcohol.

[0049] The mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.064-0.1).

[0050] When the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.064-0.0652), the degree of substitution of the double bonds in the obtained carboxylated methacryloyl polyvinyl alcohol is 0.007~0.01.

[0051] When the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.096-0.1), the degree of substitution of the double bond in the obtained carboxylated methacryloyl polyvinyl alcohol is 0.018~0.021.

[0052] The mass ratio of succinic anhydride to polyvinyl alcohol is (1~4):10.

[0053] The organic solvent is one of dimethyl sulfoxide, DMF, and chloroform.

[0054] The solvents for both glycidyl methacrylate solution and succinic anhydride solution are organic solvents.

[0055] The catalyst is p-dimethylaminopyridine. The mass ratio of p-dimethylaminopyridine to polyvinyl alcohol is (0.1~0.15):5.

[0056] The pH of the solution is adjusted by adding sodium bicarbonate solution dropwise to the reaction system.

[0057] S2, Preparation of dipotassium glycyrrhizate phenylboronic acid: Dipotassium glycyrrhizate was completely dissolved in dimethyl sulfoxide, followed by the addition of N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 3-aminophenylboronic acid. The reaction was carried out at 25-35℃ for 20-48 h. Then, the reaction solution was dialyzed for 48-72 h, and the dialysate was filtered and freeze-dried to obtain dipotassium glycyrrhizate phenylboronic acid.

[0058] The molar ratio of the carboxyl group on dipotassium glycyrrhizate to the amino group on 3-aminophenylboronic acid is 3:(1.25~1.3).

[0059] S3, the carboxylated methacryloyl polyvinyl alcohol prepared in step S1 is prepared into a solution A with a concentration of 10%~12%, and the phenylboronic acid glycyrrhizic acid prepared in step S2 is prepared into a solution B with a concentration of 6%~10%. The solutions A and B are extruded and mixed using a dual-tube syringe to obtain a rapidly moldable, highly adhesive, and highly tensile self-healing hydrogel.

[0060] The rapidly formable, highly adhesive, and highly tensile self-healing hydrogel prepared by the aforementioned method has an adhesive strength of 20-65 kPa and a tensile strain of 300-1050%, and can adhere well to various substrates, including glass, plastics, rubber, cardboard boxes, and weights.

[0061] The preparation method of the rapidly prototyping, highly adhesive, and highly tensile self-healing hydrogel provided by the present invention will be described below with reference to specific embodiments. Unless otherwise specified, the raw materials and reagents used in the embodiments of this application were purchased commercially.

[0062] Experimental Example

[0063] Preparation of dipotassium glycyrrhizate phenylboronic acid:

[0064] Dissolve 4 g of dipotassium glycyrrhizate completely in 200 ml of dimethyl sulfoxide (DMSO). Then add N-hydroxysuccinimide (NHS), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), and 3-aminophenylboronic acid, and react at 30 °C for 24 h. Dialyze the reacted liquid for 72 h, and finally filter and freeze-dry the dialysate.

[0065] The molar ratio of the carboxyl group on dipotassium glycyrrhizate to the amino group on 3-aminophenylboronic acid was changed, i.e., the amount of 3-aminophenylboronic acid was varied, and the gel state was observed to determine the appropriate molar ratio. It should be noted that the amounts of NHS and EDC were adjusted according to the amount of 3-aminophenylboronic acid to ensure that the ratio of NHS to EDC was NHS:EDC:amino = 1.2:1.2:1.

[0066] The specific molar ratios and experimental results are shown in Table 1.

[0067] Table 1

[0068]

[0069] As shown in Table 1, the molar ratio of the carboxyl group on dipotassium glycyrrhizate to the amino group on 3-aminophenylboronic acid should be determined to be 3: (1.25~1.3).

