KR20230076803A - Electrospun nanofibrous polymeric membranes for use in personal protective equipment - Google Patents

Abstract

Disclosed herein are electrospun polymer nanofibrous membranes that provide high filtering efficiency and good porosity. The membrane may be treated with one or more antimicrobial or antiviral agents. The treatment may preferably be a coating of one or more antibacterial or antiviral agents. Alternatively, one or more antibacterial or antiviral agents may be impregnated into the nanofibrous membrane. The membrane may additionally or alternatively be impregnated with one or more metal-organic frameworks (MOFs). The membrane has sufficient porosity to provide high filtration efficiency and breathability characteristics. The membrane is suitable for use in making facemasks and respirators highly resistant to infectious pathogens and/or other small particulates.

Description

Electrospun nanofibrous polymeric membranes for use in personal protective equipment

CROSS REFERENCES OF RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63/002,435 filed on March 31, 2020 and U.S. Provisional Patent Application No. 63/116,799 filed on November 20, 2020, the disclosure of which is the entirety of which is incorporated herein by reference.

technology field

This disclosure relates to materials for use in personal protective equipment.

Community acquired respiratory virus (CARV) infection includes infections caused by various viruses, including coronaviruses, rhinoviruses, influenza viruses, and metapneumoviruses. See, for example, Versluys, A.B., et al., "and Mortality Associated With Respiratory Virus Infections in Allogeneic Hematopoietic Cell Transplant: Too Little Defense or Harmful Immunity?" Front, Microbiol 2018, 9, 2795-2795, doi; 10.3389/ftnicb.2018.02795”. Numerous CARV infections result in significant morbidity and mortality. For example, the Spanish flu pandemic of 1918 killed between 20 and 50 million people worldwide. "Roos, D. "the Second Wave of the 1918 Spanish Flu Was So Deadly," History.com, 2020 (available at https://www.histoiy.com/news/spanish-flu-second-wave-resurgence )”. Moreover, influenza pandemics are known to emerge periodically. The current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become the most significant global health problem of this century and the Spanish flu fan. It's the worst pandemic since the demic.

Infectious respiratory pathogens are generally transmitted by droplets, aerosols, or airborne transmission of particles expelled from the respiratory tract of an infected person through coughing or sneezing, or in some cases simply by breathing. To prevent this form of transmission, face masks and respirators have been developed that either mechanically block infectious particles or neutralize them using a variety of mechanisms. Therefore, many research and development efforts are being made to improve the filtration efficiency of face masks and respirators.

The COVID-19 pandemic has highlighted the need for functional protective fabrics that can be used for a variety of applications. Functional protective fabrics are particularly important for use in protective clothing by medical professionals, field workers and military personnel. For example, Zhu, Q., et al., "Functionalized CNCs/PVA-co-PE Composite Nanofibrous Membrane with Flower-Like Microstructures for Photo-Induced Multi-Functional Protective Clothing," Cellulose, 2018, 25, 4819-30; doi: 10.1007/sl0570-018-188l-5”; 「Liu, Y. et al., “UV-Crosslinked Solution Blown PVDF Nanofiber Mats for Protective Applications,” Fibers Polym. 2020, 21, 489-97, doi: 10.1007/sl222l-020-9666-5.”

To limit dermal exposure to airborne solid particles, health and safety regulatory agencies have issued good practice guidelines and personal protective equipment (PPE) to minimize exposure to various hazards. wearing is recommended. Chemical and biological protective clothing (CBPC) is widely used and is considered the most economical of the PPE options. For airborne nanomaterials, type 5 CBPC is considered the last line of defense against such hazards as it provides systemic protection against airborne solid particulates according to ISO 13982-1 and ISO 13982-2 standards. Reference "International Organization for Standardization (ISO) 13982-1:2004"; Refer to 「International Organization for Standardization (ISO) 13982-2:2004」.

Nonwoven and woven materials commonly used as substrates for Type 5 CBPC have several disadvantages, such as poor breathability and filterability. For example, Liu, Y et al., above; See Wingert, L., et al., "Filtering performances of 20 Protective Fabrics Against Solid Aerosols," J. Occup. Environ. Hyg. 2019, 16, 592-606”.

