Bromo-butyl styrene (BBS) was graft-polymerized onto a high-density polyethylene film with a thickness of 35 μm, previously irradiated with an electron beam. The BBS-grafted film was converted into a strongly basic anionexchange membrane (BBS-TMA membrane) by reacting with trimethylamine hydrochloride. The thickness and resistance of the BBS-TMA membrane with a BBS grafting degree of 140% and a TMA group density of 2.2 mol/kg were 50 μm and 0.57 Ωcm2, respectively, in 0.50 M sodium chloride at 298 K. After 42-day immersion of this membrane in 5.0 M NaOH at 353 K, the transport number of the BBS-TMA membrane decreased by 1.6% to 0.925 from its initial value of 0.94.
