CN111330355B - Electret nanofiber high-efficiency filter material and preparation method thereof - Google Patents
Electret nanofiber high-efficiency filter material and preparation method thereof Download PDFInfo
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- CN111330355B CN111330355B CN202010130435.3A CN202010130435A CN111330355B CN 111330355 B CN111330355 B CN 111330355B CN 202010130435 A CN202010130435 A CN 202010130435A CN 111330355 B CN111330355 B CN 111330355B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/08—Filter cloth, i.e. woven, knitted or interlaced material
- B01D39/086—Filter cloth, i.e. woven, knitted or interlaced material of inorganic material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/0027—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions
- B01D46/0032—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions using electrostatic forces to remove particles, e.g. electret filters
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/30—Particle separators, e.g. dust precipitators, using loose filtering material
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/0007—Electro-spinning
- D01D5/0015—Electro-spinning characterised by the initial state of the material
- D01D5/003—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/0007—Electro-spinning
- D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
- D01D5/0076—Electro-spinning characterised by the electro-spinning apparatus characterised by the collecting device, e.g. drum, wheel, endless belt, plate or grid
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
- D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
- D01F8/08—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyacrylonitrile as constituent
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
- D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
- D01F8/10—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one other macromolecular compound obtained by reactions only involving carbon-to-carbon unsaturated bonds as constituent
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- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
- D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
- D04H1/728—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by electro-spinning
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
- B01D2239/025—Types of fibres, filaments or particles, self-supporting or supported materials comprising nanofibres
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/04—Additives and treatments of the filtering material
- B01D2239/0407—Additives and treatments of the filtering material comprising particulate additives, e.g. adsorbents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/04—Additives and treatments of the filtering material
- B01D2239/0435—Electret
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
- B01D2239/0604—Arrangement of the fibres in the filtering material
- B01D2239/0631—Electro-spun
Abstract
The invention provides an electret nanofiber high-efficiency filter material and a preparation method thereof, belongs to the technical field of new materials, and solves the technical problem that the electret performance of an electret nanofiber filter material in the prior art is unstable, so that the filtering efficiency of fine particles in air is low. The filter material is prepared from spinning solution through electrostatic spinning, wherein the spinning solution comprises the following components in parts by weight: 0-30 parts of a polymer; 1-30 parts of linear polarizable polymer; 40-99 parts of solvent; wherein the linear polarizable polymer is a linear polarizable polymer with an electron donor-pi conjugated system-electron acceptor dipole structural side group. The invention is realized by dissolving the linear polarizable polymer and the polymer togetherPreparation of high PM by electrostatic spinning technology2.5The air filtering material has the advantages of simple preparation method and low production cost, and has the advantages of filtering performance, low resistance pressure drop and ideal performance stability.
Description
Technical Field
The invention relates to the technical field of new materials, in particular to an electret nanofiber high-efficiency filter material and a preparation method thereof.
Background
The fine particles in the air refer to particles with an aerodynamic equivalent diameter of less than or equal to 2.5 microns in the environment, and are also called fine particles, fine particles or PM2.5The particle size is small, the retention time in the atmosphere is long, the conveying distance is long, the large harm can be caused to the health of human bodies, and various diseases such as pneumonia and pulmonary function reduction are easily caused. The air filter material prepared by adopting the melt-blown fiber, the glass fiber and the spun-bonded fiber is an effective measure for protecting fine particles in air.
At present, the traditional air filtering material mainly has the following five filtering mechanisms for fine particles in air: interception effect, sieve effect, inertia effect, brownian effect and electrostatic effect. The filter materials such as melt-blown fibers, glass fibers, spun-bonded fibers and the like have the advantages of large fiber diameter, large pore size, small specific surface, weak inertia effect and Brownian effect and low filtering efficiency on fine particles in air. The electrostatic spinning nanofiber filtering material has the characteristics of small wire diameter, small pore diameter, large specific surface area and the like, has good inertia effect and Brownian effect, and is a development trend of novel filtering materials. In order to further improve the filtering effect of the filtering material, the polymer air filtering material is usually subjected to electret modification to improve the electrostatic effect, thereby further improving the filtering efficiency. For example, when a melt-blown fabric is electret, charges generated by the electret in the method are easily disappeared by the action of an organic solvent such as isopropyl alcohol, and the filtration efficiency is greatly reduced. In addition, the electret effect can be further improved by adding inorganic nano particles such as tourmaline and the like. However, the compatibility between the inorganic particles and the polymer base material is not good, and the mechanical performance of the air filter material is easy to be reduced.
Disclosure of Invention
The invention aims to provide an electret nanofiber high-efficiency filter material and a preparation method thereof, and aims to solve the technical problem that the electret performance of an electret nanofiber filter material in the prior art is unstable, so that the filtering efficiency of fine particles in air is low. In order to achieve the purpose, the invention provides the following technical scheme:
the invention provides an electret nanofiber high-efficiency filter material which is prepared from spinning solution through electrostatic spinning, wherein the spinning solution comprises the following components in parts by weight:
0-30 parts of a polymer;
1-30 parts of linear polarizable polymer; and
40-99 parts of a solvent;
wherein the linear polarizable polymer is a linear polarizable polymer with an electron donor-pi conjugated system-electron acceptor dipole structural side group.
According to a preferred embodiment, the linearly polarizable polymer is a linearly polarizable polyester, a linearly polarizable polystyrene, a linearly polarizable polytriazole, a linearly polarizable polyurethane or a linearly polarizable polymethyl methacrylate. The linear polarizable polymer is selected from linear polarizable polymers with side groups with Donor-pi-Acceptor dipole structural characteristics. The side group of the Donor-Pi-Acceptor dipole structure is characterized in that one end of the group is an electron Donor, the other end of the group is an electron Acceptor, and a Pi conjugated system is connected with the electron Donor and the electron Acceptor.
According to a preferred embodiment, the electron donor of the linear polarizable polymer is selected from an atom or group having a lone pair of electrons containing an oxygen atom, a nitrogen atom or a sulfur atom; the electron acceptor of the linear polarizable polymer is selected from an atom or group having an electron-withdrawing tendency; the pi conjugated system is selected from an azobenzene system, a conjugated hydrocarbon system or a thiophene system.
According to a preferred embodiment, the electron donor is selected from one of hydroxyl, alkoxy, amine or mercapto; the electron acceptor is selected from one of nitro, aldehyde group, cyano, sulfonic group, carboxyl, acyl, trifluoromethyl, trichloromethyl or tribromomethyl; the pi conjugated system is an azobenzene system.
According to a preferred embodiment, the polymer is selected from one or several of the following components: polyacrylonitrile, polyamide, polyurethane, polycarbonate, polyethersulfone, polyphenylene oxide, polyimide, polyvinyl chloride, polyvinylidene fluoride, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polymethyl methacrylate, polyvinyl alcohol, chitosan, or a modified polymer thereof. Preferably, the polymer is selected from one or more of polyacrylonitrile, polyvinylidene fluoride, polyphenylene oxide or polystyrene. After the polymer is dissolved in the selected solvent, the solution viscosity is moderate, electrostatic spinning emission is facilitated, the emission amount of spinning fibers is large, and the fiber strength is high.
According to a preferred embodiment, the solvent is selected from one or several of the following components: water, formic acid, acetic acid, trifluoroacetic acid, ethanol, N-dimethylformamide, N-dimethylacetamide, dichloroethane, chloroform, tetrahydrofuran, acetone, toluene, butanone, or isopropanol. Preferably, the solvent is one or more selected from tetrahydrofuran, N-dimethylformamide or N, N-dimethylacetamide. The solvent of the invention can fully and uniformly dissolve the polymer, has small peculiar smell, small toxicity, no corrosion to machinery and low price, and is beneficial to industrial production.
According to a preferred embodiment, the spinning solution comprises the following components in parts by weight:
1-20 parts of a polymer;
1-25 parts of linear polarizable polymer; and
55-98 parts of a solvent;
wherein the linear polarizable polymer is linear polarizable polyester, linear polarizable polytriazole or linear polarizable polymethacrylate with an electron donor-pi conjugated system-electron acceptor dipole structural side group; the polymer is selected from one or more of polyacrylonitrile, thermoplastic polyimide, polymethyl methacrylate, polyvinylidene fluoride or polystyrene; the solvent is one or two of N, N-dimethylformamide or N, N-dimethylacetamide. The above formula is preferably used to make the spinning solution have more moderate viscosity, have larger spinning amount and obtain better filtration efficiency.
The invention adopts the polymer, the side group linear polarizable polymer with the dipole structure characteristic of the electron donor-pi conjugated system-electron acceptor and the solvent to prepare the spinning solution, and the obtained spinning solution has the effects of uniform mixing and dissolution, moderate viscosity, high conductivity and easy spinning.
The invention also provides a preparation method of the electret nanofiber high-efficiency filter material, which is used for preparing the electret nanofiber high-efficiency filter material and at least comprises the following steps:
s1: preparing spinning solution, and respectively weighing a polymer, a linear polarizable polymer and a solvent according to weight percentage; dissolving the polymer and the linear polarizable polymer in the solvent at 20-80 ℃ under stirring to form a uniform spinning solution;
s2: and (4) carrying out electrostatic spinning to obtain the electret nanofiber high-efficiency filter material, and loading the spinning solution obtained in the step S1 on a support material by using an electrostatic spinning method to prepare the electret nanofiber high-efficiency filter material. Preferably, the support material of the present invention may be a substrate for supporting nanofibers and making an air efficient filter material.
According to a preferred embodiment, the support material is a spunbonded, needle-punched or meltblown nonwoven.
According to a preferred embodiment, the support material is a PP meltblown nonwoven, a PP spunbond nonwoven or a PET meltblown nonwoven.
According to a preferred embodiment, said step S2 further comprises: laying the support material on a receiving electrode plate; and then, applying voltage on the transmitting electrode, grounding the receiving electrode plate or applying reverse voltage, and preparing the electret nanofiber high-efficiency filter material loaded with nanofibers with different shapes by adjusting the voltage difference between positive and negative voltages, the distance between the spinning electrode and the receiving electrode and the temperature and humidity of the environment.
Preferably, the electret nanofiber high-efficiency filter membrane prepared by the preparation method is dried for later use, and other substrate layers can be attached to the electret nanofiber high-efficiency filter membrane to form a multilayer composite structure. Preferably, a composite structure consisting of a substrate layer, an electret nanofiber material and a substrate layer can be further formed.
Based on the technical scheme, the electret nanofiber high-efficiency filter material and the preparation method thereof at least have the following technical effects:
the high-efficiency filter material for the electret nanofibers is characterized in that a linear polarizable polymer solution with a dipole structural side group of an electron donor-pi conjugated system-electron acceptor is dissolved together with a polymer and a solvent to prepare a spinning solution, the spinning solution is prepared into the electret nanofibers by an electrostatic spinning method, dipole groups on the linear polarizable polymer are polarized under the action of a high-voltage electric field in the electrostatic spinning process, and the orientation of dipole moments of the polarized dipole groups is stabilized by a solidified linear polarizable polymer skeleton, so that the polarized dipole groups are not easy to agglomerate due to the electrostatic action, the orientation of the polarized chromophore dipole moments is effectively stabilized, and the prepared nanofibers have good electret effects. Therefore, the interception effect of the electrostatic adsorption force on the fine particles is greatly improved, and the interception efficiency of the filtering material on the fine particles is effectively improved. The electret nanofiber high-efficiency filter material prepared by the method has the characteristics of small fiber diameter, large specific surface, small aperture and high porosity, and has good air permeability. Meanwhile, the linear polarizable polymer with the electron donor-pi conjugated system-electron acceptor dipole structural side group is dissolved together with the polymer, and the high PM is prepared by the electrostatic spinning technology2.5The air filtering material has the advantages of simple preparation method, low production cost and the like, and has the advantages of filtering performance, low resistance pressure drop and ideal performance stability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a surface Scanning Electron Microscope (SEM) image of the electret nanofibers prepared in example 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
Example 1
This example 1 provides an electret nanofiber high-efficiency filter material of a preferred embodiment, which is prepared by supporting a spinning solution on a support material of a PP melt-blown nonwoven fabric by an electrospinning method. The spinning solution in the embodiment comprises the following components in parts by weight:
8 parts of Polyacrylonitrile (PAN);
8 parts of linear polarizable benzoate containing azo side groups; and
84 parts of an N, N-dimethylformamide solvent.
The embodiment 1 also provides a preparation method of the material, which comprises the following specific steps:
(1) weighing 8 parts of Polyacrylonitrile (PAN) and 8 parts of linear polarizable benzoate containing azo side groups, adding the weighed materials into a container containing 84 parts of N, N-dimethylformamide solvent, placing the container in a water bath at 60 ℃, heating and stirring the mixture until the mixture is dissolved, and preparing a uniform transparent solution (namely spinning solution).
(2) Setting electrostatic spinning process parameters: the flow rate is 2mL/h, the electrode spacing is 15cm, the voltage difference is 30kV, the inner diameter of a spinning needle is 0.67mm, the spinning solution is subjected to electrostatic spinning on melt-blown cloth for 0.5h, and the melt-blown cloth is taken down and dried to obtain the electret polyester nanofiber high-efficiency filter material.
The performance of the electret polyester nanofiber high-efficiency filter material prepared in the embodiment 1 is as follows: the NaCl particulate matter filtration efficiency was 99.6% and the resistance pressure drop was 89Pa (measured using an automatic Filter tester model TSI 8130 at 85L/min).
The charge on the surface of the filter material is removed by soaking in isopropanol, and after drying, the electret nanofiber high-efficiency filter material has the following properties: the NaCl particulate matter filtration efficiency was 85.3% and the resistance pressure drop was 88Pa (measured at 85L/min using an automatic Filter tester model TSI 8130). Therefore, after the treatment with isopropanol, the filtration effect of the electret nanofiber high-efficiency filter material provided by the invention is not greatly reduced, which shows that the charge generated by the electret of the electret nanofiber high-efficiency filter material prepared by the preparation method provided by the invention is not easy to disappear even after the treatment with isopropanol.
The surface Scanning Electron Microscope (SEM) image of the electret nanofibers produced in this example is shown in FIG. 1. As can be seen from the attached figure 1, the electret nanofiber high-efficiency filter material prepared by the preparation method has the advantages of small fiber diameter, large specific surface area, small pore diameter and high porosity, so that the electret nanofiber high-efficiency filter material has good air permeability.
Comparative example 1
Compared with the filter material provided by the comparative example 1 in the example 1, the filter material has different proportions of the components in the spinning solution, and specifically comprises the following components:
8 parts of Polyacrylonitrile (PAN);
8 parts of linear benzoate which does not contain a dipole structure side group; and
84 parts of an N, N-dimethylformamide solvent.
Under the same conditions, the performance of the filter material of the comparative example is tested as follows: NaCl particulate matter filtration efficiency: 98.8%, resistance pressure drop: 88Pa (measured using an automated Filter media tester model TSI 8130 at 85L/min).
The surface charges of the filter material are removed by soaking in isopropanol, and after drying, the performance of the filter material is as follows: the NaCl particulate matter filtration efficiency was 62.3% and the resistance pressure drop was 87Pa (measured at 85L/min using an automatic Filter tester model TSI 8130). Therefore, the filtering effect is greatly reduced after the spinning solution added with the linear polarizable polymer without the dipole structure side group is subjected to electrostatic spinning to form the nanofiber filtering material and is treated by isopropanol, which shows that the electret charge generated by the nanofiber filtering material prepared by adding the linear polarizable polymer without the dipole structure side group is easy to disappear under the action of the isopropanol, and the generated electret effect is unstable.
According to the comparative example, the electret nanofiber high-efficiency filter material prepared by adding the linear polarizable polybenzoate containing the azo side group into the spinning solution has stable body charge electrostatic adsorption force and good electret effect, and the electret effect is long-lasting, so that the interception effect on fine particles is greatly improved, the interception efficiency of the filter material on the fine particles is effectively improved, and the resistance pressure drop is reduced.
Example 2
This example 2 provides another preferred embodiment of an electret nanofiber high-efficiency filter material, which is prepared by loading a spinning solution on a PP spunbonded non-woven fabric support material. The spinning solution in the embodiment comprises the following components in parts by weight:
15 parts of Polystyrene (PS);
15 parts of linearly polarizable polystyrene containing azobenzene side groups; and
70 parts of N, N-dimethylacetamide solvent.
The embodiment also provides a preparation method of the material, which comprises the following steps:
(1) weighing 15 parts of Polystyrene (PS) and 15 parts of linear polarizable polystyrene containing azobenzene side groups, adding the polystyrene and the linear polarizable polystyrene into a container containing 70 parts of N, N-dimethylacetamide solvent, heating and stirring in a water bath at 60 ℃ until the polystyrene and the linear polarizable polystyrene are dissolved, and preparing uniform and transparent spinning solution.
(2) Setting electrostatic spinning process parameters: the flow rate is 2mL/h, the electrode spacing is 15cm, the voltage difference is 28kV, the inner diameter of a spinning needle is 0.67mm, the spinning solution is subjected to electrostatic spinning on melt-blown cloth for 0.5h, and the melt-blown cloth is taken down and dried to obtain the electret polystyrene nanofiber high-efficiency filter material.
The performance of the electret polystyrene nanofiber high-efficiency filter material prepared by the embodiment is as follows: the NaCl particulate matter filtration efficiency was 96.3% and the resistance pressure drop was 92Pa (measured at 85L/min using an automatic Filter tester model TSI 8130).
The charge on the surface of the filter material is removed by soaking in isopropanol, and after drying, the electret nanofiber high-efficiency filter material has the following properties: the NaCl particulate matter filtration efficiency was 84.6% and the resistance pressure drop was 92Pa (measured at 85L/min using an automatic Filter tester model TSI 8130). Therefore, after the treatment with isopropanol, the filtration effect of the electret nanofiber high-efficiency filter material provided by the invention is not greatly reduced, which shows that the charge generated by the electret of the electret nanofiber high-efficiency filter material prepared by the preparation method provided by the invention is not easy to disappear even after the treatment with isopropanol.
Comparative example 2
Compared with the embodiment 2, the spinning solution of the comparative example 2 has different component ratios, specifically:
30 parts of Polystyrene (PS); and
70 parts of an N, N-dimethylacetamide solvent.
Under the same conditions, the performance of the filter material of the comparative example is tested as follows: NaCl particulate matter filtration efficiency: 95.8%, resistance pressure drop: 87Pa (measured at 85L/min using an automatic Filter media tester model TSI 8130).
The surface charges of the filter material are removed by soaking in isopropanol, and after drying, the performance of the filter material is as follows: the NaCl particulate matter filtration efficiency was 61.2% and the resistance pressure drop was 86Pa (measured using an automatic Filter tester model TSI 8130 at 85L/min). Therefore, the filtering effect is greatly reduced after the spinning solution without the linear polarizable polymer containing the dipole structure side group is subjected to electrostatic spinning to form the nanofiber filtering material and is treated by isopropanol, which shows that the electret charge generated by the nanofiber filtering material prepared without the linear polarizable polymer containing the dipole structure side group is easy to disappear under the action of the isopropanol, and the generated electret effect is unstable.
According to the comparative example, the linear polarizable polystyrene containing the azobenzene side group is added into the spinning solution, so that the stable body charge electrostatic adsorption force can be achieved, the electret effect is good and long-lasting, the intercepting efficiency of the filtering material on fine particles can be effectively improved, and the resistance pressure drop is reduced.
Example 3
The embodiment provides another electret nanofiber high-efficiency filter material in a preferred embodiment, which is prepared by loading a spinning solution on a PP melt-blown non-woven fabric support material, wherein the spinning solution comprises the following components in parts by weight:
10 parts of polymethyl methacrylate (PMMA);
15 parts of linear polarizable polymethyl methacrylate containing azobenzene side groups; and
75 parts of N, N-dimethylformamide solvent.
The embodiment also provides a preparation method of the material, which comprises the following steps:
(1) weighing 10 parts of polymethyl methacrylate (PMMA) and 15 parts of linear polarizable polymethyl methacrylate containing azobenzene side groups, adding the weighed materials into a container containing 75 parts of N, N-dimethylformamide solvent, placing the container in a water bath at 60 ℃, heating and stirring the mixture until the mixture is dissolved, and preparing uniform and transparent solution (namely spinning solution).
(2) Setting electrostatic spinning process parameters: the flow rate is 2mL/h, the electrode spacing is 15cm, the voltage difference is 35kV, the inner diameter of a spinning needle is 0.67mm, the PMMA spinning solution is subjected to electrostatic spinning on melt-blown cloth for 0.5h, and the melt-blown cloth is taken down and dried to obtain the electret polymethyl methacrylate nanofiber high-efficiency filter material.
