Crosslinked SPEEK membranes: Mechanical, thermal, and hydrothermal properties

Abstract

The thermal and mechanical behavior, the water uptake (WU), and water diffusion coefficient of sulfonated poly(ether ether ketone) (SPEEK)membranes annealed at 180 degrees C for different times were explored by high-resolution thermogravimetric analysis, mechanical tensile tests, dynamic mechanical analysis, and WU measurements. The mechanical and thermal stability increased with the thermal treatment time, i.e., with the degree of crosslinking. The effect of residual casting solvent, dimethyl sulfoxide (DMSO), on the WU within SPEEK was probed. In presence of residual DMSO, crosslinked SPEEK exhibited higher water sorption at low and medium relative humidity (RH), and lower water sorption at high RH. These membranes have properties well adapted to fuel cell applications

Mechanical properties of anion exchange membranes by combination of tensile stress-strain tests and dynamic mechanical analysis

“…One can relate the lower Young's modulus of the hydroxide form to the larger hydration of the membranes, also reported in Table . The presence of water in the samples reduces the stiffness, due to the plasticizing effect of water; the high dielectric constant of water reduces weak Van der Waals forces between the macromolecular chains, which are probed in the elastic domain . This conclusion is confirmed by the results obtained for hydrogen‐carbonate and carbonate ionomers, which have an intermediate water uptake and elastic modulus.…”

Building bridges: Crosslinking of sulfonated aromatic polymers—A review

“…Our recent results also showed that XL SPEEK with different treating time at 180 1C exhibited lower water vapour uptake and suppressed swelling in water-rich environment, as shown in Fig. 11 [126].…”

“…The explorations include the XL reaction mechanism, kinetic analysis, structure and characterization of the properties (transport properties, mechanical and thermal stability, water uptake and water diffusion coefficients) [23,[117][118][119][120][121][122][123][124][125][126][127][128]. As shown in Fig.…”

Comparative study of the cation permeability of protonic, anionic and ampholytic membranes

“…The enhancement of mechanical properties by reticulation is known for a long time [45][46][47] : in our case the increase of Young modulus is linked to the reduced water uptake, because the high dielectric constant of water reduces the Van der Waals interactions between the macromolecular chains.…”