An oxygen-initiated free radical polymerizable hydrogel, its preparation method and application

Abstract

This invention belongs to the field of hydrogel technology, and relates to an oxygen-initiated free radical polymerization hydrogel, its preparation method, and its applications. The method, conducted in an air atmosphere, uses monomers, sodium glycosyl sulfinate, and a crosslinking agent as reaction components. Dissolved oxygen in the reaction system or ambient oxygen serves as the free radical initiator, achieving rapid in-situ gelation of the hydrogel over a wide pH range and reaction temperature conditions. It is applicable to various monomer systems. The hydrogel prepared using this method exhibits good mechanical properties and structural stability, meeting the requirements for rapid gelation in open environments. It can be applied in fields such as biomedical materials, wearable electronic devices, bioprinting, and on-site remediation. This invention breaks through the traditional understanding of oxygen as a polymerization inhibitor in free radical polymerization, proposing a novel rapid gelation strategy for hydrogels using oxygen as the initiator.

Description

Technical Field

[0001] This invention belongs to the field of hydrogel technology, specifically relating to an oxygen-initiated free radical polymerized hydrogel, its preparation method, and its application. Background Technology

[0002] Hydrogels are three-dimensional cross-linked polymer network materials with high water content. Due to their highly tunable physicochemical properties and morphology, they have wide applications in many fields such as biomaterials and daily chemical products, including artificial cartilage, fever-reducing patches, drug delivery carriers, and superabsorbent diapers. Among these, the rapid development of fields such as biomedicine, petrochemicals, and wearable electronic devices has created an urgent need for the rapid gelation of hydrogels.

[0003] Free radical polymerization, as a highly mature and industrialized polymerization technology, has long been widely used in the preparation of functional hydrogels. However, in free radical polymerization systems, because oxygen molecules are highly efficient free radical quenchers, the polymerization reaction usually needs to be carried out in a deoxygenated environment, such as a glove box. This is because the oxygen state of the molecule has a diradical structure, which can react with growth chain radicals (R... • Rapid addition generates relatively stable peroxy radicals (ROO). • Since the chain growth rate of peroxy radicals is much lower than that of alkyl radicals, their generation process will significantly reduce the effective radical concentration, hindering chain growth and cross-linking reactions.

[0004] In the industrial production of free radical polymerization, oxygen inhibition has multiple adverse effects on production efficiency, material properties, and economic costs. First, oxygen inhibition is particularly pronounced in the early stages of the reaction, suppressing both chain initiation and chain growth, leading to prolonged polymerization induction period and reduced monomer conversion rate, and may even directly cause reaction termination. In continuous production or the preparation of rapidly curing materials, oxygen inhibition often makes it difficult to complete the reaction within the predetermined time, increasing the reaction cycle and reducing equipment utilization and economic efficiency. This effect runs counter to the development of rapid gelation. Second, oxygen inhibition leads to incomplete polymerization. The presence of residual monomers and oligomers not only reduces the molecular weight and network crosslinking density of the polymer but may also impair the mechanical properties, durability, and chemical stability of hydrogel materials. In the preparation of biomedical materials, residual monomers are more likely to pose cytotoxic risks.

[0005] At the manufacturing level, to avoid the influence of oxygen, it is often necessary to continuously introduce inert gas for protection or use large doses of oxygen scavengers. This not only significantly increases energy consumption and equipment investment but also complicates the production process, limiting the development of continuous, green, and low-cost preparation processes. However, it is difficult to completely avoid the re-infiltration of trace amounts of oxygen in large-scale continuous production, which further limits the stable production of high-performance functional hydrogel materials. Finally, the polymerization inhibition effect affects in-situ gelation and applications in open environments. With the development of technologies such as wearable electronics, bioprinting, and on-site repair, the demand for hydrogel materials to achieve rapid gelation and structural stability in open environments is increasing. However, the slowed gelation rate and incomplete network structure caused by oxygen polymerization inhibition make it difficult for traditional free radical polymerization systems to meet the practical requirements of these applications, severely restricting their engineering and industrialization potential.

