Composite film adhesive based on hyperbranched polymer as well as preparation method and application of composite film adhesive

Abstract

The invention discloses a hyperbranched polymer-based composite film adhesive as well as a preparation method and application thereof. The hyperbranched polymer disclosed by the invention is obtained by carrying out copolymerization reaction on methacrylic acid, poly (ethylene glycol) methacrylate, carbamidinone methacrylate, 2-methylene-1, 3-dioxane and 2-(2-methoxyethoxy) ethyl methacrylate, and the hyperbranched polymer disclosed by the invention is obtained by carrying out copolymerization reaction on methacrylic acid, poly (ethylene glycol) methacrylate, carbamidinone methacrylate, 2-methylene-1, 3-dioxane and 2-(2-methoxyethoxy) ethyl methacrylate. The hyperbranched polymer and a certain proportion of nanocellulose are dissolved and dried to form a composite film. The composite film has good mechanical properties, thermosensitivity, degradability and biocompatibility, and shows good adhesion strength to skin tissues. The hyperbranched polymer disclosed by the invention is simple, convenient and safe to synthesize, and the composite film disclosed by the invention is convenient to use and has relatively high application and popularization values.

Description

Technical Field

[0001] This invention belongs to the field of adhesive materials technology, specifically relating to a composite film adhesive based on hyperbranched polymers, its preparation method, and its application. Background Technology

[0002] In the field of skin wound care, ensuring wound isolation from bacteria and promoting rapid healing has always been a key objective. Bacterial infection of wounds not only prolongs the healing process but can also lead to complications such as inflammation and suppuration, and in severe cases, even affect overall health. Traditional wound care methods, such as simple gauze bandages, are insufficient to effectively prevent bacterial invasion and are prone to sticking to the wound during dressing changes, causing secondary damage. With advancements in medical technology, higher demands are placed on the performance of wound dressings, expecting them to provide a strong bacterial barrier, promote wound healing, and also be comfortable and convenient.

[0003] Currently, various materials and products for wound care exist on the market. For example, some synthetic polymer-based film dressings, while capable of isolating bacteria to some extent, often suffer from poor adhesion, easily detaching from the skin surface and failing to provide long-term effective wound protection. Some dressings also lack sufficient mechanical tensile strength, easily breaking during skin movement and affecting their protective effect. Furthermore, many existing dressings have poor biocompatibility, potentially causing adverse reactions such as skin allergies, which hinder wound healing. Among related patent inventions, some wound dressings are prepared using a single polymer, but their performance struggles to balance adhesion, mechanical properties, and biocompatibility. For instance, some patents use ordinary linear polymers, which, while low-cost, cannot function stably in the complex skin environment. Other patents involving nanocellulose, while utilizing their high specific surface area, fail to adequately consider the synergistic effects with other materials, resulting in the overall performance of the composite film still needing improvement. For example, some nanocellulose composite films exhibit agglomeration during the drying process due to material compatibility issues, affecting the film's uniformity and performance stability.

[0004] Therefore, there is still considerable room for improvement in the development of wound dressing film materials. Developing polymers with tissue adhesion, temperature sensitivity, and biodegradability through chemical design, and then combining them with nanocellulose, which possesses good mechanical properties, to precisely control their physicochemical properties and achieve good wound protection is of great significance. Summary of the Invention

[0005] This invention aims to address the shortcomings of existing wound dressings in terms of adhesion, tensile strength, and biocompatibility. By synthesizing a polymer with thermosensitive and biodegradable properties and combining it with nanocellulose, a novel composite film is expected to be obtained. This film not only adheres tightly to the skin surface wound, effectively isolating bacteria, but also remains intact during skin activity, without affecting the wound healing process. Furthermore, its excellent biocompatibility reduces the probability of adverse reactions such as skin allergies, providing a more ideal environment for wound healing.

