PURPOSE: To obtain a cation exchange membrane economically, by reducing the irradiation time and dose by graft-polymerizing an inert polymer film irradiated with an ionizing radiation by contact with α,β,β-trifluorostyrene and sulfonating the grafted film.
CONSTITUTION: An inert polymer film (e.g., polytetrafluoroethylene film) is irradiated with an ionizing radiation at a dose of 1W30 Mrad to generate radicals, and then contacted with α,β,β-trifluorostyrene or its solution in a solvent (e.g., CCl4) and graft-polymerized at 10W90°C for 1W50hr to obtain a grafted membrane of a degree of grafting of 10W50%. This grafted membrane is reacted with a sulfonating agent (e.g., chlorosulfonic acid) at 40W150°C for 10W100min, and the product is neutralized to obtain a cation exchange membrane of a degree of sulfonation of 40W100% and a membrane resistance of 0.9W5Ω.cm2.
HARADA HIROYUKI
MIYAJI HIROSHI
MOMOSE TAKASHI
KATOU HIROKO