[0006] In summary, due to the multiple negative impacts of oxygen inhibition on efficiency, performance, and cost in industrial production, there is an urgent need to develop innovative hydrogel synthesis strategies that can still achieve rapid polymerization and maintain structural integrity in an air environment, in order to overcome the bottlenecks of traditional systems in practical applications. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an oxygen-initiated free radical polymerized hydrogel, its preparation method, and its applications.

[0008] This invention provides an oxygen-initiated gelation composition comprising the following components in molar amounts: Acrylamide or its derivative monomer 1.5-6 parts, glycosyl sulfinate 0.005-0.1 parts, crosslinking agent 0-0.004 parts.

[0009] Preferably, the glycosyl sulfinate is 0.005 to 0.08 parts.

[0010] Preferably, the glycosyl sulfinate is 0.02 to 0.08 parts.

[0011] Preferably, the acrylamide or its derivative monomer is selected from at least one of acrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, methyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfobetaine methacrylate, and sulfobetaine acrylamide; And / or, the glycosyl sulfinate is selected from at least one of ribose sulfinate, cellobiose sulfinate, mannose sulfinate, and glucose sulfinate; And / or, the crosslinking agent is N,N′-methylenebisacrylamide.

[0012] Preferably, the glycosyl sulfinate is sodium glycosyl sulfinate; and / or, in the glycosyl sulfinate, the sulfinate is attached to the C-1 position of the glycosyl group; The present invention provides a hydrogel prepared by free radical polymerization of the composition as described in any of the preceding claims.

[0013] Preferably, it is prepared by free radical polymerization of the composition under dissolved oxygen conditions of 2.0~8.5 mg / L.

[0014] Preferably, the solvent for the polymerization reaction is deionized water; the pH of the polymerization reaction is 1-10; and the temperature of the polymerization reaction is 0-60°C.

[0015] The present invention provides a method for preparing the hydrogel as described in any of the preceding claims, comprising: obtaining the hydrogel from the composition by a free radical polymerization reaction.

[0016] This invention provides the application of the hydrogels described in any of the preceding claims in the preparation of biomedical materials, wearable electronic devices, bioprinting materials, or repair materials.

[0017] This invention provides a method for preparing hydrogels using oxygen-initiated free radical polymerization. This method can achieve rapid gelation in an air atmosphere using components such as monomers, sodium glycosyl sulfinate, and crosslinking agents, over a wide range of pH and reaction temperatures. It is applicable to various monomers and sodium glycosyl sulfinate. The hydrogels prepared using this method have good mechanical properties, meeting the requirements for rapid gelation and structural stability in open environments. They are expected to be used in biomedical materials, wearable electronic devices, bioprinting, and on-site repair, showing promising application prospects.

[0018] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0019] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0020] Figure 1 The results of the experiment investigating the factors affecting gelation time; among them, Figure 1 Figure a shows the gelation time results as a function of sodium ribose sulfinate concentration. Figure 1 b is a graph showing the gelation time as a function of reaction pH. Figure 1 c is a graph showing the gelation time as a function of reaction temperature; Figure 2The effect of dissolved oxygen concentration on gelation time; Figure 3 Monitoring of dissolved oxygen concentration during the reaction process of different gelation systems; Figure 4 The results of experiments investigating the temperature and viscosity of the reaction system during the gelation process; Figure 5 A comparison of the tensile properties of different rapid gelation systems; Figure 6 The effect of sodium ribose sulfinate concentration on the tensile and compressive properties of hydrogels; among which, Figure 6 a is the tensile stress-strain curve. Figure 6 b is the compressive stress-strain curve. Figure 6 Figure c shows the fracture strength and fracture toughness of the hydrogel under different concentrations of sodium ribose sulfinate. Figure 6 Figure d shows the compressive strength and compressive toughness of the hydrogel under different concentrations of sodium ribose sulfinate.

[0021] Figure 7 The results are from a general exploratory experiment. Detailed Implementation

[0022] Unless otherwise specified, all reagents and materials used in the following examples and experimental cases are commercially available.

