Asymmetric polymer membrane and preparation thereof
AssigneeDainippon Ink and Chemicals, Inc.
InventorsHusheng Zhang, Takanori Anazawa, Kazunari Sakai
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Abstract
An asymmetric polymer membrane is disclosed characterized by being formed by irradiating a monomer and/or an oligomer polymerizable with an energy ray and having a pore diameter distribution in the thickness direction of the membrane, a ratio of a permeability flux of oxygen to nitrogen of 0.9-1.1, and communicating pores.
Claims8
A method for preparing an asymmetric polymer membrane having a pore diameter gradient in the depth of the membrane, comprising the steps, in the following order, of:
- providing a homogeneous polymerizable solution including at least one member of the group consisting of a monomer and an oligomer, the member forming a crosslinked polymer upon exposure to energetic radiation;
- and a solvent for the monomer or oligomer which does not dissolve and does not swell the polymer;
- forming a layer of the homogeneous polymerizable solution;
- evaporating a portion of the solvent from the layer of the homogeneous solution;
- and
- forming said polymers substantially soley by irradiating the layer of the homogeneous solution with energetic radiation.
A method for preparing an asymmetric polymer membrane having a pore diameter gradient in the depth of the membrane, comprising the steps, in the following order, of:
- providing a homogeneous polymerizable solution including at least one member of the group consisting of a monomer and an oligomer, the member forming a crosslinked polymer upon exposure to energetic radiation;
- and a solvent for the monomer or oligomer which does not dissolve and does not swell the polymer;
- forming a layer of the homogeneous polymerizable solution and
- exposing the layer of the homogeneous solution to a temperature gradient while forming said polymers substantially soley by irradiating the layer of the homogeneous solution with energetic radiation.
An asymmetric polymer membrane comprising a polymer having a crosslinked structure formed by polymerizing at least one of a monomer and an oligomer polymerized substantially solely by exposure to radiation, the polymer membrane having continuous pores, a gradient of pore diameters from one face of the membrane to the opposing face of the membrane and a ratio of a permeability flux of oxygen to a permeability flux of nitrogen of 0.9-1.1.
Dependencies are inferred from the claim text.