摘要 |
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 -SO2F in such amount to give the above equivalent weight, deriving from F2C=CF-O-(CF2)q-SO2F, q being an integer-equal to 2 or 3; and having the following properties for a TFE/ (B) copolymer: hydration, expressed in % of H2O at 100 DEG C absorbed by the film prepared from the ionomer and after tranformation from the -SO2F form into the -SO3H form, having the following values: <TABLE> |