Currently marketed face masks and respirators do not have adequate filtration efficiency to block infectious particles or sufficient air permeability to allow frequent and convenient use. Literature "Lee, S., et al., "Polybenzimidazole Nanofiber Membrane Filter for Highly Breathable PM2.5 Dust Proof Mask" ACS Appl Mater. interfaces, 2019, 11, 2750-57, doi: 10.1021/acsami.8bl9741”. Moreover, the recent COVID-19 pandemic has increased interest in developing antiviral membranes for face masks and respirators that will eradicate pathogens that come into contact with face masks or respirators. This can prevent the transfer of infectious particles to other surfaces by accidental contact of the mask with other surfaces or by the wearer's hand touching the outer surface of the mask. Numerous antiviral agents are known that are suitable for use in coatings or that can be incorporated into personal protective equipment. See, for example, Tran, D.Ν., et al., "Nanoparticles as Potential Antiviral Agents against African Swine Fever Virus," Mater. Res. Express, 2020, 6(12), doi: 10.1Q88/2O53-1591/ab6ad8”; "Moreno, M.A., et al., "Active Properties of Edible Marine Polysaccharide-Based Coatings Containing Larrea nitida Polyphenols Enriched Extract," Food Hydrocoil. 2020, 102, 105595, doi: 10.1016/j.foodhyd.2019.105595”; "Husen, A. "Natural Product-Based Fabrication of Zinc-Oxide Nanoparticles and Their Applications," In Nanomaterials and Plant Potential, 2019, 193-219, Springer"; "Cheng, C., et al., "Functional Graphene Nanomalerials Based Architectures: Biointeractions, Fabrications, and Emerging Biological Applications," Chent. Rev. 2017, 117, 1826-1914”; 「Zhang, D.-h., et al., “In Silica Screening of Chinese Herbal Medicines with the Potential to Directly Inhibit 2019 Novel Coronavirus,” J. Integr Med. 2020, 18, 152-8, doi: 10.1016/j.joim.2020.02.005”; See U.S. Patent Nos. 9,963,611 and 8,678,002.

Various techniques are known for fabricating nanofibrous membranes, including electrospinning, phase inversion, interfacial polymerization, stretching, and track-etching. Electrospinning is a very useful technique that provides efficiency and uniformity of pore size. For example, "Ray, SS, etc., "A Comprehensive Review: Electrospinning Technique for Fabrication and Surface Modification of Membranes for Water Treatment Application," RSC Adv. 2016, 6(88), 85495-85514, doi: 10.1O39/C6RA14952A”. Electrospinning is a process that uses an electric field to create continuous fibers on the micrometer or nanometer scale. Electrospinning allows direct control of the microstructure of the scaffold, including properties such as fiber diameter, orientation, pore size and porosity.

Electrospun nanofibers have a wide range of applications. These include antibacterial food packaging, biomedical applications, and environmental applications. See, eg, Lin, L., et al., "Cold Plasma Treated 'thyme Essential Oil/Silk Fibroin Nanofibers against Salmonella Typhimurium in Poultry Meat," Food Packag. Shelf Life, 2019, 21, 100337; 「Zhu, Y., et al., “A Novel Polyethylene Oxi de/Dendrobium officinale Nanofiber: Preparation, Characterization and Application in Pork Packaging,” Food Packag. Shelf Life, 2019, 21, 100329; “Surendhiran, D., et al., “Encapsulation of Phlorotannin in Alginate/PEO Blended Nanofibers to Preserve Chicken Meat from Salmonella Contaminations,” Food Packag. Shelf Life, 2019, 21, 100346; "Khan, M.Q., et al., "The Development of Nanofiber Tubes Based on Nanocomposites of Polyvinylpyrrolidone Incorporated Gold Nanoparticles as Scaffolds for Neuroscience Application in Axons," Text Res. J. 2019, 89, 2713-20, doi: 10.1177/0040517518801185; 「Ullah, S., et al., “Antibacterial Properties of In Situ and Surface Functionalized Impregnation of Silver Sulfadiazine in Polyacrylonitrile Nanofiber Mats,” Ini. J. Nanomedicine, 2019, 14, 2693-2703, doi: 10.2147/DN.S 197665; "Khan, M.Q., et al., "Fabrication of Antibacterial Electrospan Cellulose Acetate/Silver-Sul fadiazine Nanofibers Composites for Wound Dressings Applications," Polym. Test. 2019, 74, 39-44. Doi: 10.1016/j.polymertesting.2018.12.015”; Said Ray, S.S. See et al.

Electrospun nanofibrous fabrics have been considered promising candidates for CBPC. See, for example, Lee, S et al., "Transport Properties of Layered Fabric Systems Based on Electrospun Nanofibers," Fibers Polym. 2007, 8, 501-06”; “Bagherzadeh, R., et al., “Transport Properties of Multi-Layer Fabric Based on Electrospun Nanofiber Mate as a Breathable Barrier Textile Material,” Text. Res. J. 2012, 82, 70-76”.

Electrospun polymer nanofibers can exhibit very large external surface area, good water vapor transport properties and good mechanical strength. See, for example, Huang, Z., et al., "A Review on Polymer Nanofibers by Electrospinning and Their Applications in Nanocomposites," Compos. Sci. Technol. 2003, 63, 2223-53”.

Fabrication of fabrics from electrospun polymer nanofibers results in ultrathin, lightweight and high tensile strength fabrics. See, for example, Lee, S. et al., above; Dhineshbabu, N. R., et al., “Electrospun MgO/Nylon 6 Hybrid Nanofibers for Protective Clothing,” Nano-Micro Lett 2014, 6, 46-54; 「Han, Y., et al., “Reactivity and Reusability of Immobilized Zinc Oxide Nanoparticles in Fibers on Methyl Parathion Decontamination,” Text Res. J. 2013, 86, 339-49”.

Chen et al. disclose functionalized nanofibrous mats produced by introducing nucleophilic oxime moieties through electrospinning of polyacryiamidoxime (PAAO) and PAN. These functionalized nanofibers showed significant ability to hydrolyze chemical nerve agents. See Chen, L., et al., "Multifunctional Electrospun Fabrics via Layer-by-Layer Electrostatic Assembly for Chemical and Biological Protection," Chem. Mater. 2010, 22, 1429-36.”

Choi et al. disclose engineered polyurethane nanofibers functionalized with N-chloro hydantoin (NCH-PU). These nanofibers successfully removed a simulant of V-shaped nerve gas (demeton-S-methyl). See Choi, J., et al., "N-Chloro Hydantoin Functionalized Polyurethane Fibers Toward Protective Cloth Against Chemical Warfare Agents," Polymer, 2018, 138, 146-55.

A variety of metal nanoparticle-integrated nanofibers proposed for use in protective clothing and face masks for shielding against hazardous chemicals and biologicals have been disclosed. See, for example, Ramaseshan, R., et al., “Zinc Titanate Nanofibers for the Detoxification of Chemical Warfare Simulants,” J. Am. Ceram. Soc. 2007, 90, 1836-42”.

Lee et al. disclose functional PAN nanofiber webs to protect users from simulants of chemical warfare agents (CWA). See "Lee, J., et al., "Preparation of Non-Woven Nanofiber Webs for Detoxification of Nerve Gases" Polymer, 2019, 179, 121664".

Zhao et al. disclose metal-organic frameworks (MOFs) incorporated into polyamide-6 nanofibers. The MOF-nanofiber composite showed a specific response to detoxify CWA. See Zhao, J. et al., "Ultra-Fast Degradation of Chemical Warfare Agents Using MOF-Nanofiber Kebabs," Angew. Chem. Int. Ed. 2016, 55, 13224-28”.

Antiviral agents have been incorporated into electrospun fibers to prevent HIV infection. Literature "T. N., et al., "Griffithsin-Modified Electrospun Fibers as a Delivery Scaffold To Prevent HIV Infection," Antimicrob. Agents Chemother. 2016, 60, 6518”.

A need remains for new materials to develop high performance membranes with antiviral and other antipathogenic properties with high filtration efficiency and breathability for use in face masks and respirators.

Disclosed herein are electrospun polymer nanofibrous membranes that provide high filtration efficiency and good porosity.

The membrane may be treated with one or more antimicrobial or antiviral agents. In some embodiments, the membrane can be treated with an antiviral agent selected from the group consisting of graphene, nanoparticles, nanocomposites, multivalent metal ions, and medicinal or other extracts from natural products. In the treatment method, it is preferable to coat the surface of the membrane with at least one antiviral agent. Alternatively, one or more antiviral agents may be impregnated into the nanofibrous membrane.

The membrane may additionally or alternatively be impregnated with one or more metal-organic frameworks (MOFs). The one or more MOFs may be, for example, one or more zircon MOFs. MOFs can provide filtration of chemical agents (CWAs) and other toxic chemical agents and, in some embodiments, additional or alternative filtration of small particulates and pathogens.

The membranes disclosed above may preferably have high filtration efficiencies. The porosity of the membranes disclosed above may be sufficient to provide breathability characteristics suitable for use in face masks or respirators, if desired. The disclosed membranes are suitable for making face masks and respirators with high resistance to infectious pathogens and/or other small particulates.

1 shows a representative scanning electron microscope (SEM) image of an embodiment of the disclosed nanofibrous polymer membrane.
Figure 2 shows fiber diameter measurements and distributions for a representative sample of an embodiment of the disclosed nanofibrous polymeric membrane.
FIG. 3 shows the pore size distribution determined by mercury porosimeter analysis for a representative sample of an embodiment of the disclosed nanofibrous polymeric membrane.
4 shows average porosity and average porosity distribution for a representative sample of an embodiment of the disclosed nanofibrous polymer membrane.
5 shows mechanical tensile strength test results for a representative sample of an embodiment of the disclosed nanofibrous polymeric membrane.
6 shows filtration efficiency test results for a representative sample of an embodiment of the disclosed nanofibrous polymer membrane.
7 shows latex filtration test results for a representative sample of an embodiment of the disclosed nanofibrous polymeric membrane.
8 shows virus filtration efficiency test results for a representative sample from an embodiment of the disclosed nanofibrous polymer membrane.
Figure 9 presents bacterial filtration efficiency test results for a representative sample of an embodiment of the disclosed nanofibrous polymer membrane.
10 shows flammability test results for a representative sample of an embodiment of the disclosed nanofibrous polymeric membrane.
11 shows antiviral property test results for a representative sample of an embodiment of the disclosed nanofibrous polymeric membrane.
12 presents antibacterial property test results for a representative sample of an embodiment of the disclosed nanofibrous polymeric membrane.
Figure 13 shows how the filtration efficiency is affected by the flow rate of aerosol through the membrane.
Figure 14 shows how the pressure drop across the membrane affects the flow rate of an aerosol through the membrane.

Disclosed herein are electrospun polymer nanofibrous membranes that provide high filtration efficiency and good porosity.

The membrane may be treated with one or more antimicrobial or antiviral agents. In some embodiments, the membrane can be treated with an antiviral agent selected from the group consisting of graphene, nanoparticles, nanocomposites, multivalent metal ions, and medicinal or other extracts from natural products. The treatment may preferably be a coating of one or more antiviral agents on the surface of the membrane. Alternatively, one or more antiviral agents may be impregnated into the nanofibrous membrane.

The membrane may additionally or alternatively be impregnated with one or more metal-organic frameworks (MOFs). The one or more MOFs may be, for example, one or more zircon MOFs. The MOF may provide filtration of chemical agents (CWAs) and other toxic chemicals, and in some embodiments may provide additional or alternative filtration of small particles and pathogens.

The membranes disclosed above may preferably have high filtration efficiencies. The porosity of the membranes disclosed above may be sufficient to provide breathable properties suitable for use as a face mask or respirator, preferably. The disclosed membranes are suitable for making face masks and respirators with high resistance to infectious pathogens and/or other small particulates.

The disclosed membrane may have a filtration efficiency of preferably 95% or higher, more preferably 98% or higher, even more preferably 99% or higher, and most preferably 99.5% or higher.

The disclosed membrane is preferably capable of blocking and eradicating infectious pathogens from its surface.

In some preferred embodiments, the disclosed membranes are non-flammable.

The disclosed membranes may be suitable for the manufacture of non-combustible high performance fabrics.

In some preferred embodiments, the disclosed membranes are ultra-thin and lightweight.

In some preferred embodiments, the disclosed membranes do not deteriorate upon exposure to water or selected organic solvents such as ethanol or acetone. Therefore, products manufactured using the membrane can be washed and reused.

In some embodiments, the nanofibrous polymeric membrane may be made of polyvinylidene fluoride (PVDF). In some alternative embodiments, the nanofibrous polymer membrane can be made of one or more Tecophilic™ thermoplastic polyurethanes (TPU). In some other alternative embodiments, the nanofibrous polymeric membrane can be made from a blend of polyvinylidene fluoride and one or more Tecophilic™ thermoplastic polyurethanes.

The nanofibrous polymeric membrane may be fabricated using electrospinning techniques. The polymer is dissolved in a solvent prior to electrospinning. In some embodiments, the solvent is preferably selected from the group consisting of dimethylformamide (DMF), dimethylacetamide (DMA), hexafluoroisopropanol (HFIP), acetone, water, or combinations thereof.

In some embodiments, a surfactant may be added to the polymer solution. The addition of surfactants to the polymer solution can promote smaller fiber diameters resulting in membranes with smaller pore sizes and thus higher filtration efficiencies. In some preferred embodiments, the surfactant is selected from the group consisting of cetrimum bromide (CTAB), lauramidopropyl betaine (LAPB) and alpha olefin sulfonate (AOS) It can be one or more surfactants.

In some embodiments, a salt or salt solution may be added to the polymer solution. Adding a salt or salt solution to the polymer solution can promote the formation of thinner and more uniform fibers and can also reduce bead formation. The presence of salt in the polymer solution promotes elongation of the spinning jet by increasing the charge density and conductivity, which leads to the production of thinner fibers. In some preferred embodiments, the salt or salt solution may be one or more salts or salt solutions selected from the group consisting of alkali metal halides and phosphate-buffered saline (PBS). In some more preferred embodiments, the salt or salt solution may be one or more salts selected from the group consisting of sodium chloride (NaCl), lithium chloride (LiCl) and potassium chloride (KCl).

The nanofibrous polymer membrane may be a single layer membrane or may be an integrated multi-layer membrane. In some embodiments, the membrane may be composed of multiple integrated layers with distinguishable microstructure characteristics. A membrane composed of multiple integrated layers can provide improved filtration efficiency and high breathability. The improved filtration efficiency of integrated multilayer membranes can result from superior barrier protection against small pathogen particles.

In some embodiments, integrated multilayer membranes are composed of two layers with different pore sizes. In some alternative embodiments, the integrated multilayer membrane is composed of three layers with two layers of the same pore size separated by a layer with different pore sizes. The pore size is preferably between 1 and 20 μm for the layer(s) with a smaller pore size and between 20 and 200 μm for the layer(s) with a larger pore size.

In an embodiment having three layers having two layers of the same pore size separated by a layer of different pore size, a layer of the same size may have a larger pore size, and between these two layers the layer may have a larger pore size. It is desirable to have a small pore size. This configuration reduces the pressure drop that occurs when a gas passes through the multilayer membrane, without significantly reducing the filtration efficiency of the membrane, which corresponds to increased breathability.

In some other alternative embodiments, the integrated multi-layer membrane is composed of three layers with three different pore sizes.

The pore size of the layers in the integrated multilayer membrane can be controlled by controlling the viscosity of the polymer solution and the conditions of the electrospinning process. Electrospinning process conditions can be adjusted to more stabilize the spinning jet used in the electrospinning setup. Solutions with lower viscosities typically produce smaller pore size layers, and solutions with higher viscosities typically produce larger pore size layers.

In some embodiments, the mechanical integrity and bonding strength between the layers of the membrane can be improved by electrospinning short fibers prior to electrospinning a subsequent layer. In some other embodiments, the wet fibers are electrospun by reducing the screen distance before electrospinning subsequent layers to create a "tacky surface" to improve mechanical integrity and bonding between the layers of the membrane. can make it

In some embodiments, the nanofibrous polymeric membranes disclosed above may be laminated onto textile materials. Alternatively, the nanofibers can be directly electrospun onto non-woven fabrics such as polyethylene terephthalate (PET), polypropylene (PP) and PET copolymers. The use of the PET copolymer improves the adhesion between the nanofibers and the fabric, thereby reducing delamination.

The disclosed nanofibrous polymeric membrane may be treated with an anti-pathogenic agent, such as an antiviral agent selected from the group consisting of graphene, nanoparticles, nanocomposites, multivalent metal ions, and medicinal or other extracts derived from natural products. Preferably, the nanoparticles may be metal nanoparticles, such as silver nanoparticles or zinc nanoparticles. The nanocomposite may preferably be a silver-doped titanium dioxide nanomaterial. ^The multivalent metal ion may preferably be ^a metal ion such as Cu ²⁺ or Zn ²⁺ cation. Extracts from natural products may preferably be licorice extracts.

The anti-pathogenic agent(s) may be physically coated on the surface of the membrane. The coating may be performed by chemical or electrochemical methods such as atomic layer deposition, vapor deposition methods such as physical vapor deposition (PVD) or chemical vapor deposition (CVD), spray coating methods such as plasma spray or spray painting. ), or using physical coating methods such as dip-coating or spin-coating.

The anti-pathogenic agent(s) is alternatively introduced into the membrane by mixing the anti-pathogenic agent(s) in a polymer solution prior to electrospinning, thereby leaving the membrane impregnated with the anti-pathogenic agent(s). can create

In some embodiments, the nanofibrous polymeric membranes disclosed above may be impregnated with one or more metal-organic frameworks (MOFs), such as zircon MOFs. The MOF can be introduced into the polymer solution by mixing the MOF into the polymer solution prior to electrospinning, thereby producing a membrane impregnated with the MOF.

In some embodiments, there may be MOF-impregnation into the membrane in addition to coating or impregnation with the anti-pathogenic agent(s). In another embodiment, MOF-impregnation into the membrane can be an alternative to coating or impregnating with anti-pathogenic agent(s). Membranes impregnated with MOF can filter chemical agents (CWA) and other toxic chemicals. In some embodiments, membranes impregnated with MOFs may also exhibit antiviral, antibacterial or other anti-pathogenic properties.

