JP2023507665A - Stretchable nanofiber film and its manufacturing method and application - Google Patents

Abstract

The present application relates to the technical field of medical nanofiber material production, and specifically discloses a stretchable nanofiber film and its production method and application. The stretchable nanofiber film has a core-shell structure, the core layer comprises an aminated chitosan carrier and an antimicrobial agent, the antimicrobial agent is doped into the aminated chitosan carrier, the shell layer comprises a polyurethane carrier, a poly N-isopropylacrylamide and N-TiO2/activated carbon, said poly N-isopropylacrylamide and said N-TiO2/activated carbon being doped into said polyurethane carrier. Stretchable nanofiber films are obtained produced by coaxial electrospinning technology. The nanofiber film produced by the present application has excellent stretching performance, strong adsorption performance, long antibacterial time and self-cleaning advantages, and can significantly improve the healing effect of the wound surface, and has a wide range of applications in the medical dressing field. is expected. [Selection figure] None

Description

Cross-reference to Related Applications This patent application is based on Chinese patent application No. Claims priority of CN202110483874.7. The disclosure of the prior application is incorporated herein by reference in its entirety.

TECHNICAL FIELD The present application relates to the technical field of medical nanofiber material production, and more particularly to stretchable nanofiber films and their production methods and applications.

The skin is not only an important protective barrier for the human body, but also an important component of the body's immune system. It is necessary to protect the wound with a medical dressing after the skin has been injured. Medical dressings are skin substitutes that temporarily cover wound surfaces and whose main function is to absorb wound exudate and avoid bacterial infection. Therefore, medical dressings need to have antibacterial, hemostatic and certain mechanical properties, especially when applied to areas such as fingers, knees, joints and elbows, and stretchability.

Chitosan is a basic polysaccharide with natural anticoagulant properties, has excellent biological activity and good biodegradability, and also has certain hemostatic and antibacterial anti-inflammatory effects, and is effective for wound tissue regeneration. Helps promote and reduce scar formation. However, currently commonly used chitosan-based nanofiber dressings and hydrogel-based dressings have weak bonding strength with antibacterial agents, and cannot be expected to be effective in sustained release of antibacterial agents. , cannot be suitably applied to movable joints. In addition, medical dressings are in contact with the skin for a long period of time, and blood, oil stains, etc. from skin wounds always adhere to the dressings, resulting in poor healing effects on the wound surface. Therefore, it is necessary to develop a medical nanofiber film that has excellent stretchability, a sustained drug release effect, and is self-cleaning.

In response to the problems generally existing in chitosan medical dressings in the prior art, such as poor stretchability, no drug release effect, and inability to self-clean, the present application provides a stretchable nanofiber film and its manufacture. Methods and applications are provided.

To solve the above technical problems, the technical solutions provided by the present application are as follows.

The stretchable nanofiber film has a core-shell structure, the core layer comprising an aminated chitosan carrier and an antimicrobial agent, said antimicrobial agent being doped within said aminated chitosan carrier, and the shell layer comprising a polyurethane carrier, polyN - isopropylacrylamide and N-TiO ₂ /activated carbon, said poly-N-isopropylacrylamide and said N-TiO ₂ /activated carbon being doped into said polyurethane carrier.

The polyurethane carrier is a thermoplastic polyurethane elastomer rubber (TPU).

The aminated chitosan carrier is obtained by modifying chitosan with tetraethylenepentamine and diisopropylcarbodiimide.

The amino group content in the aminated chitosan carrier is 30%-33% (mass content).

The method for producing the N-TiO ₂ /activated carbon comprises:
adding wood flour into the alkaline solution and soaking for 2-4 hours, filtering and drying the soaking liquid in turn to obtain a soaking material; calcining the mixture at 400-500° C. for 1.5-2.5 h in an active atmosphere, washing and drying the calcined product in turn to obtain N—TiO ₂ /activated carbon.

