A fibrous base air filtration material and a method of making the same

Abstract

This invention discloses a fiber-based air filter material and its preparation method, relating to the field of polymer materials. In preparing the fiber-based air filter material, 5-bromouracil and o-ethoxyaniline are reacted to obtain 5-o-ethoxyaniline pyrimidine. The obtained 5-o-ethoxyaniline pyrimidine is then reacted with phosphorus oxychloride to obtain 2,4-dichloro-5-o-ethoxyaniline pyrimidine. 2,4-dichloro-5-o-ethoxyaniline pyrimidine is then reacted with aminoethanol to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine. p-Phenylenediamine is reacted with 3,3',4,4'-biphenyl dianhydride to prepare a spinning solution, which is then electrospun to obtain a polyamic acid nanofiber film. 2,4-diamino-5-o-ethoxyaniline pyrimidine is prepared into an antibacterial treatment solution. The polyamic acid nanofiber film is treated with the antibacterial treatment solution and then dehydrated by heating to obtain the fiber-based air filter film. The fiber-based air filter material prepared by this invention has excellent antibacterial properties and mechanical tensile strength.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a fiber-based air filter material and its preparation method. Background Technology

[0002] Air pollutants are highly complex, including harmful gases, fine droplets, particulate matter, and various bacteria and viruses, all of which can seriously affect human health. Humans are exposed to numerous bacteria and viruses in the air daily. The reason people don't get sick under normal circumstances is because the human body has the ability to resist these bacteria and viruses—its resistance or immunity. However, if the body's resistance decreases under certain circumstances, bacteria and viruses can easily invade and cause illness. Suspended particulate matter in the air is also a pollutant; its size is typically less than 2.5 micrometers, hence the name PM2.5. It can directly enter the body through respiration, causing damage to the lungs and bronchial system, and in severe cases, leading to obstructive pneumonia. In practice, air filtration materials are commonly used to filter and reduce PM2.5 and bacteria and viruses in the air.

[0003] Currently, air filtration materials on the market include polyimide, polytetrafluoroethylene, polysulfonamide, alumina, carbon nanotubes, and other air filter membranes. Although polyimide membranes have strong filtration performance, the nanofibers are simply physically bonded together to form the membrane without strong chemical bonding. Therefore, the mechanical strength of the resulting fiber membrane is very limited, and the antibacterial rate is also not high. This invention produces a material with high mechanical strength that filters PM2.5 and has antibacterial properties, which can be used to reduce air pollution. Summary of the Invention

[0004] The purpose of this invention is to provide a fiber-based air filter material and its preparation method to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A fiber-based air filter material and its preparation method are disclosed. The fiber-based air filter material is prepared by treating a polyamic acid nanofiber membrane with an antibacterial treatment solution and then heating and dehydrating it.

[0007] As an optimization, the polyamic acid nanofiber film is prepared by electrospinning polyamic acid powder into a spinning solution.

[0008] As an optimization, the polyamic acid powder is prepared by reacting p-phenylenediamine, N,N-dimethylacetamide and 3,3',4,4'-biphenyl dianhydride.

[0009] As an optimization, the antibacterial treatment solution is prepared by reacting 2,4-dichloro-5-o-ethoxyaniline pyrimidine with 10-15% by mass of ammonia ethanol to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine, and then uniformly mixing 2,4-diamino-5-o-ethoxyaniline pyrimidine, N,N-diethylaniline, and anhydrous ethanol.

[0010] As an optimization, the 2,4-dichloro-5-o-ethoxyaniline pyrimidine is prepared by reacting 5-o-ethoxyaniline pyrimidine with phosphorus oxychloride.

[0011] As an optimization, the 5-o-ethoxyaniline pyrimidine is prepared from 5-bromouracil and o-ethoxyaniline.

[0012] As an optimization, the preparation method of the fiber-based air filter material includes the following preparation steps:

[0013] (1) Mix 5-bromouracil, o-ethoxyaniline and ethylene glycol in a mass ratio of 1:(4.2-4.6):(5-15) until homogeneous. Stir and reflux at 190-200℃ and 800-1200r / min for 2-4 hours under a nitrogen atmosphere. Let stand for 22-24 hours. Pour into 10 times the mass of pure water of ethylene glycol to precipitate and filter. Wash with pure water and acetone 3-5 times each. Dry at 60-90℃ for 6-8 hours to obtain 5-o-ethoxyaniline pyrimidine.