The performance of the electret polymethyl methacrylate nanofiber high-efficiency filter material prepared by the embodiment is as follows: the NaCl particulate matter filtration efficiency was 99.5% and the resistance pressure drop was 85Pa (measured at 85L/min using an automatic Filter tester model TSI 8130).
The charge on the surface of the filter material is removed by soaking in isopropanol, and after drying, the electret nanofiber high-efficiency filter material has the following properties: the NaCl particulate matter filtration efficiency was 86.3% and the resistance pressure drop was 85Pa (measured at 85L/min using a model TSI 8130 autofilter tester).
Therefore, after the treatment by isopropanol, the filtration effect of the electret nanofiber high-efficiency filter material provided by the invention is not greatly reduced, which shows that the charge generated by the electret of the electret nanofiber high-efficiency filter material prepared by the preparation method provided by the invention is not easy to disappear after the treatment by isopropanol.
Comparative example 3
Compared with the embodiment 3, the spinning solution of the comparative example 3 has different solution component ratios, specifically:
25 parts of polymethyl methacrylate (PMMA); and
75 parts of N, N-dimethylformamide solvent.
Under the same conditions, the performance of the filter material of the comparative example is tested as follows: NaCl particulate matter filtration efficiency: 96.7%, resistance pressure drop: 87Pa (measured at 85L/min using an automatic Filter media tester model TSI 8130).
The surface charges of the filter material are removed by soaking in isopropanol, and after drying, the performance of the filter material is as follows: the NaCl particulate filtration efficiency was 59.4% and the resistance pressure drop was 87Pa (measured using an automatic Filter tester model TSI 8130 at 85L/min). Therefore, the filtering effect is greatly reduced after the spinning solution without the linear polarizable polymer containing the dipole structure side group is subjected to electrostatic spinning to form the nanofiber filtering material and is treated by isopropanol, which shows that the electret charge generated by the nanofiber filtering material prepared without the linear polarizable polymer containing the dipole structure side group is easy to disappear under the action of the isopropanol, and the generated electret effect is unstable.
According to the comparative example, the linear polarizable polymethyl methacrylate containing the azobenzene side group is added into the spinning solution, so that the stable electrostatic adsorption force of the bulk charge is achieved, the electret effect is good, and the electret effect is long-lasting, so that the interception effect on fine particles is greatly improved, the interception efficiency of the filter material on the fine particles is effectively improved, and the resistance pressure drop is reduced.
The electret nanofiber high-efficiency filter material adopts a linear polarizable polymer solution with an electron donor-pi conjugated system-electron acceptor dipole structural side group, and prepares the formed spinning solution into the electret nanofiber by an electrostatic spinning method, in the electrostatic spinning process, the dipole group on the linear polarizable polymer is polarized under the action of a high-voltage electric field, the orientation of the dipole moment of the polarized dipole group is stabilized by the solidified linear polarizable polymer skeleton, so that the polarized dipole groups are not easy to agglomerate due to electrostatic action, the orientation of the dipole moment of the polarized chromophore is effectively stabilized, the prepared nano-fiber has long-acting electret effect, the electret effect is long-acting and lasting, therefore, the interception effect of the electrostatic adsorption force on the fine particles is greatly improved, and the interception efficiency of the filtering material on the fine particles is effectively improved. In addition, the electret nanofiber filter material has the advantages of simple preparation method, low production cost and the like.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention.
