Air filtering film with piezoelectric gain performance and preparation method thereof

Abstract

The invention discloses an air filtering film with piezoelectric gain performance and a preparation method thereof.The preparation method comprises the steps that a catalyst precursor serves as a skin layer spinning solution, a piezoelectric polymer and a toughening agent are dispersed in N-N dimethylformamide, the mixture is stirred and mixed to be uniform to serve as a core layer spinning solution, coaxial electrostatic spinning is conducted, and a spinning film is obtained; the spinning membrane is placed in water to be soaked and crystallized, then the spinning membrane is placed in H2O2 to be stirred, and the air filtering film is prepared. The method is simple in preparation process, the catalyst is directly loaded on the purification film in situ through the electrostatic spinning technology, the catalyst is dispersed on the purification film more evenly and combined more firmly, the purification efficiency of the filter screen is effectively improved through combination and synergy of the catalysis technology and the piezoelectric film, and meanwhile the purification effect of the filter screen is improved. The toughening agent is added into an electrostatic spinning system, so that the wind pressure resistance of the air filtering film is effectively improved, and the air filtering film has good toughness.

Description

Technical Field

[0001] The invention belongs to the technical field of air purification and relates to an air filtration film with piezoelectric gain performance and a preparation method thereof. Background Art

[0002] A clean and comfortable living environment is closely related to people's lives. Long-term inhalation of unclean air will cause diseases. Therefore, air purifiers and air conditioners are widely used, and the air quality output by air purifiers and air conditioners has long been a concern for people. The air filters in air purifiers and air conditioners play a vital role in the output air.

[0003] At present, most air filters use HEPA nets. HEPA nets are generally composed of fiber filter membranes and frames. The fiber filter membranes are generally interwoven with very fine organic fibers, with small pore sizes, strong particle capture capabilities, large adsorption capacity, and high purification efficiency. In addition, in order to further enhance the purification effect of the traditional fiber filter membrane, granular effective ingredients such as activated carbon or aluminum oxide are filled in the HEPA filter membrane. However, the filling method of activated carbon or aluminum oxide is complicated. The general filling methods currently include direct spreading, coating, and impregnation. The direct spreading method directly spreads the particles on the surface of the filter membrane, and then embeds the particles into the filter membrane by vibration or light pressure. This method is simple and fast, but may result in uneven particle distribution. The coating method mixes the particles with a binder into a slurry, which is then coated on the surface of the filter membrane. After drying, the particles are fixed on the filter membrane. This method can achieve a more uniform particle distribution, but it is necessary to control the viscosity of the slurry and the coating thickness. The impregnation method immerses the filter membrane in a solution containing particles, which is then removed and dried. This method allows particles to penetrate deeper into the filter membrane, but it may also cause the pores of the filter membrane to become clogged. In addition, after the filling is completed, the filter membrane needs to be cured, such as by heating or ultraviolet irradiation, to further enhance the bonding between the particles and the filter membrane. Therefore, the filling process is relatively complicated and costly, and it is impossible to ensure the uniform distribution of the filling particles in the fiber filter membrane. Blockage of the fiber pores will also lead to limited purification effects. After absorbing pollutants, the filtration efficiency decreases, affecting the use of the air purifier and even causing secondary pollution. At the same time, the HEPA filter membrane cannot be regenerated for a second time, resulting in waste. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides an air filtration membrane with piezoelectric gain performance and a preparation method thereof, thereby solving the technical problems in the prior art of complex process for loading purification particles on the air filtration membrane, uneven particle distribution, decreased purification efficiency after loading and difficulty in secondary regeneration.

[0005] The present invention is achieved through the following technical solutions: A method for preparing an air filter membrane with piezoelectric gain performance, comprising: using a catalyst precursor as a skin layer spinning solution, dispersing a piezoelectric polymer and a toughening agent in NN dimethylformamide, stirring and mixing them evenly to use as a core layer spinning solution, and performing coaxial electrostatic spinning to obtain a spinning membrane; after the spinning membrane is immersed in water for crystallization, it is placed in H2O2 for stirring treatment to obtain the air filter membrane.

[0006] Preferably, the catalyst precursor is tetraisopropyl titanate or tetra-n-butyl titanate.

[0007] Preferably, the piezoelectric polymer and the toughening agent are dispersed in NN dimethylformamide and stirred at 50-90° C. for 2-5 hours to obtain the core layer spinning solution.

[0008] Preferably, the piezoelectric polymer is polyvinylidene fluoride, polyvinylidene chloride or polyacrylonitrile; the toughening agent is epoxy resin, chlorinated polyethylene, acrylonitrile-styrene-acrylate terpolymer or polycarbonate-polydimethylsiloxane block copolymer.

[0009] Preferably, the mass ratio of the piezoelectric polymer to the toughening agent is 1:(0.05-1); the mass ratio of the piezoelectric polymer to the catalyst precursor is 1:(0.5-2.5).

[0010] Preferably, during the electrospinning process, the pushing speeds of the skin layer spinning solution and the core layer spinning solution are both 0.002-0.01 mm / s, and the spinning voltage is 10-40 kV.

[0011] Preferably, the spinning membrane is immersed in water for crystallization and then placed in H2O2 for stirring. Specifically, during the immersion in water, the immersion temperature is 60-100°C and the immersion time is 1-4 h; and the membrane is stirred in H2O2 for 10-40 min.

[0012] An air filtration film with piezoelectric gain performance is prepared by the above method.

[0013] An air filter net comprises the above-mentioned air filter film with piezoelectric gain performance and a frame, wherein the air filter film with piezoelectric gain performance is fixed on the frame.

[0014] An air purifier comprises the above-mentioned air filter, wherein the air filter is detachably arranged in the body of the air purifier.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a method for preparing an air filtration membrane with piezoelectric gain performance. The method uses a catalyst precursor as a skin spinning solution, disperses a piezoelectric polymer and a toughening agent in NN dimethylformamide, stirs and mixes them evenly as a core spinning solution, and performs coaxial electrostatic spinning to obtain a spinning membrane; after the spinning membrane is immersed in water for crystallization, it is placed in H2O2 for stirring treatment to obtain the air filtration membrane. The method has a simple preparation process, and the catalyst can be directly loaded on the purification membrane in situ through the electrostatic spinning technology, so that the catalyst is more evenly dispersed on the purification membrane and the combination is more firm. The combination of films works synergistically. Under the action of wind, the piezoelectric film generates a directional electric field, which makes it easier to separate the electron-hole pairs generated by the catalytic process, effectively increasing the amount of active carriers and improving the purification efficiency of the filter. In addition, the electrostatic effect of the piezoelectric film can also promote the adsorption and enrichment of pollutants, and enhance the degradation and purification effect of pollutants. At the same time, toughening agents are added to the electrospinning system to effectively improve the wind pressure resistance of the air filtration film, making the air filtration film have good toughness. At the same time, based on the good toughness of the film, the secondary regeneration of the film can be achieved through simple cleaning and drying, which effectively improves the utilization rate of the film.

[0016] Furthermore, the piezoelectric polymer is polyvinylidene fluoride, polyvinylidene chloride or polyacrylonitrile, which can effectively obtain an air filtration membrane with piezoelectric gain performance. Its piezoelectric effect can enhance the pollutant removal performance of the catalyst. At the same time, combined with the electrostatic adsorption effect of piezoelectric nanofibers, it can further adsorb pollutants and enhance purification efficiency.

[0017] Furthermore, the toughening agent is epoxy resin, chlorinated polyethylene, acrylonitrile-styrene-acrylate terpolymer or polycarbonate-polydimethylsiloxane block copolymer, which can make the air filtration membrane have a certain toughness, and it is easy to deform but not damaged when used in the field.

[0018] Furthermore, the mass ratio of the piezoelectric polymer to the toughening agent is 1:(0.05-1), which allows the air filtration membrane to have both flexibility and firmness, ensuring that it is easy to deform but not easily damaged.

[0019] Furthermore, the mass ratio of the piezoelectric polymer to the catalyst precursor is 1:(0.5~2.5), so that the catalyst precursor can be evenly distributed on the surface of the piezoelectric polymer without causing large agglomerations that would reduce its performance, ensuring that the catalyst precursor covers the surface of the polymer in the largest amount and that the maximum amount of catalyst is synthesized. Furthermore, during the electrospinning process, the pushing speed is 0.002~0.01mm / s and the spinning voltage is 10~40kV, which can make the fiber uniform in thickness and strong in air permeability. The high voltage electric field gives the piezoelectric polymer sufficient polarization ability, thereby enhancing its lifting effect on the catalyst and ensuring that the fiber can reach the receiver to form a film.