[0023] The following hydrogels were all prepared using free radical polymerization.

[0024] Example 1: An oxygen-initiated gelled hydrogel and its preparation method The preparation method of the hydrogel in this embodiment is as follows: The specific steps are as follows: Under air atmosphere, acrylamide (AM, final concentration 4M) and N,N′-methylenebisacrylamide (MBA, 0.004M) are dissolved in deionized water (3.5 mL) at pH 7.2 to prepare a precursor solution. Then, an aqueous solution of sodium ribose sulfinate (1.5 mL) is added to this precursor solution, with a final concentration of sodium ribose sulfinate of 0.06M. The mixture is rapidly mixed at room temperature and allowed to stand for 5 minutes to obtain the final product.

[0025] In other embodiments, the monomer AM can also be adjusted to N-isopropylacrylamide (NIPAM) or 2-acrylamide-2-methylpropanesulfonic acid (AMPS); sodium ribose sulfinate can also be adjusted to sodium cellobiose sulfinate, sodium mannose sulfinate, or sodium glucose sulfinate; sodium ribose sulfinate can also be adjusted within the range of 0.005 to 0.1 M; the reaction pH can also be adjusted within the range of 1 to 10; and the reaction temperature can also be adjusted within the range of 0 to 60°C.

[0026] The technical solution of the present invention will be further explained through experiments below.

[0027] Experiment Example 1: Investigation of Factors Affecting Gelation Time I. Experimental Methods 1. Gelization time test Add 3.5 mL of the precursor solution and the aforementioned 1.5 mL of sodium ribose sulfinate aqueous solution to a small glass bottle with an inner diameter of 19 mm and mix thoroughly. Let the glass bottle stand. The time when the mixture stops flowing when the glass bottle is inverted is defined as the gelation time.

[0028] 2. Determination of the effect of RibSO2Na concentration on the rate of oxygen-initiated free radical polymerization Acrylamide (AM, final concentration 4M) and N,N′-methylenebisacrylamide (MBA, final concentration 0.004 M) were dissolved in deionized water (1.5 mL, pH=7.2) under air to prepare a precursor solution. Subsequently, an aqueous solution of sodium ribosyl sulfinate (1.5 mL) was added to this precursor solution, and the mixture was rapidly mixed thoroughly at room temperature and allowed to stand. The resulting hydrogel was named PRO-n hydrogel, where n represents the molar concentration of sodium ribosyl sulfinate, and the final concentrations of sodium ribosyl sulfinate were 0.005 M, 0.01 M, 0.015 M, 0.02 M, 0.04 M, 0.06 M, 0.08 M, and 0.1 M, respectively. The gelation time was measured for each concentration.

[0029] 3. Experiment on the effect of pH on gelation time Hydrogels were prepared at room temperature according to the method and concentration of Example 1, wherein the pH of deionized water was adjusted to 1, 3, 6, 8, or 10 by acid or alkali, or PBS buffer with pH 7.2 to 7.4 was used, and the gelation time was measured respectively.

[0030] 4. Experiment on the effect of temperature on gelation time Hydrogels were prepared according to the method and concentration specified in Example 1, with the reaction temperatures adjusted to 0°C, 25°C, 35°C, 45°C, and 60°C, respectively. Additionally, the reaction medium was changed from deionized water to tap water, and the reaction temperature was set to 25°C. The gelation time was measured for each reaction.

[0031] II. Experimental Results 1. Effect of RibSO2Na concentration on oxygen-initiated free radical polymerization rate The results are as follows Figure 1As shown in (a), the concentration of RibSO2Na has a significant impact on the gelation rate, and the gelation rate exhibits a non-linear trend of first accelerating and then slowing down with increasing concentration. When using a low concentration of 0.005 M, the gelation time is 180 s. As the concentration gradually increases to 0.01 M, the gelation time shortens to about 70 s. However, further increasing the RibSO2Na concentration has an adverse effect on the gelation process, causing the gelation time to gradually extend to 340 s.

