Claims
- 1. A method for preparing a porous hydrophilic polypropylene membrane, which comprises:
- (a) forming a homogeneous mixture of hydrophobic polypropylene, functionalized polypropylene comprising from about 0.3 to about 10 mole % of functional groups selected from the group consisting of --OH, --NH.sub.2, --COOH and mixtures thereof, and at least one fugitive hydrophilic pore-forming agent in a first solvent, said pore-forming agent (i) being soluble either in water or in a non-solvent for said hydrophobic polypropylene and (ii) exhibiting a chemical affinity for the functional groups in said functionalized polypropylene;
- (b) depositing said homogeneous mixture on a casting surface;
- (c) evaporating a portion of said first solvent to initiate a conversion of said homogeneous mixture to a gelled film;
- (d) evaporating the remainder of said first solvent to complete the conversion of said homogeneous mixture into said gelled film; and
- (e) extracting said at least one hydrophilic pore-forming agent from said gelled film with a second solvent that is incapable of dissolving said hydrophobic polypropylene and said functionalized polypropylene, thereby forming a porous hydrophilic polypropylene membrane having functionalized polypropylene concentrated within the portions of the membrane that had been occupied by said fugitive pore-forming agent prior to the extraction thereof from said gelled film due to the chemical affinity of said pore-forming agent for the functional groups of said functionalized polypropylene.
- 2. The method according to claim 1, wherein said at least one fugitive hydrophilic pore-forming agent is selected from the group consisting of polyethylene glycol, polyvinylpyrrolidone, phenol and mixtures thereof.
- 3. The method according to claim 1, wherein said functionalized polypropylene has a viscosity average molecular weight of from abut 30,000 to about 1,000,000.
- 4. The method according to claim 1, wherein said casting surface is comprised of polytetrafluoroethylene.
RELATED APPLICATIONS
This application is a division of Ser. No. 08/629,176, filed Apr. 6, 1996, entitled NEW HYDROPHILIC POLYPROPYLENE MEMBRANES now U.S. Pat. No. 5,837,365.
Non-Patent Literature Citations (1)
Entry |
Chung et al., "Kinetic Aspects of the Copolymerization between x-Olefins and Borane Monomer in Ziegler-Natta Catalyst", Reprinted from Macromolecules, Dec. 26, 1993, pp. 3019-3025. |
Divisions (1)
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Number |
Date |
Country |
Parent |
629176 |
Apr 1996 |
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