[0020] Furthermore, after the spinning membrane is immersed in water for crystallization, it is placed in H2O2 for stirring treatment. Specifically, during the immersion in water, the immersion temperature is 60-100°C and the immersion time is 1-4 h. The membrane is stirred in H2O2 for 10-40 min. By directly adding a catalyst precursor, the catalyst can be synthesized in situ on the fiber to ensure its immobilization and make it difficult to fall off. Secondly, the in situ generated catalyst can be synthesized on the fiber surface as much as possible to prevent it from being wrapped by the fiber and making it difficult for it to contact with the catalyst.

[0021] At the same time, the present invention also discloses an air filtration film with piezoelectric gain performance prepared by the above method. The film has good purification effect and can be regenerated by simple water washing and drying, and has high utilization rate.

[0022] In addition, the present invention also discloses an air filtration film having the piezoelectric gain performance, and the air filtration film is directly fixed on the frame, so the assembly method is simple and easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a structural schematic diagram of the first frame on the air filter net of the present invention; Figure 2 It is a structural schematic diagram of the second frame on the air filter net of the present invention; Figure 3 The air filtration membrane prepared in Example 1 of the present invention removes NO x Test results; Figure 4 The figure is the test result of removing toluene by the air filtration membrane prepared in Example 2 of the present invention.

[0025] Among them: 1. first frame, 11. fixing position, 2. second frame, 22. buckle. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0027] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0028] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0029] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0030] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0031] The present invention provides a method for preparing an air filter film with piezoelectric gain performance, wherein a catalyst precursor is used as a skin layer spinning solution, a piezoelectric polymer and a toughening agent are dispersed in NN dimethylformamide, stirred at 50-90°C for 2-5h, and the mixture is stirred and mixed evenly to form a core layer spinning solution, and coaxial electrostatic spinning is performed to obtain a spinning film; the spinning film is placed in water for immersion and crystallization, and then placed in H2O2 for stirring treatment to obtain the air filter film. This process can grow the active ingredients in situ on the polymer substrate.

[0032] The catalyst precursor is tetraisopropyl titanate or tetra-n-butyl titanate.

[0033] The piezoelectric polymer is polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVC) or polyacrylonitrile (PAN), which can effectively obtain an air filtration membrane with piezoelectric gain performance. Its piezoelectric effect can improve the pollutant removal performance of the catalyst. At the same time, combined with the electrostatic adsorption effect of piezoelectric nanofibers, it can further adsorb pollutants and enhance purification efficiency.

[0034] The toughening agent is epoxy resin, chlorinated polyethylene (CPE), acrylonitrile-styrene-acrylate (ASA) terpolymer or polycarbonate-polydimethylsiloxane block copolymer (PC- b -PDMS). The toughening agent is epoxy resin, chlorinated polyethylene, acrylonitrile-styrene-acrylate terpolymer or polycarbonate-polydimethylsiloxane block copolymer, which can make the air filtration membrane have a certain toughness, so that it is easy to deform but not damaged when used in the field.

[0035] The mass ratio of the piezoelectric polymer to the toughening agent is 1:(0.05~1).

[0036] The mass ratio of the piezoelectric polymer to the catalyst precursor is 1:(0.5~2.5).

[0037] During the electrospinning process, the pushing speeds of the skin layer spinning solution and the core layer spinning solution are both 0.002-0.01 mm / s, and the spinning voltage is 10-40 kV.

[0038] The spinning membrane is immersed in water for crystallization and then placed in H2O2 for static treatment. Specifically, during the immersion in water, the immersion temperature is 60-100°C and the immersion time is 1-4 h; the membrane is stirred in H2O2 for 10-40 min.

[0039] In addition, the invention also discloses an air filtration film with piezoelectric gain performance obtained by the method.