By selecting tetraethylenepentamine and diisopropylcarbodiimide to modify chitosan, the amino group content in the modified chitosan can be significantly improved, and the amino group content can be increased to 30%-33%, thereby antibacterial. It helps to improve the loading of the agent on the aminated chitosan carrier.

In one embodiment, the weight ratio of said aminated chitosan carrier and said polyurethane carrier is 1:7-22.

In one embodiment, the doping amount of the antimicrobial agent in the aminated chitosan carrier is 10-50 wt%.

In one embodiment, the doping amount of the poly-N-isopropylacrylamide in the polyurethane carrier is 13-27 wt%.

In one embodiment, the doping amount of said N-TiO ₂ /activated carbon in said polyurethane carrier is 4-11 wt%.

By limiting the ratio between each substance, it can be ensured that the nanofiber film has excellent extensibility, sustained release and self-cleaning performance, which makes the nanofiber film have excellent wound surface healing ability. have

The antibacterial agent is not particularly limited in this application and may be common antibacterial agents in the art such as emodin, amoxicillin sodium, bacampicillin hydrochloride and meloxicillin sodium.

The present application further provides a method for producing the stretchable nanofiber film,
Step 1 of uniformly mixing chitosan and organic amine, heating the reaction mixture to reflux, filtering, washing and drying the product in turn after the reaction is completed to obtain aminated chitosan, wherein the organic amine is is a mixture of tetraethylenepentamine and diisopropylcarbodiimide;
step 2, adding said aminated chitosan and antimicrobial agent into dilute acid solution and mixing evenly to obtain core layer spinning solution;
Wood flour is added into the alkaline solution and soaked for 2-4 hours, the soaked liquid is filtered and dried in turn to obtain the soaked material, and the soaked material is uniformly mixed with biuret and titanium dioxide to obtain a mixture, inert Step 3: calcining the mixture at 400-500° C. for 1.5-2.5 h in an atmosphere, washing and drying the calcined product in turn to obtain N—TiO ₂ /activated carbon;
Step 4 of adding polyurethane, poly N-isopropylacrylamide and said N-TiO ₂ /activated carbon into an organic mixed solvent and mixing uniformly to obtain a shell layer spinning solution, wherein said organic mixed solvent is dimethylformamide and ethanol. a step 4 comprising
Step 5: injecting said core layer spinning solution and said shell layer spinning solution respectively into a coaxial electrospinning device, performing electrospinning, and drying the resulting electrospun fiber film to obtain said stretchable nanofiber film; include.

In one embodiment, in step 1, the mass to volume ratio of said chitosan and said organic amine is 0.08-0.12:1, ie said chitosan is weighed by mass and said organic amine is weighed by volume. , where the unit of mass is gram, the unit of volume is milliliter, and the volume ratio of said tetraethylenepentamine and said diisopropylcarbodiimide in said organic amine is 3-5:1.

The ratio of each material in step 1 helps to obtain modified chitosan with high amino group content.

In one embodiment, in step 1, the reflux time is 2-4 h.

In one embodiment, in step 2, the mass ratio of said aminated chitosan to said dilute acid solution is 0.02-0.05:1.

In one embodiment, in step 2, the weight ratio of said antimicrobial agent to said dilute acid solution is 0.005-0.01:1.

In one embodiment, the concentration of the dilute acid solution is 0.1-0.5 mol/L.

The amount of the antibacterial agent and the aminated chitosan used helps to improve the loading of the antibacterial agent on the aminated chitosan.

Specifically, the dilute acid solution is hydrochloric acid solution, acetic acid solution or lactic acid solution.

In one embodiment, in step 3, the mass-volume ratio of said wood flour and said alkaline solution is 1-2:5, i.e. said wood flour is weighed by mass and said alkaline solution is weighed by volume, wherein , the unit of mass is gram, the unit of volume is milliliter, and the concentration of the alkaline solution is 0.8-1.2 mol/L.

Specifically, the alkaline solution is a potassium hydroxide solution with a concentration of 0.8 to 1.2 mol/L.

In one embodiment, in step 3, the weight ratio of said dipping material to said biuret is 5-10:1.5-4.

