Membrana Gmbh

3m Innovative Properties Company

Celgard Inc.

Em Innovative Properties Company

Quan Huang

Oliver Schuster

Wolfgang Ansorge

Bernd Seibig

Dieter Paul

Karl Bauer

Phung Ngoc Duong

Zhengming Zhang

Frank Wiese

Britta Zimmerer

Hartmut Stenzel

Ngoc-Phung Duong

Phung Duong

Hydrophobic flat membrane made from a vinylidene fluoride polymer with a wall, a first surface, and a second surface. The membrane has on its first surface a network structure with open pores and on its second surface a continuous skin in which pores are formed, and adjacent to the skin of the second surface a supporting layer with an isotropic pore structure across the wall thickness, wherein the supporting layer extends over at least 80% of the wall thickness and wherein the pores of the supporting layer have an average diameter of less than 1 &#x3bc;m. The weight average of the molecular weight Mof the vinylidene fluoride polymer lies in the range from 300 000 to 500 000 daltons, and the polydispersivity M/Mis greater than 5.5. The pores in the skin of the second surface have a closed perimeter in the plane of the skin and an average ratio of the extension in the direction of the longest axis thereof to the extension in the direction of the shortest axis thereof of at most 5. The pores in the first surface and second surface have an essentially isotropic distribution of their orientation. The porosity of the membrane lies in the range from 50 to 90 vol. % and the wall thickness in the range from 50 to 300 &#x3bc;m. The membrane has a maximum separating pore diameter din the range from 0.05 to 1.5 &#x3bc;m.

Microporous polyvinyl fluoride planar membrane and production thereof

Hydrophobic hollow-fiber membrane made from a vinylidene fluoride polymer with a wall and a wall thickness, an outer surface on its outer side, an inner surface on its inner side and facing its lumen and adjacent to the inner surface a supporting layer having a structure that is substantially isotropic across the wall thickness, the supporting layer extending over at least 80% of the wall thickness and comprising pores having an average diameter of less than 1 &#x3bc;m, and wherein the hollow-fiber membrane has pores on its outer surface and on its inner surface, characterized in that the vinylidene fluoride polymer has a weight-average molecular weight Min the range from 550 000 to 700 000 daltons and a polydispersivity greater than 3.0; the pores in the outer and in the inner surface are formed like islands and have a maximum ratio of their longitudinal extension to the transverse extension of 10; the porosity lies in the range from 50 to 90 vol. %, the wall thickness in the range from 50 to 300 &#x3bc;m, and the diameter of the lumen in the range from 100 to 500 &#x3bc;m; and the hollow-fiber membrane has a maximum separating pore diameter din the range from 0.3 to 0.7 &#x3bc;m, determined according to the bubble point method.

Microporous polyvinylidene fluoride membrane

The invention relates to a hydrophobic, integrally asymmetrical hollow-fiber membrane made of a vinylidene fluoride homopolymer or copolymer, wherein the wall of the membrane has a microporous supporting layer having a sponge-like, open-pored, essentially isotropic pore structure without finger pores, the supporting layer extending across at least 90% of the wall thickness and having pores with an average diameter of less than 0.5 &#x3bc;m. The hollow-fiber membrane is characterized in that it has a separating layer adjacent to the supporting layer on its outer surface and that it has an outer surface with a homogeneous, uniform structure without pores, a porosity in the range from 40 to 80 vol. %, a wall thickness from 25 to 100 &#x3bc;m, a diameter of the lumen of the hollow-fiber membrane from 100 to 500 &#x3bc;m, a permeability for nitrogen of at least 25 ml/(cm&#xb7;min&#xb7;bar), and an elongation at break of at least 250%. The invention further relates to a method for producing hollow-fiber membranes of this type.

Hydrophobic ozone-stable membrane made of polyvinylidene fluoride

A direct methanol fuel cell has a proton conducting membrane (PCM), a catalyst in contact with the PCM, a gas diffusion layer in contact with the catalyst, and a conducting plate in contact with the gas diffusion membrane. The gas diffusion layer comprises a microporous membrane. The microporous membrane may be a microporous membrane, a laminate of a microporous membrane, and a skinned microporous membrane.

Direct methanol fuel cell

Method for producing foamed microporous polymer molded bodies by melting a thermoplastic polymer in a first zone of an extrusion device, mixing in a highly volatile blowing agent, conveying the polymer melt containing the blowing agent into a second zone in which dissolution of the blowing agent occurs to saturation of the polymer melt at the foaming temperature, and molding and foaming of the loaded polymer melt to a foamed structure, whereby, in the second zone, a pressure above 90 bar, a blowing agent concentration above the critical minimum concentration for complete foaming, and the foaming temperature, lying above the solidification temperature of the polymer melt saturated with blowing agent, are set such that the polymer molded body obtained has a porosity in the range between 40 and 90 vol. % and an open-cell pore structure with uniform cross-sectional distribution. Foamed microporous polymer molded bodies in the form of particles comprising a thermoplastic polymer with uniform open-cell pore structure, a porosity of 40 to 90 vol. %, an accessible proportion of pore volume of at least 0.75 and an average cell size between 1 and 100 &#x3bc;m.

Method for producing foamed polymer molded bodies and said foamed polymer molder bodies

A method using a two part process line is proposed for manufacturing foams from polymers or polymer mixtures useful for making molded bodies. The process line is divided into at least one first part and one second part. The polymer or polymer mixture is melted in the first part and a gas at a pressure increased relative to the melt pressure is added with the influence of a shearing and/or kneading device on the melted polymer or polymer mixture enriched with gas. In the second part of the process line, foam is formed from the gas-enriched polymer or polymer mixture at a higher pressure than the pressure in the first part of the process line. Membranes can be made from the molded bodies made by the method described above.

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Quan Huang