[0040] At the same time, if Figure 1~2 As shown, the present invention further discloses an air filter net, comprising the above-mentioned air filter film with piezoelectric gain performance and a frame, wherein the air filter film with piezoelectric gain performance is fixed on the frame. Specifically, the above-mentioned air filter film with piezoelectric gain performance is spread on the first frame 1, and then the second frame 2 is pressed on it, and the air filter film is fixed between the first frame 1 and the second frame 2 by using the buckle 22 on the second frame 2 and the fixing position 11 on the first frame 1, so as to form an air filter net with piezoelectric gain performance. The positions of the fixing position 11 and the buckle 22 in the present invention are not limited to Figure 1 as well as Figure 2 The position of the filter element can be in the middle, or it can be located at other positions of the frame, and its shape is not limited, and it can just play the role of fixing the filter film.

[0041] The present invention also discloses an air purifier, comprising the above-mentioned air filter, wherein the air filter is detachably arranged in the body of the air purifier.

[0042] The present invention discloses an air filter with piezoelectric gain. Effective ingredients are loaded on a piezoelectric substrate by electrospinning, and its wind resistance is enhanced by a toughening agent, so that it has a certain toughness while maintaining sufficient flexibility. By loading different components, it has multifunctional air purification capabilities, including air pollutants such as bioaerosols, toluene, formaldehyde and nitrogen oxides. The piezoelectric polymer is used as a substrate, and under the action of wind, it deforms and generates a built-in electric field, which increases the separation time and transmission rate of electrons and holes in the effective ingredients, increases the transfer of electrons and holes to the surface, and generates more free radicals, which react with pollutants to degrade them. The film prepared by electrospinning has sufficient porosity, voids and flexibility, and can act as a filter. The piezoelectric gain filter is fixed in the middle of the frame and fixed by a buckle to form an air filter.

[0043] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0044] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, are conventional commercially available products, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio: Example 1 This embodiment discloses a method for preparing an air filtration membrane with piezoelectric gain performance, specifically, PVDF and epoxy resin are dispersed in NN dimethylformamide, wherein PVDF is used as a piezoelectric polymer, epoxy resin is used as a toughening agent, and the mass ratio of the piezoelectric polymer to the toughening agent is 1:0.05, and the core layer spinning solution is obtained by stirring in a water bath at 60°C for 30 minutes, and tetraisopropyl titanate (TTIP) is used as a skin layer, and the ratio of the piezoelectric polymer to TTIP is 1:0.5, so that the catalyst precursor is loaded on the surface of the PVDF film, and the film is immersed in a water bath at 80°C for 3 hours, and then stirred in H2O2 for 30 minutes. , PVDF / TiO2 (can be abbreviated as PVDF / TO) nanofiber air filtration membrane is obtained, and during electrospinning, 5mL of spinning solution is extracted for electrospinning, the needle size is 20G, the pushing speed is 0.002mm / s, the spinning voltage is 30kV, and the drum speed is 350rpm. After spinning, the piezoelectric gain filter membrane was obtained by drying at 80°C. The air filter membrane can be used to remove NO x .

[0045] Example 2 This embodiment discloses a method for preparing an air filtration membrane with piezoelectric gain performance, which is different from Example 1 in that the catalyst precursor added is tetra-n-butyl titanate, the piezoelectric polymer is polyacrylonitrile, and the toughening agent is acrylonitrile-styrene-acrylate terpolymer, wherein the mass ratio of the piezoelectric polymer to the toughening agent is 1:0.05, and the core layer spinning solution is obtained by stirring in a water bath at 80°C for 3h, and the tetra-n-butyl titanate (TBT) is used as the skin layer spinning solution, and the mass ratio of the piezoelectric polymer to TBT is 1:1. Electrospinning is performed by coaxial co-spinning to achieve in-situ loading of the catalyst. During electrospinning, 5mL of spinning solution is extracted for electrospinning, the needle size is 20G, the pushing speed is 0.002mm / s, the spinning voltage is 30kV, and the drum speed is 350 rpm. After spinning, the obtained film was immersed in a water bath at 80°C for 3 h, and then stirred in H2O2 for 30 min. The volume ratio of H2O2 to catalyst precursor was 4:1. The pH value of the system was adjusted to 7. The film was taken out, washed and dried to obtain an air filter membrane, which was also a PVDF / TO membrane. The air filter membrane can be used to remove toluene.

[0046] In order to test the performance of the filter membrane or filter screen of the present invention, the removal performance of the filter membrane prepared in Examples 1 and 2 was evaluated by the following test method: Nitrogen oxide removal test: The photocatalytic experiment was carried out through a dynamic reaction system, and the pollutant concentration was detected online. The catalytic performance was evaluated by the ratio of the NO outlet concentration to the initial concentration and the NO2 generation. The test conditions were: the initial NO concentration was 410ppb, the film dosage was 0.4G, the light source was a xenon lamp (λ>400 nm), and the air was supplied by a fan.

[0047] Toluene removal test: The formaldehyde inlet concentration was regulated at 100 ppm by the toluene gas distribution system, and the temperature control reaction system was used to control the catalytic oxidation reaction of formaldehyde by the piezoelectric gain filter membrane at room temperature of 25°C. The formaldehyde removal rate of the membrane was evaluated by the change in toluene concentration, and a fan was used to supply air.

[0048] The air filtration membrane prepared in Example 1 of the present invention removes NO x The test results are shown in Figure 3 ,Depend on Figure 3 It can be seen that under the added stress (i.e., in the presence of flow rate), PVDF / TO removes NO X The efficiency can be increased by 25%.

[0049] The test results of the air filtration membrane prepared in Example 2 of the present invention for removing toluene are shown in Figure 4 ,Depend on Figure 4 It can be seen that under the action of added stress (i.e., in the presence of flow rate), the efficiency of PVDF / TO in removing toluene can be improved.

[0050] The above test results are summarized in Table 1. It can be seen from Table 1 that when the wind is supplied or the wind speed is high, the piezoelectric effect is generated due to the action of the piezoelectric polymer, and after combining with the catalyst, the removal efficiency of pollutants is effectively improved.

[0051] Table 1 Comparison of pollutant removal performance of the filtration membranes prepared in Examples 1 and 2

[0052] Example 3 A method for preparing an air filtration membrane with piezoelectric gain performance comprises the following steps: using a catalyst precursor as a skin spinning solution, dispersing a piezoelectric polymer and a toughening agent in NN dimethylformamide and stirring at 50°C for 5 hours, using the core spinning solution, and performing coaxial electrospinning so that the catalyst precursor is loaded on the surface of a PVDF film. The film is immersed in an 80°C water bath for 3 hours and then stirred in H2O2 for 30 minutes to obtain a nanofiber air filtration membrane.

[0053] The catalyst precursor is a soluble zinc salt selected from zinc acetate, the piezoelectric polymer is polyvinylidene chloride (PVC), and the toughening agent is chlorinated polyethylene (CPE). The mass ratio of the piezoelectric polymer, the catalyst precursor and the toughening agent is 1:1.5:0.05. During the electrospinning process, the pushing speed is 0.002 mm / s and the spinning voltage is 10 kV.

[0054] Example 4 A method for preparing an air filtration membrane with piezoelectric gain performance comprises the following steps: using a catalyst precursor as a skin spinning solution, dispersing a piezoelectric polymer and a toughening agent in NN dimethylformamide and stirring at 90°C for 2 hours, using the core spinning solution, and performing coaxial electrospinning so that the catalyst precursor is loaded on the surface of a PVDF film. The film is immersed in an 80°C water bath for 3 hours and then stirred in H2O2 for 30 minutes to obtain a nanofiber air filtration membrane.

[0055] The catalyst precursor is tetrabutyl titanate, the piezoelectric polymer is PAN, and the toughening agent is PC- b-PDMS. The mass ratio of the piezoelectric polymer, the catalyst precursor, and the toughening agent is 1:1:1. During the electrospinning process, the pushing speed is 0.01 mm / s and the spinning voltage is 40 kV.

[0056] Example 5 A method for preparing an air filtration membrane with piezoelectric gain performance, comprising the following steps: using a catalyst precursor as a skin spinning solution, dispersing a piezoelectric polymer and a toughening agent in NN dimethylformamide and stirring at 60°C for 3 hours, and using the core spinning solution for coaxial electrospinning, so that the catalyst precursor is loaded on the surface of a PVDF film. The film is immersed in an 80°C water bath for 3 hours and then stirred in H2O2 for 30 minutes to obtain a nanofiber air filtration membrane.

