Antibacterial self-repairing polyurethane material and preparation method and application thereof

Abstract

The application relates to an antibacterial self-repairing polyurethane material and a preparation method and application thereof, relates to the field of self-repairing polymer composite materials, and solves the problems that the self-repairing polyurethane material in the prior art is seriously dependent on external conditions, self-repairing efficiency is limited, the preparation process of introducing functional materials is complex and is easy to affect the micro-phase structure of the polyurethane, and mechanical properties, antibacterial function and self-repairing performance are difficult to be stably realized in cooperation. The application mixes isocyanate, polyol and a catalyst to perform a prepolymerization reaction, adds a pretreated chain extender solution to perform a chain extension reaction, adds a pretreated copper nanocluster dispersion solution, stirs, solidifies, and the antibacterial self-repairing polyurethane material is obtained; the polydopamine is used as the chain extender, the self-repairing efficiency of the polyurethane material is significantly improved through the synergistic effect of the polydopamine and the copper nanocluster, and the antibacterial performance and the mechanical performance are simultaneously optimized, and the application can be applied to the fields of medical devices, food packaging films, capsule materials, marine antifouling materials and biological protection materials.

Description

Technical Field

[0001] This invention relates to the field of self-healing polymer composite materials, specifically to an antibacterial self-healing polyurethane material, its preparation method, and its application. Background Technology

[0002] In the field of polymer materials, polyurethane, due to its tunable structure composed of soft and hard segments, exhibits excellent comprehensive properties in terms of mechanical properties, flexibility, wear resistance, and biocompatibility, and is widely used in medical devices, daily protective materials, and aerospace structural components. However, in actual use, polyurethane materials are inevitably affected by external mechanical forces and environmental factors, making them prone to scratches, microcracks, or localized structural damage. This damage gradually weakens the material's mechanical properties and structural integrity, thus affecting its service life and safety.

[0003] To address these issues, self-healing polyurethane materials have gradually become a research focus. Current research primarily utilizes dynamic covalent bonds or reversible non-covalent interactions to enable polyurethane materials to spontaneously repair themselves after damage through molecular chain reconstruction, thus extending their service life. However, in practical applications, the self-healing mechanisms of some polyurethane materials are highly dependent on temperature, light, or specific chemical environments, limiting repair efficiency under normal temperature or complex operating conditions. Furthermore, existing technologies largely focus on the physical closure of cracks or interface reconstruction, lacking effective control over the restoration of surface condition and functionality in the repaired area. Especially after microcracks have undergone structural repair, localized areas may still exhibit structural inhomogeneity or exposed polar groups, altering the material's surface free energy. This makes it more susceptible to adsorbing moisture, proteins, and other substances, increasing its potential as an active site for microbial attachment and proliferation, thereby impacting the long-term safety and stability of the material.

[0004] Therefore, existing technologies achieve antibacterial functions by introducing silver ions, quaternary ammonium salts, or antibiotic-like antibacterial components into self-healing polyurethane systems. However, since these components are mostly in the form of physical dopants, they are prone to migration and loss and uneven distribution in the matrix. This not only leads to the decay of antibacterial performance over time but also interferes with the microphase separation structure and hard segment hydrogen bonding of polyurethane, thereby affecting the mechanical properties and structural stability of the material. At the same time, physically doped antibacterial components are prone to agglomeration in the matrix and introduce structural defects, reducing the effective contact area. Antibiotic-like antibacterial agents also pose a risk of inducing microbial resistance, thus limiting their overall application effectiveness and reliability.

