CN109675450B - Antibacterial composite nanofiber membrane and preparation method and application thereof - Google Patents

Abstract

The invention discloses an antibacterial composite nanofiber membrane and a preparation method and application thereof. An antibacterial composite nanofiber membrane includes a nanofiber membrane and g _{- C3N4} nanosheets distributed on the surface and inside of the nanofiber membrane. At the same time, the preparation method of the antibacterial composite nanofiber membrane is also disclosed, and the application of the antibacterial composite nanofiber membrane is also disclosed. Compared with the prior art, the present invention can prepare a nanofiber membrane with antibacterial and filtering functions only by using plasma technology and graphite phase carbon nitride particle material, and the membrane material has low resistance and high efficiency. At the same time, the preparation process of the antibacterial composite nanofiber membrane of the present invention is safe and environmentally friendly, and the preparation method is simple and feasible.

Description

A kind of antibacterial composite nanofiber membrane and its preparation method and application

technical field

The invention relates to a nanofiber material, in particular to an antibacterial composite nanofiber membrane and a preparation method and application thereof.

Background technique

In recent years, the regional atmospheric environmental problems with pollutants characterized by inhalable particulate matter (PM10) and fine particulate matter (PM2.5) have become increasingly prominent. These particulate pollutants not only reduce the visibility of the air, but also seriously affect people's health. healthy. At the same time, in the internal environment of some human activities, in addition to dust particles, there will also be a large number of pathogenic bacteria in the air, which will also cause great harm to people's health. Compared with traditional filter materials, electrospun nanofiber membrane has the most superior performance among many filter materials due to its sparse and porous structure and relatively high specific surface area. However, because they are generally spun from high polymers, most of them can only intercept and electrostatically adsorb suspended particles in the air, but cannot remove bacteria, viruses and organic pollutants in the air. Under the guidance of this background and application requirements, it is of great practical significance to prepare nanofiber filter materials with antibacterial function.

In the prior art, Chinese patent document CN102302875A discloses a method for preparing an antibacterial air filtration membrane, comprising: blending a metal-containing inorganic antibacterial agent or an organic antibacterial agent containing sulfur and bromine, a polymer, an additive and a solvent into a solution; Or the antibacterial agent and the polymer are melt-blended to obtain a uniform melt; then the blended solution or the melt is electrospun to spin the nanofibers onto the surface of the non-woven fabric to obtain an antibacterial air filter membrane.

CN103446803A discloses an antibacterial air filter felt and a preparation method and application thereof. The electrospinning polymer nanofiber felt is used as a carrier, and the nanometer silver antibacterial agent is loaded by electrostatic spraying. When preparing, the nanometer silver antibacterial agent suspension and the macromolecule are first prepared. spinning solution, and then electrospinning to prepare nanofiber mats by synchronous electrostatic spraying to load nanoantibacterial agents, and finally vacuum drying.

CN103520999A discloses an antibacterial composite nanofiber high-efficiency air filter material and a preparation method thereof. The material sequentially comprises a non-woven support layer, a filter layer blended with antibacterial fibers and micron fibers, and a nanofiber filter layer. In the antibacterial fibers disclosed in this document, the antibacterial agent is inorganic particles containing silver, copper or zinc ions.

CN104070751A discloses an antibacterial composite fiber membrane capable of removing both haze particles and formaldehyde and a preparation method thereof. The membrane is composed of a polymer nanofiber layer and a polymer-metal oxide composite ultrafine fiber layer. The metal oxide is composed of one or more of MgO, CaO, ZnO, TiO ₂ , MnO ₂ , CuO, SnO, Fe ₂ O ₃ , and AgO.

CN104213202A discloses a spinning solution and a method for preparing an antibacterial air filtration membrane, including: (1) preparing the spinning solution; (2) preparing a nanofiber antibacterial air filtration membrane air filtration membrane through an electrospinning process. The inorganic antibacterial agent is one or both of titanate and titanium dioxide; the organic antibacterial agent is one or more of sorbic acid, benzoic acid, dehydroacetic acid and sodium diacetate.

CN104524866A discloses a composite antibacterial air filter material and a preparation method thereof, comprising: at least one layer of non-woven substrate, cellulose nanofibers adhered between fibers of the non-woven substrate to form a network structure, and loaded on the non-woven fabric The fibers of the substrate and/or the chitosan on the surface of the cellulose nanofibers.

CN104815483A discloses a composite antibacterial air filter material, a preparation method and an application thereof, including: an electret fabric layer, an electrospinning fiber film layer and a base material non-woven layer bonded in sequence, wherein the electrospinning fiber film layer and the base material are free of The surface of the spun layer is loaded with chitosan and nano- _TiO photocatalysts.

CN105544091A discloses an antibacterial nanofiber composite material and a preparation method thereof. The surface of the PLA fiber has nano-holes, and TiO ₂ nanoparticles are deposited on the surface of the PLA fiber and in the nano-holes, forming a fiber body with nano-holes and a fiber surface. Hybrid structured PLA/TiO ₂ fibrous membranes containing nanoprotrusions.

CN106039839A discloses a recyclable, high-efficiency, low-resistance, antibacterial and anti-haze air filter material, the air filter material includes a base material layer and a filter layer, the filter layer is a nanofiber layer loaded with nano-silver antibacterial agent, and the filter layer It is prepared by in-situ growth method, and the non-woven fabric is used as the base material layer.

CN107051232A discloses a sterilizing and aldehyde-removing air filter membrane, which is a three _- layer nanofiber membrane composite structure, the upper layer is an activated carbon nanofiber membrane, the middle layer is a pure _TiO2 nanofiber membrane, and the lower layer is a nanometer silver antibacterial fiber membrane. The fiber membrane is a pure TiO ₂ nanofiber membrane obtained by heat treatment of a polymer material/TiO ₂ precursor composite nanofiber membrane prepared by electrospinning. The activated carbon nanofiber membrane is an electrospun nano activated carbon particle/polymer material composite nanofiber. Membrane, nano-silver antibacterial fiber membrane is electrospun nano-silver particle/polymer material composite nano-fiber membrane.

CN107051221A discloses an antibacterial air filtration membrane and a manufacturing process thereof, comprising the following raw materials by weight: 20-35 parts of composite antibacterial agent; 10-20 parts of polymer; 1-2 parts of additives; 200-250 parts of solvent; 1-2 parts of tourmaline nanoparticles; 150-200 parts of adhesive suspension; 1-2 parts of nano-titanium dioxide; composite antibacterial agents are silver oxide, zinc oxide, silver-loaded zirconium phosphate, methylene dithiocyanate, One or more of chitin, mustard and castor oil.

CN107261865A discloses a functional air filter material, which is composed of a base material and an antibacterial electrospinning nanofiber layer, and the antibacterial agent in the antibacterial electrospinning nanofiber layer is a biological antibacterial agent.

CN107497179A discloses a nano antibacterial air filtration nonwoven material and a preparation method thereof. The nano antibacterial air filtration nonwoven material comprises a nanofiber antibacterial layer made of polypropylene nonwoven material and a nanofiber antibacterial layer formed on the surface of the nanofiber antibacterial layer. An air filter layer is provided, several adhesive points are arranged between the nanofiber antibacterial layer and the air filter layer, and the nanofiber antibacterial layer and the air filter layer are bonded through the adhesive points. The nanofiber antibacterial layer is a metal nanoantibacterial layer formed by loading a metal nanoantibacterial material on polypropylene.

CN108660611A discloses a nanofiber membrane for air sterilization and purification and a preparation method. Nylon and nanozeolite powder are added to N,N-dimethylformamide to prepare a shell spinning solution; graphene oxide, Core spinning solution is difficult to obtain by dispersing ascorbic acid and water; by coaxial electrospinning, a nanofiber membrane with nylon on the outside and graphene on the inside is obtained.

CN108560145A discloses a preparation method of bactericidal nanofiber membrane, which is to mix deionized water, polyvinyl alcohol, boric acid, hydrochloric acid, polyhexamethylene biguanide salt, undecylenamidopropyl betaine according to the corresponding mass parts, Add polyvinyl alcohol and distilled water to a beaker, stir and heat until dissolved to obtain a polyvinyl alcohol aqueous solution, add boric acid to the solution, and stir to obtain a polyvinyl alcohol-boric acid aqueous solution; add polyhexamethylene biguanide salt and undecylenamide propylene respectively. base betaine, stir evenly, add hydrochloric acid, pour the prepared electrospinning solution into a syringe, use a stainless steel needle as a spray needle, connect a high-voltage electric field to the needle to provide high voltage, and obtain nanofibers of different thicknesses according to the length of spinning time membrane.

The methods disclosed in the above documents have achieved good results, but the antibacterial effects are all based on antibacterial agents with complex chemical components, and the filter material is relatively complex, and there are also problems such as cumbersome preparation steps.

Recently, a simple and low-cost nano-antibacterial material, graphitic carbon nitride (gC ₃ N ₄ ), has attracted attention due to its high chemical stability, thermal stability, and excellent electrical and electrical conductivity. mechanical properties, etc. The most important thing is that while it has good bactericidal properties, it is also safe, green, and has no toxic side effects. CN107034585A discloses a gC ₃ N ₄ nanofiber antibacterial film and its preparation method and application. The gC ₃ N ₄ nanoparticles with loose porous structure are added into a polyethylene oxide solution to prepare a nanofiber film. Subsequently, the gC ₃ N ₄ nanofiber antibacterial membrane was dried in an oven for 4 hours, placed under a UV lamp for sterilization for 2 hours, and treated with cold plasma at 500 W for 2 minutes for use, to obtain a nanofiber membrane resistant to Escherichia coli and Staphylococcus aureus. _CN107158969A also discloses a functionalized nanofiber filter material and a preparation method and application thereof. _The C3N4 nanosheets are dispersed evenly in a solvent by ultrasonic vibration, and then polymer powder is added to dissolve them uniformly to obtain _C3N4 nanometers _. The polymer spinning solution of the sheet is prepared on a substrate by electrospinning technology to obtain a filter material that can remove organic pollutants such as formaldehyde. However, in these filter materials, C ₃ N ₄ nanomaterials exist inside the filter materials, and the air first contacts the surface of the filter materials, and the filtering effect still needs to be further improved. Therefore, how to provide a more efficient and low-resistance antibacterial filtration nanofiber membrane is a hot issue concerned by researchers in the industry.

SUMMARY OF THE INVENTION

Antibacterial nanofiber filtration membranes in the prior art generally use antibacterial agents containing metal or organic substances, and the structure of the fibrous membrane is complex and the preparation steps are cumbersome. In order to overcome the defects of the prior art and solve the technical problem of how to easily use low-cost, environmentally friendly and safe materials to prepare high-efficiency and low-resistance antibacterial filtration nanofiber materials, one of the purposes of the present invention is to provide an antibacterial composite nanofiber material. Fiber membrane, the second purpose of the present invention is to provide a preparation method of this antibacterial composite nanofiber membrane, and the third purpose of the present invention is to provide the application of this antibacterial composite nanofiber membrane.

The technical scheme adopted by the present invention is:

An antibacterial composite nanofiber membrane includes a nanofiber membrane and _gC3N4 nanosheets distributed _on the surface and inside of the nanofiber membrane.

Further, in this antibacterial composite nanofiber membrane, the gC ₃ N ₄ nanosheets are two-dimensional gC ₃ N ₄ nanosheets, and the gC _{3 N4} nanosheets exist both on the surface and inside the nanofiber membrane to form a grid distribution.

Preferably, in the antibacterial composite nanofiber membrane, there are etched pores with a pore diameter of 20 nm to 100 nm on the surface of the nanofiber membrane.

Preferably, in this antibacterial composite nanofiber film, the thickness of the nanofiber film is greater than 100 μm; further preferably, the thickness of the nanofiber film is 120 μm to 800 μm; even more preferably, the thickness of the nanofiber film is 150 μm to 500 μm

Preferably, in this antibacterial composite nanofiber film, the material of the nanofiber film is polyacrylonitrile, polyamide, polylactic acid, polyurethane, polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polycaprolactone, At least one of polyethylene oxide, polystyrene, polyester, polyimide, chitosan, silk fibroin, and collagen.