[0014] (2) Mix 5-o-ethoxyaniline pyrimidine and N,N-diethylaniline at a mass ratio of 1:(0.9-1.3) until homogeneous. Add 10-13 times the mass of 5-o-ethoxyaniline uracil with phosphorus oxychloride at a rate of 0.5-1.0 mL / s while stirring at 800-1200 r / min. Reflux at 100-110℃ for 2-4 h. Pour into pure water at 0-2℃ and stir at 800-1200 r / min. Control the pH at 5-6 with sodium carbonate. Extract repeatedly with diethyl ether until there is no solid in the aqueous phase. Combine the ether extracts from multiple extractions and dry at 35-50℃ for 4-6 h to obtain 2,4-dichloro-5-o-ethoxyaniline pyrimidine.

[0015] (3) Mix 2,4-dichloro-5-o-ethoxyaniline pyrimidine and a 10-15% ammonia-ethanol solution at a mass ratio of 1:(20-30), seal in a high-pressure reactor, react at 140-150℃ for 16-20h, cool to room temperature, open and dry at 60-70℃ and 50-100Pa for 6-8h to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine;

[0016] (4) Mix p-phenylenediamine and N,N-dimethylacetamide at a mass ratio of 1:(20-60) until homogeneous, add 3,3',4,4'-biphenyl dianhydride at a mass ratio of 2-4 times that of p-phenylenediamine, stir at 800-1200 r / min for 22-24 h at room temperature to obtain a polyamic acid solution, then add the polyamic acid solution dropwise to pure water at a volume of 3 times that of N,N-dimethylacetamide at a rate of 0.5-1.0 mL / s, let stand, filter and wash with pure water 3-5 times, freeze dry at -9--5℃ for 22-24 h, and grind until the particle size is less than 0.1 mm to obtain polyamic acid powder;

[0017] (5) Mix polyamic acid powder and N,N-dimethylformamide at a mass ratio of 1:(10-15), stir at low temperature for 3-4 hours, prepare a spinning solution for electrospinning, and dry at 6-10℃ and 10-20Pa for 20-24 hours to obtain polyamic acid nanofiber film.

[0018] (6) 2,4-Diamino-5-o-ethoxyaniline pyrimidine, N,N-diethylaniline and anhydrous ethanol are mixed evenly in a mass ratio of 1:(4~6):(4~6) to prepare an antibacterial treatment solution; the polyamic acid nanofiber membrane is immersed in the antibacterial treatment solution and left to stand at 30~40℃ for 8~10min. It is then taken out and placed in a muffle furnace and kept at 100~120℃ for 20~30min, 200~250℃ for 50~60min, and 300~350℃ for 20~30min. After cooling to room temperature, it is taken out to obtain a fiber-based air filter membrane.

[0019] As an optimization, the electrospinning process parameters in step (5) are: voltage 16-20kV, flow rate 0.6-0.8mL / h, ambient humidity 10-30%, and receiving distance 15-16cm.

[0020] As an optimization, the antibacterial treatment solution obtained in step (6) is prepared by mixing 2,4-diamino-5-o-ethoxyaniline, N,N-diethylaniline and anhydrous ethanol in a mass ratio of 1:(4-6):(4-6).

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0022] In preparing the fiber-based air filter material, the present invention first reacts 5-bromouracil and o-ethoxyaniline to obtain 5-o-ethoxyaniline pyrimidine. The obtained 5-o-ethoxyaniline pyrimidine is then reacted with N,N-diethylaniline to obtain 2,4-dichloro-5-o-ethoxyaniline pyrimidine. The 2,4-dichloro-5-o-ethoxyaniline pyrimidine is then reacted with aminoethanol to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine. The substituents on the benzene ring of 2,4-diamino-5-o-ethoxyaniline pyrimidine interact with pathogens through dispersion forces. The aniline pyrimidine structure can inhibit the production of pathogen infecting enzymes, thereby preventing pathogen infection and killing pathogens.

