Ion-exchange structures of copolymer blends useful in electrolytic cells
AssigneeE. I. Du Pont de Nemours and Company
InventorsCharles J. Molnar, Edward H. Price, Paul R. Resnick
Life of this patent
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Abstract
Ion-exchange films, membranes and laminar structures incorporating a layer of a blend of a first fluorinated polymer which contains sulfonyl groups in ionizable form and a second fluorinated polymer which contains carboxylic acid functional groups, when used to separate the anode and cathode compartments of an electrolysis cell, permit operation at high current efficiency and low power consumption. They can be made by synthesis of precursor polymers in melt-fabricable form, blending, fabrication of the film, membrane or laminar structure, and hydrolysis of the functional groups to ionizable form, such as the free acid form or alkali metal salt thereof.
Claims12
A film or membrane of a blend of 10 to 90% by wt. of a first fluorinated polymer which has repeating units ##STR17## where m is 3 to 15,
- n is 1 to 10,
- p is 0, 1 or 2,
- the X's taken together are four fluorines or three fluorines and one chlorine,
- Y is F or CF.sub.3, and
- R.sub.f is F, Cl, or a C.sub.1 to C.sub.10 perfluoroalkyl radical, and 90 to 10% by wt. of a second fluorinated polymer which has repeating units ##STR18## where q is 3 to 15,
- r is 1 to 10,
- s is 0, 1 or 2,
- t is 2,
- the X's taken together are four fluorines or three fluorines and one chlorine,
- Y is F or CF.sub.3,
- Z is F or CF.sub.3, and
- R is lower alkyl.
An ion exchange film or membrane of a blend of 10 to 90% by wt. of a first fluorinated polymer which has repeating units ##STR20## where m is 3 to 15,
- n is 1 to 10,
- p is 0, 1 or 2,
- the X's taken together are four fluorines or three fluorines and one chlorine,
- Y is F or CF.sub.3,
- R.sub.f is F, Cl, or a C.sub.1 to C.sub.10 perfluoroalkyl radical, and
- M is H or alkali metal,
- and 90 to 10% by wt. of a second fluorinated polymer which has repeating units ##STR21## where q is 3 to 15,
- r is 1 to 10,
- s is 0, 1 or 2,
- t is 2,
- the X's taken together are four fluorines or three fluorines and one chlorine,
- Y is F or CF.sub.3,
- Z is F or CF.sub.3, and
- M is H or alkali metal.
Dependencies are inferred from the claim text.