Preferably, in the antibacterial composite nanofiber membrane, the size of the gC ₃ N ₄ nanosheets is 10 nm to 100 nm.

The preparation method of the above-mentioned antibacterial composite nanofiber membrane comprises the following steps:

1) mixing gC ₃ N ₄ nanoparticles with a solvent, and placing the obtained mixed solution in a plasma atmosphere for processing to obtain a dispersion liquid containing gC ₃ N ₄ nanosheets;

2) mixing and stirring the dispersion liquid containing gC ₃ N ₄ nanosheets with the electrospinable polymer to obtain a polymer spinning solution;

3) electrospinning the polymer spinning solution to obtain a nanofiber membrane;

4) The nanofiber membrane is treated in a plasma atmosphere, and then the dispersion liquid containing _gC3N4 nanosheets obtained in step ₁ ) is coated to obtain the antibacterial composite nanofiber membrane of the above composition.

Preferably, in step 1) of the preparation method of the antibacterial composite nanofiber membrane, the dosage ratio of gC ₃ N ₄ nanoparticles to the solvent is (1-8) g:1L.

Preferably, in step 1) of the preparation method of the antibacterial composite nanofiber membrane, the gC ₃ N ₄ nanoparticles are prepared by a high temperature calcination method.

Preferably, in step 1) of the preparation method of this antibacterial composite nanofiber membrane, the solvent is water, acetone, halomethane, haloacetic acid, formic acid, N,N-dimethylformamide, tetrahydrofuran, dimethylmethylene At least one of sulfones; further preferably, in step 1) of the preparation method, the solvent is water, acetone, dichloromethane, trifluoroacetic acid, formic acid, N,N-dimethylformamide, tetrahydrofuran, dimethylsulfoxide At least one of the sulfones; further preferably, in step 1) of the preparation method, the solvent is at least one of water, formic acid, and N,N-dimethylformamide.

Preferably, in step 1) of the preparation method of the antibacterial composite nanofiber membrane, the particle size of the _gC3N4 nanosheets in the dispersion containing the _gC3N4 nanosheets is ₁₀ nm _- 100 nm.

Preferably, in steps 1), 2) and ₄ ) of the preparation method of the antibacterial composite nanofiber membrane, the mass percentage _{of gC3N4} nanosheets in the dispersion containing _gC3N4 nanosheets is optionally 0.05 % to 5%.

Preferably, in step 2) of the preparation method of the antibacterial composite nanofiber membrane, the mass ratio of the dispersion containing gC ₃ N ₄ nanosheets to the electrospinable polymer is 1:(5-30).

Preferably, in step 2) of the preparation method of this antibacterial composite nanofiber membrane, the electrospun polymer is polyacrylonitrile, polyamide, polylactic acid, polyurethane, polyvinyl alcohol, polyvinyl butyral, polyacrylonitrile At least one of vinylpyrrolidone, polycaprolactone, polyethylene oxide, polystyrene, polyester, polyimide, chitosan, silk fibroin, and collagen; further preferably, in step 2) of the preparation method , Electrospinning polymers are polyacrylonitrile, polyamide, polylactic acid, polyurethane, polyvinyl alcohol, polyethylene oxide, polystyrene, polyester, polyimide, chitosan, silk fibroin, collagen At least one of the proteins; further preferably, in step 2) of the preparation method, the electrospinable polymer is at least one of polyacrylonitrile, polyamide, polyvinyl alcohol, and silk fibroin.

Preferably, in step 3) of the preparation method of the antibacterial composite nanofiber membrane, the thickness of the obtained nanofiber membrane is greater than 100 μm; further preferably, in step 3) of the preparation method, the thickness of the nanofiber membrane is 120 μm～800 μm; Preferably, in step 3) of the preparation method, the thickness of the nanofiber membrane is 150 μm˜500 μm.

Preferably, in step 4) of the preparation method of this antibacterial composite nanofiber membrane, the coating method is any one or more of spray coating, shower coating, roller coating, and dip coating; further preferably, the preparation method step 4 ), the coating method is spraying; further, in step 4) of the preparation method, the spraying time is 10s-60s.

Preferably, in step ₄ ) of the preparation method of the antibacterial composite nanofiber membrane, the mass percentage of _gC3N4 nanosheets in the dispersion containing _gC3N4 nanosheets is 0.05% to ₂ %; further preferably, In step 4) of the preparation method, the mass percentage of gC ₃ N ₄ nano flakes in the dispersion containing gC ₃ N ₄ nano flakes is 0.1% to 1%.

Preferably, in step ₄ ) of the preparation method of the antibacterial composite nanofiber membrane, the particle size of the _gC3N4 nanosheets in the dispersion containing the _gC3N4 nanosheets is ₁₀ nm-100 nm.

Preferably, in step 1) of the preparation method of the antibacterial composite nanofiber membrane, the plasma is generated by at least one gas selected from nitrogen, air, oxygen, argon, and helium, and the plasma is treated in a plasma atmosphere. The time is greater than 60s; further preferably, in step 1) of the preparation method, the time for the plasma atmosphere treatment is 90s˜300s.

Preferably, in step 4) of the preparation method of the antibacterial composite nanofiber membrane, the plasma is the plasma generated by the uniform glow discharge of the discharge gas, and the discharge gas is nitrogen, argon, helium, or in the air. At least one, the time of plasma atmosphere treatment is no more than 300s; further preferably, in step 4) of the preparation method, the time of plasma atmosphere treatment is 20s to 300s; even more preferably, in step 4) of the preparation method, the plasma atmosphere The time for body atmosphere treatment is 30s to 200s.

The application of this antibacterial composite nanofiber membrane as an air filtration membrane and/or a food cling film and/or a medical dressing.

Further preferred, the application of this antibacterial composite nanofiber membrane as an air filtration membrane.

The beneficial effects of the present invention are:

Compared with the prior art, the present invention can prepare a nanofiber membrane with both antibacterial and filtration functions only by using plasma technology and graphite phase carbon nitride (gC ₃ N ₄ ) particulate material, and the membrane material has low resistance and high efficiency. . At the same time, the preparation process of the antibacterial composite nanofiber membrane of the present invention is safe and environmentally friendly, no waste water and waste chemical reagents are generated, and the preparation method is simple and feasible.

Description of drawings

Fig. 1 is the surface topography of the outer nanofiber of the antibacterial composite nanofiber membrane of Example 1;

FIG. 2 is the surface topography of the nanofibers in the outer layer of the nanofiber membrane of Comparative Example 3. FIG.

Detailed ways

The invention discloses an antibacterial composite nanofiber air filtration membrane, which is composed of nanofibers and two _- dimensional _gC3N4 nanosheets, and nanopores exist _on the surface of the nanofibers in the outer layer of the membrane, and _gC3N4 nanosheets coexist Nanofiber membrane surface and interior. In the present invention, the gC ₃ N ₄ nano-sheets and nano-fibers are designed in the composite manner and structure, so that the gC ₃ N ₄ nano-sheets exist on the surface and inside of the nano-fiber membrane at the same time, thereby forming a grid-like dense distribution. When in use, the side coated with nanosheets corresponds to the side in contact with the polluted air containing bacteria, when the bacteria-laden particles contact the nanofiber web, _gC3N4 in the nanopores _on the surface of the outer nanofibers The nanosheets work with the nanosheets inside to inhibit the bacteria's survival. The preparation method of the present invention adopts the plasma technology. First, gC ₃ N ₄ nanoparticles prepared by a high-temperature calcination method are added to the solvent required for spinning, and then placed in a plasma atmosphere for treatment, so that the nanoparticles are exfoliated into nano-particles of a certain size. At the same time, active groups are introduced into the surface of the nanosheets. The polymer to be spun is then added and stirred until uniformly dispersed. The obtained polymer spinning solution is spun by conventional electrospinning technology to obtain a nanofiber membrane with a thickness greater than a certain thickness. The obtained nanofiber membrane was then placed in a plasma atmosphere for treatment, and then a dispersion liquid containing _{gC3N4 nanosheets} was sprayed.