[0070] Example 1

[0071] This embodiment provides a method for preparing a rapidly prototyping, highly adhesive, and highly tensile self-healing hydrogel, comprising the following steps:

[0072] S1, Preparation of carboxylated methacryloyl polyvinyl alcohol (PGC):

[0073] Weigh 5g of polyvinyl alcohol (PVA) into a 250ml three-necked flask, add 90ml of dimethyl sulfoxide (DMSO), stir at 40℃ until completely dissolved, and then add 0.11g of catalyst (p-dimethylaminopyridine).

[0074] 0.326 g of glycidyl methacrylate (GMA) was dissolved in 10 ml of DMSO and added to a three-necked flask. The reaction mixture was then reacted for 6 h. Next, 0.5 g of succinic anhydride (SAA) was dissolved in 10 ml of DMSO and added to the reaction system. The reaction was continued for another 6 h until the reaction was complete. The resulting reaction solution was then adjusted to pH 8 with 1 mol / L sodium bicarbonate solution, and precipitated with 500 ml of acetone for 24 h. After filtration, the precipitate was dialyzed for 48 h. Finally, the dialysate was freeze-dried and lyophilized to obtain carboxylated methacrylamide polyvinyl alcohol (PGC). The synthesis process is as follows: Figure 1 As shown.

[0075] In this case, the mass ratio of PVA to GMA is 1:0.0652, and the degree of substitution of the double bond of the resulting carboxylated methacryloyl polyvinyl alcohol is 0.01, which is denoted as low-substituted carboxylated methacryloyl polyvinyl alcohol, PGC-L.

[0076] S2, Preparation of dipotassium glycyrrhizate phenylboronic acid;

[0077] 4 g of dipotassium glycyrrhizate was completely dissolved in 200 ml of dimethyl sulfoxide (DMSO). Then, 0.754 g of N-hydroxysuccinimide (NHS), 1.254 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), and 1.43 g of 3-aminophenylboronic acid were added, and the mixture was reacted at 30 °C for 24 h. The reacted liquid was dialyzed for 72 h, and finally, the dialysate was filtered and freeze-dried to obtain phenylboronicated glycyrrhizic acid (GB).

[0078] The synthesis process of dipotassium glycyrrhizate with phenylboronic acid is as follows: Figure 2 As shown.

[0079] The molar ratio of the carboxyl group on dipotassium glycyrrhizate to the amino group on 3-aminophenylboronic acid is 3:1.3.

[0080] S3, dissolve the carboxylated methacrylamide polyvinyl alcohol prepared in step S1 in ultrapure water to prepare a solution A (12% PGC-L) with a mass percentage concentration of 12% (m / v). Dissolve the dipotassium glycyrrhizate prepared in step S2 in ultrapure water to prepare a solution B (8% GB) with a mass percentage concentration of 8% (m / v). Mix solution A and solution B (volume ratio of 1:1) by extrusion using a dual-tube syringe to obtain a rapidly formable, highly adhesive, and highly tensile self-healing hydrogel.

[0081] Please see Figure 3 The image shows the NMR spectra of 3-aminophenylboronic acid (B), dipotassium glycyrrhizate (G), and dipotassium glycyrrhizate phenylboronic acid (GB) in this embodiment.

[0082] As can be seen in the NMR spectrum, the three strong peaks 7-8 on GB belong to the hydrogen on the benzene ring of 3-aminophenylboronic acid, indicating that dipotassium glycyrrhizate phenylboronic acid was successfully synthesized.

[0083] Figure 4 This is a diagram of the hydrogel self-healing process in Example 1.

[0084] First, cut the gel into two parts and then stick them together. After 2 minutes, stretch it. The gel did not break from the cut, indicating that the gel can self-heal within 2 minutes, demonstrating its excellent self-healing properties.

[0085] Figure 5 The image shows the tensile properties test results of the hydrogel in Example 1.

[0086] As can be seen, the hydrogel can be stretched from the initial 4cm to 30cm without breaking, indicating that it has good tensile properties.

[0087] Figure 6 The graph shows the adhesion performance test results of the hydrogel in Example 1.

[0088] As can be seen, hydrogels can adhere well to various substrates, including glass, plastics, rubber, cardboard boxes, and weights.