[0023] Secondly, p-phenylenediamine was reacted with 3,3',4,4'-biphenyl dianhydride to prepare a spinning solution for electrospinning, thereby obtaining a polyamic acid nanofiber film. 2,4-Diamino-5-o-ethoxyaniline pyrimidine was prepared as an antibacterial treatment solution. During the treatment of the polyamic acid nanofiber film with this solution, heating and dehydration were performed, which allowed unreacted polyamic acid to dehydrate and cyclize into polyimide. Simultaneously, the increased temperature further enhanced the crosslinking effect of 2,4-diamino-5-o-ethoxyaniline pyrimidine, thus improving tensile strength. Through chemical reaction and overlapping to form a film, strong chemical bonding was achieved, resulting in improved mechanical strength of the obtained fiber film. The combined effect of the polarity of the nitrogen atom in the pyrimidine ring and the rigidity of p-phenylenediamine in the polymer molecular chain gives the polymer better mechanical properties. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the fiber-based air filter material prepared in the following embodiments are as follows:

[0026] Antibacterial properties: The fiber-based air filter materials obtained in each example and the comparative material were taken in the same area and shape, and the antibacterial rate was determined by Escherichia coli cell test according to GB / T20944 standard.

[0027] Tensile strength: The tensile strength was tested using an INSTRON-1121 electronic universal testing machine with a tensile rate of 5 mm / min and a sample size of 50 mm x 10 mm.

[0028] Example 1

[0029] (1) Mix 5-bromouracil, o-ethoxyaniline and ethylene glycol in a mass ratio of 1:4.2:5. Stir and reflux at 190°C and 800 r / min for 4 h under a nitrogen atmosphere. Let stand for 22 h. Pour into 10 times the mass of ethylene glycol in pure water to precipitate and filter. Wash with pure water and acetone 3 times each. Dry at 60°C for 8 h to obtain 5-o-ethoxyaniline pyrimidine.

[0030] (2) Mix 5-o-ethoxyaniline and N,N-diethylaniline at a mass ratio of 1:0.9. Add phosphorus oxychloride at a rate of 10 times the mass of 5-o-ethoxyaniline uracil at 0.5 mL / s while stirring at 800 r / min. Reflux at 100 °C for 4 h. Pour into pure water at 0 °C and stir at 800 r / min. Control the pH at 5 with sodium carbonate. Extract repeatedly with diethyl ether until there is no solid in the aqueous phase. Combine the ether extracts from multiple extractions and dry at 35 °C for 6 h to obtain 2,4-dichloro-5-o-ethoxyaniline pyrimidine.

[0031] (3) 2,4-dichloro-5-o-ethoxyaniline pyrimidine and a 10% ammonia-ethanol solution were mixed evenly at a mass ratio of 1:20, placed in a high-pressure reactor and sealed. The mixture was reacted at 140℃ for 20h, cooled to room temperature, opened and dried at 60℃ and 50Pa for 8h to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine.

[0032] (4) Mix p-phenylenediamine and N,N-dimethylacetamide at a mass ratio of 1:20, add 3,3',4,4'-biphenyl dianhydride at twice the mass of p-phenylenediamine, stir at 800 r / min for 24 h at room temperature to obtain a polyamic acid solution, then add the polyamic acid solution dropwise at 0.5 mL / s into pure water at three times the volume of N,N-dimethylacetamide, let stand, filter and wash three times with pure water, freeze dry at -9℃ for 24 h, and grind to a particle size of less than 0.1 mm to obtain polyamic acid powder;

[0033] (5) Polyamic acid powder and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:10. After stirring at low temperature for 3 hours, a spinning solution was prepared for electrospinning. The solution was dried at 6℃ and 10Pa for 24 hours to obtain polyamic acid nanofiber film.

[0034] (6) 2,4-Diamino-5-o-ethoxyaniline pyrimidine, N,N-diethylaniline and anhydrous ethanol were mixed evenly in a mass ratio of 1:4:4 to prepare an antibacterial treatment solution; the polyamic acid nanofiber membrane was immersed in the antibacterial treatment solution and kept still at 30°C for 10 min. It was then taken out and placed in a muffle furnace and kept at 100°C for 30 min, 200°C for 60 min and 300°C for 30 min in sequence. After cooling to room temperature, it was taken out to obtain a fiber-based air filter membrane.