The content of the present invention will be further described in detail below through specific embodiments. The raw materials used in the examples can be obtained from conventional commercial channels unless otherwise specified. The preparation of gC ₃ N ₄ nanoparticles by the high-temperature calcination method mentioned in the examples, and the electrospinning method are both conventional techniques.

Example 1

0.1 g of gC ₃ N ₄ nanoparticles prepared by high-temperature calcination were added to 50 ml of N,N-dimethylformamide (DMF) solvent, and then placed in an air plasma atmosphere for treatment for 120 s, so that the nanoparticles were exfoliated into particle sizes. 15nm nanosheets. Then add the polyacrylonitrile polymer to be spun, and stir until the dispersion is uniform; spin the obtained polymer spinning solution by electrospinning to obtain a nanofiber membrane with a thickness of 300 microns; Placed in a uniform glow discharge plasma atmosphere of helium for 180s, then sprayed a dispersion containing 0.1wt.% of _{gC3N4 nanosheets} , sprayed for 20s, and dried at room temperature to obtain an antibacterial composite nanofiber membrane product.

Figure 1 shows the surface topography of the nanofibers in the middle and outer layers of the antibacterial composite nanofiber membrane obtained in this example. It can be seen from Figure 1 that the surface of the nanofibers has etched channels and is loaded with nanosheets.

The filtration effect of the nanofiber membrane is tested by the general cigarette smoke filtration test method, and the air flow pressure difference of the filter membrane is measured by a pressure gauge. More than 97.8%, the filtration pressure drop is between 10 and 50Pa. According to the national standard GB/T20944.3-2008, the antibacterial performance of the fiber membrane was tested, and the antibacterial rate of the fiber membrane against Staphylococcus aureus reached 98.6%, and the antibacterial rate against Escherichia coli reached 97.5%.

Example 2

0.15 g of gC ₃ N ₄ nanoparticles prepared by high temperature calcination were added to 60 ml of formic acid solvent, and then placed in an argon plasma atmosphere for 90 s, so that the nanoparticles were exfoliated into nanosheets with a particle size of 20 nm. Then add the polyamide polymer to be spun, and stir until the dispersion is uniform; spin the obtained polymer spinning solution by electrospinning to obtain a nanofiber membrane with a thickness of 450 microns; place the obtained nanofiber membrane again Treated in argon uniform glow discharge plasma atmosphere for 150s, then sprayed a dispersion liquid containing 0.2wt.% _{gC3N4 nanosheets} , sprayed for 30s, and dried at room temperature to obtain an antibacterial composite nanofiber membrane product.

The filtration effect of the nanofiber membrane is tested by the general cigarette smoke filtration test method, and the air flow pressure difference of the filter membrane is measured by a pressure gauge. The results show that the filtration efficiency of the fiber membrane prepared in this example for PM in the air is as high as 96.9% or more. , the filtration pressure drop is between 20 and 50Pa. According to the national standard GB/T 20944.3-2008, the antibacterial performance of the fiber membrane was tested, and the antibacterial rate of the fiber membrane against Staphylococcus aureus reached 97.8%, and the antibacterial rate against Escherichia coli reached 96.5%.

Example 3

0.4 g of gC ₃ N ₄ nanoparticles prepared by high-temperature calcination were added to 100 ml of deionized water solvent, and then placed in an oxygen plasma atmosphere for 300 s, so that the nanoparticles were exfoliated into nanosheets with a particle size of 30 nm. Then add the polyvinyl alcohol polymer to be spun, and stir until the dispersion is uniform; spin the obtained polymer spinning solution by electrospinning to obtain a nanofiber membrane with a thickness of 500 microns; Placed in a nitrogen uniform glow discharge plasma atmosphere for 200s, then sprayed a dispersion containing 0.5wt.% of _{gC3N4 nanosheets} , sprayed for 15s, and dried at room temperature to obtain an antibacterial composite nanofiber membrane product.