In one embodiment, in step 3, the weight ratio of said biuret to said titanium dioxide is 2-4:1.

In one embodiment, in step 3, temperature programming ramps the temperature to 400-500° C., with a ramp rate of 1.5-2.5° C./min.

The ratio of each material in step 3 improves the loading of N—TiO ₂ on the activated carbon, improves the self-cleaning performance of the nanofiber film, and does not affect the stretching performance of the shell layer, and is 400-500 By incubating at ℃ for 1.5 to 2.5 hours, activated carbon with a large specific surface area and a rich pore structure can be obtained, which improves the adsorption performance of the nanofiber film and quickly removes exudate from the wound surface. In addition, the favorable reaction conditions further contribute to the nitrogen doping of titanium dioxide, obtaining N- _TiO2 with excellent visible light responsiveness and improving the self-cleaning performance of nanofiber films. , thereby helping to promote wound surface healing.

In one embodiment, in step 4, the weight ratio of said polyurethane to said poly N-isopropylacrylamide to said N-TiO ₂ /activated carbon is 18-22:3-5:1-2.

In one embodiment, in step 4, the weight ratio of said polyurethane to said organic solvent mixture is 0.18-0.22:1.

In one embodiment, in step 4, the volume ratio of said dimethylformamide and said ethanol is 1-2:1.

The amount of poly N-isopropylacrylamide added can improve the temperature sensitivity of the nanofiber film, and when the nanofiber film contacts the skin, the volume of the nanofiber film can be rapidly shrunk, the pore size of the nanofiber film can be increased, and so on. promotes the release of antibacterial agents, and the added amount of N—TiO ₂ /activated carbon imparts good self-cleaning and adsorption performance to the nanofiber film on the premise that it does not affect the stretching performance of the shell layer. be able to.

The inert gas in the present application is a common inert gas in this field, such as nitrogen gas, argon gas, and the like.

In one embodiment, in step 5, the weight ratio of aminated chitosan in the core layer spinning solution to polyurethane in the shell layer spinning solution is 1:7-22.

In one embodiment, in step 5, the electrospinning parameters are: the distance between the nozzle and the aluminum foil in the electrospinning apparatus is 10-15 cm; the spinning voltage is 20-30 kV; 0.5-1 mL/h, the shell layer spinning flow rate is 1-2 mL/h, and the humidity is 25%-35%.

The electrospinning parameters help form a continuous core/shell structure nanofiber film, further provide a basis for the sustained release of the antimicrobial agent, and aid in the volatilization of the solvent, and the nanofiber film produced is Possessing a porous structure, it facilitates the release of antibacterial agents and gas exchange, prevents bacterial invasion and effectively absorbs wound exudate, maintains a warm wound healing environment, thereby accelerating wound healing. do.

The present application further provides application of said stretchable nanofiber films in the manufacture of medical dressings.

The N—TiO ₂ /activated carbon described herein is a composite of nitrogen-doped nano-TiO ₂ -loaded activated carbon.

It should be understood that the numerical ranges disclosed herein may be any value within the range interval and the numerical values disclosed are only preferred selections. Of course, other numbers may be used in other embodiments, but are not so limited.

In contrast to the prior art, the stretchable nanofiber film provided by the present application adopts aminated chitosan as a carrier for antibacterial agents, and the amino on the aminated chitosan molecular chain obtained after modification is effective against antibacterial agents. Large-area adsorption and bonding, improve the binding strength between the antibacterial agent and chitosan and the amount of the antibacterial agent supported on chitosan, and reduce the loss of the antibacterial agent in the manufacturing process of the nanofiber film, thereby improving the antibacterial agent The load efficiency of the nanofiber film is improved, and the aminated chitosan is used as the core layer, the elastic polyurethane is used as the shell layer, and the shell layer covers the core layer, so that the nanofiber film has excellent extensibility, and the polyurethane The carrier is conjugated with temperature-sensitive poly-N-isopropylacrylamide, which causes the nanofiber film to rapidly shrink in volume at the moment of contact with the skin and increase the pore size of the nanofiber film, thereby enhancing the antibacterial agent. It achieves sustained release in the pore structure and improves the antibacterial time and effectiveness of the nanofiber film. In addition, the polyurethane carrier is compounded with N-TiO ₂ /activated carbon, and the N-TiO ₂ /activated carbon has excellent adsorption performance and photocatalytic self-cleaning performance, and can remove blood and oil stains that come into contact with the nanofiber film with visible light. to improve the self-cleaning performance of the wound surface and antibacterial persistence, and by doping N-TiO ₂ /activated carbon, the adsorption of the shell layer to the antibacterial agent is improved, and the antibacterial agent is released from the core layer. It helps to migrate to the shell layer, further improving the antibacterial persistence of the nanofiber film.

