Polyacrylonitrile‐based proton conducting membranes containing sulfonic acid and tetrazole moieties

Abstract

Proton conducting membranes based on polymers containing sulfonic acid and tetrazole moieties were developed. Successful syntheses of poly(acrylonitrile-co-styrene sulfonic acid) (PAN-co-PSSA), poly(acrylonitrile-co-5-vinyl tetrazole) (PAN-co-PVTz), and poly(acrylonitrile-co-5-vinyl tetrazole-co-styrene sulfonic acid) (PAN-co-PVTz-co-PSSA) were confirmed by 1 H-nuclear magnetic resonance spectroscopy, elemental analysis, and Fourier transform infrared spectroscopy. Two approaches were performed to study the effects of molar ratio of sulfonic acid to tetrazole and tetrazole content on membrane properties. In the first approach, PAN-co-PSSA was blended with PAN-co-PVTz at three molar ratios. The second approach focused on PAN-co-PVTz-co-PSSA membranes with various tetrazole contents. PAN-co-PSSA membrane was also prepared. All solution-cast membranes were hydrolytically stable, except for PAN-co-PVTz-co-PSSA with 71% tetrazole. Surface morphologies of blend membranes were studied using scanning electron microscopy, and no phase separation was observed. Water uptake was shown to increase with increasing tetrazole. All membranes exhibited high thermal stability (up to 250 8C) and high storage moduli. Proton conductivity was found to depend significantly on relative humidity. The influences of sulfonic acid to tetrazole ratio and tetrazole content on proton conduction were observed and discussed. A maximum proton conductivity of 7.1 3 10 23 S/cm at 26 8C was obtained from PAN-co-PSSA membrane. In addition, all tested membranes showed relatively good oxidative stability after treatment in Fenton's reagent. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45411.

Facile synthesis and properties of a cation exchange membrane with bifunctional groups prepared by pre-irradiation graft copolymerization

“…12 ; we can see that the membrane with 68.6% grafting yield responded and recovered more rapidly than the membrane with 59.1% grafting yield. In comparison with the result reported by Sangthumchai, 39 the total response and recovery time of our prepared membrane with bifunctional groups –COOH and –SO 3 Na were shorter than those of a membrane that contained only –SO 3 Na groups. Due to weak interactions between the –COOH groups and absorbed H 2 O, the adsorbed H 2 O was easily desorbed; thus, the total response and recovery time became shorter.…”

Composite proton conducting membranes from crosslinked poly(vinyl alcohol)/chitosan and silica particles containing poly(2‐acrylamido‐2‐methyl‐1‐propansulfonic acid)

“… 20,34 Upon grafting PAMPS onto the Si particles, a new band corresponding to the C═O vibration (for PAMPS) appeared at 1636 cm −1 35 . In addition, the intensity of the band at 1003 cm −1 increased, and this could be attributed to the S═O stretching of the SO 3 H groups in PAMPS 34,36,37 …”