[0006] One objective of this invention is to provide a method for preparing a hyperbranched polymer that combines tissue adhesion properties, temperature sensitivity, and biodegradability. This invention synthesizes a monomer, ureapyridinone methacrylate (UPyMA), with double-bond functionalized quadruple hydrogen bonds by combining 2-amino-4-hydroxy-6-methylpyrimidine (MIS) and isocyanate ethyl methacrylate (ICEMA). A supramolecular branched polymer (PUM) solution with adhesive, thermosensitive, and biodegradable properties was synthesized in one step via RAFT polymerization using the thermosensitive monomer 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA), the long-chain monomer poly(ethylene glycol) methacrylate (PEGMA), methacrylic acid (MA), the tetradehydrogenated monomer (UPyMA), and the biodegradable functional monomer 2-methylene-1,3-dioxane (MDO). N,N-dimethylformamide (DMF) was used as the solvent, azobisisobutyronitrile (AIBN) as the initiator, and 4-cyano-4-(phenylthiocarbamoylthio)valerate as the chain transfer agent. The PUM was then obtained by dialysis in water and vacuum freeze-drying. Compared with traditional polymers used in wound dressings, this polymer exhibits excellent tissue adhesion, thermosensitivity, biodegradability, and biocompatibility.

[0007] The second objective of this invention is to provide a hyperbranched polymer obtained by the above preparation method.

[0008] A third objective of this invention is to provide a method for preparing thin films using the above-mentioned hyperbranched polymer and nanocellulose composite.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a hyperbranched polymer that combines tissue adhesion properties, temperature sensitivity, and biodegradability includes the following steps: (1) Add 2-amino-4-hydroxy-6-methylpyrimidine (MIS) to dimethyl sulfoxide (DMSO) solvent, purge the oxygen in the system with nitrogen gas, and continue heating and stirring to dissolve the MIS and obtain a MIS solution. (2) Add ethyl isocyanate methacrylate (ICEMA) dropwise to the MIS solution in step (1), stop heating and stir until homogeneous to obtain a mixed reaction solution; (3) The reaction solution of the mixture in step (2) is recrystallized with acetone, and the precipitate is dried under vacuum to obtain white ureapyrimidinone methacrylate (UPyMA) powder; (4) Add the ureidopyrimidinone methacrylate (UPyMA) and ethyl 2-(2-methoxyethoxy)methacrylate (MEO2MA), poly(ethylene glycol) methacrylate (PEGMA), methacrylic acid (MA) and 2-methylene-1,3-dioxane (MDO) from step (3) to N,N-dimethylformamide (DMF) solvent and stir until dissolved. (5) Add azobisisobutyronitrile (AIBN) as an initiator and 4-cyano-4-(phenylthiocarbamoylthio)valerate (CTA) as a chain transfer agent to the reaction solution in step (4), seal the reaction flask, purge with nitrogen, and heat the reaction under stirring. (6) Dialyze the reaction solution from step (5) in water; (7) Freeze-dry the reaction solution after dialysis in step (6) to obtain the aggregate, which is the hyperbranched polymer with tissue adhesion, temperature sensitivity and degradability, named PUM.

[0010] Furthermore, all water mentioned in this invention is deionized water.

[0011] Furthermore, the ratio of MIS, DMSO, and ICEMA is 1-10 g: 1-100 mL: 1-10 mL; preferably 3-5 g: 40-60 mL: 4-5 mL; most preferably 4 g: 50 mL: 5 mL; and the amount of acetone used is 3 to 5 times the volume of the mixture reaction solution.

[0012] Further, the heating temperature in step (1) is 160-180℃; preferably 165-175℃; most preferably 170℃.

[0013] Further, in the reaction solution described in step (4), the concentration of UPyMA is 0.2-0.4 g / 100 mL; the concentration of PEGMA is 0.2-0.42 g / 100 mL; the concentration of MEO2MA is 1-2 g / 100 mL; the concentration of MA is 0.05-0.1 g / 100 mL; and the concentration of MDO is 0.1-0.2 g / 100 mL.

