Fluoropolymer dispersions and membranes

A polymer and dispersion technology, applied in solid electrolyte fuel cells, electrochemical generators, fuel cell components, etc., can solve the problems that cannot be used as large-scale solvents for dispersion casting media, are not easy to dissolve or disperse, etc.

Inactive Publication Date: 2009-06-17
EI DU PONT DE NEMOURS & CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The non-uniform nature of the front-end reaction with ammonia does not provide a uniform crosslink density throughout the film
[0006] hyperfluorinated or -SO of fluoropolymer electrolyte material 2 The F precursor form is not readily soluble or dispersible in common organic liquids, but may be soluble in fluorinated solvents under certain conditions
However, cost and environmental considerations associated with fluorinated solvents may preclude their use as large-scale solvents for dispersion casting media

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-8

[0039] Poly(PSEPVE-co-TFE) and poly(PSEVE-co-TFE) partial hydrolysis and dispersion formation

Embodiment 1

[0041] 52.3 grams of poly(PSEPVE-co-TFE), which is a copolymer of tetrafluoroethylene (TFE) and perfluoro(3,6-dioxa-4-methyl-7-octenesulfonyl fluoride) (PSEPVE) material with an equivalent weight of 647 g / mol (80.8 mmol SO 2 F)) was divided into small portions and filled in dry 1 liter 3 neck round bottom (RB) flasks. The flask was equipped with mechanical stirring, a heating mantle, a reflux condenser with a nitrogen pad, and a thermocouple. Add approximately 185 ml of 2H-perfluoro(5-methyl-3,6-dioxanonane) ( E2) and slowly dissolve the polymer with stirring and heating to gentle reflux for 0.5 hours. Heat was reduced and the solution was cooled to 50-70°C. Then 60 mL of N,N-dimethylformamide (DMF) was slowly added via syringe (stirred at approximately 320-RPM), resulting in a translucent mixture. A solution of 4.90 g (48.4 mmol) triethylamine (TEA), 1.74 g water (96.7 mmol) and approximately 20 mL DMF was then added via syringe over 5 minutes. After 10 minutes, the mix...

Embodiment 2

[0043] 50.1 g of poly(PSEPVE-co-TFE) copolymer (77.4 mmol SO 2 F) Divide into small portions and fill in dry 500 ml 3 neck round bottom (RB) flasks. The flask was equipped with mechanical stirring, a heating mantle, and a reflux condenser with a nitrogen blanket. Add about 175ml E2 and slowly dissolve the polymer under stirring and moderate heating (50-60° C.) for 1-2 hours. With stirring at 320-RPM, 125 mL of DMF was slowly added via syringe. The mixture was homogenized with up to about 80 mL of DMF. Further addition of DMF provided a white emulsion. Then 4.73 g (46.7 mmol) TEA was added via pipette, followed by approximately 1.85 g (103 mmol) water. The emulsion was heated to gentle reflux and held at this temperature for about 1.5 hours. Reduce the heat and cool the emulsion below reflux temperature. The mechanical stirring was replaced with magnetic stirring and the reflux condenser was replaced with a short path distillation unit. The mixture was distilled under v...

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Abstract

The invention is directed to fluoropolymer organic-liquid dispersions and membranes containing a homogeneous mixture of reacted and unreacted sulfonyl halide groups. The dispersions are useful in the preparation of crosslinked membranes.

Description

technical field [0001] The present invention relates to organic liquid dispersions of fluoropolymers and films containing a homogeneous mixture of reacted and unreacted sulfonyl halide groups. This dispersion can be used to prepare crosslinked films. Background technique [0002] Electrochemical cells generally include an anode and a cathode separated by an electrolyte, using a proton exchange membrane (hereinafter "PEM") as the polymer electrolyte. The anode and cathode are typically formed using a metal catalyst and electrolyte mixture. A well known use of electrochemical cells is in fuel cells (cells that convert fuel and oxidant into electrical energy). Fuel cells are typically formed as a stack or assembly of membrane electrode assemblies (MEAs) each including a PEM, an anode and a cathode, and other optional components. In such cells, the anode is supplied with a reactant or reducing fluid, such as hydrogen or methanol, and the cathode is supplied with an oxidant, s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J5/22H01M8/10C08J3/09C08L27/12
CPCC08J3/091H01M8/1016H01M8/0291C08J5/225C08J5/2237Y02E60/523C08J2327/12C08J3/09H01M8/0289Y02E60/50
Inventor R·D·卢森伯格
Owner EI DU PONT DE NEMOURS & CO
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