Usf Filtration & Separations Group Inc.

USA As Represented by Secretary of the Navy

Pall Corporation

Memtec America Corporation

Domnick Hunter Filters Ltd.

Jerome F Ditter

I-Fan Wang

Todd Benson

Robert F Zepf

Richard A Morris

Rey Sarabia

Mike Gaughan

Eugene B Klusmann

Rick Morris

Francis J Gerhart

Robert E Williams

Jeffrey Porter

Richard Mcdonogh

Steven Lamon

Highly asymmetric polymeric membranes with large pores which yield bubble points in the range of 0.5 to 25 psid and superior flow characteristics. The membranes can be cast from both metastable dispersions and from homogenous casting formulations. The technique of synthesis involves exposure of the cast membrane to humid air to create large surface pores on the exposed side.

Large pore synthetic polymer membranes

The present invention relates to the field synthetic polymeric membrane materials formed from casting polyvinylidene difluoride (PVDF) polymer solutions and/or dispersions. Membranes formed in accordance with the present invention are all highly porous. Both internally isotropic membranes and highly asymmetric PVDF membranes are disclosed. Membranes of the invention may be hydrophobic or hydrophilic. The membranes of the invention are useful in a variety of microfiltration and ultrathin applications.

Highly porous polyvinylidene difluoride membranes

The present invention relates to the field synthetic polymeric membrane materials formed from casting polyvinylidene difluoride (PVDF) polymer solutions and/or dispersions. Membranes formed in accordance with the present invention are all highly porous. Both internally isotropic membranes and highly asymmetric PVDF membranes are disclosed. The membranes of the invention are useful in a variety of microfiltration and ultrathin applications.

Process of making a polyvinylidene difluoride membrane

The present invention relates to highly asymmetric polymer membranes for ultrafiltration (UF), and to a simplified method of their manufacture. Disclosed herein are UF membranes with a high degree of asymmetry between the size of pores at the skin face of the membrane and the size of pores at the opposite face of the membrane. Asymmetry ratios of these membranes range from about 20 to about 1000. The porous support layer between the skin face and the opposite face is reticular and is substantially free of macrovoids. These membranes thus have higher flow rates than prior UF membranes. The membranes are cast from polymer dope mixes that are either homogeneous solutions or stable colloidal dispersions.

Highly asymmetric ultrafiltration membranes

The present invention relates to the field synthetic polymeric microfiltration membrane materials that are fabricated to separate liquids from solids contained therein. One aspect of the invention relates to a sulfone polymer membrane with high surface porosity (high pore density) and distinctive asymmetry that can separate solids (i.e., blood cells) from a liquid (i.e., plasma) without the need for centrifugation. The membrane is further rendered hydrophilic through co-casting the sulfone polymer (which is a hydrophobic polymer) with a hydrophilic polymer, such as polyvinylpyrrolidone. Because of these properties and the fact that it requires only a small amount of the solid containing liquid (i.e., whole blood) to be applied to the larger pore surface, the membranes of the invention are highly useful in testing devices for the quick detection of properties or components contained in liquid samples, such as diagnostic applications (i.e., the detection of physiological conditions (i.e., pregnancy, insulin levels, stomach ulcer, and the like) and infectious diseases (i.e., AIDS, hepatitis, and the like)).

Microfiltration membranes having high pore density and mixed isotropic

Polyamide membranes

The .beta.-methylation of 2,4-dicarba-closo-heptaborane-7 through the reaon of methyl chloride with the parent carborane in the presence of metal trichloride selected from the group consisting of aluminum chloride and ferric chloride in a methyl chloride-to-carborane mole ratio from 1:1 to 6:1 and a metal trichloride-to-carborane from 0.3:1 to 5:1 at a temperature from about 30.degree. C to about 60.degree. C and at a pressure of at least 50 psig.

Synthesis of .beta.-methyl derivatives of 2,4-dicarba-closo-heptaborane-7

A method for preparing a mixture of decaborane-14 and an alkyl-substituted ecaborane-14 which comprises admixing an ethereal solution of nonaborane-14 ions with an alkaliboron halide at a temperature from 20.degree. C to 30.degree. C and at pressure from atmospheric pressure to 400 psig and a method of preparing decaborane-14 which comprises preparing an ethereal solution of nonaborane-14 by a reaction in an ethereal solution of an alkali metal borohydride with an excess of pentaborane-9 at temperature from 20.degree. C to 30.degree. C and admixing this ethereal solution of nonaborane-14 ions with diborane-6 at a temperature from 20.degree. C to 30.degree. C and at a pressure of at least 50 psig. Such compounds are useful as precursor compounds for the synthesis of important carborane derivatives, such as n-hexylcarborane (a catalyst for rocket propellants) and high-temperature-resistant carborane/siloxane polymers.

Synthesis of decaborane-14 and alkyl-substituted decaborane-14

This disclosure describes the process for producing an apparently amorphous porous boron carbide having a mean particle size less than 1 micron in diameter, effective pore sizes on the order of 30 Angstrom units, and surface areas on the order of 100 m.sup.2 /gr and greater. The process involves the gaseous phase reaction of acetylene (C.sub.2 H.sub.2) with diborane (B.sub.2 H.sub.6). The reaction is produced in a closed chamber initiated by an appropriate igniting device, such as a hot wire. This disclosure defines an optimum ratio of four parts diborane to one part acetylene and it describes the operating conditions under which the reaction occurs and the variation in physical properties and yield resulting from changes of ratio of the constituents. It also describes modification of the present batch process to a continuous production process. Typical uses for the material in its basic or altered form are described, such as a catalyst for gas-solid reactions, as a catalyst-supporting substrate for certain transition metals and other catalytic materials, as a gelling agent or grease thickener, as a thermal neutron absorber, either neat or in admixture with oils, etc., as a high temperature insulation material and as a fluidized bed heat exchange medium.

Growing community of inventors

Santa Ana, CA, United States of America

Jerome F Ditter