RAMAN-SPECTROSCOPY INVESTIGATION AND IMPROVED KNOWLEDGE ON INDUSTRIALCATION-EXCHANGE MEMBRANES INVOLVED IN ELECTRODIALYSIS PROCESS

Raman spectra of three specific, industrial, cation-exchange membranes (CEMs) have shown the existence of an extra vibrational band. The rel ative intensity of this band is different in each membrane spectrum re corded. Chlorosulfonation of polymeric ethylenetrifluoroethylene (ETFE ) film grafted with polystyrene chains is used to obtain these CEMs in volved in the electrodialysis process. A Raman study of the above reac tion has been undertaken and has shown that non-sulfonated polystyrene rings give rise to this extra vibrational band. Different behavior of CEMs synthesized under similar conditions can be explained by a varia ble amount of non-sulfonated polystyrene rings contained in these mate rials.