Electrospinning process control method for high-efficiency nanofiber air filters

Abstract

This invention provides a method for controlling the electrospinning process of a high-efficiency nanofiber air filter. Based on air filtration theory, the electrospinning preparation process is mathematically modeled and optimized. According to the theoretical relationship between spinning voltage and spinning time, target particle removal efficiency, and pressure drop, a semi-empirical mathematical prediction model is established through data fitting analysis. This allows for the manufacture of a nanofiber air filter with a minimum pressure drop, i.e., minimum filtration resistance, while achieving the target particulate matter filtration efficiency. This reduces the energy consumption of the nanofiber filter in practical use, achieving high efficiency, low resistance, energy saving, and cost reduction.

Description

Technical Field

[0001] This invention belongs to the field of nanofiber air filter manufacturing technology in the field of environmental protection technology, specifically relating to a method for controlling the electrospinning process of a high-efficiency nanofiber air filter. Background Technology

[0002] Air filters are often used in environmental protection technologies to purify the air. Commonly used filter materials for air filters include natural fibers, synthetic fibers, glass fibers, ceramics, and minerals. These materials can be further classified according to their processing technology into: 1) woven fabrics, knitted fabrics, woven meshes, and fiber bundles; 2) spunbond and meltblown nonwoven fabrics; 3) porous ceramic materials; 4) organic and inorganic membrane materials; and 5) electrospun materials.

[0003] Traditional fiber filter materials have straight pores with a porosity of only 30% to 40%. Furthermore, the traditional fiber weaving filter material manufacturing process is long and the production efficiency is low. It mainly filters through the pores between warp and weft yarns, resulting in relatively high resistance from the filter material itself. Woven filter materials can only effectively block smaller particulate matter after a dust layer has formed. If the dust layer is damaged before it forms, during filter cleaning, or for other reasons, the filtration efficiency of traditional fiber filter materials will decrease significantly.

[0004] Electrospun materials possess characteristics such as small fiber diameter, good uniformity, small pore size, high porosity and high flux, large specific surface area, strong adsorption capacity, renewability, energy saving and environmental protection, low cost, variety, and controllable processes. They not only meet lightweight requirements—weighing only 10–20 mg / m²—but their optical effects are comparable to glass, with a light transmittance of up to 95%. Simultaneously, they exhibit excellent air filtration properties, low airflow resistance, and a filtration efficiency of up to 98% for particles with a diameter of 0.2–0.3 μm. Electrospinning technology can produce ultralight fabrics with superior filtration and optical properties compared to other similar materials, significantly improving air purification effects. Electrospinning technology is the preferred method for large-scale industrial production of nanofibers. Since its inception, electrospun nanofiber filter materials have been widely used in many demanding filtration fields, particularly showing broad application prospects in electronics, biology, medicine, and protective applications.

[0005] Overview of existing technologies:

[0006] Electrospinning equipment typically employs a needle-type electrospinning device, mainly consisting of three parts: a high-voltage power supply, a spinneret (needle), and a receiving device. The technical principle primarily utilizes a high-voltage electrostatic field to excite the polymer, generating a large amount of electrostatic charge on its surface. Under the influence of electrostatic repulsion, polymer droplets form a jet that is ejected through the needle, accelerating the stretching and refining of the polymer. Finally, it solidifies and cools to form nanoscale ultrafine fibers, which are then composited onto a substrate. Therefore, the relationship between electrospinning voltage and time parameters significantly affects the particle removal efficiency and pressure drop (filtration resistance) of air filters.

[0007] To manufacture electrospun nanofiber air filters that meet the target particulate matter filtration requirements and filtration efficiency, and have relatively low pressure drop (low filtration resistance), we experimented with combining different electrospinning voltage and spinning time parameters to prepare nanofiber air filters. After manufacturing, we measured the filtration performance of these nanofiber air filters, first screening out products that could meet the target filtration efficiency, and then selecting the nanofiber air filter with the lowest pressure drop.

[0008] The shortcomings of existing technology:

[0009] 1. In order to manufacture an air filter with low pressure drop (low filtration resistance) and target particulate filtration efficiency, it is necessary to randomly prepare and measure a large number of nanofiber air filters and select the filters that can meet the usage target. This method is not only time-consuming and labor-intensive but also uneconomical, so its production practicality is low.

[0010] 2. Even if a large number of different nanofiber air purifiers are manufactured and tested according to the above method, and a filter that can achieve the target filtration effect is selected, it is impossible to calculate the required parameters and predict the effect of the prepared nanofiber filter before repeating the preparation process because no empirical formula has been summarized.

[0011] 3. When the target filtration needs change, it is impossible to calculate the required electrospinning process parameters based on the desired filtration effect before the preparation process, which means that a personalized customization process cannot be achieved. Summary of the Invention

[0012] To address the aforementioned problems in the existing technology, the present invention aims to provide a method for controlling the electrospinning process of a high-efficiency nanofiber air filter. The manufactured nanofiber air filter can achieve a minimum filtration resistance, i.e., the lowest pressure drop, thereby improving the filtration efficiency of the nanofiber air filter; it consumes less time, saves energy, reduces costs, and is highly efficient.

[0013] The technical solution adopted in this invention is as follows:

[0014] A method for controlling the electrospinning process of a high-efficiency nanofiber air filter includes the following steps:

[0015] first step:

[0016] Select the powder raw materials according to the usage requirements;

[0017] The powdered raw material is dissolved in a solvent and magnetically stirred to prepare an electrospinning solution.

[0018] A syringe filled with electrospinning solution is installed on an electrospinning machine, and the syringe is equipped with a tubing and a micro needle.

[0019] Under controlled temperature and humidity conditions, an injection pump is used to drive the syringe, and the electrospinning solution is continuously injected through a micro-needle.

[0020] Step Two:

[0021] When a high-voltage power supply is connected to the electrospinning machine and the electrospinning machine is started, the electrospinning solution continuously injected by the syringe is drawn into nanofibers under high voltage conditions. The nanofibers are then collected through a substrate to form a nanofiber membrane, which constitutes a nanofiber air filter sample.

[0022] Step 3:

[0023] Nanofiber air filter samples were prepared using an electrospinning machine under M different electrospinning voltages and N different spinning times. The M electrospinning voltages are labeled as V. m N spinning time markers are t n M×N batches of nanofiber air filter samples were obtained;

[0024] Step 4: Measure the particulate filtration efficiency η(V) of M×N sample batches of nanofiber air filter specimens. m , t n ) and pressure drop ΔP(V m , t n ), and obtain the values ​​of particulate filtration efficiency η and pressure drop ΔP corresponding to each other in M×N groups;

[0025] Step 5:

[0026] Based on the particulate filtration efficiency η and pressure drop ΔP values ​​of the above M×N group, plot the η-ΔP relationship curve; under the same η value, select the curve with the smallest ΔP value, whose corresponding V m That is, the optimal voltage V opt ;

[0027] Step 6:

[0028] Filter out η(V) opt, t n ) and t n The numerical values ​​were then fitted to a polynomial function using mathematical software:

[0029] η = f(t) = 1 - exp(a·t + b)

[0030] Where: a and b are constants, η is the particulate matter filtration efficiency, and t is the electrospinning time;

[0031] Step 7:

[0032] Set the target particulate filtration efficiency η tar The corresponding electrospinning time t can be calculated using the formula η = f(t). opt ;

[0033] Step 8:

[0034] At the electrospinning voltage V opt and spinning time t opt Nanofiber filters were prepared under specific conditions to obtain high-efficiency nanofiber air filters that achieve the target particulate matter filtration efficiency while minimizing pressure drop.

[0035] The powder raw material selected in the first step is PAN, PVDF, PS or PVP, which are high molecular polymer materials.

[0036] In the first step, the micro-needles of the syringe of the electrospinning machine are all set in a vertical direction, and the micro-needles are set at the center of the lower end of the syringe.

[0037] In the second step, the injection pump drives a syringe connected to a micro-needle. The electrospinning solution sprayed out forms a Taylor cone under the action of high voltage and is continuously injected into the electrospinned fibers along a dynamic spiral trajectory.

[0038] In the second step, nanofibers are collected by a copper mesh substrate covering a cylindrical roller arranged laterally along the horizontal direction to form a nanofiber air filter.

[0039] The substrate is constructed by collecting and arranging nanofibers at random angles to form a nanofiber air filter.

[0040] In the third step, M is any integer greater than or equal to 5, N is any integer greater than or equal to 3; m is an integer greater than or equal to 1 and less than or equal to M, and n is an integer greater than or equal to 1 and less than or equal to N.

[0041] In the fourth step, a particulate matter counter is used to measure the particulate matter filtration efficiency, and a differential pressure gauge is used to measure the pressure drop.

[0042] In the fifth step, the particulate filtration efficiency η and pressure drop ΔP values ​​of the M×N group are imported into an Excel spreadsheet, and the η-ΔP relationship curve is plotted in the Excel spreadsheet.

[0043] In the sixth step, η(V) opt , t n ) and t n The numerical values ​​are imported into the MATLAB mathematical software and fitted into a polynomial function using the curve fitter function.

[0044] The beneficial effects of this invention are as follows:

[0045] A method for controlling the electrospinning process of a high-efficiency nanofiber air filter is proposed, based on air filtration theory, through mathematical modeling and optimization. Specifically, M×N sample batches of nanofiber air filter physical models are prepared under arbitrary initial electrospinning voltage and initial spinning time conditions. The particulate matter removal efficiency and pressure drop of the M×N sample batches of nanofiber air filters are measured using physical models. An η-ΔP relationship curve is plotted in an Excel spreadsheet, and the curve with the smallest ΔP value is selected as the corresponding V. m That is, the optimal voltage V opt Then, the electrospinning time t that meets the target filtration efficiency requirement is calculated using MATLAB mathematical software. opt ; at the electrospinning voltage V opt and spinning time t opt Nanofiber filters were prepared under specific conditions to obtain high-efficiency nanofiber air filters that achieve the target particulate filtration efficiency while minimizing pressure drop.

[0046] Through theoretical model analysis, the target particulate matter purification efficiency is achieved, and the manufactured nanofiber air filter has the lowest pressure drop, that is, the filtration resistance can reach the minimum value, thereby improving the filtration efficiency of the nanofiber air filter; it consumes less time, saves energy, reduces costs, and is highly efficient. Attached Figure Description

[0047] Figure 1 This is a schematic diagram illustrating the principle of the electrospinning process control method for the high-efficiency nanofiber air filter according to Embodiment 1 of the present invention;

[0048] Figure 2 This is a schematic diagram of the electrospinning machine structure used in the electrospinning process control method of the high-efficiency nanofiber air filter of Embodiment 1 of the present invention.

[0049] Figures 3-4 This is a 1:1 scale schematic diagram of the preparation of a nanofiber air filter by collecting data on a copper mesh substrate in the electrospinning process control method of the high-efficiency nanofiber air filter according to Embodiment 1 of the present invention.

[0050] Figure 5 This is a magnified schematic diagram of a partial structure of a nanofiber air filter prepared in the electrospinning process control method of the high-efficiency nanofiber air filter of Embodiment 1 of the present invention, with a magnification of 500:1.

[0051] Figure 6 yes Figure 5 A further enlarged schematic diagram of the local structure;

[0052] Figures 7-10 This is a schematic diagram of the operation interface of each step in the fitting process of the electrospinning process control method of the high-efficiency nanofiber air filter of Embodiment 1 of the present invention.

[0053] Figure 11 This is a schematic diagram showing the import of 20 sets of corresponding η and ΔP values ​​into an Excel spreadsheet in the electrospinning process control method of the high-efficiency nanofiber air filter according to Embodiment 1 of the present invention.

[0054] Figure 12 This is a schematic diagram of the η-ΔP relationship curve plotted in an Excel spreadsheet for the electrospinning process control method of the high-efficiency nanofiber air filter according to Embodiment 1 of the present invention.

[0055] Figure 13 This is a schematic diagram of the fitting results of the function relationship established by the curve fitter in MATLAB for the electrospinning process control method of the high-efficiency nanofiber air filter of Embodiment 1 of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] like Figures 1-13 As shown, this invention provides a method for controlling the electrospinning process of a high-efficiency nanofiber air filter. The overall planning scheme includes the following steps:

[0058] first step:

[0059] Select the powder raw materials according to the usage requirements;

[0060] The powdered raw material was dissolved in a specified solvent and magnetically stirred to prepare electrospinning solution 1;

[0061] A syringe 2 filled with electrospinning solution 1 is installed on an electrospinning machine, and a tubing and a micro needle 7 are provided on the syringe 2.

[0062] Under controlled temperature and humidity, an injection pump is used to drive the syringe 2, and the electrospinning solution is continuously injected through the micro needle 7.

[0063] The tubing and injection pump are not shown in detail in the figure; the conventional structure of an electrospinning machine in the existing technology can be used.

[0064] Step Two:

[0065] A high-voltage power supply 3 is connected in the electrospinning machine, the electrospinning machine is started, and the electrospinning solution continuously injected by the syringe is drawn into nanofibers 5 under high voltage conditions. The nanofibers 5 are collected through the substrate 4 to form a nanofiber membrane 8, which constitutes a nanofiber air filter sample.

[0066] The syringe 2 is placed on the electrospinning machine; the electrospinning solution of the specified material will be drawn into nanofibers 5 under the action of high voltage in the electrospinning machine;

[0067] Step 3:

[0068] Nanofiber air filter samples were prepared using an electrospinning machine under M different electrospinning voltages and N different spinning times. The M electrospinning voltages are labeled as V. m N spinning time markers are t n M×N batches of nanofiber air filter samples were obtained;

[0069] Step 4: Measure the particulate filtration efficiency η(V) of M×N sample batches of nanofiber air filter specimens. m , t n ) and pressure drop ΔP(V m , t n ), and obtain the corresponding particulate filtration efficiency η and pressure drop ΔP values ​​for M×N groups;

[0070] The particulate filtration efficiency η is the percentage of airborne particles with a particle size that the nanofiber air filter can filter out.

[0071] The pressure drop ΔP is the air pressure difference between the two sides of the nanofiber air filter;

[0072] Step 5:

[0073] Based on the particulate filtration efficiency η and pressure drop ΔP values ​​of the above M×N group, plot the η-ΔP relationship curve; under the same η value, select the curve with the smallest ΔP value, whose corresponding V m That is, the optimal voltage Vopt ;

[0074] Step 6:

[0075] Filter out η(V) opt , t n ) and t n The numerical values ​​were then fitted to a polynomial function using mathematical software:

[0076] η = f(t) = 1 - exp(a·t + b)

[0077] Where: a and b are constants, η is the particulate matter filtration efficiency, and t is the electrospinning time;

[0078] Step 7:

[0079] Set target filtration efficiency η tar The corresponding electrospinning time t can be calculated using the formula η = f(t). opt ;

[0080] Step 8:

[0081] At the electrospinning voltage V opt and spinning time t opt Nanofiber filters were prepared under specific conditions to obtain high-efficiency nanofiber air filters that achieve the target particulate matter filtration efficiency while minimizing pressure drop.

[0082] Nanofiber air filters are constructed by collecting nanofibers on a substrate covering a roller, i.e., by using a roller to collect nanofiber membranes. In subsequent actual production of nanofiber air filters, the nanofiber membranes can be cut to the appropriate size according to the usage requirements.

[0083] Furthermore, the powder raw material selected in the first step is a high molecular polymer material, specifically PAN, PVDF, PS or PVP.

[0084] Furthermore, in the first step, both the syringe 2 and the micro needle 7 of the electrospinning machine are arranged in a vertical direction, with the micro needle 7 located at the center of the lower end of the syringe 2; the syringe 2 can adopt the conventional technical structure of electrospinning machines in the prior art.

[0085] For example, an injection port can be provided at the top of the syringe to fill and deliver the electrostatic solution into the syringe cavity. Alternatively, an injection pump can extend from the top of the syringe into the syringe cavity, pushing the electrostatic solution downwards along the syringe cavity for continuous injection from the microneedle.

[0086] Furthermore, in the second step, the injection pump drives a syringe connected to a micro-needle, and the electrospinning solution sprayed out forms a Taylor cone under the action of high voltage, and continuously injects electrospinned nanofibers 5 along a dynamic spiral trajectory.

[0087] Specifically, it can be a conventional technical structure in the existing technology that can form a Taylor cone and achieve a dynamic spiral trajectory by using a high voltage to spray the electrospinning solution.

[0088] Furthermore, in the second step, the substrate 4 is a copper mesh substrate; the copper mesh substrate, which is covered by a cylindrical roller 6 arranged horizontally along the horizontal direction, collects nanofibers to form a nanofiber air filter. The cylindrical roller 6 drives the substrate 4 to rotate around the horizontal axis, thereby continuously collecting nanofibers 5 to form a nanofiber membrane 8. When making nanofiber air filter samples and finished products, the nanofiber membranes of the appropriate area size can be cut according to the usage requirements.