[0035] Example 2

[0036] (1) 5-bromouracil, o-ethoxyaniline and ethylene glycol are mixed evenly in a mass ratio of 1:4.4:10. The mixture is stirred and refluxed at 195°C and 1000r / min for 3 hours under a nitrogen atmosphere. After standing for 23 hours, it is poured into pure water at 10 times the mass of ethylene glycol. The precipitate is precipitated and filtered. The precipitate is washed 4 times each with pure water and acetone and dried at 75°C for 7 hours to obtain 5-o-ethoxyaniline pyrimidine.

[0037] (2) Mix 5-o-ethoxyaniline and N,N-diethylaniline at a mass ratio of 1:1.1. Add phosphorus oxychloride at a mass of 11 times that of 5-o-ethoxyaniline uracil at 0.75 mL / s while stirring at 1000 r / min. Reflux at 105 °C for 3 h. Pour into pure water at 1 °C and stir at 1000 r / min. Control the pH at 5.5 with sodium carbonate. Extract repeatedly with diethyl ether until there is no solid in the aqueous phase. Combine the ether extracts from multiple extractions and dry at 43 °C for 5 h to obtain 2,4-dichloro-5-o-ethoxyaniline pyrimidine.

[0038] (3) 2,4-dichloro-5-o-ethoxyaniline pyrimidine and a 13.5% (w / w) ammonia ethanol solution were mixed evenly at a mass ratio of 1:25, placed in a high-pressure reactor and sealed. The mixture was reacted at 145°C for 18 h, cooled to room temperature, unsealed and dried at 65°C and 75 Pa for 7 h to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine.

[0039] (4) Mix p-phenylenediamine and N,N-dimethylacetamide at a mass ratio of 1:40, add 3,3',4,4'-biphenyl dianhydride at 3 times the mass of p-phenylenediamine, stir at 1000 r / min for 23 h at room temperature to obtain a polyamic acid solution, then add the polyamic acid solution dropwise to pure water at 0.75 mL / s at 3 times the volume of N,N-dimethylacetamide, let stand, filter and wash 4 times with pure water, freeze dry at -7℃ for 23 h, and grind to a particle size of less than 0.1 mm to obtain polyamic acid powder;

[0040] (5) Polyamic acid powder and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:13. After stirring at low temperature for 4 hours, a spinning solution was prepared for electrospinning. The solution was dried at 8℃ and 15Pa for 23 hours to obtain polyamic acid nanofiber film.

[0041] (6) 2,4-Diamino-5-o-ethoxyaniline pyrimidine, N,N-diethylaniline and anhydrous ethanol were mixed evenly in a mass ratio of 1:5:5 to prepare an antibacterial treatment solution; the polyamic acid nanofiber membrane was immersed in the antibacterial treatment solution and left to stand at 35°C for 9 min. It was then taken out and placed in a muffle furnace and kept at 110°C for 25 min, 225°C for 55 min and 325°C for 15 min in sequence. After cooling to room temperature, it was taken out to obtain a fiber-based air filter membrane.

[0042] Example 3

[0043] (1) 5-bromouracil, o-ethoxyaniline and ethylene glycol are mixed evenly in a mass ratio of 1:4.6:15. The mixture is stirred and refluxed at 200°C and 1200r / min for 2 hours under a nitrogen atmosphere. After standing for 24 hours, it is poured into pure water at 10 times the mass of ethylene glycol. The precipitate is precipitated and filtered. The precipitate is washed 5 times each with pure water and acetone. It is then dried at 90°C for 6 hours to obtain 5-o-ethoxyaniline pyrimidine.

[0044] (2) Mix 5-o-ethoxyaniline pyrimidine and N,N-diethylaniline at a mass ratio of 1:1.3. Add phosphorus oxychloride at a rate of 1.0 mL / s with stirring at 1200 r / min. Reflux at 110 °C for 2 h. Pour into pure water at 2 °C and stir at 1200 r / min. Control the pH at 6 with sodium carbonate. Extract repeatedly with diethyl ether until there is no solid in the aqueous phase. Combine the ether extracts from multiple extractions and dry at 50 °C for 4 h to obtain 2,4-dichloro-5-o-ethoxyaniline pyrimidine.

[0045] (3) 2,4-dichloro-5-o-ethoxyaniline pyrimidine and a 15% (w / w) ammonia-ethanol solution were mixed evenly at a mass ratio of 1:30, placed in a high-pressure reactor and sealed. The mixture was reacted at 150°C for 16 h, cooled to room temperature, opened and dried at 70°C and 100 Pa for 6 h to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine.

