Abstract: To provide a polymer electrolyte material for polymer electrolyte fuel cells, which is an electrolyte material having a high ion exchange capacity and a low resistance, and which has a higher softening temperature than a conventional electrolyte material.

Abstract: A compound containing two fluorosulfonyl groups which are groups convertible to sulfonic acid groups, an intermediate therefor, and methods for their production with high productivity, are provided. Also provided are a fluorosulfonyl group-containing polymer obtained by polymerizing such a compound, and a sulfonic acid group-containing polymer obtained from such a polymer. A method for producing a compound of the following formula (m0), such a compound, a fluorosulfonyl group-containing polymer obtained by polymerizing such a compound, and a sulfonic acid group-containing polymer obtained from such a polymer, provided that RF01 is a single bond or a C1-6 bivalent perfluoro organic group, RF02 is a C1-6 bivalent perfluoro organic group, and n is 0 or 1.

Abstract: To provide a process for producing a perfluorocarbon polymer, whereby a perfluorocarbon polymer having a high content of —SO2F groups and a high molecular weight can be efficiently obtained. The process comprises polymerizing a monomer mixture comprising the liquid monomer (A) of the following formula (1) and tetrafluoroethylene at a polymerization temperature of from 25 to 45° C. by sequentially or continuously adding an initiator of the following formula (2): CF2?CF(OCF2CFX1)k—O1—(CF2)m—(CF2CFX2)n—SO2F??(1) wherein each of X1 and X2 which may be the same or different, is a fluorine atom or a trifluoromethyl group, k is an integer of from 0 to 3, l is 0 or 1, m is an integer of from 0 to 12, and n is an integer of from 0 to 3, [CF3CF2CF2O(CF(CF3)CF2O)pCF(CF3)COO]2??(2) wherein p is an integer of from 0 to 8.

Abstract: A compound containing two fluorosulfonyl groups which are groups convertible to sulfonic acid groups, an intermediate therefor, and methods for their production with high productivity, are provided. Also provided are a fluorosulfonyl group-containing polymer obtained by polymerizing such a compound, and a sulfonic acid group-containing polymer obtained from such a polymer.

Abstract: A compound containing two fluorosulfonyl groups which are groups convertible to sulfonic acid groups, an intermediate therefor, and methods for their production with high productivity, are provided. Also provided are a fluorosulfonyl group-containing polymer obtained by polymerizing such a compound, and a sulfonic acid group-containing polymer obtained from such a polymer.

Abstract: An electrolyte membrane for a polymer electrolyte fuel cell, which comprises an ion exchange membrane made of a fluoropolymer having a softening temperature of at least 90° C. and having acidic groups, and contains cerium atoms.

Abstract: To provide an electrolyte material having high electrical conductivity (ion exchange capacity) and a high softening temperature. An electrolyte material comprising a copolymer containing repeating units represented by the following formula (1) and repeating units represented by the following formula (2): wherein RF is a fluorine atom or the like, each of X1 and X2 is a fluorine atom or a trifluoromethyl group, m is from 2 to 4, and Y is a hydroxyl group or the like.

Abstract: A compound containing two fluorosulfonyl groups which are groups convertible to sulfonic acid groups, an intermediate therefor, and methods for their production with high productivity, are provided. Also provided are a fluorosulfonyl group-containing polymer obtained by polymerizing such a compound, and a sulfonic acid group-containing polymer obtained from such a polymer.

Abstract: To provide a polymer electrolyte material for polymer electrolyte fuel cells, which is an electrolyte material having a high ion exchange capacity and a low resistance, and which has a higher softening temperature than a conventional electrolyte material.

Abstract: To provide an electrolyte membrane for a polymer electrolyte fuel cell, capable of generating power in high energy efficiency, having high power generation performance regardless of the dew point of the feed gas and capable of generating stable power over a long period of time. A membrane used as an electrolyte membrane for a polymer electrolyte fuel cell, which comprises a cation exchange membrane made of a fluorinated polymer having cation exchange groups and having an ion exchange capacity of from 1.0 to 2.5 meq/g dry polymer, wherein some of the cation exchange groups are ion-exchanged with at least one type of ions selected from the group consisting of cerium ions and manganese ions.