[0014] Furthermore, in the reaction solution described in step (4), the concentration of UPyMA is 0.310 g / 100 mL; the concentration of PEGMA is 0.332 g / 100 mL; the concentration of MEO2MA is 1.316 g / 100 mL; the concentration of MA is 0.066 g / 100 mL; and the concentration of MDO is 0.160 g / 100 mL.

[0015] Further, in the reaction solution described in step (5), the concentration of AIBN is 0.01-0.05 g / 100 mL; the concentration of CTA is 0.01-0.05 g / 100 mL.

[0016] Furthermore, in the reaction solution described in step (5), the concentration of AIBN is 0.032 g / 100 mL and the concentration of CTA is 0.028 g / 100 mL.

[0017] Furthermore, the nitrogen purging time in step (5) is 20-40 min; preferably 30 min.

[0018] Further, the stirring conditions in step (5) are: stirring speed of 200-400 rpm; preferably 300 rpm.

[0019] Further, the heating reaction conditions in step (5) are: temperature 60-80℃, time 5-20 h; preferably temperature 65-75℃, time 10-15 h; most preferably temperature 70℃, time 12 h.

[0020] Furthermore, the dialysis bag used in step (6) has a molecular weight cutoff of 1500-2500 Da and a duration of 2-4 days.

[0021] A hyperbranched polymer is obtained by the above preparation method.

[0022] A method for preparing thin films using the above-mentioned hyperbranched polymer and nanocellulose composite includes the following steps: (I) The PUM and nanocellulose CNF were mixed in an ice-water bath with water as the solvent to obtain a homogeneous solution; (II) The mixed solution obtained in step (I) is added dropwise into a special container and dried to obtain a PUM-CNF film. The obtained film is the composite film for skin wounds.

[0023] The composite film is denoted as PUM-CNFx, where x is the concentration of CNF in the mixed solution of step (II) (x g / 1000 mL).

[0024] Further, in step (I), the concentration of PUM in the mixed solution is 1-10 g / 100 mL, and the concentration of CNF is 0.1-0.4 g / 100 mL.

[0025] Furthermore, the concentration of PUM in the mixed solution in step (I) is 5 g / 100 mL, and the concentration of CNF is 0.2 g / 100 mL.

[0026] Further, the drying conditions described in step (II) are: temperature 30-40℃, humidity RH ≤ 20%, and time 10-15 h.

[0027] Furthermore, the drying conditions described in step (II) are: temperature 35°C, humidity RH ≤ 15%, and time 12h.

[0028] Furthermore, the special container described in step (II) is a polytetrafluoroethylene vessel.

[0029] A composite film adhesive is obtained by the above preparation method.

[0030] The application of the above-mentioned composite film adhesive in the preparation of wound repair dressings or drugs.

[0031] The hyperbranched polymer of this invention undergoes a hydrophobic phase transition at around 35°C. As the temperature increases, its hydrophobicity and adhesion to tissues improve. The mechanical strength of the composite film increases with the increase of CNF content. Due to the presence of numerous multiple hydrogen bonds in the components, the composite film of this invention can adhere firmly to the skin without detachment. By controlling the amount of CNF added, a film with mechanical properties consistent with skin tissue can be obtained, resulting in better conformability. The composite film is used to adhere to wound sites on the skin as a physical barrier to prevent infection and promote wound healing.

[0032] The present invention has the following advantages and effects compared with the prior art: (1) The present invention overcomes the problem of lack of tissue adhesion in existing wound care film materials.

[0033] (2) The present invention overcomes the problems that existing wound care film materials are not easy to use in joints and have poor mechanical properties and soft tissue compatibility.

[0034] (3) The present invention overcomes the problem that wound care liquid dressings are easy to lose and difficult to peel off after drying.

[0035] (4) The supramolecular polymer prepared by the present invention has good degradability.

[0036] (5) The composite film prepared by the present invention has both excellent breathability and waterproofness, and can effectively isolate bacteria in the external environment from contacting the wound.

[0037] (6) The composite film prepared by the present invention has good biocompatibility and can effectively promote wound healing. Attached Figure Description

[0038] Figure 1 This is a cell growth diagram of fibroblasts using the polymer PUM prepared in Example 1.

