Single-step synthesis of sulfonated polyoxadiazoles and their use as proton conducting membranes

Sulfonated polyoxadiazole composites containing carbon nanotubes prepared via in situ polymerization

“…The polyoxadiazole sulfonation reaction which occurs during this synthesis method by the presence of sulfuric acid in the solution of hydrazine sulfate has been recently recognized and characterized by Gomes et al [10]. The polyoxadiazole sulfonation level (S/C) has been shown to be dependent on the reaction time [11], reaching the value range 0.098-0.085 for the synthesis performed in 4 h. Here, the sulfonation level has been mainly changed for the higher CNT contents (Table 1). In the range of concentration 0.1 to 5 wt.% the differences are most within the ones observed for the sulfonated polyoxadiazoles.…”

“…6). The higher the sulfonation level, the higher is the T g [11]. When a filler is homogeneously distributed in a polymeric matrix, the T g of the composites should increase with filler content.…”

“…POD fibers present a combination of properties (such as good strength and stiffness, good fatigue resistance and low density) that makes these fibers competitive in performance when compared to other reinforcing agents, such as glass, steel, and commercial high-temperature fibers (Kevlar, X-500, Cermel, Nomex) [3][4][5]. Technological applications have also been reported in connection with the basic nitrogen atoms and aromatic character of the oxadiazole heterocyclic ring [6], enabling their use as emissive layers in light-emitting diodes [7][8][9], electron/proton conducting materials [10,11], electrochemical/acid sensors [12,13] and materials to prevent metal corrosion [14,15].…”

Polymer electrolyte based on chemically stable and highly conductive alkali-doped polyoxadiazole for direct borohydride fuel cell

“…In such case, the affinity between polymer matrix and alkali could significantly affect the conductivity. As mentioned in other literature [4,18,19], the electronegative heteroatom could interact with the ionic hydroxide via hydrogen bonding. The IR spectrum of aPOD-PDE also confirmed this interaction resulting in high conductivity of aPOD-DPE.…”

Proton Conducting Membranes Based on Benzimidazole Sulfonic Acid Doped Sulfonated Poly(Oxadiazole–Triazole) Copolymer for Low Humidity Operation

“…According to some previous reports [16][17][18], sulphonated polyoxadiazoles and polytriazole copolymers offer a very convenient possibility for the formation of a hydrogen-bonding network to promote proton conduction. In the present work particular emphasis is given to the improvement of the polymer proton conductivity by doping molecules.…”