[0032] Regarding the above experimental results, the underlying principle of this invention is as follows: When the RibSO2Na concentration is low, the rate of active free radical generation in the system is low, and the free radical polymerization reaction is limited by the initial initiation process. At this time, appropriately increasing the concentration of the reducing agent can promote the electron transfer reaction between it and oxygen, thereby accelerating the initiation and growth of the polymerization chain. However, when the RibSO2Na concentration is further increased to 0.04 M and higher, the high concentration of RibSO2Na is prone to molecular aggregation due to hydrogen bonding, which leads to the masking of its effective active sites and reduces the reaction efficiency with oxygen and monomers. In addition, excessive RibSO2Na may undergo free radical quenching reaction with the oxidizing free radicals (such as superoxide anion free radicals) generated in the system, thereby consuming some active species and inhibiting the chain initiation process.

[0033] The above results show that the gelation system of the present invention can achieve rapid gelation in a wide range of RibSO2Na concentrations (0.005~0.1M), wherein the preferred RibSO2Na concentration is 0.01~0.02M, and the gelation time is 55~76s at this preferred concentration.

[0034] 2. Results of the effect of pH on gelation time The results are as follows Figure 1 As shown in (b), the oxygen-initiated reaction system exhibits excellent acid-base tolerance. In a strongly acidic environment at pH = 1, the gelation time is slightly prolonged to 220 s. When the pH fluctuates within the range of 3 to 10, the reaction rate shows good robustness, and the gelation time is significantly shortened compared to deionized water. Under conditions of pH = 6, the entire process can be completed in about 20 s. When we use 1 × PBS buffer (pH = 7.2 ~ 7.4), which is close to physiological conditions, as the reaction solution, the gelation process still proceeds smoothly, with a reaction time of about 630 s.

[0035] The above results show that the gelation system of the present invention can achieve rapid gelation in a wide pH range (1~10). In this experimental example, the pH is preferably 3~10, and the gelation time is 23~45s at this preferred pH.

[0036] 3. Results of the effect of temperature on gelation time The results are as follows Figure 1 As shown in (c), temperature has a significant impact on the gelation process of the AM precursor. The gelation time gradually increases with decreasing reaction temperature; however, even at 0°C, the entire gelation process can still be completed within 100 s. When the reaction medium is changed from deionized water to tap water, the gelation time extends to 700 s. This may be due to the inhibitory effect of ions and trace impurities in tap water on the free radical polymerization process.

[0037] The above results show that the gelation system of the present invention can achieve rapid gelation in a wide temperature range (0~60°C). In this experimental example, the reaction medium is preferably deionized water, and the gelation time is 27~91s under the preferred reaction temperature and reaction medium.

[0038] The excellent tolerance of oxygen-initiated free radical polymerization systems to varying pH and temperature conditions is of significant practical importance. Traditional free radical initiation systems typically require stringent reaction environments, necessitating precise control of pH and temperature to prevent decreased initiation efficiency or runaway polymerization. Oxygen-initiated systems, however, maintain high polymerization activity and gel stability over a wider operating window, significantly enhancing their applicability under complex or non-ideal reaction conditions. This environmental tolerance not only helps reduce the stringent requirements for reaction conditions in industrial processes, decreasing energy consumption and environmental control costs, but also makes hydrogel synthesis more convenient and economically feasible. Furthermore, this characteristic offers promising potential for the large-scale application of oxygen-initiated systems in continuous flow polymerization, in-situ gelation, and biological or environmental systems, demonstrating their important value in the field of sustainable polymer material preparation.

[0039] Based on the results of this experiment, the oxygen-initiated gelation system of the present invention can achieve rapid gelation over a wide range of RibSO2Na concentrations, pH values, and temperatures. Preferably, the RibSO2Na concentration is 0.01~0.02M, the pH value is 3~10, the reaction temperature is 0~60°C, and the reaction medium is deionized water. Under the preferred reaction conditions, the gelation time is less than or equal to 90s, and can even be as fast as 23s.