[0089] Furthermore, the substrate collects and arranges nanofibers at random angles to form a nanofiber air filter. That is, when the substrate collects nanofibers, the nanofibers are arranged and distributed on the substrate in an irregular state without order, so that the nanofibers in the nanofiber air filter are distributed in a multi-angled state.

[0090] Furthermore, in the third step, M is any integer greater than or equal to 5, N is any integer greater than or equal to 3; m is an integer greater than or equal to 1 and less than or equal to M, and n is an integer greater than or equal to 1 and less than or equal to N.

[0091] That is, the number of data model samples should be no less than 5×3 to ensure that the calculation results are accurate and reliable.

[0092] Furthermore, in the fourth step, a particulate matter counter is used to measure the particulate matter filtration efficiency, and a differential pressure gauge is used to measure the pressure drop. The operation is convenient and the measurement results are accurate.

[0093] Furthermore, in the fifth step, the particulate filtration efficiency η and pressure drop ΔP values ​​of the M×N groups are imported into an Excel spreadsheet, and the η-ΔP relationship curve is plotted in the Excel spreadsheet.

[0094] Furthermore, in the sixth step, η(V) opt , t n ) and t n The numerical values ​​are imported into the MATLAB mathematical software and fitted into a polynomial function using the curve fitter function.

[0095] MATLAB, or Matrix Labs, is a mathematical software.

[0096] MATLAB can perform matrix operations, plot functions and data, implement algorithms, create user interfaces, and connect programs in other programming languages. It largely breaks away from the editing mode of traditional non-interactive programming languages ​​(such as C and Fortran) and represents the advanced level of international scientific computing software today.

[0097] MATLAB, along with Mathematica and Maple, is considered one of the three major mathematical software programs. It is unparalleled in numerical computation among mathematical and scientific application software. MATLAB can perform matrix operations, plot functions and data, implement algorithms, create user interfaces, and connect programs in other programming languages. It is primarily used in fields such as engineering calculations, control design, signal processing and communications, image processing, signal detection, and financial modeling and analysis.

[0098] The electrospinning process control method for high-efficiency nanofiber air filters of the present invention is based on air filtration theory, and involves mathematical modeling and optimization. Specifically, M×N sample batches of nanofiber air filter physical models are prepared under arbitrary initial electrospinning voltage and initial spinning time conditions. The particulate matter removal efficiency and pressure drop of the M×N sample batches of nanofiber air filters are measured based on the physical models. An η-ΔP relationship curve is plotted using an Excel spreadsheet, and the curve with the smallest ΔP value is selected as the corresponding V. m That is, the optimal voltage V opt Then, the electrospinning time t that meets the target filtration efficiency requirement is calculated using Matlab mathematical software. opt ; at the electrospinning voltage V opt and spinning time t opt Nanofiber filters were prepared under specific conditions to obtain high-efficiency nanofiber air filters that achieve the target particulate matter filtration efficiency while minimizing pressure drop.

[0099] Through theoretical model analysis, the target particulate matter purification efficiency is achieved, and the manufactured nanofiber air filter has the lowest pressure drop, that is, the filtration resistance can reach the minimum value, thereby improving the filtration efficiency of the nanofiber air filter; it consumes less time, saves energy, reduces costs, and is highly efficient.

[0100] Example 1:

[0101] In the above process control method, the powder raw material selected in the first step is polyacrylonitrile (PAN), and the specified solvent is dimethylformamide (DMF).

[0102] The specific operating procedure is as follows:

[0103] first step:

[0104] Polyacrylonitrile (PAN) with a molecular weight of 150,000 was selected as the powder raw material, and dimethylformamide (DMF) was selected as the solvent.

[0105] Dissolve 1g of PAN powder in 9g of DMF solvent to prepare a 10wt% PAN / DMF mixed solution. Stir the solution magnetically at room temperature for 10 hours to obtain an electrospinning solution.

[0106] Install a syringe (20 mL) containing the electrospinning solution on the electrospinning machine, and equip it with a tubing and a needle;

[0107] Under controlled temperature and humidity (25±2℃, 50±3%RH), an injection pump was used to drive the syringe through a micro-needle to continuously inject the electrostatic solution at a flow rate of 1mL / h.

[0108] Step Two:

[0109] A high-voltage power supply is connected to an electrospinning machine. Under high-voltage conditions, the continuously injected electrostatic solution is drawn into nanofibers. The nanofibers are then collected by a horizontal roller device that wraps around a copper mesh substrate to form a nanofiber membrane and manufacture a set of sample nanofiber air filters.

