Atochem

Produits Chimiques Ugine Kuhlmann

Institut Franco-allemand De Recherches De Saint-louis

Jean Blaise

Patrick Kappler

Henri Mathais

Francois Bauer

Edouard Grimaud

Charles Laviron

Francis Leroux

Michel Jaccaud

Dominique Ravier

Christian Baras

Jean-Louis Herisson

Eric Fousson

François Bauer

A method of manufacturing, by suspension polymerization, dielectric copolymers, including injecting an initial mixture of constituent monomers into an autoclave at constant temperature and pressure, wherein the mixture of constituent monomers including vinylidene difluoride (VDF), trifluoroethylene (TrFE), and a monomer 2 to 10 times more reactive than VDF and TrFE; and continuously reinjecting at constant pressure, as soon as the reaction is initiated and throughout the duration of polymerization, a second mixture of the constituent monomers, wherein the molar composition of the initial mixture and the second mixture are determined by calculation, in a manner known of itself, taking into account the desired molar composition of the copolymer and the higher reactivity of the third monomer.

Method of manufacturing vinylidene difluoride and trifluoroethylene-based dielectric copolymers

The invention pertains to a perfluorated ionic polymer. This polymer is prepared starting with polymers presenting carboxylic groupings, these groupings being transformed in reactive entities which are later eliminated.

Fluorated ionic polymer, method for its preparation and membranes

Heterogeneous copolymers of vinylidene fluoride and chlorotrifluoroethylene are obtained by copolymerization in suspension or emulsion in two stages. In a first stage the vinylidene fluoride and the chlorotrifluoroethylene are copolymerized, and in a second stage the polymerization of vinvylidene fluoride is continued after discontinuance of the introduction of chlorotrifluoroethylene.

Heterogeneous copolymer of vinylidene fluoride and

Heterogeneous copolymers of vinylidene fluoride and chlorotrifluoroethylene are obtained by copolymerization in suspension or emulsion in two stages. In a first stage the vinylidene fluoride and the chlorotrifluroethylene are copolymerized, and in a second stage the polymerization of vinylidene fluoride is continued after discontinuance of the introduction of chlorotrifluoroethylene.

A treatment procedure for aqueous colloidal polytetrafluoroethylene dispersions obtained by polymerization of tetrafluoroethylene in the presence of the lithium salt of a perfluoroalkanesulfonic acid as the emulsifier, characterized by the fact that a basic hydroxide or a soluble ammonium, alkali metal or alkaline-earth salt, with the exception of lithium hydroxide or a lithium salt, is added to the dispersion.

Process for the manufacture of polytetrafluoroethylene

A process for the polymerization of vinylidene fluoride H.sub.2 C=CF.sub.2 using a novel class of fluorinated emulsifiers having the general formula:

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Lyon, France

Jean Blaise