[0057] The catalyst precursor is tetraisopropyl titanate, the piezoelectric polymer is polyvinylidene chloride (PVC), and the toughening agent is acrylonitrile-styrene-acrylate (ASA) terpolymer. The mass ratio of the piezoelectric polymer, the catalyst precursor, and the toughening agent is 1:0.8:0.08. During the electrospinning process, the pushing speed is 0.009 mm / s and the spinning voltage is 25 kV.

[0058] The present invention loads effective ingredients on a piezoelectric substrate by electrospinning, and enhances its wind resistance by a toughening agent, so that it has a certain toughness while maintaining sufficient flexibility, and has multifunctional air purification capabilities by loading different components, including air pollutants such as bioaerosols, toluene, formaldehyde and nitrogen oxides. The piezoelectric polymer is used as a substrate, and under the action of wind, it deforms and generates a built-in electric field, which increases the separation time and transmission rate of electrons and holes of the effective ingredients, and increases the generation of more free radicals after the electrons and holes are transferred to the surface, which react with pollutants to degrade them. The film prepared by electrospinning has sufficient porosity, cavities and flexibility, and can act as a filter. The piezoelectric gain filter is fixed in the middle of the frame and fixed by a buckle to form an air filter. The present invention provides an air filter with piezoelectric gain, which uses a piezoelectric polymer as a substrate, generates a built-in electric field under the action of a fan, and can produce a gain effect on the performance of the effective ingredient in purifying the air. The film can effectively improve toughness without losing flexibility under the action of toughening agents, and can easily deform under the action of fans. Under the action of electrospinning, it forms a porous structure to replace the HEPA net and directly act as a filter. It has sufficient interception performance for particulate matter, has the ability to degrade bioaerosols and indoor air pollutants, and has a sufficiently small pressure drop. It can be reused repeatedly through direct cleaning, which is convenient for replacement.

[0059] Example 6 A method for preparing an air filter membrane with piezoelectric gain performance, using a catalyst precursor as a skin layer spinning solution, dispersing a piezoelectric polymer and a toughening agent in NN dimethylformamide, stirring at 50°C for 5 hours, stirring and mixing evenly as a core layer spinning solution, and coaxial electrospinning to obtain a spinning membrane; the spinning membrane is placed in water for immersion and crystallization, and then placed in H2O2 for stirring treatment to obtain the air filter membrane. This process can grow the active ingredients in situ on the polymer substrate.

[0060] The catalyst precursor is TTIP, the piezoelectric polymer is polyvinylidene fluoride (PVDF), and the toughening agent is epoxy resin.

[0061] The mass ratio of the piezoelectric polymer to the toughening agent is 1:0.05, the mass ratio of the piezoelectric polymer to the catalyst precursor is 1:0.5, and during the electrospinning process, the pushing speeds of the skin spinning solution and the core spinning solution are both 0.002 mm / s, and the spinning voltage is 10 kV.

[0062] The spinning membrane was immersed in water for crystallization. During the immersion in water, the immersion temperature was 60° C. and the immersion time was 4 h. The membrane was stirred in H 2 O 2 for 10 min.

[0063] Example 7 A method for preparing an air filter membrane with piezoelectric gain performance, using a catalyst precursor as a skin layer spinning solution, dispersing a piezoelectric polymer and a toughening agent in NN dimethylformamide, stirring at 90°C for 2 hours, stirring and mixing evenly as a core layer spinning solution, coaxial electrostatic spinning to obtain a spinning membrane; placing the spinning membrane in water for crystallization, and then placing it in H2O2 for static treatment to obtain the air filter membrane. This process can grow the active ingredients in situ on the polymer substrate.

[0064] The catalyst precursor is TBT, the piezoelectric polymer is polyvinylidene chloride (PVC), and the toughening agent is chlorinated polyethylene (CPE).

[0065] The mass ratio of the piezoelectric polymer to the toughening agent is 1:1, the mass ratio of the piezoelectric polymer to the catalyst precursor is 1:1, and during the electrospinning process, the pushing speeds of the skin spinning solution and the core spinning solution are both 0.01 mm / s, and the spinning voltage is 10 kV.