[0005] Against this backdrop, relying solely on externally added antibacterial components is insufficient to simultaneously ensure the structural stability and functional durability of materials. Therefore, it is necessary to introduce structural units with good interfacial compatibility and multifunctional properties from the perspective of material system construction to achieve synergistic regulation of antibacterial and self-healing properties. Based on this, polydopamine (PDA), due to its ability to self-polymerize under mild conditions and adhere to various substrate surfaces, has been increasingly used for material functionalization. Existing technologies often use it as a surface coating or interfacial modification layer to improve adhesion and impart certain antioxidant or antibacterial properties. However, these post-treatment methods primarily rely on surface interactions, resulting in limited bonding with the substrate, susceptibility to detachment or performance degradation during long-term use, and functional limitations confined to the material surface, making it difficult to achieve synergistic regulation of the overall structure and performance. Furthermore, there are few studies on directly introducing PDA as a reactive component into polyurethane systems, and its role in the polymerization process and its impact on material structure and properties remain unclear. On the other hand, copper nanomaterials, especially copper nanoclusters, have certain antibacterial advantages due to their small size and large specific surface area. However, they are prone to oxidation or aggregation in applications, which leads to reduced activity. Furthermore, the uniformity of dispersion in polyurethane matrices is difficult to control, which can easily lead to local enrichment and affect the stability of material performance. In addition, the preparation methods of some copper nanoclusters rely on complex ligands or multi-step processes, which have high requirements for conditions and also limit their practical applications to some extent. Summary of the Invention

[0006] To address the problems of existing self-healing polyurethane materials being heavily reliant on external conditions, having limited self-healing efficiency, complex preparation processes involving the introduction of functional materials that easily affect the polyurethane microphase structure, and the difficulty in achieving a synergistic and stable balance between mechanical properties, antibacterial function, and self-healing performance, this invention proposes an antibacterial self-healing polyurethane material, its preparation method, and its applications. The technical solution of this invention is as follows: A method for preparing an antibacterial self-healing polyurethane material includes the following preparation steps: Isocyanate, polyol and catalyst are mixed and prepolymerized to obtain prepolymer; pretreated chain extender solution is added to carry out chain extension reaction; after the reaction is completed, pretreated copper nanocluster dispersion is added, stirred and cured to obtain antibacterial self-healing polyurethane material. The chain extender includes PDA; the mass fraction of PDA is 0.08% to 2.3% based on the total mass of the polyurethane material. The copper nanoclusters have a mass fraction of 1% to 8% based on the total mass of the polyurethane material.

[0007] Furthermore, the isocyanate is a diisocyanate; the polyol is a polydiol with a number average molecular weight of 1000-2000; and the catalyst is an organotin catalyst.

[0008] Furthermore, the diisocyanate is an aliphatic diisocyanate and / or an aromatic diisocyanate, preferably isophorone diisocyanate. The polydiol is a polyether diol and / or a polyester diol, wherein the polyether diol is polyethylene glycol and / or polytetrahydrofuran (PTMG); the polyester diol is polycaprolactone diol and / or polycarbonate diol; and the organotin catalyst is either dibutyltin dilaurate (DBTDL) or stannous octoate (SnOct).

[0009] Furthermore, both the prepolymerization reaction and the chain extension reaction are carried out in an inert gas atmosphere, wherein the inert gas is any one of argon, nitrogen, or helium.

[0010] Furthermore, the molar ratio of the isocyanate, polyol and catalyst is 1:0.9:0.01 to 1:1.1:0.01; the temperature of the prepolymerization reaction is 60 to 100°C, and the time is 1 to 3 hours.

[0011] Furthermore, the chain extension reaction is carried out at a temperature of 50-70°C for 5-8 hours; the chain extender further includes 1,4-butanediol (BDO); ​​the pretreatment step of the chain extender solution is as follows: dissolve the chain extender in tetrahydrofuran and sonicate for 5-10 minutes to obtain the chain extender solution; the mass ratio of BDO to PDA is 9:1-45:1.

[0012] Further, the preparation steps of the PDA are as follows: add dopamine hydrochloride to a mixed solution of ammonia-water-ethanol at pH=8.5 (the volume ratio of ammonia, water and ethanol is 1:20:45), stir at room temperature for 24 h; add acetone, precipitate out, centrifuge, discard the supernatant, and obtain PDA.

[0013] Furthermore, the pretreatment step of the copper nanoclusters is as follows: dissolve the copper nanoclusters in tetrahydrofuran and sonicate for 5-10 min to obtain a dispersion of copper nanoclusters.

