| 摘要 |
A composite, substantially completely fluorinated film containing ion exchange groups and its use as an ion exchange membrane in an electrolytic cell is described. The membranes are comprised of at least two layers wherein the layers have equivalent weights that differ by less than 150 and contain ion exchange groups. When each layer contains sulfonyl ion exchange groups the equivalent weight of the two layers differ by less than 250. When the equivalent weight difference exceeds 250, at least one layer has an equivalent weight of less than 1000. The higher equivalent weight layer should face the cathode in an electrolytic cell. When the first layer contains carboxylic acid ion exchange groups and the second layer contains sulfonyl ion exchange groups, at least one layer has an equivalent weight of less than 1000. The carboxylic acid containing layer faces the cathode in an electrolytic cell.
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