Sulfonated Binaphthyl-Containing Poly(arylene ether ketone)s with Rigid Backbone and Excellent Film-Forming Capability for Proton Exchange Membranes

Abstract

Sterically hindered (S)-1,1′-binaphthyl-2,2′-diol had been successfully copolymerized with 4,4′-sulfonyldiphenol and 4,4′-difluorobenzophenone to yield fibrous poly(arylene ether ketone)s (PAEKs) containing various amounts of binaphthyl unit, which was then selectively and efficiently sulfonated using ClSO3H to yield sulfonated poly(arylene ether ketone)s (SPAEKs) with ion exchange capacities (IECs) ranging from 1.40 to 1.89 mmol·g−1. The chemical structures of the polymers were confirmed by 2D 1H–1H COSY NMR and FT-IR. The thermal properties, water uptake, swelling ratio, proton conductivity, oxidative stability and mechanical properties of SPAEKs were investigated in detail. It was found that the conjugated but non-coplanar structure of binaphthyl unit endorsed excellent solubility and film-forming capability to SPAEKs. The SPAEK-50 with an IEC of 1.89 mmol·g−1 exhibited a proton conductivity of 102 mS·cm−1 at 30 °C, much higher than that of the state-of-the-art Nafion N212 membrane and those of many previously reported aromatic analogs, which may be attributed to the likely large intrinsic free volume of SPAEKs created by the highly twisted chain structures and the desirable microscopic morphology. Along with the remarkable water affinity, thermal stabilities and mechanical properties, the SPAEKs were demonstrated to be promising proton exchange membrane (PEM) candidates for potential membrane separations.

Ionic Liquid Composite Polybenzimidazol Membranes for High Temperature PEMFC Applications

“…The addition of the IL enables a crosslinking network, which improves the stability of the composite membranes as already observed for other blend membranes. The oxidative stabilities of composite membranes are in the same range as those reported for other non-fluorinated analogs in literature [60].…”

Facile Fabrication and Characterization of Improved Proton Conducting Sulfonated Poly(Arylene Biphenylether Sulfone) Blocks Containing Fluorinated Hydrophobic Units for Proton Exchange Membrane Fuel Cell Applications

“…The calculated activation energies of SPABES-PAE membranes (1:2, 1:1 and 2:1) were 10.89, 10.39, and 9.22 kJ·mol −1 (Figure 5 and Table 4) [41], respectively, while that of Nafion 212 was 9.56 kJ·mol −1 . According to the results, the activation energies of SPABES-PAE and Nafion 212 membranes were low, indicating that proton transport is easy in the prepared membranes and Nafion 212 because low activation energies mean low membrane resistance.…”

Study of High Performance Sulfonated Polyether Ether Ketone Composite Electrolyte Membranes

“…Due to rising costs in natural energy resources and growing concerns for environmental protection, modern society has been in great demand for more efficient energy storage and consumption technologies [1,2,3,4]. However, the production of usable energy from the combustion of fuels is an inefficient process due to intrinsic thermodynamic principles.…”