[0110] like Figures 3-4 As shown, Figure 3 This is a 1:1 scale schematic diagram of a nanofiber air filter prepared by collecting data on a copper mesh substrate after being unfolded and flattened. Figure 4 This is a schematic diagram of a nanofiber air filter after being folded in half.

[0111] Repeat the above steps, with the electrospinning machine operating at 5 electrospinning voltages V. m and 4 spinning times t n The parameters were sequentially combined to prepare 20 batches of nanofiber air filters; the electrospinning voltage range was 12–20 kV, and the spinning time range was 0.25–2 h.

[0112] Where m is an integer from 1 to 5, and n is an integer from 1 to 4.

[0113] Step 3:

[0114] The particulate filtration efficiency η(V) of 20 sample batches of nanofiber air filters was measured using a particulate counter and a differential pressure gauge. m , t n ) and pressure drop ΔP(V m , t n ), obtaining 20 sets of corresponding η and ΔP values, and listing them as attached. Figure 11 As shown.

[0115] Step 4:

[0116] Import the above 20 sets of corresponding η and ΔP values ​​into Excel, and plot the η-ΔP relationship curve, as shown in Figure 12:

[0117] Under the same η value, the curve that can achieve the minimum ΔP is 14kV, which is the optimal voltage V. opt =14kV.

[0118] Step 5:

[0119] Using η(14kV, t) n ) and t n The numerical values ​​are obtained, the data is imported into MATLAB, and the curve fitter is used to fit the curve and establish a functional relationship, which is in the following functional form:

[0120] η = f(t) = 1 - exp(a·t + b)

[0121] Where: a and b are constants, η is the particulate matter filtration efficiency, and t is the electrospinning time;

[0122] The fitting results are attached. Figure 13 As shown.

[0123] The results show that

[0124] η=f(t)=1-exp(-3.5·t+1.24)

[0125] Step 6:

[0126] Set target efficiency η tar =95%, the corresponding electrospinning time t is calculated using the formula η=f(t). opt for:

[0127]

[0128] That is, the corresponding spinning time should be 1.21 hours.

[0129] Step 7:

[0130] Electrospinning voltage V opt =14kV and spinning time t opt =1.21h to prepare nanofiber filters, which is the target filter that can achieve the target efficiency while minimizing the pressure drop.

[0131] For a given PAN material, following the electrospinning procedure described above, the material powder is dissolved in a specific solvent and magnetically stirred. The prepared solution is then poured into a syringe equipped with a microneedle and continuously injected using a syringe pump. Subsequently, the material solution is drawn into nanofibers under high pressure in an electrospinning machine. The nanofibers are collected using a substrate covering a roller to form a nanofiber membrane, i.e., an air filter, which can be used to remove particulate pollutants from the air.

[0132] In the process of manufacturing nanofibers, the electrospinning voltage and time values ​​of an electrospinning machine have a significant impact on particle removal efficiency and pressure drop effect.

[0133] In the fifth step, η(14kV, t) is used. n ) and t n The specific fitting process for importing numerical values ​​into MATLAB, using the curve fitter, and establishing the functional relationship is as follows:

[0134] Step 1: Open MATLAB and input M×N pairs of η(V) opt , t n ) and t n For example, with values ​​of M=5 and N=4: the user interface is as follows. Figure 7 As shown;

[0135] Step 2: After saving the data, enter the command "cftool" in the command line window to bring up the curve fitter: The interface is as follows. Figure 8 As shown;

[0136] Step 3: Select the fitting data as electrospinning time t n and particulate matter filtration efficiency η(V) opt , t n Parameter values: The operation interface is as follows Figure 9 As shown;

[0137] Step 4: Select the custom equation form as: y = 1 - exp(a*x + b), and obtain the fitting result. The operation interface is as follows. Figure 10 As shown.