[0014] Further, the preparation steps of the copper nanoclusters are as follows: copper nitrate solution is added to polyethylene glycol-200 (PEG-200) aqueous solution (PEG-200 mass fraction is 80%), glutathione solution is added under stirring conditions, and the mixture is stirred for 1~3 min; then calcium chloride solution is added, and the mixture is stirred for 3~5 min to induce the formation of copper nanocluster self-assemblies; the mixture is centrifuged, and the precipitate is washed multiple times with ethanol to remove residual PEG-200 and small molecule impurities, and then freeze-dried to obtain copper nanocluster powder; the freeze-drying time is 48~120 h; the freeze-drying temperature is -30~-10℃.

[0015] Furthermore, the stirring time is 15~60 min, the curing temperature is 45~75℃, and the curing time is 12~48 h.

[0016] An antibacterial self-healing polyurethane material prepared by the above preparation method.

[0017] One application of the above-mentioned antibacterial self-healing polyurethane material is in the fields of medical devices, food packaging films, capsule materials, marine antifouling materials, and biological protection materials.

[0018] Compared with existing technologies, this invention solves the problems of existing self-healing polyurethane materials being heavily dependent on external conditions, having limited self-healing efficiency, having complex preparation processes for introducing functional materials that easily affect the microphase structure of polyurethane, and having difficulty in achieving coordinated and stable mechanical properties, antibacterial functions, and self-healing properties. Specifically, the beneficial effects are as follows: 1. This invention significantly enhances the self-healing ability of antibacterial self-healing polyurethane materials under mild conditions (25℃, 40RH) by introducing PDA into a polyurethane system to construct a multi-layered dynamic reversible network. The elongation at break and tensile strength repair rates reach as high as 112% and 89%, respectively. PDA molecules are rich in catechol and amine groups, which can form hydrogen bonds, π–π interactions, and dynamic coordination between the soft and hard segments of polyurethane, thereby improving the migration ability of molecular chains and the efficiency of interface reconstruction, achieving a transformation from physical adhesion to molecular-scale healing. Simultaneously, PDA has a coordination anchoring effect on copper nanoclusters, ensuring their stable dispersion in the system without disrupting the original dynamic network structure. This avoids the microphase separation disturbances and structural defects caused by the introduction of traditional fillers, thus achieving antibacterial function without affecting self-healing performance. This effectively overcomes the problems of self-healing effect dependence on external conditions, low repair efficiency, and poor interface stability in existing technologies.

[0019] 2. This invention achieves simultaneous optimization of the antibacterial and mechanical properties of antibacterial self-healing polyurethane materials through the synergistic effect of PDA and copper nanoclusters. PDA not only generates reactive oxygen species through redox processes but also stably anchors copper nanoclusters and promotes their uniform dispersion, thereby realizing a synergistic antibacterial mechanism of copper ion release and oxidative stress, significantly improving antibacterial efficiency (up to 99%) and durability. Simultaneously, PDA acts as an interface bridge and structural regulator in the polyurethane system, enhancing the interaction between hard segments and improving the stability of the microphase structure. Meanwhile, the nanoscale dispersed copper nanoclusters facilitate stress transfer and dispersion, avoiding the performance degradation caused by the agglomeration of traditional antibacterial fillers. Thus, while endowing the material with highly efficient antibacterial capabilities, it maintains or even improves its mechanical properties, achieving a synergistic and stable improvement in multiple properties.

[0020] 3. The preparation process of this invention is simple and highly controllable. By introducing polydopamine and copper nanoclusters into a conventional polyurethane synthesis system, functional integration can be achieved without complex post-treatment or multi-step surface modification. PDA can be formed in situ under mild conditions, simultaneously completing the coordination anchoring and dispersion control of copper nanoclusters, avoiding the process complexity and stability problems caused by nanomaterial pre-modification, surface grafting, or multi-step composite in traditional antibacterial systems. Furthermore, the components exhibit good compatibility, eliminating the need for additional strong reaction conditions or special equipment, which is beneficial for large-scale preparation and industrial scale-up, combining ease of operation with process stability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an antibacterial self-healing polyurethane material; Figure 2 The diagram shows the test results of the self-healing properties of the antibacterial self-healing polyurethane materials prepared in Examples 1-5 and the polyurethane materials prepared in Comparative Examples 1-7. Figure 2 a represents the fracture morphology of each sample after cutting; Figure 2 b represents the self-healing morphology of each sample. Detailed Implementation

