| abstract |
Sulphonic fluorinated ionomers crosslinked by radical crosslinking of:A) crosslinkable sulphonic fluorinated ionomers, having equivalent weight 380-1300 g/eq and comprising: from 48% to 85% by moles of monomeric units deriving from tetrafluoroethylene (TFE);from 15% to 47% by moles of fluorinated monomeric units containing sulphonyl groups -SO2F; from 0.01% to 5% by moles of monomeric units deriving from a bis-olefin of formula:wherein: m=2-10, preferably 4-8; R1, R2, R5, R6, equal to or different from each other, are H or C1-C5 alkyl groups;B) a fluorinated compound as crosslinking radical initiator;C) a fluorinated bis-olefin of structure (I) as crosslinking agent;the radical crosslinking being carried out at a temperature in the range 250° C.-310° C., preferably 260° C.-300° C. |