Claims (8)
1. The electret nanofiber high-efficiency filter material is characterized by being prepared from a spinning solution through electrostatic spinning, wherein the spinning solution comprises the following components in parts by weight: 0-30 parts of a polymer; 1-30 parts of linear polarizable polymer; 40-99 parts of solvent; wherein the linear polarizable polymer is a linear polarizable polymer with an electron donor-pi conjugated system-electron acceptor dipole structural side group; the polymer content is not zero; the linear polarizable polymer is linear polarizable polyester, linear polarizable polystyrene, linear polarizable polytriazole, linear polarizable polyurethane or linear polarizable polymethyl methacrylate; the electron donor of the linear polarizable polymer is selected from an atom or group having a lone pair of electrons and containing an oxygen atom, a nitrogen atom, or a sulfur atom; the electron acceptor of the linear polarizable polymer is selected from an atom or group having an electron-withdrawing tendency; the pi conjugated system is selected from an azobenzene system, a conjugated hydrocarbon system or a thiophene system, and the electret nanofiber high-efficiency filter material is prepared by adopting the following preparation method: the method comprises the following steps: s1: preparing spinning solution, and respectively weighing a polymer, a linear polarizable polymer and a solvent according to weight percentage; stirring and dissolving the polymer and the linear polarizable polymer in the solvent at 20-80 ℃ to form a uniform spinning solution; s2: and (4) carrying out electrostatic spinning to obtain the electret nanofiber high-efficiency filter material, and loading the spinning solution obtained in the step S1 on a support material by using an electrostatic spinning method to prepare the electret nanofiber high-efficiency filter material.
2. The electret nanofiber high-efficiency filter material as claimed in claim 1, wherein the electron donor is selected from one of hydroxyl, alkoxy, amine or mercapto; the electron acceptor is selected from one of nitro, aldehyde group, cyano, sulfonic group, carboxyl, acyl, trifluoromethyl, trichloromethyl or tribromomethyl; the pi conjugated system is an azobenzene system.
3. The electret nanofiber high-efficiency filter material as claimed in claim 1, wherein the polymer is selected from one or more of the following components: polyacrylonitrile, polyamide, polyurethane, polycarbonate, polyethersulfone, polyphenylene oxide, polyimide, polyvinyl chloride, polyvinylidene fluoride, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polymethyl methacrylate, polyvinyl alcohol, chitosan, or a modified polymer thereof.
4. The electret nanofiber high-efficiency filter material as claimed in claim 1, wherein the solvent is selected from one or more of the following components: water, formic acid, acetic acid, trifluoroacetic acid, ethanol, N-dimethylformamide, N-dimethylacetamide, dichloroethane, chloroform, tetrahydrofuran, acetone, toluene, butanone, or isopropanol.
5. The electret nanofiber high-efficiency filter material as claimed in any one of claims 1 to 4, wherein the spinning solution comprises the following components in parts by weight: 1-20 parts of a polymer; 1-25 parts of linear polarizable polymer; 55-98 parts of a solvent; wherein the linear polarizable polymer is linear polarizable polyester, linear polarizable polytriazole or linear polarizable polymethacrylate with a dipole structure side group of an electron donor-pi conjugated system-electron acceptor; the polymer is selected from one or more of polyacrylonitrile, thermoplastic polyimide, polymethyl methacrylate, polyvinylidene fluoride or polystyrene; the solvent is one or two of N, N-dimethylformamide or N, N-dimethylacetamide.
6. A method for preparing an electret nanofiber high-efficiency filter material, which is used for preparing the electret nanofiber high-efficiency filter material as claimed in any one of claims 1 to 5, wherein the preparation method at least comprises the following steps: s1: preparing spinning solution, and respectively weighing a polymer, a linear polarizable polymer and a solvent according to weight percentage; stirring and dissolving the polymer and the linear polarizable polymer in the solvent at 20-80 ℃ to form a uniform spinning solution; s2: and (4) carrying out electrostatic spinning to obtain the electret nanofiber high-efficiency filter material, and loading the spinning solution obtained in the step S1 on a support material by using an electrostatic spinning method to prepare the electret nanofiber high-efficiency filter material.
7. The method of claim 6, wherein the support material is a spunbond, needle-punched or meltblown nonwoven.
8. The method for preparing a composite material according to claim 6, wherein the step S2 further includes: laying the support material on a receiving electrode plate; then, voltage is applied to the transmitting electrode, the receiving electrode plate is grounded or reverse voltage is applied, and the electret nanofiber high-efficiency filter material loaded with nanofibers with different shapes is prepared by adjusting the pressure difference of positive and negative voltages, the distance between the spinning electrode and the receiving electrode and the temperature and humidity of the environment.
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| CN116949682B (en) * | 2023-06-03 | 2024-01-26 | 广东爱航环境科技有限公司 | Non-woven fabric for deodorizing and antibacterial air purifier and preparation method thereof |
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