Multi-acid polymers are produced having the formula R—SO.sub.2—NH—(SO.sub.3.sup.−H.sup.+).sub.n or R—SO.sub.2—NH—(PO.sub.3.sup.−H.sup.2+).sub.n and made from a polymer precursor in sulfonyl fluoride form or sulfonyl chloride form The R is one or more units of the polymer precursor without sulfonyl fluoride or sulfonyl chloride, n is one or more, and the multi-acid polymer has two or more proton conducting groups. A method of making the multi-acid polymers includes reacting an amino acid having multiple sulfonic acids or phosphonic acids with a polymer precursor in sulfonyl fluoride form or sulfonyl chloride form in a mild base condition to produce the multi-acid polymer having two or more proton conducting groups.

To provide a polymer electrolyte membrane capable of producing a polymer electrolyte fuel cell excellent in power generation characteristics and excellent in hydrogen gas utilization efficiency, as well as a membrane electrode assembly and a polymer electrolyte fuel cell obtainable by using it.

The polymer electrolyte membrane of the present invention comprises a polymer electrolyte, of which the hydrogen gas permeation coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10% is at most 2.4×10.sup.−9 cm.sup.3.Math.cm/(s.Math.cm.sup.2.Math.cmHg) and has a membrane thickness of from 7 to 20 μm.

Disclosed are polyimide blends and methods of making and using same. The disclosed polyimide blends are prepared by first blending an ionic polymer and a poly(amic acid) to form a poly(amic acid) precursor, followed by cyclization. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.

Provided are membranes useful for electrochemical or fuel cells. A membrane may be formed of or include a sulfonated polymer whereby the sulfonated polymer is covalently or ionically associated with a multi-nitrogen containing heterocyclic molecule. The resulting membranes possess excellent ion conductivity and selectivity.

The copolymer includes divalent units represented by formula —[CF.sup.2—CF.sup.2]—, divalent units represented by formula: (I), and one or more divalent units independently represented by formula: (II) When Z is hydrogen, the copolymer has an alpha transition temperature of up to 100 ?C. The copolymer has an —SO.sub.3Z equivalent weight in a range from 300 to 1400, and a variation of the copolymer in which —SO.sub.3Z is replaced with —SO.sub.2F has a melt flow index of up to 80 grams per ten minutes measured at a temperature of 265° C. and at a support weight of 5 kg. A catalyst ink or polymer electrolyte membrane including the copolymer are also provided. ##STR00001##

A fluorosulfonyl group-containing polymer having units represented by the following formula u1, a sulfonic acid group-containing polymer having fluorosulfonyl groups in the fluorosulfonyl group-containing polymer converted into sulfonic acid groups, its production method and its applications: ##STR00001##
wherein R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used:

##STR00001##

wherein R.sup.1 and R.sup.2 are a C.sub.1-3 alkylene group, and R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

A processing method of a base material sheet includes winding out the base material sheet wound up by a first core and a first porous sheet wound up by a second core, winding up by a third core the base material sheet and the first porous sheet to be overlapped with each other, and processing the base material sheet by a first processing liquid held in the first porous sheet; and winding out the base material sheet and the first porous sheet overlappingly wound up by the third core, winding up the first porous sheet by the second core, and winding up the base material sheet by the first core.

The present invention pertains to a membrane for an electrochemical device, to a process for manufacturing said membrane and to use of said membrane in a process for manufacturing an electrochemical device.

To provide an ion-exchange membrane that, when being used in a redox flow battery, provides excellent current efficiency and can suppress reduction in voltage efficiency. The ion-exchange membrane contains a fluorinated polymer having sulfonic acid-type functional groups and is characterized in that the difference (D−Dc) between the distance D between ion clusters measured by the small angle X-ray scattering method, and the diameter Dc of an ion cluster is larger than 0 and at most 0.50 nm.