[0039] Figure 2 The cell viability of fibroblasts against the polymer PUM prepared in Example 1 is shown in the figure.

[0040] Figure 3 This is a product illustration of the composite film PUM-CNF2 prepared in Example 2.

[0041] Figure 4 This is an application diagram of the composite film PUM-CNF2 prepared in Example 2, applied to the skin of a joint.

[0042] Figure 5 The graph shows the changes in molecular weight of Example 1 and Comparative Example 1 after different degradation treatment times.

[0043] Figure 6 The graph shows the mechanical test results of the composite films of Example 2 and Comparative Example 2.

[0044] Figure 7 The graph shows the adhesion test results of the composite films of Example 2 and Comparative Example 2. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. However, the implementation of the present invention is not limited thereto. The advantages and features of the present invention will become clearer as the description proceeds. However, the embodiments are merely exemplary in nature and do not constitute any limitation on the scope of the present invention.

[0046] The following description of the raw materials used in the examples is as follows: 2-amino-4-hydroxy-6-methylpyrimidine (MIS), isocyanate ethyl methacrylate, 2-(2-methoxyethoxy) ethyl methacrylate, poly(ethylene glycol) methacrylate, methacrylic acid, 2-methylene-1,3-dioxane, N,N-dimethylformamide, azobisisobutyronitrile, acetone, 4-cyano-4-(phenylthiocarbamoylthio)valerate, and nanocellulose were all purchased from Aladdin.

[0047] Example 1 (1) In a sealed container, add 4 g of 2-amino-4-hydroxy-6-methylpyrimidine to 50 mL of dimethyl sulfoxide (DMSO) solvent, purge the oxygen in the system with nitrogen, heat and stir at 170 °C at a stirring speed of 300 rpm to dissolve MIS; then add 5 mL of isocyanate methacrylate (ICEMA) dropwise, stop heating and stir until homogeneous.

[0048] (2) The reaction solution in step (1) was recrystallized with 150 mL of acetone, and the precipitate was dried under vacuum to obtain white ureapyrimidine methacrylate (UPyMA) powder; (3) Add 0.155 g of ureidopyrimidinone methacrylate (UPyMA), 0.658 g of ethyl 2-(2-methoxyethoxy)methacrylate (MEO2MA), 0.166 g of poly(ethylene glycol) methacrylate (PEGMA), 0.033 g of methacrylic acid (MA) and 0.08 g of 2-methylene-1,3-dioxane (MDO) to 50 mL of N,N-dimethylformamide (DMF) solvent and stir until dissolved. (4) Add 0.016 g of azobisisobutyronitrile (AIBN) as an initiator and 0.014 g of 4-cyano-4-(phenylthiocarbamoylthio)valerate (CTA) as a chain transfer agent to the reaction solution in step (3), seal the reaction flask, purge with nitrogen for 30 min, and stir in an oil bath at 70 °C for 12 h in a nitrogen atmosphere at a stirring speed of 300 rpm to obtain the reaction solution; (5) Transfer the reaction solution in step (4) to a dialysis bag with a molecular weight cutoff of 2000 Da and dialyze for 3 days. Then freeze-dry the dialyzed reaction solution to obtain the polymer PUM with adhesive properties, temperature sensitivity and degradability.

[0049] Cell compatibility of the polymer PUM extract and nanocellulose CNF extract in step (5) was characterized using mouse fibroblast L929 cells: L929 cells were cultured in DMEM complete medium at 37°C and 5% CO2. After sterilization, PUM and CNF were immersed in sterile DMEM complete medium for 24 hours to obtain an extract of 5 mg / mL. Then, 1 mL of L929 cell suspension was seeded into each well of a 24-well plate at a seeding density of 1 × 10⁻⁶ cells / well. 4Cells / mL were cultured for one day to ensure full adhesion, then the complete medium was replaced with the extraction medium. Cells were cultured in the extraction medium for 1, 3, and 5 days, with the medium being changed daily to ensure sufficient nutrients. The cytotoxicity of the sample extraction was assessed using a CCK-8 assay kit. On days 1, 3, and 5, some non-adhered cells or cell debris were gently washed away with sterile PBS. Then, 500 μL of CCK-8 working solution was added to each well, and the cells were incubated in a 37°C, 5% CO2 incubator in the dark for 2 h. After incubation, 100 μL of CCK-8 incubation solution was aspirated from each well containing cells and added to a 96-well plate. The absorbance of the incubation solution was measured at 450 nm using a multi-mode microplate reader to assess the cell viability of L929 cells. Next, remove excess CCK-8 working solution from the 24-well plate, gently wash one to three times with sterile PBS, and then add 200 μL of live / dead staining solution (0.05% (v / v) Calcein AM and 0.15% (v / v) PI in PBS) to each well. Incubate in a constant temperature incubator at 37°C and 5% CO2 for 30 min in the dark. Then, gently remove the staining solution and gently wash with sterile PBS to remove excess dye. Finally, add 100 μL of sterile PBS to the well plate and observe the cell live / dead status using a confocal microscope.

[0050] The results are as follows Figure 1 , 2 As shown in the figure, the PUM polymer and nanocellulose prepared in this embodiment have good cell compatibility.

[0051] Example 2 (1) Prepare a solution containing 5 w / v% of polymer PUM in Example 1 and 0.2 w / v% of nanocellulose in 20 mL of deionized water, stir in an ice-water bath for 2 h at a stirring speed of 300 rpm to obtain a homogeneous mixed solution; (2) The mixed solution obtained in step (1) is added dropwise into a Teflon container and dried (temperature 35℃, humidity RH ≤15%, time 12 h) to obtain a composite film, denoted as film PUM-CNF2. The obtained film is the composite film for skin wounds.

[0052] Take the PUM-CNF2 film prepared in this embodiment, cut it to a suitable size, and attach it to the corresponding backing paper. For example... Figure 3 As shown, PUM-CNF2 film can be manufactured into patch or roll form as needed, and has advantages such as easy handling and immediate application. Subsequently, as... Figure 4As shown, when a PUM-CNF2 film of appropriate size is attached to a person's finger joint and bent, it can be seen that the PUM-CNF2 film has good skin adhesion properties and remains stable after undergoing dynamic deformations such as bending and straightening.

[0053] Comparative Example 1 (without MDO) (1) Add 4 g of 2-amino-4-hydroxy-6-methylpyrimidine (MIS) to dimethyl sulfoxide (DMSO) solvent in a sealed container, purge the oxygen in the system with nitrogen, heat and stir at 170°C at a stirring speed of 300 rpm to dissolve MIS; then add 5 mL of isocyanate methacrylate (ICEMA) dropwise, stop heating and stir until homogeneous.

[0054] (2) The reaction solution in step (1) was recrystallized with 150 mL of acetone, and the precipitate was dried under vacuum to obtain white ureapyrimidine methacrylate (UPyMA) powder; (3) Add 0.155 g of ureidopyrimidinone methacrylate (UPyMA), 0.658 g of ethyl 2-(2-methoxyethoxy)methacrylate (MEO2MA), 0.166 g of poly(ethylene glycol) methacrylate (PEGMA) and 0.033 g of methacrylic acid (MA) to 50 mL of N,N-dimethylformamide (DMF) solvent and stir until dissolved; (4) Add 0.016 g of azobisisobutyronitrile (AIBN) as an initiator and 0.014 g of 4-cyano-4-(phenylthiocarbamoylthio)valerate (CTA) as a chain transfer agent to the reaction solution in step (3), seal the reaction flask, purge with nitrogen, and stir in an oil bath at 70°C for 12 h at a stirring speed of 300 rpm to obtain the reaction solution; (5) Transfer the reaction solution in step (4) to a dialysis bag with a molecular weight cutoff of 2000 Da and dialyze for 3 days. Then freeze-dry the dialyzed reaction solution and the resulting substance is called polymer PU. Polymer PU prepared in this comparative example and polymer PUM prepared in Example 1 were respectively added to deionized water at a concentration of 1 w / v%, and the pH was adjusted to 2 with hydrogen chloride solution. After soaking and degradation for 0 / 6 / 12 / 24 / 48 / 96 hours respectively, 5 mL of the corresponding solution was taken out, freeze-dried, and the weight-average molecular weight of the obtained substances was measured by gel permeation chromatography. The results are as follows. Figure 5 As shown, it can be seen that the molecular weight of Example 1 containing MDO monomers decreased significantly with increasing degradation time, while the molecular weight of Comparative Example 1 without MDO monomers did not change significantly with increasing degradation time.

