Method for producing a fluorinated copolymer membrane
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsKyoji Kimoto, Mikio Ebisawa
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Abstract
A method for producing a fluorinated copolymer membrane comprising a first layer made from a fluorinated copolymer having pendant sulfonylchloride groups and a second layer made from a fluorinated copolymer having sulfonylfluoride groups. The membrane is treated with a reducing agent to introduce carboxylic acid groups onto the surface of said first layer. The membrane may be used as a cation exchange membrane. If necessary, a supporting material may be embedded in the second layer.
Claims5
A method of producing a fluorinated copolymer membrane comprising a first layer substantially parallel to the surface of said membrane and said first layer being made from a fluorinated copolymer containing pendant sulfonylchloride groups, and a second layer substantially parallel to the surface of said membrane and said second layer being made from a fluorinated copolymer containing pendant sulfonylfluoride groups, which comprises bringing a starting fluorinated copolymer membrane into contact with phosphorous pentachloride or a mixture of phosphorous trichloride and chlorine at a temperature of 80.degree.-140.degree. C., said starting membrane comprising (1) a first layer substantially parallel to the membrane, said first layer being made from a fluorinated copolymer containing pendant sulfonic acid groups or salts thereof, and (2) a second layer substantially parallel to the membrane, said second layer being made from a fluorinated polymer containing pendant sulfonylfluoride groups.
Dependencies are inferred from the claim text.