[0066] The spinning membrane is immersed in water for crystallization, and then placed in H2O2 for stirring. Specifically, during the immersion in water, the immersion temperature is 100°C and the immersion time is 1 h; and the membrane is stirred in H2O2 for 10 min.

[0067] Example 8 A method for preparing an air filter membrane with piezoelectric gain performance, wherein a catalyst precursor is used as a skin layer spinning solution, a piezoelectric polymer and a toughening agent are dispersed in NN dimethylformamide, stirred at 60°C for 3 hours, and the mixture is stirred and mixed to form a core layer spinning solution, and coaxial electrospinning is performed to obtain a spinning membrane; the spinning membrane is placed in water for immersion and crystallization, and then placed in H2O2 for stirring treatment to obtain the air filter membrane. This process can grow the active ingredients in situ on the polymer substrate.

[0068] The catalyst precursor is TTIP / TBT, the piezoelectric polymer is polyacrylonitrile (PAN), and the toughening agent is acrylonitrile-styrene-acrylate (ASA) terpolymer. The mass ratio of the piezoelectric polymer to the toughening agent is 1:0.5, the mass ratio of the piezoelectric polymer to the catalyst precursor is 1:2.5, and during the electrospinning process, the pushing speeds of the skin spinning solution and the core spinning solution are both 0.008 mm / s, and the spinning voltage is 30 kV.

[0069] The spinning membrane is immersed in water for crystallization. Specifically, during the immersion in water, the immersion temperature is 80° C. and the immersion time is 2 h; and the membrane is stirred in H 2 O 2 for 30 min.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing an air filtration membrane having piezoelectric gain performance, characterized in that: The catalyst precursor is used as the skin spinning solution, the piezoelectric polymer and the toughening agent are dispersed in NN dimethylformamide, stirred and mixed evenly as the core spinning solution, and coaxial electrospinning is performed to obtain a spinning membrane; the spinning membrane is immersed in water for crystallization, and then placed in H2O2 for stirring treatment to obtain the air filter film.

2. The method for preparing an air filtration membrane having piezoelectric gain performance according to claim 1, characterized in that: The catalyst precursor is tetraisopropyl titanate or tetra-n-butyl titanate.

3. The method for preparing an air filtration membrane having piezoelectric gain performance according to claim 1, characterized in that: The piezoelectric polymer and the toughening agent are dispersed in NN dimethylformamide, and stirred at 50-90° C. for 2-5 hours to obtain the core layer spinning solution.

4. The method for preparing an air filtration membrane having piezoelectric gain performance according to claim 1, characterized in that: The piezoelectric polymer is polyvinylidene fluoride, polyvinylidene chloride or polyacrylonitrile; the toughening agent is epoxy resin, chlorinated polyethylene, acrylonitrile-styrene-acrylate terpolymer or polycarbonate-polydimethylsiloxane block copolymer.

5. The method for preparing an air filtration membrane having piezoelectric gain performance according to claim 1, characterized in that: The mass ratio of the piezoelectric polymer to the toughening agent is 1:(0.05-1); the mass ratio of the piezoelectric polymer to the catalyst precursor is 1:(0.5-2.5).

6. The method for preparing an air filtration membrane having piezoelectric gain performance according to claim 1, characterized in that: During the electrospinning process, the pushing speeds of the skin layer spinning solution and the core layer spinning solution are both 0.002-0.01 mm / s, and the spinning voltage is 10-40 kV.

7. The method for preparing an air filtration membrane having piezoelectric gain performance according to claim 1, characterized in that: After the spinning membrane is immersed in water for crystallization, it is placed in H2O2 for stirring treatment. Specifically, during the immersion in water, the stirring immersion temperature is 60-100°C, the immersion time is 1-4 h; and the stirring in H2O2 is 10-40 min.

8. An air filtration membrane having piezoelectric gain performance, characterized in that: Prepared by the method according to any one of claims 1 to 7.

9. An air filter, characterized in that: It comprises an air filtration membrane with piezoelectric gain performance as described in claim 8 and a frame, wherein the air filtration membrane with piezoelectric gain performance is fixed on the frame.

10. An air purifier, characterized in that: It comprises an air filter as described in claim 9, and the air filter is detachably arranged in the body of the air purifier.

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