[0022] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0023] Example 1. S1: Add 0.5 g of dopamine hydrochloride to 130 mL of a mixture of ammonia, water and ethanol at pH 8.5 (the volume ratio of ammonia, water and ethanol is 1:20:45), stir at room temperature for 24 h; add acetone, precipitate out, centrifuge, discard the supernatant to obtain PDA.

[0024] S2: 0.5 mL of copper nitrate solution (concentration 20 mmol / L) was added to 9 g of polyethylene glycol-200 (PEG-200 mass fraction 80%) aqueous solution. 0.5 mL of glutathione solution (concentration 75 mmol / L) was added under stirring and stirred for 1 min. Then, 0.5 mL of calcium chloride solution (concentration 40 mmol / L) was added and stirred for 3 min to induce the formation of copper nanoclusters self-assembly. After centrifugation, the precipitate was washed three times with ethanol to remove residual PEG-200 and small molecule impurities. The precipitate was then freeze-dried at -25℃ for 48 h to obtain copper nanoclusters.

[0025] S3: Mix 10.0 g PTMG (Mn=2000), 2.22 g IPDI and 0.01 g DBTDL, and react at 80 °C for 2 h under argon protection to obtain the prepolymer; S4: Dissolve 10 mg of PDA and 0.43 g of BDO prepared in S1 in 5 mL of tetrahydrofuran and sonicate for 5 min to obtain a pretreated chain extender solution; add the chain extender solution to the prepolymer prepared in S3 and react at 60 °C for 6 h under argon protection to obtain a polyurethane matrix; S5: Dissolve 0.6 g of the copper nanoclusters prepared in S2 in 5 mL of tetrahydrofuran and sonicate for 10 min to obtain a pretreated copper nanocluster dispersion; add the copper nanocluster dispersion to the polyurethane matrix prepared in S4 and stir at room temperature for 30 min. Pour the solution into a mold and cure at 40℃ for 24 h to obtain an antibacterial self-healing polyurethane material. Figure 1 The diagram shows the structure of the antibacterial self-healing polyurethane material.

[0026] Example 2. The difference between this embodiment and Example 1 is that the amount of PDA is adjusted to 20 mg, while the rest of the preparation steps and conditions are the same as in Example 1, resulting in antibacterial self-healing polyurethane.

[0027] Example 3. The difference between this embodiment and Example 1 is that the amount of PDA is adjusted to 30 mg, while the rest of the preparation steps and conditions are the same as in Example 1, resulting in antibacterial self-healing polyurethane.

[0028] Example 4. The difference between this embodiment and Example 1 is that the amount of PDA is adjusted to 40 mg, while the rest of the preparation steps and conditions are the same as in Example 1, resulting in antibacterial self-healing polyurethane.

[0029] Example 5. The difference between this embodiment and Example 1 is that the amount of PDA is adjusted to 50 mg, while the rest of the preparation steps and conditions are the same as in Example 1, resulting in antibacterial self-healing polyurethane.

[0030] Comparative Example 1. The difference between this comparative example and Example 1 is that PDA is not added, but only 0.45 g of BDO is added as a chain extender. The rest of the preparation steps and conditions are the same as in Example 1, and a polyurethane material is obtained.

[0031] Comparative Example 2. The difference between this comparative example and Example 1 is that copper nanoclusters are not added, while the rest of the preparation steps and conditions are the same as in Example 1, resulting in a polyurethane material.

[0032] Comparative Example 3. The difference between this comparative example and Example 2 is that copper nanoclusters are not added, while the rest of the preparation steps and conditions are the same as in Example 2, resulting in a polyurethane material.

