POLYMER ELECTROLYTE MEMBRANE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a polymer electrolyte membrane which is made of sulfonized polyimide that is superior in membrane forming and has a large capacity of ion exchange group and excellent mechanical strength and water holding capacity, and which is suitable for the ion exchange membrane of a solid polymer fuel cell, and its manufacturing method. SOLUTION: This is a polymer electrolyte membrane that is formed of block- copolymer sulfonized polyimide that contains a polymer block (A) having a structural unit as expressed by the formula (I) and a polymer block (B) having a structural unit as expressed by the formula (II) in a molar rate (A:B) of 5:95-95:5. In the formula (I), Ar1 shows a bivalent organic group which is substituted by at least one sulfonic acid group. In the formula (II), Ar2 shows a bivalent organic group which does not have a sulfonic acid group.