Patent ID: 8008361

Claim:
A method for preparing a polymer anion-exchange membrane, comprising the steps of: (a) dissolving in a first solvent, 1 weight part of a polymer comprising in its main chain benzene and ether repeat units; adding between 0.05 and 0.5 weight parts of zinc powder or aluminum powder and between 0.1 and 1 weight parts of a fluorine-containing organic acid; adding between 1 and 5 weight parts of chloromethyl methyl ether; and stirring at between 20° C. and 50° C. for between 2 and 20 hours to yield a first reaction mixture comprising a chloromethylated polymer; pouring said first reaction mixture into a lower alcohol to precipitate said chloromethylated polymer; and optionally, washing, grinding, and drying said chloromethylated polymer; (b) dissolving in a second solvent said chloromethylated polymer obtained in step (a) to yield a solution of said chloromethylated polymer; vaporizing a trimethylamine solution to obtain trimethylamine vapor, drying said trimethylamine vapor to obtain dried trimethylamine vapor; and passing said dried trimethylamine vapor through said solution of said chloromethylated polymer for not less than 5 minutes to yield a quaternary ammonium polymer solution; and (c) casting said quaternary ammonium polymer solution and drying at between 40° C. and 100° C.