[0040] Experiment Example 2: Investigation into the mechanism of oxygen-induced rapid gelation I. Experimental Methods 1. To investigate whether oxygen directly acts as an initiator in the free radical polymerization process, different pretreatment methods were applied to the AM precursor solution, and its gelation behavior was examined. The specific steps are as follows: Hydrogels were prepared according to the method of Example 1, wherein the concentration of RibSO2Na was 0.02M and the concentration of AM was 4M; the reaction environment was adjusted from a normal air environment (dissolved oxygen concentration of 7.8~8.5) to a glove box filled with nitrogen (dissolved oxygen concentration of 4.4~4.9); the precursor solution was subjected to ultrasonic and nitrogen deoxygenation operations and transferred to the glove box (dissolved oxygen concentration of 2.1~2.5); and the gelation time was measured according to the method of Experiment 1.

[0041] 2. To further investigate the role of oxygen in the system, the free radical scavenging reagent TEMPO was added to the detection system of Example 1, wherein the concentration of RibSO2Na was 0.02M and the concentration of AM was 4M; the reaction environment was a conventional air environment.

[0042] 3. Determination of dissolved oxygen concentration during gelation This experiment set up four non-oxygen-induced gelation systems as control groups: KPS-TMEDA-AM system, KPS-TMEDA-L-serine-AM system, KPS-THDB-AM system, and KPS-RibSO2Na-AM system. The reaction conditions for each gelation system were the same as in Example 1, and the specific formulations are shown below: Table 1 Note: KPS stands for potassium persulfate, which is a free radical polymerization initiator.

[0043] Dissolved oxygen concentration during gelation was determined using a dissolved oxygen meter (JPBJ-608) at room temperature and pH 7.0–7.2. The electrodes were calibrated before measurement. During measurement, the probe was directly inserted into the hydrogel solution to be tested, and the solution was gently stirred to avoid air bubbles adhering to the electrode surface. The dissolved oxygen value was recorded after the reading stabilized. Each sample was measured three times, and the average value was taken as the final result. The temperature and ambient pressure during measurement were also recorded for correction.

[0044] 4. Determination of reaction heat and viscosity during the gelation process Determination of the heat of reaction during gelation: The exothermic kinetics of the PRO hydrogel gelation process were determined using an infrared thermal imager. The hydrogel precursor solution was placed on a low-reflectance black substrate, and images were taken at room temperature, maintaining a distance of approximately 20 cm between the camera and the sample during acquisition. To capture the exothermic behavior during rapid gelation, continuous recording was performed from before reactant mixing until the completion of gelation and the cooling stage. After exporting the obtained thermal image data using software, the temperature changes in different regions of the sample surface were analyzed to obtain temperature-time curves, thereby evaluating the thermodynamics and temperature uniformity during the gelation process. Viscosity determination during gelation: The viscosity change during the gelation process was measured using a rheometer. A time-scan method was used, with parameters set at 25℃, 1 Hz, and a fixed strain of 1%. The reaction solution of the PRO hydrogel was added to a 40 mm diameter rheometer platform, and the viscosity change over time during gelation was recorded. A frequency-scan method was used to investigate the structure and viscoelasticity of the hydrogel, with parameters set at 25℃, 1 Pa amplitude, and angular frequency of 0.1 ~ 1 rad / s.

[0045] II. Experimental Results 1. The role of oxygen in the reaction system of this invention The results are as follows Figure 2 As shown in Table 2, under reaction conditions of room temperature and pH 7.0–7.2, and with concentration determined according to the gelation time described in Experimental Example 1, gelation was completed in approximately 50 s when the reaction was carried out in a normal air environment. However, when the reaction system was transferred to a nitrogen-filled glove box, the gelation time was significantly extended to 320 s. This indicates that oxygen in the system plays an important promoting role in the polymerization process. Furthermore, after ultrasonication and nitrogen deoxygenation of the precursor solution followed by transfer to a glove box, the gelation time was extended to 1 h, and the reaction system almost no longer exhibited rapid gelation characteristics.

[0046] Table 2 The addition of the free radical scavenging reagent TEMPO to the reaction system completely inhibited the gelation process, indicating that the rapid gelation initiated by O2-RibSO2Na is carried out through a free radical mechanism.