[0055] Comparative Example 2 (film without nanocellulose) (1) Prepare a solution of polymer PUM in Example 1 with 20 mL of deionized water, stir in an ice-water bath for 2 h at a stirring speed of 300 rpm to obtain a homogeneous mixed solution; (2) The solution obtained in step (1) is added dropwise into a Teflon container and dried to obtain a film, which is denoted as film PUM.

[0056] Comparative Example 3 (Effect of different amounts of nanocellulose added) (1) Prepare solutions containing 0.1 w / v% and 0.4 w / v% nanocellulose and 5 w / v% polymer PUM from Example 1 using 20 mL of deionized water respectively. Stir in an ice-water bath for 2 h at a stirring speed of 300 rpm to obtain a homogeneous mixed solution. (2) The two mixed solutions obtained in step (1) are added dropwise into Teflon containers and dried to obtain composite films, which are respectively named film PUM-CNF1 and film PUM-CNF4.

[0057] The mechanical and adhesive properties of films PUM, PUM-CNF1, PUM-CNF2, and PUM-CNF4 were tested using a universal testing machine to measure their tensile strength and adhesive strength. The results are as follows: Figure 6 , 7 As shown. From Figure 6 It can be seen that the tensile strength of pure PUM film is not high, while the different contents of nanocellulose added affect the mechanical strength of the composite film. With the increase of nanocellulose content, the tensile strength of the PUM-CNF composite film increases, while the elongation at break decreases. Among them, the PUM-CNF2 film has the mechanical properties most similar to those of human skin. Figure 7 As can be seen, the amount of nanocellulose added affects the adhesion strength of the composite film. As the nanocellulose content increases, the adhesion strength of the composite film PUM-CNF decreases slightly, but the strength is still relatively high.

[0058] According to YY / T 0471 "Test Methods for Contact Wound Dressings", the films PUM, PUM-CNF1, PUM-CNF2, and PUM-CNF4 were tested to evaluate their breathability, water resistance, and antibacterial properties. The results are shown in Table 1. It can be seen that the composite films all have good breathability, water resistance, and antibacterial properties.

[0059] Table 1. Evaluation results of breathability, water resistance, and antibacterial properties .

[0060] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a hyperbranched polymer possessing tissue adhesion properties, temperature sensitivity, and biodegradability, characterized in that: Includes the following steps: (1) Add 2-amino-4-hydroxy-6-methylpyrimidine (MIS) to dimethyl sulfoxide (DMSO) solvent, purge the oxygen in the system with nitrogen gas, and continue heating and stirring to dissolve the MIS and obtain a MIS solution. (2) Add ethyl isocyanate methacrylate (ICEMA) dropwise to the MIS solution in step (1), stop heating and stir until homogeneous to obtain a mixed reaction solution; (3) The reaction solution of the mixture in step (2) is recrystallized with acetone, and the precipitate is dried under vacuum to obtain white ureapyrimidinone methacrylate (UPyMA) powder; (4) Add the ureidopyrimidinone methacrylate (UPyMA) and ethyl 2-(2-methoxyethoxy)methacrylate (MEO2MA), poly(ethylene glycol) methacrylate (PEGMA), methacrylic acid (MA) and 2-methylene-1,3-dioxane (MDO) from step (3) to N,N-dimethylformamide (DMF) solvent and stir until dissolved. (5) Add azobisisobutyronitrile (AIBN) as an initiator and 4-cyano-4-(phenylthiocarbamoylthio)valerate (CTA) as a chain transfer agent to the reaction solution in step (4), seal the reaction flask, purge with nitrogen, and heat the reaction under stirring. (6) Dialyze the reaction solution from step (5) in water; (7) Freeze-dry the reaction solution after dialysis in step (6) to obtain the aggregate, which is the hyperbranched polymer with tissue adhesion, temperature sensitivity and degradability, named PUM.

