Synthesis and characterization of fluorinated ionomer p-perfluoro-[1-(2-sulfonic)ethoxy]ethylated polyacrylonitrile-styrene

Fluorinated ionomer p-perfluoro[1-(2-sulfonic)ethoxy]ethylated polyacrylonitrile-styrene (SFAS) (5) was synthesized via electron transfer reaction between polyacrylonitrile-styrene (AS) (1) and perfluoro-di[2-(2-fluorosulfonyl)ethoxy]propionyl peroxide (FAP) (2) and followed by alkali hydrolysis and acidification of p-perfluoro[1-(2-fluorosulfonyl)ethoxy]ethylated polyacrylonitrile-styrene (3). The microstructure of ionomer 5 was well characterized by FTIR and 19F NMR. Its desulfonation occurred above 197 °C was found by TGA, the degree of substitution (DS) and ion exchange capacity (IEC) determined by titration were well controlled through changing the molar ratio of 2:1. The proton exchange membranes made of ionomer 5 have water uptake from 13.4 to 135.3% and conductivity up to 10−2 S cm−1 at 25 °C.