[0033] Comparative Example 4. The difference between this comparative example and Example 3 is that copper nanoclusters are not added, while the rest of the preparation steps and conditions are the same as in Example 3, resulting in a polyurethane material.

[0034] Comparative Example 5. The difference between this comparative example and Example 4 is that copper nanoclusters are not added, while the rest of the preparation steps and conditions are the same as in Example 4, resulting in a polyurethane material.

[0035] Comparative Example 6. The difference between this comparative example and Example 5 is that copper nanoclusters are not added, while the rest of the preparation steps and conditions are the same as in Example 5, resulting in a polyurethane material.

[0036] Comparative Example 7. The difference between this comparative example and Example 1 is that the amount of PDA added was adjusted to 400 mg, while the rest of the preparation steps and conditions were the same as in Example 1, resulting in a polyurethane material.

[0037] Antibacterial performance test: The antibacterial self-healing polyurethane materials prepared in Examples 1-5 and Comparative Examples 2-6 were used to test the antibacterial properties against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. The test method followed international standard ISO 22196, using the plate count method to determine the antibacterial properties. (Escherichia coli...) E. coli ) and Staphylococcus aureus ( S. aureus This represents Gram-negative and Gram-positive bacteria. The bacterial suspension was diluted to a concentration of 10 with sterile PBS. 6The CFU / mL polyurethane membrane samples were uniformly cut into small discs with a diameter of 8 mm. The sterilized samples and a certain volume of diluted bacterial solution were placed together in centrifuge tubes and incubated in a constant temperature incubator for 24 h. After incubation, the bacterial solution was serially diluted 10-fold using sterile PBS solution, and 100 μL of the diluted solution was evenly spread on a solid culture medium and incubated in a constant temperature incubator for 24 h. After incubation, the culture dishes were removed and photographed to record the number of colonies. Based on the data in Table 1, it can be seen that, in Comparative Examples 2-6, without the introduction of copper nanoclusters, the PDA-modified polyurethane system showed a generally low antibacterial rate against *Escherichia coli* and *Staphylococcus aureus* (both below 25%). However, it can be observed that as the PDA content gradually increased from 10 mg to 50 mg, its antibacterial performance showed a slow upward trend. This is mainly attributed to the redox reaction of the catechol groups in PDA, which generates reactive oxygen species and disrupts the bacterial membrane structure. The antibacterial self-healing polyurethane materials prepared in Examples 1-5 showed an antibacterial rate of up to 99% against *Escherichia coli* and *Staphylococcus aureus*, with a slightly better antibacterial effect against *Staphylococcus aureus* than against *Escherichia coli*. This is because the outer membrane structure of *E. coli* has a certain inhibitory effect on the penetration of metal ions. These results indicate that a synergistic antibacterial mechanism is formed between PDA and copper nanoclusters. PDA stabilizes and anchors the copper nanoclusters through coordination and promotes their uniform dispersion. Simultaneously, its redox properties promote the release of copper ions and the generation of reactive oxygen species (ROS), thereby achieving a synergistic enhancement effect of metal ion sterilization and oxidative stress sterilization.

[0038] Meanwhile, this invention utilizes a PDA to construct an interface bridging structure, enabling copper nanoclusters to be embedded in the polyurethane network in an in-situ fixed manner. This effectively avoids the problems of easy migration, loss, aggregation, and uneven distribution of antibacterial components in traditional physical doping systems, thereby significantly improving the stability and durability of antibacterial performance. Furthermore, the hydrogen bonds and interactions between the PDA and the polyurethane hard segments enhance the microphase structural stability of the system, and the nano-dispersion of the copper nanoclusters also facilitates stress transfer and dispersion. Therefore, while achieving highly efficient antibacterial properties, the material's mechanical properties are not weakened; on the contrary, strength and toughness are improved to a certain extent. Thus, the antibacterial self-healing polyurethane material not only effectively overcomes the problems of easy failure of antibacterial components and structural interference in the prior art, but also achieves synergistic optimization of antibacterial and mechanical properties.