[0047] Real-time dynamic monitoring results of dissolved oxygen during the gelation process are as follows: Figure 3 As shown, in the initial stage of the reaction, the dissolved oxygen in the O2-RibSO2Na-AM solution decreased sharply, approaching the detection limit at 120 s, indicating that the oxygen in the solution was almost completely consumed. This phenomenon suggests that the dissolved oxygen in the system is rapidly utilized in the early stages of polymerization, and oxygen directly participates in the generation and initiation of free radicals in this system. In contrast, although the dissolved oxygen concentration in the three non-oxygen-initiated rapid gelation systems KPS-TMEDA-L-serine-AM, KPS-THDB-AM, and KPS-RibSO2Na-AM also showed a gradual decreasing trend, the overall rate of decrease was relatively slow, and it eventually remained at a relatively stable level. This phenomenon may mainly stem from the oxygen-consuming behavior of free radicals during polymerization. The active free radicals generated in the polymerization reaction can react with dissolved oxygen to generate peroxy free radicals. In other words, oxygen in this type of system mainly acts as an inhibitor of the polymerization reaction rather than an initiator, and its concentration change reflects more the activity of free radical reactions in the system.

[0048] The results showed that the gelation time increased continuously as the dissolved oxygen concentration gradually decreased. This phenomenon fully demonstrates that oxygen in this system does not act as a conventional free radical quencher, but rather directly participates in the initiation process.

[0049] 2. Changes in reaction heat and viscosity during the gelation process induced by the O2-RibSO2Na system The heat of reaction results are as follows Figure 4 As shown in Figure a, compared to the KPS-initiated rapid gelation system, the temperature of the O2-initiated system did not show a significant upward trend throughout the polymerization process, reaching a maximum of 37.2℃. This difference indicates that the two systems have significant differences in the mechanisms of free radical generation and energy release. This may be due to the low solubility of oxygen in water and the slow diffusion process avoiding the instantaneous accumulation of active free radical concentration, thus reducing local exothermic reactions. Conversely, in the KPS-RibSO2Na system, the electron transfer reaction occurs almost synchronously throughout the system, leading to a significant instantaneous accumulation of free radicals and a pronounced local exothermic effect, thus exhibiting a higher temperature rise. However, although the concentration of active free radicals in the O2-initiated system is limited, sodium ribose sulfinate has high chain initiation activity, and the high acrylamide concentration allows each generated active free radical to quickly initiate chain growth, achieving efficient polymerization.

[0050] The viscosity change results are as follows Figure 4 As shown in b, the viscosity of the system increases slowly in the initial stage of polymerization, and then increases exponentially with the growth of free radical chains and the progress of cross-linking reactions, eventually reaching a gel state rapidly within tens of seconds. The oxygen-initiated system achieves rapid gelation at room temperature, indicating that its initiation efficiency is sufficient to drive free radical polymerization, but its energy release is more dispersed and controllable. This characteristic not only reflects the lower energy barrier required for electron transfer in the O2-RibSO2Na system, but also implies greater operational safety and temperature stability in large-volume, closed, or thermosensitive environments. This mild thermal behavior is of great significance for subsequent applications in biomaterials, environmentally responsive gels, and in-situ polymerization systems.

[0051] The above results show that the gelation induced by the O2-RibSO2Na system of this invention is significantly different from the reaction mechanism of traditional free radical polymerization. Moreover, oxygen in this system does not act as a conventional free radical quencher, but directly participates in the initiation process. RibSO2Na is not only a reducing agent, but also has high chain initiation activity, which together achieves efficient polymerization.

[0052] Experiment Example 3: Investigation into the mechanical properties of oxygen-induced rapid gelation hydrogels I. Experimental Methods 1. Mechanical property testing (1) Tensile property test The synthesized hydrogel samples were subjected to tensile measurements using an Instron 3367 tensile testing machine (Instron Corporation, MA, USA) to characterize the mechanical properties of the gel. For the tensile tests, the hydrogel samples were cut into dumbbell shapes with a gauge length of 20 mm, a width of 4 mm, and a thickness of 1 mm. The samples were stretched at a strain rate of 100 mm / min until fracture, and the stress-strain curves were recorded. The strength at fracture is called the fracture stress, and the fracture toughness is determined by the area under the stress-strain curve at fracture.

