Sulfonated polyether sulfone‐poly(vinylidene fluoride) blend membrane for DMFC applications

Abstract

Direct methanol fuel cell (DMFC) proton exchange membranes were prepared by blending poly (vinylidene fluoride) (PVDF) with sulfonated poly(ether sulfone) (SPES). Using a diffusion cell and gas chromatographic technique, the effects of PVDF content on methanol permeability in the blended membranes were investigated. The thermal resistance and proton conductivity of the membranes were also determined by using a thermal gravimetric analysis (TGA) and an impedance analysis technique respectively. The presence of sulfonic acid groups in SPES was confirmed by Fourier transform infrared (FTIR). It was found that the methanol permeability in the blended membranes decreased with PVDF content at the expense of proton conductivity. Blended membranes show methanol permeability values much lower than that of Nafion 115, whereas the proton conductivities of the membranes are comparable with that of Nafion. The thermal stability of these blended membranes is above 250 C, which is sufficiently high for use in DMFC.

Chitosan‐polyvinyl alcohol‐sulfonated polyethersulfone mixed‐matrix membranes as methanol‐barrier electrolytes for DMFCs

“…The second weight loss between 393 and 673 K is due to the thermal degradation of CS‐PVA matrix. In addition, the second transition occurring over the temperature range between 600 and 723 K is attributed to the loss of sulfonic acid (SO 3 H) group, i.e., desulfonation in SPES 37. The third weight loss observed between 673 and 973 K is due to the decomposition of main chains of CS and PVA.…”

“…The third weight loss observed between 673 and 973 K is due to the decomposition of main chains of CS and PVA. However, the weight loss observed beyond 900 K is for the decomposition of SPES main chain 37. There is a decrease in weight loss for CS‐PVA‐SPES mixed‐matrix membranes during three stages of degradation due to the introduction of SPES which in turn increases its intermolecular ionic interaction and thermal stability.…”

“…Ion‐exchange capacity (IEC) indicates the number of milli‐equivalents of ions in 1 g of dry polymer. IEC of SPES was determined by titration method using the procedure described elsewhere 37. In brief, required amount of SPES sample was soaked in 50 mL of 3 M sodium chloride (NaCl) solution for 24 h, to convert SPES‐H + into SPES‐Na + .…”

Effect of dispersion state of Cloisite15A® on the performance of SPEEK/Cloisite15A nanocomposite membrane for DMFC application

“…Based on the DS obtained, the ion exchange capacity (IEC) can be determined as well. 1 HNMR spectra were recorded on a Varian Unity Inova spectrometer at a resonance frequency of 399.961 MHz at room temperature. For each analysis, 3 wt % polymer solutions were prepared in deuterated dimethyl sulfoxide (DMSO-d 6 ).…”

Crosslinked electrolytes based on poly(butoxymethylenenorbornene) for proton exchange membrane

“…There has been considerable effort focusing on the development of alternative low-cost, high-temperature, polymer-based electrolytes membranes. [1][2][3][4][5][6][7][8] The vinyl-type polynorbornene (PNB) exhibits excellent optical transparency, high thermal stability, high glass transition temperature and low moisture absorption. However, the poor solubility in common organic solvents, mechanical brittleness and low adhesion property limit the further application of PNB.…”