The present application dissolves the shell layer material and the core layer material in appropriate solvents respectively, and uses coaxial electrospinning technology to produce nanofiber films with core-shell structure, where the evaporation of the solvent in the spinning process and the fiber film With the molding of the nanofibers can be constructed with a porous structure, the porous structure helps to improve the stretchability of the nanofiber film, also helps to improve the adsorption performance of the shell layer, and , the porous structure also helps to improve the loading of the antibacterial agent in the core layer, and realizes the sustained release of the antibacterial agent in the pore structure, improving the wound surface healing properties of the nanofiber film.

The method for producing stretchable nanofiber films provided by the present application is easy to operate, and can realize the production of stretchable nanofiber films with excellent coalescence ability in a one-step process, and has relatively high practicality. have value.

The nanofiber film provided by the present application has excellent stretching performance, strong adsorption performance, long antibacterial time and self-cleaning advantages, and can significantly improve the healing effect of the wound surface, especially in movable joints. It can be applied to wounds at different sites, and is expected to find wide-ranging applications in the medical dressing field.

In order to make the objectives, technical solutions and advantages of the present application clearer, the following describes the present application in more detail with reference to examples. It should be understood that the specific examples described herein are only used to interpret the present application and are not intended to limit the present application.

In order to better explain the present application, the following examples are further illustrated.

(Example 1)
An embodiment of the present application provides a method of manufacturing a stretchable nanofiber film, comprising the following steps 1-5,
Step 1, weigh 10 g of chitosan and dissolve in 100 mL of organic amine mixed solution, the organic amine mixed solution contains tetraethylenepentamine and diisopropylcarbodiimide, where the volume ratio of tetraethylenepentamine and diisopropylcarbodiimide is 5:1, followed by heating the reaction mixture to reflux for 2 h, obtaining a mixture containing the crude product after the reaction is complete, cooling the mixture containing the crude product to room temperature, followed by Filter, wash the crude product with absolute ethanol and water respectively and dry to obtain the aminated chitosan.
Step 2, the aminated chitosan obtained in step 1 was added to 5 mL of 0.3 mol/L acetic acid solution, mixed evenly, then emodin was added, followed by ultrasonication in a water bath at 50 °C for 2 h to spin the core layer. A solution is obtained, wherein the added amount of aminated chitosan is 2 wt% of the acetic acid solution mass and the added amount of emodin is 1 wt% of the acetic acid solution mass.
Step 3, 5 g of wood flour is soaked in 25 mL of 1.0 mol/L KOH solution, soaked for 3 h, the soaked liquid is filtered and dried in turn to obtain the soaked material, and the soaked material is combined with biuret and titanium dioxide. Mix uniformly to obtain a mixture, heat up to 450°C at a rate of 2°C/min in a nitrogen atmosphere, calcine the mixture for 2h, wash the calcined product to neutrality, and vacuum at 120°C. Drying yields N—TiO ₂ /activated carbon, wherein the weight ratio of soaking material to biuret is 5:4 and the weight ratio of biuret to titanium dioxide is 2:1.
Step 4, TPU, poly N-isopropylacrylamide and N-TiO ₂ /activated carbon are added to 10 mL of organic mixed solvent and mixed evenly to obtain a shell layer spinning solution, the organic mixed solvent contains dimethylformamide and ethanol, wherein , the added amount of TPU is 20 wt% of the organic mixed solvent mass, the added amount of poly N-isopropylacrylamide is 4 wt% of the organic mixed solvent mass, and the added amount of N-TiO ₂ /activated carbon is the organic mixed solvent mass. , and the volume ratio of dimethylformamide and ethanol in the organic mixed solvent is 1:1.
Step 5, the shell layer spinning solution and the core layer spinning solution are put into 10 mL and 5 mL syringes respectively, and the two syringes are connected to the nozzle in the coaxial electrospinning device, and the spinning parameters are: The distance is 12 cm, the spinning voltage is 20 kV, the core layer spinning flow rate is 1 mL/h, the shell layer spinning flow rate is 2 mL/h, the humidity is 30%, and the resulting electrospun fiber The film is vacuum dried for 24 h to obtain a stretchable nanofiber film.

Amino group content measurement is performed on the aminated chitosan prepared in step 1 using an elemental analyzer (EA) and the amino group content is determined to be 33%.

(performance test)
Refer to the People's Republic of China National Standard GB/T 20944.3-2008 "Evaluation of Antibacterial Performance of Textiles" Antibacterial rate method to calculate the antibacterial rate under stretchable conditions.

An electronic universal testing machine is used to test the mechanical performance of the nanofiber composite film, the sample size is a rectangular spline of 5 mm×35 mm, the gauge length is 20 mm, and the test speed is 4 mm/min.

The drawing strength of the nanofiber film produced according to this example is 35.4 MPa, and the elongation at break is 55.4%. The antibacterial rate of the nanofiber film produced according to this example at a draw rate of 20% was 99.1%. The antibacterial rates of the nanofiber films produced according to the examples correspond to 98.7%, 97.6% and 96.9% respectively.

(Example 2)
An embodiment of the present application provides a method of manufacturing a stretchable nanofiber film, comprising the following steps 1-5,
Step 1, weigh 10 g of chitosan and dissolve in 100 mL of organic amine mixed solution, the organic amine mixed solution contains tetraethylenepentamine and diisopropylcarbodiimide, where the volume ratio of tetraethylenepentamine and diisopropylcarbodiimide is 3:1, followed by heating the reaction mixture to reflux for 4 h to obtain a mixture containing the crude product after the reaction is completed, cooling the mixture containing the crude product to room temperature, followed by Filter, wash the crude product with absolute ethanol and water respectively and dry to obtain the aminated chitosan.
Step 2, add aminated chitosan obtained in step 1 to 5 mL of 0.1 mol/L acetic acid solution, add emodin after evenly mixing, and then sonicate in a water bath at 50 °C for 2 h to spin the core layer. A solution is obtained, where the added amount of aminated chitosan is 3 wt% of the acetic acid solution mass and the added amount of emodin is 0.8 wt% of the acetic acid solution mass.
Step 3, 10 g of wood flour is soaked in 25 mL of 1.0 mol/L KOH solution, soaked for 2 h, the soaked liquid is filtered and dried in turn to obtain the soaked material, and the soaked material is combined with biuret and titanium dioxide. Mix uniformly to obtain a mixture, heat up to 500° C. at a rate of 2.5° C./min in a nitrogen atmosphere, calcine the mixture for 1.5 h, wash the calcined product to neutrality, Vacuum drying at 120° C. yields N—TiO ₂ /activated carbon, wherein the mass ratio of soaking material to biuret is 10:1.5 and the mass ratio of biuret to titanium dioxide is 3:1.
Step 4, TPU, poly N-isopropylacrylamide and N-TiO ₂ /activated carbon are added to 10 mL of organic mixed solvent and mixed evenly to obtain a shell layer spinning solution, the organic mixed solvent contains dimethylformamide and ethanol, wherein , the added amount of TPU is 22 wt% of the organic mixed solvent mass, the added amount of poly N-isopropylacrylamide is 3 wt% of the organic mixed solvent mass, and the added amount of N-TiO ₂ /activated carbon is the organic mixed solvent mass. , and the volume ratio of dimethylformamide and ethanol in the organic mixed solvent is 1.5:1.
Step 5, the shell layer spinning solution and the core layer spinning solution are put into 10 mL and 5 mL syringes respectively, and the two syringes are connected to the nozzle in the coaxial electrospinning device, and the spinning parameters are: The distance was 10 cm, the spinning voltage was 30 kV, the core layer spinning flow rate was 0.5 mL/h, the shell layer spinning flow rate was 1 mL/h, and the humidity was 25%. The spun fiber film is vacuum dried for 24 h to obtain a stretchable nanofiber film.

Amino group content determination is performed on the aminated chitosan prepared in step 1 using an elemental analyzer (EA) and the amino group content is determined to be 32%.

Antibacterial and mechanical performance tests were performed on the nanofiber film produced according to this example according to the test method of Example 1, and the tensile strength of the nanofiber film produced according to this example was 38.2 MPa. , the elongation at break is 61.3%. The antibacterial rate of the nanofiber film produced according to this example at a stretch ratio of 20% was 99.5%. The antibacterial rates of the nanofiber films produced according to the examples correspond to 98.9%, 98.3% and 97.9% respectively.

(Example 3)
An embodiment of the present application provides a method of manufacturing a stretchable nanofiber film, comprising the following steps 1-5,
Step 1, weigh 10 g of chitosan and dissolve in 100 mL of organic amine mixed solution, the organic amine mixed solution contains tetraethylenepentamine and diisopropylcarbodiimide, where the volume ratio of tetraethylenepentamine and diisopropylcarbodiimide is 4:1, followed by heating the reaction mixture to reflux for 3 h, obtaining a mixture containing the crude product after the reaction is complete, cooling the mixture containing the crude product to room temperature, followed by Filter, wash the crude product with absolute ethanol and water respectively and dry to obtain the aminated chitosan.
Step 2, add aminated chitosan obtained in step 1 to 5 mL of 0.5 mol/L acetic acid solution, add emodin after mixing evenly, and then sonicate in a water bath at 50 °C for 2 h to spin the core layer. A solution is obtained, wherein the added amount of aminated chitosan is 5 wt% of the acetic acid solution mass and the added amount of emodin is 0.5 wt% of the acetic acid solution mass.
Step 3, 8 g of wood flour is soaked in 25 mL of 1.0 mol/L KOH solution, soaked for 4 h, the soaked liquid is filtered and dried in turn to obtain the soaked material, and the soaked material is combined with biuret and titanium dioxide. Mix uniformly to obtain a mixture, heat up to 400° C. at a rate of 1.5° C./min in a nitrogen atmosphere, calcine the mixture for 2.5 h, wash the calcined product to neutrality, Vacuum drying at 120° C. yields N—TiO ₂ /activated carbon, wherein the mass ratio of soaking material to biuret is 8:4 and the mass ratio of biuret to titanium dioxide is 4:1.
Step 4, TPU, poly N-isopropylacrylamide and N-TiO ₂ /activated carbon are added to 10 mL of organic mixed solvent and mixed evenly to obtain a shell layer spinning solution, the organic mixed solvent contains dimethylformamide and ethanol, wherein , the added amount of TPU is 18 wt% of the organic mixed solvent mass, the added amount of poly N-isopropylacrylamide is 5 wt% of the organic mixed solvent mass, and the added amount of N-TiO ₂ /activated carbon is the organic mixed solvent mass. , and the volume ratio of dimethylformamide and ethanol in the organic mixed solvent is 2:1.
Step 5, the shell layer spinning solution and the core layer spinning solution are put into 10 mL and 5 mL syringes respectively, and the two syringes are connected to the nozzle in the coaxial electrospinning device, and the spinning parameters are: The distance is 15 cm, the spinning voltage is 25 kV, the core layer spinning flow rate is 0.8 mL/h, the shell layer spinning flow rate is 1.6 mL/h, the humidity is 35%, and the The electrospun fiber film is vacuum dried for 24 h to obtain a stretchable nanofiber film.

Amino group content measurement is performed on the aminated chitosan prepared in step 1 using an elemental analyzer (EA) and the amino group content is determined to be 31%.

Antibacterial and mechanical performance tests were performed on the nanofiber film produced in this example according to the test method of Example 1, and the tensile strength of the nanofiber film produced in this example was 32.2 MPa. , the elongation at break is 50.1%. The antibacterial rate of the nanofiber film produced according to this example at a stretch rate of 20% was 99.2%. The antibacterial rates of the nanofiber films produced according to the examples correspond to 98.8%, 97.9% and 96.8% respectively.

The acetic acid solution described in step 2 in Examples 1-3 may further be replaced with hydrochloric acid solution or lactic acid solution, and emoxycillin may be further replaced with other antibacterial agents such as amoxicillin sodium, bacampicillin hydrochloride and meloxicillin sodium. etc., and any of them can achieve technical effects basically corresponding to those of Examples 1 to 3.

(Comparative example 1)
This comparative example provides a method for producing stretchable nanofiber films, which is exactly the same as Example 1, except that no N—TiO ₂ /activated carbon is added to the shell layer spinning solution. be.

Antibacterial performance and mechanical performance tests were performed on the nanofiber film produced by this comparative example according to the test method of Example 1, and the tensile strength of the nanofiber film produced by this comparative example was 32 MPa. Breaking elongation is 52.8%. The antibacterial rate of the nanofiber film manufactured according to this comparative example at a stretch rate of 20% was 97.1%, and after being used at a stretch rate of 20% for 2, 4, and 6 hours, respectively, the comparison was performed. The antibacterial rates of the nanofiber films produced according to the example correspond to 87.1%, 75.1% and 71.1% respectively.

(Comparative example 2)
This comparative example provides a method for producing a stretchable nanofiber film, which is exactly the same as in Example 1, except that tetraethylenepentamine and diisopropylcarbodiimide in step 1 are mixed with an equal amount of triethylene Just replace with tetramine and carbodiimide.

Antibacterial performance and mechanical performance tests were performed on the nanofiber film produced by this comparative example according to the test method of Example 1, and the tensile strength of the nanofiber film produced by this comparative example was 32 MPa. Breaking elongation is 52.5%. The antibacterial rate of the nanofiber film manufactured according to this comparative example at a stretch ratio of 20% was 93.3%. The antibacterial rates of the nanofiber films produced according to the example correspond to 84.2%, 72.8% and 69.3% respectively.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. Any modification, equivalent replacement or improvement made within the spirit and principle of the present application shall fall within the protection scope of the present application. should be included.

Claims (8)

