Heat-treated fluorocarbon sulfonamide cation exchange membrane and process therefor

摘要

An ion exchange membrane of a fluorinated polymer which contains sulfonyl groups, wherein the sulfonyl groups on one surface of the membrane are in the form of N-monosubstituted sulfonamide groups formed from a di- or polyamine, is treated by heating at a temperature of 100 DEG to 160 DEG C. for a time of at least 15 minutes. The resulting membrane is useful as the membrane in a chloralkali electrolysis cell, and permits operation of such cells at high current efficiency over extended periods of time.