NEW SULFONATED ENGINEERING POLYMERS VIA THE METALATION ROUTE - II - SULFINATED SULFONATED POLY (ETHER SULFONE) PSU UDEL AND ITS CROSS-LINKING/

New mixed sulfinated/sulfonated polysulfone PSU Udel has been produced by partial oxidation of sulfinated PSU with NaOCl. From the mixed sul finated/sulfonated PSU, thin crosslinked polymer films have been produ ced by S-alkylation of the residual sulfinate groups with alpha,omega- diiodoalkanes having 4-10 -(CH2)- units. The advantages of the partial oxidation process using NaOCl are as follows: (1) The desired oxidati on degree can be adjusted finely. (2)No side reactions take place duri ng oxidation. (3)The partially oxidized polymers is stable at ambient temperature. By variation of the oxidation degree of the sulfinated/su lfonated prepolymer and by variation of the chain length of the diiodo crosslinker, crosslinked membranes with a large range of properties i n terms of ionic conductivity, swelling, and permselectivity have been produced. The partially oxidized polymers have been characterized by redox titration, H-1-NMR, and FTIR. The crosslinked membranes have bee n characterized in terms of ionic conductivity( resistance), permselec tivity, and swelling in dependence on ion-exchange capacity and oxidat ion degree of the prepolymers. In addition, the thermal stabilities of the membranes have been determined by TGA, and FTIR spectra have been recorded on the crosslinked films. Selected membranes show low ionic resistances, low swelling, and good temperature stability which makes them promising candidates for application in (electro)membrane process es. (C) 1998 John Wiley & Sons, Inc.