[0039] Table 1

[0040] Self-healing performance test: The self-healing polyurethane materials prepared in Examples 1-5 and Comparative Examples 1-7 were tested for their self-healing properties. The samples were cut into dumbbell shapes with a thickness of 1 mm, cut in half with a scalpel, and then the cracks were joined together. The samples were allowed to self-heal for 24 hours at 25°C and 40% RH. The results are as follows: Figure 2 a and Figure 2 As shown in b, where Figure 2 a represents the fracture morphology of each sample after cutting. Figure 2 b shows the self-healing results of each sample at room temperature. Comparative Example 1, lacking a PDA system, relied solely on BDO chain extension to form a relatively fixed polyurethane network structure. The system lacked dynamic functional sites capable of participating in reversible interactions, making it difficult for polymer chains to migrate and recombine effectively at the damaged interface. The damaged area could not form a stable interface reconstruction, thus cracks or cuts were difficult to close effectively and recover structurally after external force damage, exhibiting no significant self-healing effect overall. Comparative Examples 2–6, although constructing polyurethane systems with different PDA contents, still relied on dynamic interactions regulated by PDA due to the absence of copper nanoclusters. It was observed that as the PDA content increased from 10 mg to 50 mg, the self-healing effect gradually increased, and the fracture interface changed from clear to blurred, indicating that PDA effectively improved the cross-interface migration and reconstruction capabilities of molecular chains in the system. This is because PDA molecules are rich in catechol and amine groups, which can construct multiple reversible interactions between the soft and hard segments of polyurethane, including strengthening the hydrogen bond network, π–π interactions, and dynamic coordination, thereby significantly improving chain mobility and interface reconstruction capabilities. This is the fundamental reason why the self-healing performance of the examples increases with increasing PDA content. In Examples 1–5, copper nanoclusters were further introduced at the same PDA gradient. The repair morphology was basically consistent with the corresponding ratio, and no significant degradation was observed. This indicates that the introduction of copper nanoclusters did not destroy the dynamic network structure and chain mobility of the polyurethane system, and the system could still achieve efficient self-healing. However, when the PDA addition was too high (comparative example 7, 400 mg), the rigid structure and excessive interaction density in the system inhibited molecular chain movement, which was detrimental to the self-healing process, and therefore defects remained at the repair interface. This invention introduces a PDA to construct a dynamic network and utilizes the coordination and anchoring effect of the PDA on copper nanoclusters to achieve uniform dispersion. This ensures that the introduction of antibacterial components does not interfere with self-healing behavior, avoiding structural defects caused by traditional fillers and overcoming the problems of self-healing effect depending on external conditions and unstable interface function after repair in the prior art. Thus, it achieves synergistic optimization of self-healing performance and antibacterial performance.

[0041] Table 2 below shows the mechanical properties of the antibacterial self-healing polyurethane materials prepared in Examples 1-5 and the polyurethane materials prepared in Comparative Examples 1-7 before and after the self-healing performance test. As can be seen from Table 2, with the increase of PDA addition, the tensile strength recovery rate and elongation at break recovery rate of Comparative Examples 2-6 all showed a gradual increasing trend. This indicates that PDA can form numerous reversible crosslinking points with the polyurethane molecular chains through dynamic non-covalent bonds. When the material is damaged, these dynamic bonds can break and recombine. Simultaneously, the good interfacial compatibility between PDA and the polyurethane matrix can increase the repair sites, leading to enhanced self-healing performance of the composite material. However, when the PDA addition amount is further increased to 400 mg (Comparative Example 7), the PDA addition amount is too high. Excessive crosslinking of PDA with polyurethane restricts the movement of the molecular chains, which is not conducive to the effective reconstruction of the damaged interface and hinders self-healing. Meanwhile, in Examples 1-5, the overall recovery rate of mechanical properties after repair remained at a high level after the introduction of copper nanoclusters, and there was no significant decrease compared with the corresponding ratio. This indicates that the introduction of copper nanoclusters did not significantly damage the dynamic network structure and self-healing behavior of the polyurethane system, and the system could still maintain good segment migration ability and interface reconstruction ability. Therefore, this invention constructs a dynamic reversible network through PDA and combines it with the stabilizing dispersion effect of copper nanoclusters by PDA, thereby endowing the material with antibacterial properties while maintaining excellent self-healing properties, achieving a synergistic and stable improvement in antibacterial and self-healing properties.

