The preparation and evaluation of a composite membrane from a single sheet of a microporous separator, Daramic, by incorporation of Amberlite CG 400 as an anion exchange resin and further crosslinking with divinylbenzene was successfully employed in the vanadium battery as described previously. Further modification and characterisation of the composite membrane are now described. A detailed FESEM, TGA, IR and C-13 NMR analysis of the composite membrane has been carried out The ion exchange capacity of the composite membrane was also evaluated. Formation of a thin layer of poly( divinylbenzene) after crosslinking was confirmed by morphological studies. None of the experiments showed incorporation of the ion exchange resin into the composite membrane, although its presence in the monomer/solvent mixture appears to somehow affect the final properties of the composite membrane prepared.