Preparation and characterization of a thermoplastic proton-exchange system based on SEBS and polypropylene blends

Abstract

Abstract. The paper focuses on a series of blends prepared with different contents of polystyrene-block-poly-(ethylene-ranbutylene)-block-polystyrene (SEBS) and polypropylene (PP) for the purpose of examining the potential as proton exchange membranes. Polymer blends were prepared by twin-screw extrusion and then compressed by means of a hot-press device into thin films of 125 μm and then ionic sides were created by solid state sulfonation in a chlorosulfonic acid solution. Obtained films were characterized by means of water-uptake, mechanical properties, ion-exchange capacities (IEC) and ion conductivities. It was observed that the rigidity of the films increased with rising sulfonation durations. However humidity absorption from the air decreased the rigidity at high sulfonation levels. Improved water uptake values were obtained when compared to previously reported values in the literature. On the other hand ion exchange values showed an increase parallel to the sulfonation duration up to 45 minutes, but a decrease thereafter was observed due to the diffusion of some sulfonated polymer chains into the ion-exchange medium thereby calculated ion exchange values of S-SEBSH45 and S-SEBSH60 were found less than expected. All films showed ion conductivities up to 432 mS/cm at 25°C. Only S-SEBSH45 and S-SEBSH60 were successful in conducting protons at 80°C owing to the high water retaining capacity.

Highly stretchable and aqueous solution-stable poly(3,4-ethylenedioxythiophene) doped with elastomeric sulfonated-SEBS

“…The peak at 1030 cm −1 is due to the inplane bending vibrations of sulphonated styrene and the peak at 1200 cm −1 is attributed to the asymmetric stretching of the O-S-O from the SO 3 H and SO 3 − groups. [28][29][30] The wide absorption band centred at 3400 cm −1 arises from the O-H bond vibrations caused by the residual water in sSEBS, which was likely to be captured via the strong hydrogen bonding interactions between water and the sulphonate groups. 28 In addition to this, elemental analysis was performed using X-ray photoelectronic spectroscopy (XPS).…”

Indirect sulfonation of telechelic poly(styrene-ethylene-butylene-styrene) via chloromethylation for preparation of sulfonated membranes as proton exchange membranes

“…Finally, the decomposition temperature of the functionalized pristine polymers occurred around 400 °C. It should be noted that the sulfonated membrane is thermally stable up to 150 °C, sufficient for application in fuel cells, which usually operate between 20 and 80 °C [39].…”

“…On the other hand, there is a certain trend to reduce the elongation at break, tensile strength, and toughness as functionalization time increases, especially for the sSEBS-7H membrane, which is related to its chemical structure, due to the sulfonic acid group's formation. The introduction of sulfonic acid groups can be caused some loss of elastomeric character of the membranes, reducing the chain mobility [48,39].…”

Sulfonation and Characterization of Tert-Butyl Styrene/Styrene/Isoprene Copolymer and Polypropylene Blends for Blood Compatibility Applications

“…The film was prepared from blending the tSEPS, the hydrogenated tSIS-7:3, with PP at different weight ratios (Table 2). Several studies articulated that the sulfonation process was quite efficient to obtain a highly sulfonated film in 45 min [25,26]. Moreover, these studies have mentioned that chloro-sulfonic acid started to deteriorate mechanical strength by polymer chains scissoring in 5 min.…”