摘要 |
Electrochemical properties of a cation exchange membrane of a carboxylic acid type fluorinated polymer which is used for an electrolysis of an aqueous solution of an alkali metal chloride is recovered by converting ion exchange groups of -COO)mM; wherein M represents an alkali metal or an alkaline earth metal; and m represents a valence of M; to the corresponding acid or ester groups of -COOR wherein R represents hydrogen or a C1 - C5 alkyl group and heat-treating the fluorinated polymer having the groups of -COOR. |