[0053] (2) Compression performance test The synthesized hydrogel samples were subjected to tensile measurements using an Instron 3367 tensile testing machine (Instron Corporation, MA, USA) to characterize the mechanical properties of the gel. For compression testing, the hydrogel samples were prepared as cylinders with a diameter of 19 mm and a height of 22 mm, and compressed to the point of maximum strain (set to 80%) at a speed of 5 mm / min. The stress-strain curves were recorded.

[0054] 3. Different rapid gelation initiation systems Using different rapid gelation initiation systems, a series of hydrogels (named PLS-1.0, PBK-0.04, PRK-0.02, and PRO-0.06, respectively) were prepared with the same concentration of AM (4.0 M) monomer. The formulations of each hydrogel are shown in Table 1.

[0055] 4. Effect of RibSO2Na Concentration on the Mechanical Properties of PRO Hydrogel Following the method of Example 1, the final concentrations of RibSO₂Na were 0.005 M, 0.015 M, 0.02 M, 0.06 M, and 0.08 M, respectively, and the hydrogels were named PRO-0.005, PRO-0.015, PRO-0.02, PRO-0.06, and PRO-0.08. The formulations of each hydrogel are shown in Table 3. The mechanical properties of each hydrogel were measured.

[0056] Table 3 II. Experimental Results 1. Comparison of tensile properties of different rapid gelation systems The results are as follows Figure 5As shown, PRK-0.02 hydrogel exhibited the best tensile strength (0.498 MPa), while PLS-0.1 and PBK-0.04 hydrogels showed excellent ductility and toughness (tensile strains of 2060% and 1650%, respectively). The tensile strength and tensile strain of PRO-0.06 hydrogel were 0.360 MPa and 1183%, respectively.

[0057] 2. Effect of RibSO2Na concentration on the mechanical properties of PRO hydrogel The experimental results of tensile properties are as follows: Figure 6 As shown in a and 6c, the RibSO₂Na concentration has a significant regulatory effect on the hydrogel properties. As the RibSO₂Na concentration gradually increases from 0.005 M to 0.08 M, the fracture strength, fracture strain, and toughness of the hydrogel all show a trend of first increasing and then decreasing, reaching a peak at 0.06 M (0.360 MPa and 1183%, 1.82 MJ / m). 3 ).

[0058] The experimental results of compression performance are as follows: Figure 6 As shown in b and 6d, the compressive strength and compressive toughness are both optimal at a RibSO₂Na concentration of 0.06 M, which are 1.167 MPa and 21.176 MJ / m, respectively. 3 It is worth noting that when using the same concentration of reducing agent, the mechanical properties of the PRO gel are superior to those of the traditional PTK system. This indicates that the system has unique advantages in constructing strong and tough networks, demonstrating promising prospects for widespread application.

[0059] The results of this experiment show that the hydrogel prepared by this invention has good tensile and compressive strength, especially the hydrogel prepared with RibSO2Na concentration of 0.06M has even better mechanical properties.

[0060] Experiment Example 4: Investigation into the universality of the oxygen-sodium glycosyl sulfinate initiation system I. Experimental Methods This experimental example extends the use of gel monomers and RibSO2Na to evaluate the applicability of the oxygen initiation system of the present invention.

[0061] Hydrogels were prepared according to the method of Example 1, wherein the monomers were expanded from AM to N,N-dimethylacrylamide (DMAA), N-isopropylacrylamide (NIPAM), methyl methacrylate (MMA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sulfobetaine methacrylate (SBMA), and sulfobetaine acrylamide (SBAA), respectively. The amounts of monomers and RibSO2Na are shown in Table 4.

