Sulfonation and characterization of styrene-indene copolymers for the development of proton conducting polymer membranes

Abstract

Abstract:The aim of this work is to obtain polymer precursors based on styrene copolymers with distinct degrees of sulfonation, as an alternative material for fuel cell membranes. Acetyl sulfate was used to carry out the sulfonation and the performance of the polyelectrolyte was evaluated based on the content of acid polar groups incorporated into the macromolecular chain. Polymeric films were produced by blending the sulfonated styrene-indene copolymer with poly(vinylidene fluoride). The degree of sulfonation of the polymer was strongly affected by the sulfonation reaction parameters, with a direct impact on the ionic exchange capacity and the ionic conductivity of the sulfonated polymers and the membranes obtained from them. The films produced with the blends showed more suitable mechanical properties, although the conductivity of the membranes was still lower than that of commercially available membranes used in fuel cells.

Fabrication, Characterisation and Electrochemical Properties of Heterogeneous Multiwalled Carbon Nanotubes Cation Exchange Membranes (MWCNT-CEMs)

“…The obtained Nyquist plot was similar to those found in the literature. 9,10 The first loop of the Nyquist plot can be associated to the ionic pathway, while the second line at lower frequency (on the right) was due to the diffusion of counterions in the bulk polymeric membrane. 11 The Nyquist plot provides a visual verification of the good agreement between the modified equivalent circuit model and the experimental data.…”

Physicochemical characterization of SEPS block copolymer membranes for CO2 separation

“…2) showed changes in the shape and intensity of "five aromatic fingers" bands and it is identified merely one peak at 836 cm -1 , caused by a substitution in the para-position of the phenyl group during the sulfonating process. The absorption bands at approximately 1005 and 1127 cm -1 are assigned to the vibrations of sulfonic acid (-SO3H) in the para-position [10,11,[13][14][15][16]. The peaks centered on 1200 and 1040 cm -1 can be ascribed to the asymmetric [10,11,17] and symmetric stretching [13,14] vibrations of sulfonate group (O-S-O), respectively.…”

“…The absorption bands at approximately 1005 and 1127 cm -1 are assigned to the vibrations of sulfonic acid (-SO3H) in the para-position [10,11,[13][14][15][16]. The peaks centered on 1200 and 1040 cm -1 can be ascribed to the asymmetric [10,11,17] and symmetric stretching [13,14] vibrations of sulfonate group (O-S-O), respectively. The broad absorption band at 3400 cm -1 in sulfonated membranes suggests the presence of hydroxyl groups due to the interactions between -SO3H and water molecules through hydrogen bonding [17].…”