Membrane polymer compositions
First Claim
1. A membrane comprising:
- a terpolymer of about 35 wt. % to about 40 wt. % of polyvinylidene fluoride monomer, from about 17 wt. % to about 20 wt. % of hexafluoropropylene monomer, and from about 40 wt. % to about 48 wt. % of tetrafluoroethylene monomer; and
a hydrophobicity modifying agent.
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Abstract
The invention relates to a terpolymer of tetrafluoroethylene (TFE) monomer, polyvinylidene fluoride (PVDF) monomer and hexafluoropropylene (HFP) monomer for forming an ultrafiltration or microfiltration membrane, method of forming said membranes, and to the ultrafiltration or microfiltration membranes themselves. The invention also relates to a method of forming a polymeric ultrafiltration or microfiltration membrane including preparing a leachant resistant membrane dope which incorporates a leachable pore forming agent, casting a membrane from the dope and leaching the pore forming agent from the membrane. The invention also relates to a method of preparing a polymeric ultrafiltration or microfiltration membrane of improved structure including the step of adding a nucleating agent to the membrane dope before casting.
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Citations
15 Claims
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1. A membrane comprising:
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a terpolymer of about 35 wt. % to about 40 wt. % of polyvinylidene fluoride monomer, from about 17 wt. % to about 20 wt. % of hexafluoropropylene monomer, and from about 40 wt. % to about 48 wt. % of tetrafluoroethylene monomer; and a hydrophobicity modifying agent. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of preparing a polymeric membrane comprising:
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preparing a membrane dope resistant to a leachant, the membrane dope comprising a terpolymer derived from about 35 wt. % to about 40 wt. % of polyvinylidene fluoride monomer, about 17 wt. % to about 20 wt. % of hexafluoropropylene monomer, and about 40 wt. % to about 48 wt. % of tetrafluoroethylene monomer, and a leachable pore forming agent; casting the membrane dope into the polymeric membrane; and leaching the leachable pore forming agent from the polymeric membrane with the leachant. - View Dependent Claims (8, 9, 10, 11)
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12. A method of casting a polymeric membrane, the method comprising:
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preparing a membrane dope comprising a terpolymer and a catalytic amount of a nucleating agent, wherein said terpolymer is derived from about 35 wt. % to about 40 wt. % of polyvinylidene fluoride monomer, from about 17 wt. % to about 20 wt. % of hexafluoropropylene monomer, and from about 40 wt. % to about 48 wt. % of tetrafluoroethylene monomer; and casting a filtration membrane from the membrane dope. - View Dependent Claims (13, 14, 15)
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Specification