[0046] (4) Mix p-phenylenediamine and N,N-dimethylacetamide at a mass ratio of 1:60, add 3,3',4,4'-biphenyl dianhydride at 4 times the mass of p-phenylenediamine, stir at 1200 r / min for 22 h at room temperature to obtain a polyamic acid solution, then add the polyamic acid solution dropwise to pure water at 1.0 mL / s at 3 times the volume of N,N-dimethylacetamide, let stand, filter and wash 5 times with pure water, freeze dry at -5℃ for 22 h, and grind to a particle size of less than 0.1 mm to obtain polyamic acid powder;

[0047] (5) Mix polyamic acid powder and N,N-dimethylformamide at a mass ratio of 1:15, stir at low temperature for 4 hours, prepare a spinning solution for electrospinning, and dry at 10℃ and 20Pa for 20 hours to obtain polyamic acid nanofiber film.

[0048] (6) 2,4-Diamino-5-o-ethoxyaniline pyrimidine, N,N-diethylaniline and anhydrous ethanol were mixed evenly in a mass ratio of 1:6:6 to prepare an antibacterial treatment solution; the polyamic acid nanofiber membrane was immersed in the antibacterial treatment solution and left to stand at 40°C for 8 min. It was then taken out and placed in a muffle furnace and kept at 120°C for 20 min, 250°C for 50 min, and 350°C for 20 min in sequence. After cooling to room temperature, it was taken out to obtain a fiber-based air filter membrane.

[0049] Comparative Example 1

[0050] (1) Mix p-phenylenediamine and N,N-dimethylacetamide at a mass ratio of 1:40, add 3,3',4,4'-biphenyl dianhydride at 3 times the mass of p-phenylenediamine, stir at 1000 r / min for 23 h at room temperature to obtain a polyamic acid solution, then add the polyamic acid solution dropwise to pure water at 0.75 mL / s at 3 times the volume of N,N-dimethylacetamide, let stand, filter and wash 4 times with pure water, freeze dry at -7℃ for 23 h, and grind to a particle size of less than 0.1 mm to obtain polyamic acid powder;

[0051] (2) Polyamic acid powder and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:13. After stirring at low temperature for 4 hours, a spinning solution was prepared for electrospinning. The solution was dried at 8℃ and 15Pa for 23 hours to obtain polyamic acid nanofiber film.

[0052] (3) The polyamic acid nanofiber film was placed in a muffle furnace and kept at 110°C for 25 min, 225°C for 55 min, and 325°C for 15 min in sequence. After cooling to room temperature, it was taken out to obtain a fiber-based air filter film.

[0053] Comparative Example 2

[0054] (1) 5-bromouracil, o-ethoxyaniline and ethylene glycol are mixed evenly in a mass ratio of 1:4.4:10. The mixture is stirred and refluxed at 195°C and 1000r / min for 3 hours under a nitrogen atmosphere. After standing for 23 hours, it is poured into pure water at 10 times the mass of ethylene glycol. The precipitate is precipitated and filtered. The precipitate is washed 4 times each with pure water and acetone and dried at 75°C for 7 hours to obtain 5-o-ethoxyaniline pyrimidine.

[0055] (2) Mix 5-o-ethoxyaniline and N,N-diethylaniline at a mass ratio of 1:1.1. Add phosphorus oxychloride at a mass of 11 times that of 5-o-ethoxyaniline uracil at 0.75 mL / s while stirring at 1000 r / min. Reflux at 105 °C for 3 h. Pour into pure water at 1 °C and stir at 1000 r / min. Control the pH at 5.5 with sodium carbonate. Extract repeatedly with diethyl ether until there is no solid in the aqueous phase. Combine the ether extracts from multiple extractions and dry at 43 °C for 5 h to obtain 2,4-dichloro-5-o-ethoxyaniline pyrimidine.

[0056] (3) 2,4-dichloro-5-o-ethoxyaniline pyrimidine and a 13.5% (w / w) ammonia ethanol solution were mixed evenly at a mass ratio of 1:25, placed in a high-pressure reactor and sealed. The mixture was reacted at 145°C for 18 h, cooled to room temperature, unsealed and dried at 65°C and 75 Pa for 7 h to obtain 2,4-diamino-5-o-ethoxyaniline pyrimidine.

