Abstract:Crosslinked sulfonated poly(ether ether ketone) (SPEEK) membranes were prepared through the electron beam (EB)‐irradiation crosslinking of SPEEK/1,4‐butanediol under various irradiation conditions and used as a proton exchange membrane (PEM) for fuel cell applications. The crosslinked membranes were characterized by gel fraction, a universal testing machine (UTM), dynamic mechanical analysis (DMA), and small‐angle X‐ray scattering (SAXS). The gel fraction of the crosslinked membranes was used to estimate the d… Show more
“…It was reported that the crosslinking could mitigate excess swelling of IEC membranes . The crosslinking could be generally made by acid–base (electrostatic) interactions or covalent bonds . The ionically crosslinked membranes are not very stable particularly at high temperature and humidity due to the relatively weak electrostatic interactions.…”
“…It was reported that the crosslinking could mitigate excess swelling of IEC membranes . The crosslinking could be generally made by acid–base (electrostatic) interactions or covalent bonds . The ionically crosslinked membranes are not very stable particularly at high temperature and humidity due to the relatively weak electrostatic interactions.…”
“…Gel fraction was measured to evaluate the cross-linking degree of the membranes. The prepared membranes were immersed in ethanol at room temperature for 12 h and then dried under vacuum conditions at 60 °C for 24 h. The gel fraction was calculated according to the following equation: where m 0 (g) and m i (g) are the weights of dry membranes before and after ethanol treatment, respectively.…”
A solvent-free UV-initiated free-radical photopolymerization was employed to synthesize a series of cation-exchange membranes (CEMs) based on tertrabutylammonium styrene sulfonate (SSTBA). A novel casting solution was formed by dissolving SSTBA and an initiator in a mixture of styrene and trimethylolpropane triacrylate monomers without any organic solvent. Polymerization and membrane formation were simultaneously progressed to obtain the cross-linked CEMs within only 15 min, and the electrochemical properties were not inferior to those of the commercial CEMs. The effects of SSTBA content on mechanical stability, ion-exchange capacity (IEC), water uptake, and membrane resistance were investigated. It was found that with the increasing content of SSTBA, the overall properties of membranes were improved. The practicability of prepared membranes was evaluated by desalination performance in electrodialysis. The membrane with the most superior performance exhibited IEC of 2.2 mmol•g −1 , a resistance of 0.78 Ω•cm 2 , and a desalination ratio up to 99.3%, better than commercial CEMs. These results confirmed the possibility of preparing CEMs with an environmentally friendly strategy.
“…While scattering experiments are largely helpful in inferring the static structure of these polymer membranes, computer simulation is another useful tool that can provide insight into the structure as well as suggest ways to tailor them. Currently, there are a number of experiments on sPEEK in pristine, branched, composite, crosslinked, and functionalized forms, aiming for high performance in terms of microphase separation, proton conductivity, and thermal and mechanical stability. However, the simulation studies on sPEEK mostly focus on linear chain systems and have relied on molecular dynamics (MD) or field theoretic models .…”
For mesoscale structural studies of polymers, obtaining maximum level of coarse‐graining that maintains the chemical specificity is highly desirable. Here we present a systematic coarse‐graining study of sulfonated poly(ether ether ketone), sPEEK, and show that a 71:3 coarse‐grained (CG) mapping is the maximum possible map within a CG bead‐spring model. We perform single chain atomistic simulation on the system to collect various structural distributions, against which the CG potentials are optimized using iterative Boltzmann inversion technique. The potentials thus extracted are shown to reproduce the target distributions for larger single chains as well as for multiple chains. The structure at the atomistic level is shown to be preserved when we back‐map the CG system to re‐introduce the atomistic details. By using the same CG mapping for another repeat unit sequence of sPEEK, we show that the nature of the effective interaction at the CG level depends strongly on the polymer sequence and cannot be assumed based on the nature of the corresponding atomistic unit. These CG potentials will be the key to future mesoscopic simulations to study the structure of sPEEK based polymer electrolyte membranes.
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