[0042] Table 2

[0043] In summary, this invention significantly enhances the self-healing ability of antibacterial self-healing polyurethane materials under mild conditions (25°C, 40RH) by introducing PDA into the polyurethane system to construct a multiple dynamic reversible interaction network, achieving a fracture elongation repair rate of up to 112% and a tensile strength repair rate of up to 89%. Simultaneously, this invention utilizes the synergistic effect of PDA and copper nanoclusters to maintain or even improve the mechanical properties while endowing the material with highly efficient antibacterial capabilities, achieving simultaneous optimization of antibacterial and mechanical properties, with an antibacterial rate as high as 99%.

[0044] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an antibacterial self-healing polyurethane material, characterized in that, The preparation steps include the following: Isocyanate, polyol and catalyst are mixed and prepolymerized to obtain prepolymer; pretreated chain extender solution is added to carry out chain extension reaction; after the reaction is completed, pretreated copper nanocluster dispersion is added, stirred and cured to obtain antibacterial self-healing polyurethane material. The chain extender includes polydopamine; the mass fraction of the polydopamine is 0.08% to 2.3% based on the total mass of the polyurethane material. The copper nanoclusters have a mass fraction of 1% to 8% based on the total mass of the polyurethane material.

2. The method for preparing the antibacterial self-healing polyurethane material according to claim 1, characterized in that, The isocyanate is a diisocyanate; the polyol is a polydiol with a number average molecular weight of 1000-2000; and the catalyst is an organotin catalyst.

3. The method for preparing the antibacterial self-healing polyurethane material according to claim 2, characterized in that, The diisocyanate is an aliphatic diisocyanate and / or an aromatic diisocyanate; the polydiol is a polyether diol and / or a polyester diol, wherein the polyether diol is polyethylene glycol and / or polytetrahydrofuran; the polyester diol is polycaprolactone diol and / or polycarbonate diol; and the organotin catalyst is any one of dibutyltin dilaurate and stannous octoate.

4. The method for preparing the antibacterial self-healing polyurethane material according to claim 1, characterized in that, Both the prepolymerization reaction and the chain extension reaction are carried out in an inert gas atmosphere, wherein the inert gas is any one of argon, nitrogen, or helium.

5. The method for preparing the antibacterial self-healing polyurethane material according to claim 1, characterized in that, The molar ratio of isocyanate, polyol and catalyst is 1:0.9:0.01 to 1:1.1:0.01; the temperature of the prepolymerization reaction is 60 to 100°C and the time is 1 to 3 hours.

6. The method for preparing the antibacterial self-healing polyurethane material according to claim 1, characterized in that, The chain extension reaction is carried out at a temperature of 50-70°C for 5-8 hours. The chain extender also includes 1,4-butanediol. The pretreatment step of the chain extender solution is as follows: dissolve the chain extender in tetrahydrofuran solvent and sonicate for 5-10 minutes to obtain the chain extender solution. The mass ratio of 1,4-butanediol to polydopamine is 9:1-45:

1.

7. The method for preparing the antibacterial self-healing polyurethane material according to claim 1, characterized in that, The pretreatment step of the copper nanoclusters is as follows: dissolve the copper nanoclusters in tetrahydrofuran solvent and sonicate for 5-10 min to obtain a dispersion of copper nanoclusters.

8. The method for preparing the antibacterial self-healing polyurethane material according to claim 1, characterized in that, The stirring time is 15~60 min, the curing temperature is 45~75℃, and the curing time is 12~48 h.

9. An antibacterial self-healing polyurethane material prepared by the preparation method according to any one of claims 1-8.

10. An application of the antibacterial self-healing polyurethane material as described in claim 9, characterized in that, It is used in the fields of medical devices, food packaging films, capsule materials, marine antifouling materials, and biological protection materials.

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