[0057] (4) Mix p-phenylenediamine and N,N-dimethylacetamide at a mass ratio of 1:40, add 3,3',4,4'-biphenyl dianhydride at 3 times the mass of p-phenylenediamine, stir at 1000 r / min for 23 h at room temperature to obtain a polyamic acid solution, then add the polyamic acid solution dropwise to pure water at 0.75 mL / s at 3 times the volume of N,N-dimethylacetamide, let stand, filter and wash 4 times with pure water, freeze dry at -7℃ for 23 h, and grind to a particle size of less than 0.1 mm to obtain polyamic acid powder;

[0058] (5) Polyamic acid powder and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:13. After stirring at low temperature for 4 hours, a spinning solution was prepared for electrospinning. The solution was dried at 8℃ and 15Pa for 23 hours to obtain polyamic acid nanofiber film.

[0059] (6) 2,4-Diamino-5-o-ethoxyaniline pyrimidine, N,N-diethylaniline and anhydrous ethanol were mixed evenly in a mass ratio of 1:5:5 to prepare an antibacterial treatment solution; the polyamic acid nanofiber membrane was immersed in the antibacterial treatment solution, stood at 35°C for 9 min, and dried at 8°C and 15 Pa for 23 h to obtain a fiber-based air filter membrane.

[0060] Comparative Example 3

[0061] (1) Mix p-phenylenediamine and N,N-dimethylacetamide at a mass ratio of 1:40, add 3,3',4,4'-biphenyl dianhydride at 3 times the mass of p-phenylenediamine, stir at 1000 r / min for 23 h at room temperature to obtain a polyamic acid solution, then add the polyamic acid solution dropwise to pure water at 0.75 mL / s at 3 times the volume of N,N-dimethylacetamide, let stand, filter and wash 4 times with pure water, freeze dry at -7℃ for 23 h, and grind to a particle size of less than 0.1 mm to obtain polyamic acid powder;

[0062] (2) Polyamic acid powder and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:13. After stirring at low temperature for 4 hours, a spinning solution was prepared for electrospinning. The solution was dried at 8℃ and 15Pa for 23 hours to obtain a fiber-based air filter membrane.

[0063] Example of effect

[0064] Table 1 below shows the analysis results of the antibacterial properties and tensile strength of the fiber-based air filter materials of Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0065] Table 1

[0066]

[0067] Experimental data comparison reveals that the fiber-based air filter material prepared by this invention has good antibacterial properties and tensile strength.

[0068] A comparison of the experimental data from Examples 1, 2, and 3 with Comparative Example 1 reveals that Examples 1, 2, and 3 exhibit higher antibacterial rates and tensile strengths compared to Comparative Example 1. This indicates that treatment of polyamic acid nanofiber films with 2,4-diamino-5-o-ethoxyaniline pyrimidine allows the aniline pyrimidine structure to inhibit the production of pathogenic enzymes, thereby preventing bacterial infection and killing bacteria, thus improving antibacterial properties. Furthermore, the amino groups on 2,4-diamino-5-o-ethoxyaniline pyrimidine can dehydrate and amide the carboxyl groups on the fiber membrane. The tensile strength is improved by cross-linking at the fiber contact surface through electrostatic adsorption or chemical reaction. A comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 2 shows that Examples 1, 2, and 3 have higher tensile strength than Comparative Example 2. This indicates that heating and dehydration during the preparation of the fiber-based air filter membrane can dehydrate and cyclize unreacted polyamic acid into polyimide. At the same time, the increase in temperature further enhances the cross-linking effect of 2,4-diamino-5-o-ethoxyaniline pyrimidine, thereby improving the tensile strength.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fibrous-based air filtration material, characterized in that, The fiber-based air filtration material is prepared by treating polyamide acid nanofiber film with an antibacterial treatment solution and then heating and dehydrating; The polyamide acid nanofiber film is prepared by electrospinning after polyamide acid powder is configured into a spinning solution; The polyamide acid powder is prepared by reacting p-phenylenediamine and 3,3',4,4'-biphenyl dianhydride; The antibacterial treatment solution is prepared by reacting 2,4-dichloro-5-o-ethoxy aniline pyrimidine and 10-15% ammonia alcohol solution by mass fraction to obtain 2,4-diamino-5-o-ethoxy aniline pyrimidine, and then mixing 2,4-diamino-5-o-ethoxy aniline pyrimidine, N,N-diethyl aniline and anhydrous ethanol uniformly; The 2,4-dichloro-5-o-ethoxy aniline pyrimidine is prepared by reacting 5-o-ethoxy aniline pyrimidine and phosphorus oxychloride; The 5-o-ethoxy aniline pyrimidine is prepared by 5-bromouracil and o-ethoxy aniline.

2. A process for the production of a fibrous air filtration material, characterized in that, The preparation method of the fiber-based air filtration material comprises the following preparation steps: (1) 5-bromouracil, o-ethoxy aniline and ethylene glycol are uniformly mixed in a mass ratio of 1:(4.2-4.6):(5-15), stirred at 800-1200 r / min under nitrogen atmosphere at 190-200 ℃ for 2-4 h, placed for 22-24 h, poured into pure water with the mass of ethylene glycol being 10 times, precipitated and filtered, washed with pure water and acetone for 3-5 times, and dried at 60-90 ℃ for 6-8 h to prepare 5-o-ethoxy aniline pyrimidine; (2) 5-o-ethoxy aniline pyrimidine and N,N-diethyl aniline are uniformly mixed in a mass ratio of 1:(0.9-1.3), 5-o-ethoxy aniline pyrimidine is added dropwise at a rate of 0.5-1.0 mL / s under stirring at 800-1200 r / min, 2,4-dichloro-5-o-ethoxy aniline pyrimidine is prepared by refluxing at 100-110 ℃ for 2-4 h, poured into pure water at 0-2 ℃ under stirring at 800-1200 r / min, the pH is controlled at 5-6 by sodium carbonate, the ether liquid is repeatedly extracted until there is no solid in the water phase, the ether liquid is combined and dried at 35-50 ℃ for 4-6 h; (3) 2,4-dichloro-5-o-ethoxy aniline pyrimidine and 10-15% ammonia alcohol solution by mass fraction are uniformly mixed in a mass ratio of 1:(20-30), sealed in an autoclave, reacted at 140-150 ℃ for 16-20 h, cooled to room temperature, opened and dried at 60-70 ℃ under 50-100 Pa for 6-8 h to prepare 2,4-diamino-5-o-ethoxy aniline pyrimidine; (4) mixing p-phenylenediamine and N,N-dimethylacetamide uniformly according to a mass ratio of 1:(20-60), adding 3,3',4,4'-biphenyl dianhydride in an amount of 2-4 times the mass of p-phenylenediamine, stirring at a speed of 800-1200 r / min at room temperature for 22-24 h to obtain a polyamic acid solution, then dropping the polyamic acid solution into pure water in an amount of 3 times the volume of N,N-dimethylacetamide at a rate of 0.5-1.0 mL / s, filtering after standing and washing 3-5 times with pure water, freeze-drying at-9--5℃ for 22-24 h, and grinding to a particle size of less than 0.1 mm to obtain a polyamic acid powder; (5) mixing the polyamic acid powder and N,N-dimethylformamide uniformly according to a mass ratio of 1:(10-15), stirring at low temperature for 3-4 h, then preparing a spinning solution for electrospinning, drying at 6-10℃ and 10-20 Pa for 20-24 h to obtain a polyamic acid nanofiber film; (6) mixing 2,4-diamino-5-o-ethoxyanilino pyrimidine, N,N-diethylaniline and anhydrous ethanol uniformly according to a mass ratio of 1:(4-6):(4-6) to prepare an antibacterial treatment solution; immersing the polyamic acid nanofiber film in the antibacterial treatment solution, standing at 30-40℃ for 8-10 min, taking out and placing in a muffle furnace, and sequentially keeping at 100-120℃ for 20-30 min, at 200-250℃ for 50-60 min, and at 300-350℃ for 20-30 min, taking out after cooling to room temperature to obtain a fiber-based air filtration film.

3. The method of making a fibrous-based air filtration material according to claim 2, wherein, The process parameters of electrospinning in step (5) are as follows: voltage 16-20 kV, flow rate 0.6-0.8 mL / h, ambient humidity 10-30%, and receiving distance 15-16 cm.

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