[0089] Examples 2-4 and Comparative Example 1

[0090] Examples 2-4 and Comparative Example 1 provide a method for preparing a hydrogel. The difference from Example 1 is that the concentrations of solution A and solution B are changed in step S3, as shown in Table 2. The rest is roughly the same as in Example 1 and will not be repeated here.

[0091] Example 5

[0092] Example 5 provides a method for preparing a hydrogel. Compared with Example 1, the difference is that 0.5g of GMA is used in step S1, the mass ratio of PVA to GMA is 1:0.1, and the degree of substitution of the double bond of the obtained carboxylated methacryloyl polyvinyl alcohol is 0.02, which is denoted as highly substituted carboxylated methacryloyl polyvinyl alcohol, PGC-H; the rest is roughly the same as in Example 1, and will not be repeated here.

[0093] Table 2

[0094]

[0095] Experiments show that when the mass-volume fraction of solution A (carboxylated methacryloyl polyvinyl alcohol aqueous solution) is less than 10%, the resulting hydrogel has poor molding and is prone to collapse after demolding.

[0096] When the mass-volume fraction of solution A is greater than 12%, the gelation speed is too fast, and gelation occurs before the double tubes are completely extruded, making it impractical.

[0097] When the mass-volume fraction of solution B (dipotassium glycyrrhizate aqueous solution with phenylboronic acid) is less than 6%, the ratio of the storage modulus to the loss modulus of the resulting hydrogel is close to 1, resulting in poor gel performance and making it unsuitable for instrument testing.

[0098] When the mass-volume fraction of solution A is greater than 10%, it can form a relatively stable gel when mixed with 6% to 10% solution B. The resulting gel has a wide range of modulus distribution depending on the concentration of solution B.

[0099] Please see Figure 7 The figure shows the rheological properties-gel time diagram of the hydrogels of Examples 1-3, 5 and Comparative Example 1.

[0100] As can be seen, in Example 1, when 8% GB and low-substituted PGC (PGC-L) were blended, a gel point appeared at 2 seconds, indicating a sol-gel transition. In Comparative Example 1, however, the blending of 4% GB and low-substituted PGC required 52 seconds, while the high-substituted PGC (Example 4) and the higher concentration of GB (Example 3) did not show a detectable gel point (the time for the sol-gel transition) due to the rapid gelation.

[0101] In summary, gels of different concentration ratios can all form gels within 1 minute, and the modulus of gels obtained from different concentration ratios is also different.

[0102] The gel formed with 4% GB had the lowest modulus and G' and G” were relatively close, indicating that the formed gel was soft and located near the sol-gel transition boundary, suggesting that the formed gel was unstable and not conducive to practical applications.

[0103] When the concentration of PGC is kept constant, the modulus of the gel formed gradually increases with the increase of GB solution concentration. Similarly, when the concentration of GB is kept constant, the modulus of the gel formed gradually increases with the increase of PGC substitution degree. In Example 5, when 8% GB forms a gel with highly substituted PGC (PGC-H), the modulus reaches 10. 3 Pa. It should be noted that the modulus of the hydrogel prepared by the present application can be controlled by adjusting the concentrations of GB and PGC.

[0104] Please see Figure 8 The figure shows the rheological properties-shear thinning diagram of the hydrogels in Examples 1-3, 5 and Comparative Example 1.

[0105] As can be seen, the viscosity of the prepared hydrogel decreases with increasing shear rate, indicating that it is injectable.

[0106] The rheological properties-oscillatory strain of the hydrogels from Examples 1-3, 5 and Comparative Example 1 were tested, and the results are shown in Table 3 and... Figure 9 As shown.

[0107] Table 3

[0108]

[0109] Please see Figure 9 The figure shows the rheological properties-oscillation strain diagrams of the hydrogels in Examples 1-3, 5 and Comparative Example 1. It can be seen that the maximum strain that the hydrogels with different concentration ratios can withstand varies, with the hydrogels capable of withstanding a maximum strain of 3000%.

