Sulfonation of polyglycidyl methacrylate (PGMA) chains grafted onto nonwoven polypropylene fabric is investigated in detail. Sulfonation reaction consists in implantation of sulfonate groups via epoxy ring-opening of PGMA chains grafted onto nonwoven polypropylene fabric by reaction between the GMA-grafted sample and sodium hydrogensulfite in water-dimethylformamide solution. On the basis of analyses of IR spectra of the appropriate samples and data of backward titration, two simultaneous processes are demonstrated to take place during the sulfonation reaction. These processes are the implantation of sulfonate groups via opening of the GMA epoxy rings and hydrolysis of the GMA epoxy rings with alpha-glycol groups formation. The main peculiarities of the sulfonation reaction in depending on the GMA grafting degree are reported. (c) 2007 Wiley Periodicals, Inc.