Importance

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Abstract

Semicrystalline sulphonic fluorinated ionomers having an equivalent weight higher than 700 g/eq, up to 1,700, comprising: (A) monomeric units deriving from one or more fluorinated monomers containing at least one ethylene unsaturation; (B) fluorinated monomeric units containing sulphonyl groups --SO.sub.2 F in such amount to give the above equivalent weight, deriving from F.sub.2 C.dbd.CF--O--(CF.sub.2).sub.q --SO.sub.2 F, q being an integer equal to 2 or 3; and having the following properties for a TFE/(B) copolymer: hydration, expressed in % of H.sub.2 O at 100.degree. C. absorbed by the film prepared from the ionomer and after tranformation from the --SO.sub.2 F form into the --SO.sub.3 H form, having the following values:

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First Claim