The filtration effect of the nanofiber membrane is tested by the general cigarette smoke filtration test method, and the air pressure difference of the filter membrane is measured by a pressure gauge. , the filtration pressure drop is between 20 and 60Pa. According to the national standard GB/T 20944.3-2008, the antibacterial performance of the fiber membrane was tested, and the antibacterial rate of the fiber membrane against Staphylococcus aureus reached 98.8%, and the antibacterial rate against Escherichia coli reached 98.1%.

Example 4

0.2 g of gC ₃ N ₄ nanoparticles prepared by high-temperature calcination were added to 80 ml of formic acid solvent, and then placed in a nitrogen plasma atmosphere for 180 s, so that the nanoparticles were exfoliated into nanosheets with a particle size of 10 nm. Then add the silk fibroin polymer to be spun, and stir until the dispersion is uniform; spin the obtained polymer spinning solution by electrospinning to obtain a nanofiber membrane with a thickness of 150 microns; Placed in a uniform glow discharge plasma atmosphere for 30s, then sprayed a dispersion containing ₁ wt.% of _gC3N4 nanosheets, sprayed for 45s, and dried at room temperature to obtain an antibacterial composite nanofiber membrane product.

The filtration effect of the nanofiber membrane is tested by the general cigarette smoke filtration test method, and the air pressure difference of the filter membrane is measured by a pressure gauge. The results show that the filtration efficiency of the fiber membrane prepared in this example for PM in the air is as high as 99.1% or more. , the filtration pressure drop is between 30 and 70Pa. According to the national standard GB/T 20944.3-2008, the antibacterial performance of the fiber membrane was tested, and the antibacterial rate of the fiber membrane against Staphylococcus aureus reached 98.2%, and the antibacterial rate against Escherichia coli reached 99.0%.

Comparative Example 1

Add 0.2 g of gC ₃ N ₄ nanoparticles prepared by high temperature calcination into formic acid solvent, without plasma treatment, and then directly add the silk fibroin polymer to be spun. After stirring, it was found that the nanoparticles had agglomeration and could not be dissolved uniformly. , so conventional electrospinning cannot be performed.

Comparative Example 2

0.2 g of gC ₃ N ₄ nanoparticles prepared by high-temperature calcination were added to 80 ml of formic acid solvent, and then placed in a nitrogen plasma atmosphere for 180 s, so that the nanoparticles were exfoliated into nanosheets with a particle size of 10 nm. Then add the silk fibroin polymer to be spun, and stir until dispersed uniformly; spin the obtained polymer spinning solution by conventional electrospinning technology to obtain a nanofiber membrane with a thickness of 150 microns; It is then placed in a uniform glow discharge plasma atmosphere in air for 30 s, and then the gC ₃ N ₄ nanosheets are not sprayed to obtain the final product.

Comparative Example 3

Using the same polyacrylonitrile polymer as in Example 1, spinning was carried out by the same electrospinning method to obtain a nanofiber membrane with a thickness of 300 microns. Figure 2 is the surface topography of the nanofibers in the outer layer of the nanofiber membrane obtained in this comparative example.

The general cigarette smoke filtration test method was used to test the filtration effect of the nanofiber membrane, and the air pressure difference of the filter membrane was measured by a pressure gauge. Above, the filtration pressure drop is between 40-70Pa. According to the national standard GB/T 20944.3-2008, the antibacterial performance of the fiber membrane was tested, and the antibacterial rate of the fiber membrane against Staphylococcus aureus was only 87.2%, and the antibacterial rate against Escherichia coli was only 88.0%.

As can be seen from Comparative Example 1 and Comparative Example 2, the lack of plasma treatment causes the nanoparticles to agglomerate, making conventional spinning impossible. Without the post _- treatment sprayed nanosheets, the _gC3N4 nanosheets only exist inside the nanofiber membrane, which significantly reduces its antibacterial and bacteriostatic effect.

