TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The perfluoro vinyl ether containing sulfonyl fluoride group has structure of formula: CF2=CF(OCF2CF(CF3))mO(CF2)nSO2F.m=0-10;andn=1-5.    TECHNOLOGY FOCUS - POLYMERS - Preferred Material: The modified fluoro resin is produced from raw material chosen from tetrafluoro ethylene group polymer, tetrafluoro ethylene/perfluoro (alkyl vinyl ether) group copolymer and/or tetrafluoro ethylene/hexafluoro propylene group copolymer. 23-80 wt.% of tetrafluoro ethylene unit is introduced into graft chain with respect to the monomer using tetrafluoro ethylene as a co-monomer. Preferred Properties: The graft ratio of the grafted material is 10 wt.% or more. The modified fluoro resin has sulfonic acid equivalent weight of 2000 g/eq or less. EXAMPLE - Polytetrafluoro ethylene (PTFE) film was irradiated with electron beam of 120 kGy (800 keV of acceleration voltage) under heating temperature of 340degreesC in nitrogen gas atmosphere and with oxygen concentration of 0.5 torr, and a modified polytetrafluoro ethylene film was obtained. The unmodified PTFE film had melting point of 330degreesC and crystallization point of 310degreesC. The modified PTFE film had melting point of 315degreesC and crystallization point of 290degreesC. Subsequently, perfluoro vinyl ether monomer containing sulfonyl fluoride group of formula: CF2=CFOCF2CF(CF3)O(CF2)2SO2F was introduced into a pressure-resistant ampoule with a cock, and vacuum degassing was performed. The modified PTFE film was introduced into glass ampoule and substituted with argon gas, followed by irradiation with 45 kGy gamma-ray at room temperature. The formed film was washed by n-pentane, and vacuum-dried at 60degreesC for 24 hours. The graft ratio of the PTFE film was 55%. The graft modified PTFE film was further processed with sodium hydroxide solution and sulfuric acid solution. The film was washed with pure water. The film was immersed in 0.1 mol/l potassium chloride aqueous solution for 24 hours. The modified PTFE film had ionic conductivity of 8.2x10-2 S/cm, and had excellent ion exchange property and durability.