Accordingly, the MOFs described herein are not necessarily intended to be distinguished from anti-pathogenic agents, eg, antiviral or antibacterial agents, described herein. Rather, the anti-pathogenic agent may be a MOF, or alternatively may be one of the other anti-pathogenic agents described herein. Further, the MOFs described herein are not necessarily intended to exhibit antiviral, antibacterial or other anti-pathogenic properties. Although the MOFs impregnated in the disclosed membranes can provide filtration of chemical agents (CWAs) and other toxic chemicals, in some embodiments, they do not exhibit antiviral, antibacterial or other anti-pathogenic properties or filtration of small particles. can provide

To increase the breathability of textile materials coated with the nanofibrous polymer membranes described above, multiple nanofibrous layers of different thicknesses may be electrospun on the same or opposite side of the textile material. The textile material in the form of a roll of textile material may be coated by electrospinning with one or more layers of nanofibers, and in some embodiments the one or more first layers of nanofibers may be coated at a first winding speed. is electrospun onto a first side of the textile material, the roll of textile material is flipped, and at least one second nanofiber layer is rolled onto the second side of the textile material at a second winding speed. electrospun on the top, wherein the first winding speed is different from the second winding speed. In another embodiment, one or more first nanofiber layers are electrospun onto the first side of the textile material at a first windup speed, and then one or more second nanofiber layers are electrospun onto the first side of the textile material at a second windup speed. Electrospun on one side, wherein the first winding speed is different from the second winding speed. In another embodiment, one or more first nanofibrous layers are electrospun onto a first side of the textile material at a first windup speed and then one or more second nanofiber layers are electrospun on the textile material at a second windup speed. electrospun on a first side, then the roll of textile material is flipped, and at least one third nanofiber layer is electrospun on a second side of the textile material at a third winding speed, wherein the first winding speed is different from the second winding speed. In another embodiment, an additional electrospinning step may be added to further include nanofibrous layers of different thicknesses on one or both sides of the fabric material.

Also disclosed herein is a face mask or respirator made of the nanofibrous polymeric membranes described above. The face mask or respirator preferably has a high filtration capacity and suitable breathability properties so that the wearer can use it comfortably. The face mask or respirator disclosed above preferably has a filtration efficiency of 95% or greater, more preferably 98% or greater, even more preferably 99% or greater, and most preferably 99.9% or greater.

Also disclosed herein is a method of making a face mask or respirator from the nanofibrous polymeric membranes described above. The method may preferably allow fine-tuning of anti-pathogenic, physical, chemical and mechanical properties according to specific application requirements.

sample preparation

The following sample preparation materials and methods are illustrative. Other suitable materials and methods may be used within the scope of the present invention.

materials. Multiple Tecophitic™ thermoplastic polyurethane (PEU) was purchased from Lubrizol. Knyar 2801 polyvinylidene fluoride (PVDF) was purchased from Arkema. Hexafluoroisopropanol (HFIP) was purchased from Oakwood Products Inc. Dimethylacetamide (DMA), acetone, cetrimonium bromide (CTAB), and lithium chloride (LiCl) were purchased from Fisher Scientific. Silver nanoparticles (15 mm) were purchased from Skyspring Nanomaterials. ZnO and CuO (Zn-Cu) were purchased from Sigma-Aldrich. Ag-doped TiO ₂ (Ag-TiO ₂ ) nanoparticles were purchased from JM Material Technology Inc. Licorice extracts were supplied by XSL USA Inc.

solution preparation. PEU polymer was added to HFIP to make 7 and 15 w/v solutions. 16.5% by weight of PVDF was dissolved in 3:1 DMAc/acetone containing 0.85% CTAB and 0.04% LiCl. All solutions were thoroughly mixed on a stir plate until completely dissolved.

antiviral treatment. Two antiviral treatment methods were used: (1) the membrane was immersed in an aqueous dispersion containing the antiviral particles, or (2) the antiviral nanofibrous membrane was directly prepared by adding the antiviral agent to the polymer solution. Antiviral agents used were 2% stric acid and silver, Ag-TtO ₂ and Zn-Cu nanoparticles, and licorice extract.

membrane fabrication. The membrane fabrication process is roll to roll, in which a textile material is wound from one side to the other and a layer of nanofibers is laminated onto the fabric during the winding process. The thickness of the nanofiber layer was controlled by controlling the winding speed.

Characterization of representative samples

To investigate the potential use of the disclosed nanofibrous polymer membranes in face masks and respirators, the morphology, fiber diameter, filtration efficiency, porosity, wettability, Mechanical strength and antiviral activity were characterized.

The nanofibrous polymeric membrane was characterized using scanning electron microscopy (SEM) imaging. 1 shows a representative SEM image of an embodiment of the nanofibrous polymer membrane described above. Large images are shown magnified at 2000× magnification, and each inset is shown magnified at 5000 × magnification.

