Sulfonated amine poly(ether sulfone)s (S APES)s were prepared by nitration reduction and sulfonation of poly(ether sulfone) (ultrason (R) S6010) Poly(ether sulfone) was reacted with ammonium nitrate and trifluoroacetic anhydride to produce the nitrated poly(ether sulfone), and was followed by reduction using tin(II)chloride and sodium iodide as reducing agents to give the amino poly(ether sulfone) The S-APES was obtained by reaction of 1 3 propanesultone and the amino poly(ether sulfone) (NH(2) PES) with sodium methoxide The different degrees of nitration and reduction of poly(ether sulfone) were successfully synthesized by an optimized process The reduction of nitro group to amino was done quantitatively and this controlled the contents of the sulfonic acid group The films were converted from salt to acid forms with dilute hydrochloric acid Different contents of sulfonated unit of the S APES were studied by FT IR, (1)H NMR spectroscopy, differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol The ion exchange capacity (IEC), a measure of proton conductivity was evaluated The S APES membranes exhibit conductivities (25 degrees C) from 1 05 x 10(-3) to 4 83 x 10(-3) S/cm water swell from 30 25 to 66 50% IEC from 0 38 to 0 82 meq/g and methanol diffusion coefficients from 3 10 x 10(-7) to 4 82 x 10(-7) cm(2)/S at 25 degrees C (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved