The present invention generally relates to a dual density air filtration media that comprises a plurality of nanofibers layers formed from nanofibers having different fiber diameters. Due to the presence of these multiple nanofiber layers with different nanofiber diameters, the resulting filtration media of the present invention comprises a gradient density. In particular, the present invention uses a novel combination of two or more layers of nanofibers made via an electrospinning process, wherein the nanofiber layers made up from different fiber sizes are strategically applied to a cellulose or synthetic base material or substrate, to thereby maximize the filtration efficiency and dust holding capacity of the resulting filtration media.

Articles such as filter media, which include dendrimers and/or other components, are provided. The filter media may further include a water repellant (e.g., a fluorinated species) to impart desirable properties to the media such as high water repellency. The filter media may also have a high efficiency as a function of pressure drop (i.e., high gamma values). In some embodiments, the filter media includes a fiber web which may be formed of various components such as glass fibers. The fiber web can also include additional components such as synthetic fibers, binder components, as well as other additives. The media may be incorporated into a variety of filter element products.

A moisture-retentive fabric medium includes a hydrophilic, thermoplastic polyester fiber as a blend of from 10-905% or 20-80% by total weight of textile fibers and 90-10% or 80-20% by total weight of hydrophilic textile fibers and less than 0.5% by weight of total fabric medium as microfibrillated cellulose fiber and less than 0.05% by weight superabsorbent polymers, the polyester having a melting point between 190-500 F when measured in accordance with ASTM D-3418.

A nonwoven fabric, including fibers, in which the fibers have an elongational viscosity, as measured under conditions at an elongational strain rate of 2.5×10.sup.2 (1/s) and a temperature of 160° C., of from 430 Pa.Math.s to 1200 Pa.Math.s, and a ratio of the elongational viscosity (Pa.Math.s) to a shear viscosity (Pa.Math.s) of the fiber, as measured under conditions at a shear strain rate of 2.5×10.sup.2 (1/s) and a temperature of 160° C., is from 35 to 65.

An improved technology for inactivation of viruses, for example the SARS-CoV-2 virus that is causing the Covid-19 pandemic, is described. The technology can include a device that includes a substrate coated in a polymer that is infused with a pathogen inactivating material. In various embodiments, at a given time, a portion of the pathogen inactivating material is exposed to the environment, and the device is configured to periodically or intermittently expose additional pathogen inactivating material to the environment. For example, the polymer can be ablative or sacrificial.

Provided are a sub-micron fibrous membrane in which sub-micron fibers aligned along one axis and sub-micron fibers in a random pattern form a network, and a method for producing the sub-micron fibrous membrane.

The present invention discloses a Fe—Al-based metal porous membrane and a preparation method thereof, which relate to the technical field of industrial gas-solid and liquid-solid separation and purification, and mainly address problems in the prior art, such as cracking-prone and peeling of a membrane layer of an existing Fe—Al-based metal porous membrane during its preparation and use. The preparation method of the present invention comprises the steps of: adding a Fe—Al-based metal powder and a metal fiber powder into an organic-additive-added water-based solvent, and mixing them into a slurry; casting the slurry, through a casting machine, to form a membrane green body on a metal substrate layer, and letting it dry; and placing the dried membrane green body in a sintering furnace, to remove organic substances and perform high-temperature sintering and predetermined-temperature reaction synthesis.

The disclosure provides improved vent filters useful in single-use in-line transfusion systems. In a first aspect, the disclosure provides filter comprising (i) a layer comprising a fluoropolymer membrane and (ii) a layer comprising at least two air-permeable thermoplastic polymeric layers, the air-permeable thermoplastic polymeric layers comprised of a first polymeric layer and a second polymeric layer, wherein the first polymeric layer is in bonded contact with the fluoropolymer membrane, possesses a melting point of about 95° C. to about 180° C., and wherein the second polymeric layer is in bonded contact with the first polymeric layer and has a melting point of about 220° C. to about 265° C. These filters exhibit excellent bonding strength between the various layers while preserving a considerable amount of the original fluoropolymer membrane air flux.

Articles and methods involving filter media are generally provided. In certain embodiments, the filter media includes at least a first layer, a second layer, and an adhesive resin positioned between the first layer and the second layer. In some embodiments, the first layer may be a pre-filter layer or a support layer. The second layer may, for example, comprise fibers formed by a solution spinning process and/or may comprise fine fibers. In some embodiments, the adhesive resin may be present in a relatively low amount and/or may have a low glass transition temperature. The filter media as a whole may have one or more advantageous properties, including one or more of a high stiffness, a high bond strength between the first layer and the second layer, a high gamma, and/or a low increase in air resistance after being subjected to an IPA vapor discharge. The filter media may be, for example, a HEPA filter and/or an ULPA filter.

A filter media construct includes a plurality of flexible laminas joined in a stack, each lamina including an array of nanofibers extending from a surface thereof. Each lamina is configured to be permeable to a fluid such that the fluid can flow through each lamina normal to the surface thereof and in any direction along at least a portion of said surface when the fluid is flowed through the construct. The laminas can include a plurality of perforations extending therethrough such that the fluid flows through at least some of the perforations of the laminas when the fluid is flowed through the construct. A contaminant contained in the fluid is at least partially filtered from the fluid by the nanofibers when the fluid is flowed along the surface of any lamina or into or through the perforations.