The surface topography of the nanofibers in the outer layer of the nanofiber membranes of Comparative Example 1 and Comparative Example 3, that is, Figures 1 and 2, it can be seen that in the etching channels formed by plasma treatment in Example 1, the surface of the nanofibers is obviously rough, and loaded with nanosheets.

It can be seen from the above examples that the nanofiber membrane of the present invention has a simple structure, does not contain metal or organic antibacterial agents, is safe, efficient, and environmentally friendly. The preparation method of the nanofiber membrane provided by the invention is simple and feasible, and does not generate chemical residues and waste water.

Claims (10)

1. An antibacterial composite nanofiber membrane, characterized in that: comprising a nanofiber membrane and _gC3N4 nanosheets distributed _on the surface and inside of the nanofiber membrane; The antibacterial composite nanofiber membrane is made by the following method, which includes the following steps: 1) mixing gC ₃ N ₄ nanoparticles with a solvent, and placing the obtained mixed solution in a plasma atmosphere for processing to obtain a dispersion liquid containing gC ₃ N ₄ nanosheets; 2) mixing and stirring the dispersion liquid containing gC ₃ N ₄ nanosheets with the electrospinable polymer to obtain a polymer spinning solution; 3) electrospinning the polymer spinning solution to obtain a nanofiber membrane; 4) The nanofiber membrane is treated in a plasma atmosphere, and then the dispersion liquid containing _gC3N4 nanosheets obtained in step ₁ ) is coated to obtain an antibacterial composite nanofiber membrane. 2 . The antibacterial composite nanofiber membrane according to claim 1 , wherein the surface of the nanofiber membrane has etching pores with a pore diameter of 20 nm to 100 nm. 3 . 3 . The antibacterial composite nanofiber membrane according to claim 1 or 2 , wherein the thickness of the nanofiber membrane is greater than 100 μm. 4 . 4 . The antibacterial composite nanofiber membrane according to claim 1 , wherein the size of the gC ₃ N ₄ nanosheets is 10 nm to 100 nm. 5 . 5. a preparation method of antibacterial composite nanofiber membrane is characterized in that: comprise the following steps: 1) mixing gC ₃ N ₄ nanoparticles with a solvent, and placing the obtained mixed solution in a plasma atmosphere for processing to obtain a dispersion liquid containing gC ₃ N ₄ nanosheets; 2) mixing and stirring the dispersion liquid containing gC ₃ N ₄ nanosheets with the electrospinable polymer to obtain a polymer spinning solution; 3) electrospinning the polymer spinning solution to obtain a nanofiber membrane; 4) The nanofiber membrane is treated in a plasma atmosphere, and then the dispersion liquid containing _gC3N4 nanosheets obtained in step ₁ ) is coated to obtain the antibacterial composite nanofiber membrane according to any one of claims 1-4. 6. The preparation method of an antibacterial composite nanofiber membrane according to claim 5, wherein in step 1), step 2) and step ₄ ), _gC3N in the dispersion containing _gC3N4 nanosheets The mass percentage of the ₄ nanosheets is optionally 0.05% to 5%. 7. The preparation method of an antibacterial composite nanofiber membrane according to claim 5 or 6, characterized in that: in step ₂ ), the dispersion liquid containing _gC3N4 nanosheets and the mass of the electrospinable polymer The ratio is 1:(5～30). 8. the preparation method of a kind of antibacterial composite nanofiber membrane according to claim 5 or 6, is characterized in that: in step 1), plasma adopts at least one in nitrogen, air, oxygen, argon, helium The plasma generated by the gas, the plasma atmosphere treatment time is more than 60s. 9. the preparation method of a kind of antibacterial composite nanofiber membrane according to claim 5 or 6, it is characterized in that: in step 4), plasma is the plasma that discharge gas produces through uniform glow discharge, and described discharge gas It is at least one of nitrogen, argon, helium, and air, and the time for plasma atmosphere treatment is no more than 300s. 10. The application of an antibacterial composite nanofiber membrane according to any one of claims 1 to 4 as an air filtration membrane and/or a food preservation film and/or a medical dressing.

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