Pall Corporation

Joseph A Gregg

Peter J Degen

Richard F Salinaro

Ioannis P Sipsas

Gregory C Rapisarda

The present invention provides an isotropic, skinless, porous, polyvinylidene fluoride membrane having a K.sub.UF of at least about 15 psi (103 kPa), and preferably below about 50 psi (345 kPa), when tested using liquid pairs having an interfacial tension of about 4 dynes/cm (4 mN/m). The present inventive membrane preferably has a titer reduction of at least about 10.sup.8 against T.sub.1 bacteriophage, more preferably also against PR772 coliphage, and even more preferably also against PP7 bacteriophage. The present inventive membrane can have a thickness of about 20 mil (500 .mu.m) or less and even as low as about 5 mil (125 .mu.m) or less. The present invention also provides a method of preparing such a membrane by providing a casting solution comprising polyvinylidene fluoride and a solvent therefor, heating the casting solution to a uniform temperature of about 57.degree. C. to about 60.degree. C., spreading the casting solution onto a substrate to form a film, quenching the film in a quench bath so as to form a porous membrane, and washing and drying the porous membrane.

Polyvinylidene fluoride membrane and method for removing viruses from

A PVDF membrane exposed to a quarternary ammonium hydroxide solution retains it hydrophobicity and resistance to corrosive environments, yet spontaneously and completely wets with concentrated sulfuric and nitric acids. The modified membrane is incorporated into filtration devices that are in situ integrity testable in concentrated inorganic mineral acids.

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Glen Head, NY, United States of America

Joseph A Gregg