[0138] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A method for controlling the electrospinning process of a high-efficiency nanofiber air filter, characterized in that: Includes the following steps: first step: Select the powder raw materials according to the usage requirements; The powdered raw material was dissolved in a solvent and magnetically stirred to prepare an electrospinning solution (1); A syringe (2) filled with electrospinning solution (1) is installed on an electrospinning machine, and a tubing and a micro needle (7) are provided on the syringe (2); Under the premise of controlling temperature and humidity, an injection pump is used to drive the syringe (2) to continuously inject the electrospinning solution through the micro needle (7); Step Two: Connect a high voltage power supply (3) in the electrospinning machine, start the electrospinning machine, and draw the electrospinning solution continuously injected by the syringe (2) into nanofibers (5) under high voltage conditions. Collect the nanofibers (5) through the substrate (4) to form a nanofiber membrane (8) and constitute a nanofiber air filter sample. Step 3: Nanofiber air filter samples were prepared using an electrospinning machine under M different electrospinning voltages and N different spinning times. The M electrospinning voltages are labeled as V. m N spinning time markers are t n M×N batches of nanofiber air filter samples were obtained; Step 4: Measure the particulate filtration efficiency η(V) of M×N sample batches of nanofiber air filter specimens. m ,t n ) and pressure drop ΔP(V m ,t n ), and obtain the values ​​of particulate filtration efficiency η and pressure drop ΔP corresponding to each other in M×N groups; Step 5: Based on the above M×N group particulate matter filtration efficiency η and pressure drop ΔP values, plot the η-ΔP relationship curve; under the same η value, select the curve with the smallest ΔP value, and its corresponding V m That is, the optimal voltage V opt ; Step 6: Filter out η(V) opt ,t n ) and t n The numerical values ​​were then fitted to a polynomial function using mathematical software: η = f(t) = 1 - exp(a·t + b) Where: a and b are constants, η is the particulate matter filtration efficiency, and t is the electrospinning time; Step 7: Set the target particulate filtration efficiency η tar The corresponding electrospinning time t can be calculated using the formula η = f(t). opt ; Step 8: At the electrospinning voltage V opt and spinning time t opt Nanofiber filters were prepared under specific conditions to obtain high-efficiency nanofiber air filters that achieve the target particulate matter filtration efficiency while minimizing pressure drop.

2. The electrospinning process control method for the high-efficiency nanofiber air filter according to claim 1, characterized in that: The powder raw material selected in the first step is PAN, PVDF, PS or PVP, which are high molecular polymer materials.

3. The electrospinning process control method for the high-efficiency nanofiber air filter according to claim 2, characterized in that: In the first step, the syringe (2) and micro needle (7) of the electrospinning machine are arranged in a vertical direction, and the micro needle (7) is located at the center of the lower end of the syringe (2).

4. The electrospinning process control method for the high-efficiency nanofiber air filter according to claim 3, characterized in that: In the second step, the injection pump drives the syringe (2) to spray the electrospinning solution through the micro needle (7) to form a Taylor cone under the action of high voltage, and continuously inject electrospinning fibers along a dynamic spiral trajectory.

5. The method for controlling the electrospinning process of the high-efficiency nanofiber air filter according to claim 4, characterized in that: In the second step, nanofibers (5) are collected by a copper mesh substrate covering a cylindrical roller (6) arranged laterally along the horizontal direction to form a nanofiber air filter.

6. The method for controlling the electrospinning process of the high-efficiency nanofiber air filter according to claim 5, characterized in that: The substrate (4) is constructed by collecting and arranging nanofibers (5) at random angles to form a nanofiber air filter.

7. The method for controlling the electrospinning process of the high-efficiency nanofiber air filter according to claim 6, characterized in that: In the third step, M is any integer greater than or equal to 5, N is any integer greater than or equal to 3; m is an integer greater than or equal to 1 and less than or equal to M, and n is an integer greater than or equal to 1 and less than or equal to N.

8. The method for controlling the electrospinning process of the high-efficiency nanofiber air filter according to claim 7, characterized in that: In the fourth step, a particulate matter counter is used to measure the particulate matter filtration efficiency, and a differential pressure gauge is used to measure the pressure drop.

9. The method for controlling the electrospinning process of the high-efficiency nanofiber air filter according to claim 8, characterized in that: In the fifth step, the particulate filtration efficiency η and pressure drop ΔP values ​​of the M×N group are imported into an Excel spreadsheet, and the η-ΔP relationship curve is plotted in the Excel spreadsheet.

10. The method for controlling the electrospinning process of the high-efficiency nanofiber air filter according to claim 9, characterized in that: In the sixth step, η(V) opt ,t n ) and t n The numerical values ​​are imported into the MATLAB mathematical software and fitted into a polynomial function using the curve fitter function.

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