A stretchable nanofiber film having a core-shell structure, wherein the core layer comprises an aminated chitosan carrier and an antimicrobial agent, the antimicrobial agent is doped within the aminated chitosan carrier, and the shell layer comprises a polyurethane carrier , poly-N-isopropylacrylamide and N-TiO ₂ /activated carbon, said poly-N-isopropylacrylamide and said N-TiO ₂ /activated carbon being doped within said polyurethane carrier;
Here, the polyurethane carrier is a thermoplastic polyurethane elastomer rubber, the aminated chitosan carrier is obtained by modifying chitosan with tetraethylenepentamine and diisopropylcarbodiimide, and the amino group content in the aminated chitosan carrier is 30% to 33%,
The method for producing the N-TiO ₂ /activated carbon comprises:
adding wood flour into the alkaline solution and soaking for 2-4 hours, filtering and drying the soaking liquid in turn to obtain a soaking material; calcining the mixture at 400-500° C. for 1.5-2.5 h in an active atmosphere, washing and drying the calcined product in turn to obtain N—TiO ₂ /activated carbon. stretchable nanofiber film. The mass ratio of the aminated chitosan carrier and the polyurethane carrier is 1:7-22, and/or the doping amount of the antibacterial agent in the aminated chitosan carrier is 10-50 wt%, and/or the poly The doping amount of N-isopropylacrylamide in the polyurethane carrier is 13-27 wt% and/or the doping amount of the N-TiO ₂ /activated carbon in the polyurethane carrier is 4-11 wt%. Item 2. The stretchable nanofiber film of Item 1. Step 1 of uniformly mixing chitosan and organic amine, heating the reaction mixture to reflux, filtering, washing and drying the product in turn after the reaction is completed to obtain aminated chitosan, wherein the organic amine is is a mixture of tetraethylenepentamine and diisopropylcarbodiimide;
step 2, adding said aminated chitosan and antimicrobial agent into dilute acid solution and mixing evenly to obtain core layer spinning solution;
Wood flour is added into the alkaline solution and soaked for 2-4 hours, the soaking liquid is filtered and dried in turn to obtain the soaking material, and the soaking material is uniformly mixed with biuret and titanium dioxide to obtain a mixture, inert Step 3: calcining the mixture at 400-500° C. for 1.5-2.5 h in an atmosphere, washing and drying the calcined product in turn to obtain N—TiO ₂ /activated carbon;
Step 4 of adding polyurethane, poly N-isopropylacrylamide and said N-TiO ₂ /activated carbon into an organic mixed solvent and mixing uniformly to obtain a shell layer spinning solution, wherein said organic mixed solvent is dimethylformamide and ethanol. a step 4 comprising
Step 5: injecting said core layer spinning solution and said shell layer spinning solution respectively into a coaxial electrospinning device, performing electrospinning, and drying the resulting electrospun fiber film to obtain said stretchable nanofiber film; A method for producing a stretchable nanofiber film according to any one of claims 1 to 2, characterized in that it comprises: In step 1, the mass to volume ratio of said chitosan to said organic amine is 0.08-0.12:1, wherein the unit of mass is gram and the unit of volume is milliliter; The volume ratio of said tetraethylenepentamine and said diisopropylcarbodiimide in step 2 is 3-5:1, and/or in step 2, the mass ratio of said aminated chitosan and said dilute acid solution is 0.02-0. 05:1, and/or in step 2, the mass ratio of said antimicrobial agent to said dilute acid solution is between 0.005 and 0.01:1. Methods of producing possible nanofiber films. In step 3, the mass-volume ratio of the wood flour and the alkaline solution is 1-2:5, where the unit of mass is grams, the unit of volume is milliliters, and the concentration of the alkaline solution is 0.8-1.2 mol/L, and/or in step 3, the mass ratio of said soaking material to said biuret is 5-10:1.5-4, and/or in step 3, said The mass ratio of biuret to said titanium dioxide is 2-4:1 and/or in step 3 the temperature is ramped to 400-500°C by temperature programming with a rate of 1.5-2.5°C/ The method for producing a stretchable nanofiber film according to claim 3, characterized in that it is min. In step 4, the weight ratio of said polyurethane to said poly N-isopropylacrylamide to said N-TiO ₂ /activated carbon is 18-22:3-5:1-2, and/or in step 4, said polyurethane and The mass ratio of the organic mixed solvent is 0.18-0.22:1, and/or in step 4, the volume ratio of the dimethylformamide and the ethanol is 1-2:1. The method for producing a stretchable nanofiber film according to claim 3. In step 5, the mass ratio of aminated chitosan in said core layer spinning solution to polyurethane in said shell layer spinning solution is 1:7-22, and/or in step 5, said electrospinning parameters are: The distance between the nozzle and the aluminum foil in the electrospinning apparatus is 10 to 15 cm, the spinning voltage is 20 to 30 kV, the core layer spinning flow rate is 0.5 to 1 mL/h, and the shell layer spinning flow rate is The method for producing a stretchable nanofiber film according to claim 3, characterized in that the flow rate is 1-2 mL/h and the humidity is 25%-35%. Application of the stretchable nanofiber film according to any one of claims 1-2 in the manufacture of medical dressings.