Method for forming fluorinated ionomers
AssigneeE. I. DuPont de Nemours and Company
InventorsPaul Gregory Bekiarian, William Brown Farnham
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Abstract
This invention concerns a method for forming ionomers by treatment with ammonium carbonate of copolymers having a substantially fluorinated, but not perfluorinated, polyethylene backbone having pendant groups of fluoroalkoxy sulfonyl fluoride. Ionomers derived therefrom by ion exchange are useful in electrochemical applications such as batteries, fuel cells, electrolysis cells, ion exchange membranes, sensors, electrochemical capacitors, and modified electrodes.
Claims19
A process for forming an ionomer, comprising
- contacting a polymer comprising
- monomer units of vinylidene fluoride and 0.5-50 mole % of a perfluoroalkenyl monomer having a pendant group of the formula
- O—CF2CFR)aO—CF2(CFR′)bSO2F
- wherein R and R′ are independently selected from F, Cl or a perfluorinated alkyl group having 1 to 10 carbon atoms, a=0, 1 or 2, b=0 to 6,
- with an excess of a solution of ammonium carbonate for a period of time sufficient to obtain the degree of conversion desired to the ammonium sulfonate form of the polymer, thereby forming an ammonium ionomer.
An ionomer comprising monomer units of vinylidene fluoride and 0.5-50 mole % of a perfluoroalkenyl monomer having a pendant group of the formula
- —(O—CF2CFR)aO—CF2(CFR′)bSO3−NH4+
- wherein R and R′ are independently selected from F, Cl or a perfluorinated alkyl group having 1 to 10 carbon atoms, a=0, 1 or 2, b=0 to 6.
Dependencies are inferred from the claim text.