2. The method for preparing the hyperbranched polymer with tissue adhesion properties, temperature sensitivity, and biodegradability according to claim 1, characterized in that: The ratio of MIS, DMSO, and ICEMA is 1-10 g: 1-100 mL: 1-10 mL; In the reaction solution described in step (4), the concentration of UPyMA is 0.2-0.4 g / 100 mL; the concentration of PEGMA is 0.2-0.42 g / 100 mL; the concentration of MEO2MA is 1-2 g / 100 mL; the concentration of MA is 0.05-0.1 g / 100 mL; and the concentration of MDO is 0.1-0.2 g / 100 mL. In the reaction solution described in step (5), the concentration of AIBN is 0.01-0.05 g / 100 mL; the concentration of CTA is 0.01-0.05 g / 100 mL.

3. The method for preparing the hyperbranched polymer with tissue adhesion properties, temperature sensitivity, and biodegradability according to claim 1, characterized in that: The ratio of MIS, DMSO, and ICEMA is 4 g: 50 mL: 5 mL; the amount of acetone used is 3 to 5 times the volume of the mixture reaction solution. In the reaction solution described in step (4), the concentration of UPyMA is 0.310 g / 100 mL; the concentration of PEGMA is 0.332 g / 100 mL; the concentration of MEO2MA is 1.316 g / 100 mL; the concentration of MA is 0.066 g / 100 mL; and the concentration of MDO is 0.160 g / 100 mL. In the reaction solution described in step (5), the concentration of AIBN is 0.032 g / 100 mL and the concentration of CTA is 0.028 g / 100 mL.

4. The method for preparing the hyperbranched polymer with tissue adhesion properties, temperature sensitivity, and biodegradability according to any one of claims 1-3, characterized in that: The heating temperature in step (1) is 160-180℃; The nitrogen purging time in step (5) is 20-40 min; The stirring conditions described in step (5) are: stirring speed 200-400 rpm; The conditions for the heating reaction in step (5) are: temperature 60-80℃, time 5-20 h; The dialysis bag used in step (6) has a molecular weight cutoff of 1500-2500 Da and a duration of 2-4 days.

5. A hyperbranched polymer, characterized in that: It is obtained by the preparation method described in any one of claims 1-4.

6. A method for preparing a thin film using the hyperbranched polymer and nanocellulose composite as described in claim 5, characterized in that: Includes the following steps: (I) The PUM and nanocellulose CNF were mixed in an ice-water bath with water as the solvent to obtain a homogeneous solution; (II) The mixed solution obtained in step (I) is added dropwise into a special container and dried to obtain a PUM-CNF film. The obtained film is the composite film for skin wounds.

7. The method for preparing thin films by compositing hyperbranched polymers with nanocellulose according to claim 6, characterized in that: The concentration of PUM in the mixed solution described in step (I) is 1-10 g / 100 mL; the concentration of CNF is 0.1-0.4 g / 100 mL. The drying conditions described in step (I) are: temperature 30-40℃, humidity RH ≤ 20%, and time 10-15 h.

8. The method for preparing thin films by combining hyperbranched polymers and nanocellulose according to claim 6, characterized in that: The concentration of PUM in the mixed solution described in step (I) is 5 g / 100 mL; the concentration of CNF is 0.2 g / 100 mL. The drying conditions described in step (II) are: temperature 35℃, humidity RH ≤ 15%, and time 12 h.

9. A composite film adhesive, characterized in that: It is obtained by the preparation method described in any one of claims 6-8.

10. The use of the composite film adhesive of claim 9 in the preparation of wound repair dressings or medicines.

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