As shown in Figure 1, the inner and outer surfaces of each nanofibrous membrane exhibit a consistent morphology between samples. In addition, the nanofibrous membrane exhibited good orientation and was free from breading, splitting and other undesirable morphological properties.

Figure 2 shows fiber diameter measurements and distributions for a representative sample of an embodiment of the nanofibrous polymer membrane described above. The average fiber diameter of the representative sample was 0.224 μm, with a median fiber diameter of 0.210 μm and a standard deviation of 0.196. The average orientation was 79° and the area coverage was 16%.

Figure 3 shows the pore size distribution determined by mercury porosimetry analysis for a representative sample of an embodiment of the nanofibrous polymer membrane described above. The average pore diameter was found to be 0.0025 μm.

4 depicts average porosity and average porosity distribution for a representative sample of an embodiment of the nanofibrous polymer membrane described above. The average porosity measured gravimetrically was found to be distributed around a center point of 78.5%. As shown in Figure 4, all samples showed constant porosity ranging from 75% to 83%. A high porosity membrane is an important requirement to increase the breathability of a face mask or filter made from the membrane.

5 shows mechanical tensile strength test results for a representative sample of an embodiment of the nanofibrous polymer membrane described above.

A representative sample of an embodiment of the nanofibrous polymer membrane described above was also tested for filtration efficiency. The observed efficiency was 99.61% for 30 L/min, indicating a pressure loss of 1.265 mbar, and 99.85% for 95 L/min, indicating a pressure loss of 4.3 mbar.

Table 1 below shows a summary of the test results for a representative sample of an embodiment of the membrane:

[Table 1]

Representative samples of this embodiment of the membrane did not degrade after washing with water or ethanol. On the other hand, samples of melt-blown membranes showed a significant decrease in filtration efficiency after washing with ethanol.

A comparison between a representative sample of an embodiment of the nanofibrous polymer membrane described above and a typical melt-blown membrane is shown in Table 2 below:

[Table 2]

The filtration efficiencies and observed pressure drops for the various membrane samples are shown in Table 3 below:

[Table 3]

6-12 show filtration efficiency, flammability, and antiviral and antimicrobial test results for representative samples of embodiments of the nanofibrous polymer membranes described above.

Figure 13 shows how the filtration efficiency is affected by the flow rate of aerosol through the membrane.

Figure 14 shows how the flow rate of aerosol through the membrane affects the transverse pressure drop across the membrane, which is a measure of the air permeability of the membrane.

Description of the embodiments disclosed above is provided to those skilled in the art to make or use the invention disclosed herein. While various aspects of the present invention are disclosed in the context of one or more illustrated embodiments, practices and examples, those skilled in the art will appreciate that the invention goes beyond the specifically disclosed embodiment to other alternative embodiments and/or uses and obvious variations of the present invention. and their equivalents. It is also to be understood that the scope of the present disclosure includes various combinations or sub-combinations of the specific features and aspects of the embodiments disclosed herein, such that the various features, practices and aspects of the disclosed subject matter may be combined with or substituted for one another. . The general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Accordingly, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

All references are expressly incorporated herein by reference.

Claims (36)