[0110] Testing the rheological properties of hydrogels - alternating strain:

[0111] Dynamic self-healing test method:

[0112] The fracture strain of the hydrogel was determined by amplitude scanning at 1 Hz within a strain range of 0.1–10000%. Subsequently, alternating step strain tests were performed, with modulus measured at a constant frequency of 1 Hz, alternating strains between 1% and 3000%, and large and small strains alternating for 2 seconds and 60 seconds.

[0113] Please see Figure 10As shown, it is the rheological property - alternating strain diagram of the hydrogels of Example 1-2, 5 and Comparative Example 1.

[0114] Among them, G’ is the storage modulus and G’’ is the loss modulus. When G’ < G’’, it indicates a sol state at this time; when G’ > G’’, it indicates a gel state. With the alternation of large and small strains, G’ > G’’ under small strains represents the gel state, and G’ < G’’ under large strains represents the sol state. It can recover to the gel state (G’ > G’’) within 60 s after the gel structure is destroyed. This shows that the gel has self-healing properties.

[0115] Please refer to Figures 11 to 12 As shown, they are the adhesion energy diagrams and adhesion strength diagrams of the hydrogels of Example 1-2 and Example 4-5 respectively.

[0116] It can be seen that the adhesion strength of the hydrogel can reach 60 kPa and the adhesion energy can reach 450 J / m 2 , both indicating that the hydrogel prepared in this application has good adhesion performance. And it can be seen that with the increase of the concentration of GB or PGC, the adhesion performance of the hydrogel is improved. This shows that its adhesion can be regulated by changing the concentration ratio as needed.

[0117] Please refer to Figure 13 As shown, it is the compression performance diagram of the hydrogels of Example 1-2 and Example 5.

[0118] It can be seen that the hydrogels prepared with low-substituted PGC (PGC-L) and different concentration ratios of GB can all withstand 90% compression and the compression strength can reach 260 kPa, while the high-substituted PGC breaks at 64%.

[0119] Comparative Example 2

[0120] Comparative Example 2 provides a preparation method of a hydrogel. Compared with Example 1, the difference is that in step S2, ultrapure water is used to replace dimethyl sulfoxide, that is, glycyrrhizic acid is modified under aqueous conditions, and the rest is roughly the same as Example 1 and will not be elaborated here.

[0121] It can be known from experiments that no matter how the ratio of phenylboronic acid and dipotassium glycyrrhizinate or the pH value of the solution is regulated under aqueous conditions, the grafting of aminophenylboronic acid cannot be successful, that is, dipotassium phenylboronate glycyrrhizinate cannot be obtained.

[0122] Comparative Examples 3-4

[0123] Comparative Examples 3-4 provide a preparation method of a hydrogel. Compared with Example 1, the difference is that in step S1, the pH of the reaction solution is changed, as shown in Table 4 specifically; the rest is roughly the same as Example 1 and will not be elaborated here.

[0124] Table 4

[0125]

[0126] As shown in Table 4, when the pH of the reaction solution is less than 7, carboxylated methacryloylated polyvinyl alcohol cannot be obtained. When the pH is greater than 9, the gel formed by mixing the obtained carboxylated methacryloylated polyvinyl alcohol with dipotassium glycyrrhizate of phenylboronic acid has poor gel properties.

[0127] The hydrogels prepared in Examples 1-5 were tested for tensile strain, gel time and self-healing properties, and the results are shown in Table 5.

[0128] Table 5

[0129]

[0130] As shown in Table 5, the gel obtained in Example 1 has the best tensile properties and the fastest gelation speed. Meanwhile, the hydrogels of Examples 1-5 have a wide range of tensile strain and storage modulus distribution, and their adhesion strength can reach more than 20 kPa. They can all achieve rapid gelation and heal within 30 minutes.

[0131] The gel in Comparative Example 1 formed poorly and collapsed after demolding, making it impossible to test its mechanical properties on a machine. Its gel time was 52 seconds.

[0132] The gel obtained in Comparative Example 4 was too brittle and had poor mechanical properties; its gelation time was also longer compared to the examples.