[0062] Table 4. Concentrations of each component in the study of the universality of the oxygen initiation system. Hydrogels were prepared according to the method in Example 1, wherein RibSO2Na was extended to glycosyl sulfinates such as Ribnosyl, Glycosyl, Mannosyl and Cellobinosyl, and the amounts of monomers and glycosyl sulfinates are shown in Table 5.

[0063] Table 5. Concentrations of each component in the study of the universality of sodium glycosyl sulfinate in the oxygen initiation system. II. Experimental Results The results are as follows Figure 7 As shown in Tables 4-5, under air atmosphere, using 5 mL of deionized water as a solution, both sodium mannose sulfinate and sodium cellobiose sulfinate could induce ultra-fast gelation of AM monomers within 120 s. When using sodium glucose sulfinate, the gelation time was 420 s. Meanwhile, under the O2-RibSO2Na initiation system, the gelation time for NIPAM was 820 s, and for AMPS, it was 510 s. Although other monomers such as DMAA, MMA, SBAA, and SBMA failed to meet the rapid gelation characteristics under this system, requiring gelation times greater than 2 h, these systems could still achieve polymerization under oxygen initiation conditions. This phenomenon itself has significant scientific value and application implications, and there is still potential for further optimization of the reaction system for monomers with poor performance.

[0064] The results of this experiment show that the gelation system of the present invention is applicable to a variety of monomers and sodium glycosyl sulfonates, wherein the preferred monomers are AM, NIPAM, and AMPS, and the preferred sodium glycosyl sulfonates include sodium ribose sulfonate, sodium cellobiose sulfinate, sodium mannose sulfinate, and sodium glucose sulfinate.

[0065] As can be seen from the above embodiments and experimental examples, the present invention provides a method for preparing hydrogels by oxygen-initiated free radical polymerization. This method can achieve rapid gelation in an air atmosphere using components such as monomers, sodium glycosyl sulfinate, and crosslinking agents, over a wide range of pH and reaction temperatures. It is applicable to various monomers and sodium glycosyl sulfinate. The hydrogels prepared by the method of the present invention have good mechanical properties, meeting the requirements of rapid gelation and structural stability in open environments. They are expected to be used in biomedical materials, wearable electronic devices, bioprinting, and on-site repair, showing promising application prospects.

Claims

1. A composition for oxygen-initiated gelation, characterized in that: It comprises the following molar amounts of components: Acrylamide or its derivative monomer 1.5-6 parts, glycosyl sulfinate 0.005-0.1 parts, crosslinking agent 0-0.004 parts.

2. The composition according to claim 1, characterized in that: The glycosyl sulfinate is present in amounts of 0.005 to 0.08 parts.

3. The composition according to claim 2, characterized in that: The glycosyl sulfinate is present in amounts of 0.02 to 0.08 parts.

4. The composition according to claim 1, characterized in that: The acrylamide or its derivative monomer is selected from at least one of acrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, methyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfobetaine methacrylate, and sulfobetaine acrylamide; And / or, the glycosyl sulfinate is selected from at least one of ribose sulfinate, cellobiose sulfinate, mannose sulfinate, and glucose sulfinate; And / or, the crosslinking agent is N,N′-methylenebisacrylamide.

5. The composition according to claim 1, characterized in that: The glycosyl sulfinate is sodium glycosyl sulfinate; and / or, in the glycosyl sulfinate, the sulfinate is attached to the C-1 position of the glycosyl group.

6. A hydrogel, characterized in that: It is prepared by free radical polymerization of the composition according to any one of claims 1-6.

7. The hydrogel according to claim 6, characterized in that: It is prepared by free radical polymerization of the composition under dissolved oxygen conditions of 2.0~8.5 mg / L.

8. The hydrogel according to claim 7, characterized in that: The solvent for the polymerization reaction is deionized water; the pH of the polymerization reaction is 1-10; and the temperature of the polymerization reaction is 0-60°C.

9. A method for preparing the hydrogel according to any one of claims 6-8, characterized in that, It includes: The composition is prepared by free radical polymerization.

10. The use of the hydrogel according to any one of claims 6-8 in the preparation of biomedical materials, wearable electronic devices, bioprinting materials or repair materials.

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