In one embodiment is provided a polymer blend of poly(vinyl acetate) (PVAc) and poly(acrylic acid) (PAA), wherein the poly(vinylacetate) is present in an amount ranging between about 20 wt % and about 80 wt %, and poly(acrylic acid) is present in an amount ranging between about 80 wt % and about 20 wt %, based on the total weight of the blend. In another embodiment is provided a fiber produced from this polymer blend, and which has cells therein. In another embodiment is provided a flavorant release material comprising the porous fiber disclosed herein, and one or more flavorants disposed in a longitudinally extending core within the fiber. In another embodiment is provided a polymer fiber membrane containing a hollow, porous fiber formed from the polymer blend disclosed herein. In another embodiment is provided a filter containing the fiber described herein. In another embodiment is provided a process for producing the fibers disclosed herein by addition of the polymers to an extruder or blender, and extruding or melt spinning the mixture into a fiber containing cells therein.

A polyolefin multilayer microporous membrane is disclosed. The polyolefin multilayer microporous membrane has at least three layers, the membrane comprising a first microporous layer composed of a polyethylene resin containing an ultrahigh molecular weight polyethylene (surface layers) and a second microporous layer composed of a polyolefin rein containing a high-density polyethylene and polypropylene (intermediate layer), wherein (I) the pin puncture strength is at least 25 g/m, (II) the coefficient of static friction with respect to a metal foil is at least 0.40, and (III) the meltdown temperature is at least 180 C.

Disclosed is a method of producing a microporous polymer membrane, comprising: providing a polymer material; melting the polymer material; forming a precursor film by cooling and crystallizing the molten polymer material using an air knife; extending the precursor film; annealing the extended precursor film, primary stretching the annealed precursor film; forming a preliminary membrane by subjecting the primary stretched film to secondary stretching at a high temperature, and forming a microporous polymer membrane by heat setting the preliminary membrane. A microporous polymer membrane produced by the method is also provided.

The present invention is directed to methods of treating a hydrocarbon-containing waste stream to form a hydrocarbon-containing retentate and an aqueous permeate which is substantially free of hydrocarbon. The method includes passing the hydrocarbon-containing waste stream through a microporous membrane to yield the hydrocarbon-containing retentate and the aqueous permeate. The membrane comprises a substantially hydrophobic, polymeric matrix and substantially hydrophilic, finely divided, particulate filler distributed throughout the matrix. The polymeric matrix has pores with a volume average diameter less than 1.0 micron, and at least 50 percent of the pores have a mean diameter of less than 0.35 micron.

A method for removing retroviruses from liquid samples and a nanofiber containing liquid filtration medium that simultaneously exhibits high liquid permeability and high microorganism retention is disclosed. Retroviruses are removed from a liquid by passing the liquid through a porous nanofiber containing filtration medium having a retrovirus LRV greater than about 6, and the nanofiber(s) has a diameter from about 10 nm to about 100 nm. The filtration medium can be in the form of a fibrous electrospun polymeric nanofiber liquid filtration medium mat.

Provided is a black porous polytetrafluoroethylene membrane including a porous polytetrafluoroethylene membrane dyed black. A whiteness of a principal face of the black porous polytetrafluoroethylene membrane as measured according to JIS L 1015 (Hunter method) is 18.0 to 23.0%, and the whiteness of the principal face falls within a range of 18.0 and 25.0% after heating at 350 C. for 1 minute. This black porous PTFE membrane is suitable as a gas-permeable membrane that blocks entry of water and/or dust and that allows permeation of gases; specifically, the black porous PTFE membrane is suitable, for example, as a waterproof sound-transmitting membrane, a waterproof gas-permeable membrane, and a dustproof gas-permeable membrane.

A polyolefin microporous membrane is disclosed. The membrane includes at least one microporous membrane layer, where the microporous membrane layer has an air permeability between about 100 sec/100 cc and about 220 sec/100 cc, a pin puncture strength of at least 550 gf, and a crystallization half time t.sub.1/2 of from 10 to 35 minutes when subjected to isothermal crystallization at 117 C. The air permeability and the pin puncture strength are normalized to a thickness of 16 m.

In one embodiment is provided a polymer blend of poly(vinyl acetate) (PVAc) and poly(acrylic acid) (PAA), wherein the poly(vinylacetate) is present in an amount ranging between about 20 wt % and about 80 wt %, and poly(acrylic acid) is present in an amount ranging between about 80 wt % and about 20 wt %, based on the total weight of the blend. In another embodiment is provided a fiber produced from this polymer blend, and which has cells therein. In another embodiment is provided a flavorant release material comprising the porous fiber disclosed herein, and one or more flavorants disposed in a longitudinally extending core within the fiber. In another embodiment is provided a polymer fiber membrane containing a hollow, porous fiber formed from the polymer blend disclosed herein. In another embodiment is provided a filter containing the fiber described herein. In another embodiment is provided a process for producing the fibers disclosed herein by addition of the polymers to an extruder or blender, and extruding or melt spinning the mixture into a fiber containing cells therein.

A membrane is a microporous sheet made of a blend of a first ultra high molecular weight polyolefin and a second ultra high molecular weight polyolefin. Each polyolefin has a molecular weight, both of those molecular weights are greater than 1 million, and one molecular weight is greater than the other. Additionally, the intrinsic viscosity (IV) of the membrane may be greater than or equal to 6.3.

The invention relates to a method for assembling a bipolar membrane, and bipolar membrane thereof. The method comprises the steps of electrospinning and centrifugal spinning and electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer, electrospinning and centrifugal spinning and electrocentrifugal spinning a junction layer. Further, the method comprises electrospinning and centrifugal spinning and electrocentrifugal spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. A system comprising a bipolar membrane according to the invention is also disclosed.