Structure and properties of sulfonated poly [(vinylidene fluoride)–g-styrene] norous membranes porous membranes

Phase separation and crystallinity in proton conducting membranes of styrene grafted and sulfonated poly(vinylidene fluoride)

“…The details of the preparation of the styrene grafted PVDF membranes (PVDF-g-PS) and the sulfonated membranes (PVDF-g-PSSA) have been described elsewhere. 15 The composition of the PVDF-g-PSSA membranes are collected in Figure 1 and Table I. …”

“…Because of incompatibility of polystyrene and PVDF, the grafts form phase separated regions, which are further reorganized in the following sulfonation reaction. 15,16 To further study the influence of crosslinking on the structure of the membranes, their crystallinity was determined. The inherent crystallinity of the PVDF decreases in the grafting process in the absence of crosslinkers and decreases further during the sulfonation.…”

“…The preparation involves the preirradiation of the PVDF film with electron beam, graft polymerization of styrene into the matrix, and sulfonation of the grafted film. 15 The characterization of these membranes involved thermal analysis, X-ray diffraction [wide-angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS)] measurements, 16 and electrochemical analysis. 17 Preliminary fuel cell tests show promise for the development of these membranes.…”

“…15,16,30 Raman measurements of the degree of sulfonation are based on the analysis of the 1127-cm Ϫ1 mode characteristic of sulfonated PS, 31 relative to the 1600-cm Ϫ1 mode assigned to the 8a vibration of PS 29 taken as a measure of the total amount of PS. In this analysis it was found that the membranes with low degrees of grafting were not sulfonated fully and that the degree of sulfonation varies at different points and also decreases into the membrane.…”

Association of Nafion with Polypyrrole Nanoparticles in a Hydrophilic Polymer Network: Effects on Proton Transport

“…The current trend in this field is directed at the preparation of speciality polymers that consist of a hydrophobic backbone and hydrophilic side chains terminating in acid groups such as the sulfonic acid group (2,3). Among the polymers, the perfluorosulfonic polymer Nafion (acid form) has been recognized as the best of the proton-conducting polymer electrolytes that have been synthesized because of its amphiphilic nature.…”