As an electrospun polymer nanofibrous membrane with high filtration efficiency,
polyvinylidene fluoride, one or more Tecophilic™ thermoplastic polyurethanes (TPUs), or a blend of polyvinylidene fluoride and one or more Tecophilic™ thermoplastic polyurethanes;
wherein the membrane is treated with one or more anti-pathogenic agents. According to claim 1,
wherein the one or more anti-pathogenic agents include an antiviral agent. According to claim 2,
wherein the antiviral agent is selected from the group consisting of graphene, nanoparticles, nanocomposites, multivalent metal ions and extracts from natural products. According to claim 2,
The membrane, wherein the antiviral agent is coated on the surface of the membrane. According to claim 3,
The membrane of claim 1 , wherein the antiviral agent is selected from the group consisting of silver nanoparticles and zinc nanoparticles. According to claim 3,
The membrane of claim 1, wherein the antiviral agent comprises a silver-doped titanium dioxide nanomaterial. According to claim 3,
The antiviral agent comprises ^a multivalent Cu ²⁺ or ^{Zn 2+} cation. According to claim 3,
The membrane, wherein the antiviral agent comprises licorice extract. According to claim 1,
wherein the membrane is impregnated with one or more metal-organic frameworks (MOFs). According to claim 5,
wherein the one or more metal-organic frameworks comprise zirconium metal-organic frameworks. According to claim 1,
wherein the membrane is electrospun from a polymer solution comprising a surfactant. According to claim 11,
Wherein the surfactant is selected from the group consisting of cetrimum bromide (CTAB), lauramidopropyl betaine (LAPB) and alpha olefin sulfonate (AOS). According to claim 1,
wherein the membrane is electrospun from a polymer solution comprising a salt. According to claim 13,
wherein the salt is selected from the group consisting of alkali metal halides. According to claim 2,
wherein the membrane comprises multiple integrated layers having distinguishable microstructure characteristics. According to claim 15,
wherein the membrane is composed of three layers comprising a first layer and a third layer having the same pore size separated by a second layer having a different pore size. 17. The method of claim 16,
wherein the first and third layers have a larger pore size and the second layer has a smaller pore size. According to claim 15,
wherein the membrane is composed of three layers with three different pore sizes. 18. The method of claim 17,
Electrospinning short fibers prior to electrospinning subsequent layers of the membrane, or by electrospinning wet fibers with a reduced screen distance prior to electrospinning subsequent layers of the membrane, to obtain "tackiness" Membrane wherein the mechanical integrity and bonding between the layers of the membrane is improved by creating a "tacky surface". According to claim 15,
The membrane is formed by winding a textile material roll comprising a textile material from a first side to a second side, followed by the following steps:
(a) electrospinning at least one first layer of nanofibers on a first side of the textile material at a first winding speed;
(b) flipping the roll of fabric material; and
(c) electrospinning at least one second nanofibrous layer on a second side of the textile material at a second winding speed;
Is formed by performing in the order described,
wherein the first winding speed is different from the second winding speed. According to claim 15,
The membrane is formed by winding a textile material roll comprising textile material from the first side to the second side, and then performing the following steps:
(a) electrospinning at least one first layer of nanofibers on a first side of the textile material at a first winding speed; and
(b) electrospinning at least one second layer of nanofibers on the first side of the textile material at a second windup speed;
Is formed by performing in the order described,
wherein the first winding speed is different from the second winding speed. According to claim 15,
The membrane is formed by winding a textile material roll comprising textile material from the first side to the second side, and then performing the following steps:
(a) electrospinning at least one first layer of nanofibers on a first side of the textile material at a first winding speed;
(b) electrospinning at least one second layer of nanofibers on the first side of the textile material at a second windup speed;
(c) flipping the roll of fabric material; and
(d) electrospinning at least one third nanofibrous layer on the second side of the textile material at a third winding speed;
Is formed by performing in the order described,
wherein the first winding speed is different from the second winding speed. As an electrospun polymer nanofibrous membrane with high filtration efficiency,
polyvinylidene fluoride, one or more Tecophilic™ thermoplastic polyurethanes (TPUs), or a blend of polyvinylidene fluoride and one or more Tecophilic™ thermoplastic polyurethanes;
wherein the membrane is impregnated with one or more anti-pathogenic agents. 24. The method of claim 23,
wherein the membrane is impregnated with one or more metal-organic frameworks. 25. The method of claim 24,
wherein the one or more metal-organic frameworks comprise zircon metal-organic frameworks. 24. The method of claim 23,
wherein the membrane is electrospun from a polymer solution comprising a surfactant. 27. The method of claim 26,
wherein the surfactant is selected from the group consisting of cetrimonium bromide (CTAB), lauramidopropyl betaine (LAPB) and alpha olefin sulfonate (AOS). 24. The method of claim 23,
wherein the membrane is electrospun from a polymer solution comprising a salt. 29. The method of claim 28,
wherein the salt is selected from the group consisting of alkali metal halides. 24. The method of claim 23,
wherein the membrane comprises a plurality of integrated layers having distinguishable microstructural properties. 31. The method of claim 30,
wherein the membrane is composed of three layers comprising a first layer and a third layer having the same pore size separated by a second layer having a different pore size. 32. The method of claim 31,
wherein the first and third layers have a larger pore size and the second layer has a smaller pore size. 31. The method of claim 30,
wherein the membrane is composed of three layers with three different pore sizes. 33. The method of claim 32,
layers of the membrane by electrospinning short fibers prior to electrospinning subsequent layers of the membrane, or by electrospinning wet fibers with decreasing screen distance to create a "sticky surface" prior to electrospinning subsequent layers of the membrane. Membrane with improved mechanical integration and bonding strength between As an electrospun polymer nanofibrous membrane with high filtration efficiency,
polyvinylidene fluoride, one or more Tecophilic™ thermoplastic polyurethanes (TPUs), or a blend of polyvinylidene fluoride and one or more Tecophilic™ thermoplastic polyurethanes;
wherein the membrane is impregnated with one or more metal-organic frameworks. 23. The method of claim 22,
wherein the one or more metal-organic frameworks comprise zircon metal-organic frameworks.

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