[0133] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a rapidly formable, highly adhesive, and highly tensile self-healing hydrogel, characterized in that, The following steps are involved: S1, Preparation of carboxylated methacryloyl polyvinyl alcohol: Polyvinyl alcohol was completely dissolved in a reaction vessel containing an organic solvent, and then a catalyst was added; subsequently, a glycidyl methacrylate solution was added, and the reaction was carried out for 5-10 hours. Then, a succinic anhydride solution was added, and the reaction was continued for another 5-10 hours. After the reaction was completed, the pH of the reaction solution was adjusted to 7-9; then, acetone was used for precipitation, and after filtration, the precipitate was dialyzed for 48-72 hours. Finally, the dialysate was frozen and freeze-dried to obtain carboxylated methacryloyl polyvinyl alcohol. S2, Preparation of dipotassium glycyrrhizate phenylboronic acid: Dipotassium glycyrrhizate was completely dissolved in dimethyl sulfoxide, followed by the addition of N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 3-aminophenylboronic acid. The reaction was carried out at 25-35℃ for 20-48 h. Then, the reaction solution was dialyzed for 48-72 h, and the dialysate was filtered and freeze-dried to obtain dipotassium glycyrrhizate phenylboronic acid. S3, the carboxylated methacrylamide polyvinyl alcohol prepared in step S1 is prepared into a solution A with a mass-volume fraction of 10%~12%, and the dipotassium glycyrrhizate phenylboronic acid prepared in step S2 is prepared into a solution B with a mass-volume fraction of 6%~10%. The solutions A and B are extruded and mixed using a dual-tube syringe to obtain a rapidly moldable, highly adhesive, and highly tensile self-healing hydrogel.

2. The method for preparing the rapidly formable, highly adhesive, and highly tensile self-healing hydrogel according to claim 1, characterized in that, In step S1, the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.064-0.1).

3. The method for preparing the rapidly formable, highly adhesive, and highly tensile self-healing hydrogel according to claim 2, characterized in that, When the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.064-0.0652), the degree of substitution of the double bonds in the obtained carboxylated methacryloyl polyvinyl alcohol is 0.007~0.01; when the mass ratio of polyvinyl alcohol to glycidyl methacrylate is 1:(0.096-0.1), the degree of substitution of the double bonds in the obtained carboxylated methacryloyl polyvinyl alcohol is 0.018~0.

021.

4. The method for preparing the rapidly formable, highly adhesive, and highly tensile self-healing hydrogel according to claim 1, characterized in that, In step S2, the molar ratio of the carboxyl group on dipotassium glycyrrhizate to the amino group on 3-aminophenylboronic acid is 3:(1.25~1.3).

5. The method for preparing the rapidly formable, highly adhesive, and highly tensile self-healing hydrogel according to claim 1, characterized in that, In step S1, the mass ratio of succinic anhydride to polyvinyl alcohol is (1~4):

10.

6. The method for preparing the rapidly formable, highly adhesive, and highly tensile self-healing hydrogel according to claim 1, characterized in that, In step S1, the organic solvent is one of dimethyl sulfoxide, DMF, and chloroform.

7. The method for preparing the rapidly formable, highly adhesive, and highly tensile self-healing hydrogel according to claim 1, characterized in that, In step S1, the catalyst is p-dimethylaminopyridine, and the mass ratio of p-dimethylaminopyridine to polyvinyl alcohol is (0.1~0.15):

5.

8. The method for preparing the rapidly formable, highly adhesive, and highly tensile self-healing hydrogel according to claim 1, characterized in that, In step S1, the pH of the solution is adjusted by adding sodium bicarbonate solution dropwise into the reaction system.

9. A rapidly moldable, highly adhesive, and highly tensile self-healing hydrogel, characterized in that, The preparation method according to any one of claims 1-8 yields a self-healing hydrogel with strong adhesion and high tensile strength that can be rapidly formed, with an adhesion strength of 20-65 kPa and a tensile strain of 300-1050%.

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