Novel hydrophilic membrane materials: sulfonated polyethersulfone Cardo

Sulfonated polyethersulfone Cardo was prepared by solvent-free reaction of concentrated sulfuric acid on the polymer. The polymer can be sulfonated to different degrees by control of the reaction temperature and time. The deg radation of it main chain was shown to occur at high reaction temperature o r at very long time. Higher sulfonation obtained at longer reaction times l ed to soluble polyelectrolytes. Polymers with an ion exchange capacity lowe r than 1.75 equiv. kg(-1) are not soluble in water while bring hydrophilic. Asymmetric membranes can be prepared from the latter polymers by the wet p hase-inversion method with water as the precipitation medium. They can be u sed as hydrophilic membranes for ultrafiltration or nanofiltration. (C) 200 1 Elsevier Science B.V. All rights reserved.