Cationic charge modified microporous membrane
First Claim
1. A cationic charge modified microporous hydrophilic membrane, comprising:
- a microporous membrane substrate comprising polyethersulfone and at least one non-leachable polymeric additive selected from polyvinylpyrrolidone and polyethylene glycol, which additive enhances hydrophilicity and has functional groups latently reactive with respective groups of charge modifying agents; and
a primary charge modifying agent comprising polyethyleneimine-epichlorohydrin resin which contains polyamines, can chemically react with electrophile-containing compounds and thus impart a net positive charge, and is chemically grafted to said polymeric additive.
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Abstract
Cationic charge modified microporous hydrophilic membranes are provided, as well as preparation of the same by post-treatment. Typically, as an illustration, a microporous hydrophilic membrane substrate which contains non-leachable polymeric additive having functional groups is treated in an alkaline solution for simultaneous or sequential reaction with 1) a primary charge modifying agent which is an epichlorohydrin modified polyamine, and 2) a secondary polymeric charge modifying agent containing a fixed formal positive charge (or for reaction with the primary charge modifying agent alone); then cured at elevated temperature; and finally washed and dried. The cationically charged microporous membranes are used in various applications such as the filtration of fluids and the macromolecular transfer from electrophoresis gels.
93 Citations
38 Claims
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1. A cationic charge modified microporous hydrophilic membrane, comprising:
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a microporous membrane substrate comprising polyethersulfone and at least one non-leachable polymeric additive selected from polyvinylpyrrolidone and polyethylene glycol, which additive enhances hydrophilicity and has functional groups latently reactive with respective groups of charge modifying agents; and a primary charge modifying agent comprising polyethyleneimine-epichlorohydrin resin which contains polyamines, can chemically react with electrophile-containing compounds and thus impart a net positive charge, and is chemically grafted to said polymeric additive. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 33, 34, 35, 36, 37, 38)
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23. A cationic charge modified microporous hydrophilic membrane, comprising:
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a microporous membrane substrate comprising polyethersulfone and at least one non-leachable active polymeric additive selected from polyvinylpyrrolidone and polyethylene glycol, which additive enhances hydrophilicity and has functional groups latently reactive with reactive groups of charge modifying agents; a primary charge modifying agent comprising polyethyleneimine-epichlorohydrin resin which contains polyamines, can chemically react with electrophile-containing compounds and thus impart a net positive charge, and is chemically grafted to said polymeric additive; and a secondary charge modifying agent containing functionality that is reactive with the primary charge modifying agent, selected from the group consisting of partially phosphinated polyvinylbenzyl chloride ammonium and sulfonium analogs thereof, and quaternized poly(dimethylamine-co-epichlorohydrin) said secondary agent being reacted with the primary agent in an amount either such that the magnitude of the final formal positive charge is increased over that due to its reaction with the primary agent or such that the sensitivity of the primary agent to the variance of environmental pH is decreased. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification