Synthesis and characterization of aniline‐containing anion‐conducting polymer electrolyte membranes by radiation‐induced graft polymerization

Abstract

Poly(trimethylaminostyrene hydroxide)‐grafted poly(ethylene‐co‐tetrafluoroethylene) (ETFE) membranes (An‐AEM/OH) were prepared by the radiation‐induced graft polymerization of N,N‐dimethylaminostyrene and successive quaternization and anion‐exchange reactions. An‐AEM/OH with an ion‐exchange capacity (IEC) of 1.59 mmol/g exhibited a conductivity of 74 mS/cm (60°C) and a water uptake of 66%. These values were lower than those of poly(vinylbenzyltrimethylammonium hydroxide)‐grafted ETFE (BA‐AEM/OH) with a similar IEC. The conductivities of An‐AEM/OH with IECs = 0.67 mmol/g and 1.59 mmol/g decreased to 40% and 46% of the initial values after a week, while the membranes maintained their shape even after immersion in 1 M KOH at 80°C for 3 weeks. An‐AEM/OH exhibited higher chemical stability than BA‐AEM/OH. The main degradation route is confirmed to be the nucleophilic attack of hydroxide ions on the methyl groups of the aniline nitrogen from the results of thermal and chemical stability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46886.

Alkaline membrane fuel cells: anion exchange membranes and fuels

“…101 The impedance was measured over a broad frequency range (from 1 MHz to 100 Hz, 88,101 100 mHz to 100 kHz, 95,98 100 kHz (ref. 92, 94 and 160)). The ionic conductivity was then calculated from the obtained data.…”

“…101 The standard method for the measurement of ion conductivity is impedance spectroscopy, which is carried out on the AEM samples aer the pre-treatment. A two-point probe, 95 or four-point probe 92,94,101 alternating (AC) impedance spectroscopy technique can be used. Usually measurements are made in the longitudinal direction.…”

“…Conductivity was measured under fully hydrated conditions in a beaker lled with N 2 saturated deionised water under specic temperature (60 C in many articles). 92,94 The cell is also immersed in water, which was previously degassed and blanketed with owing Ar to avoid carbonation and preserve the OH À form of the samples. 95,98 Some research groups also placed the testing assembly into an oven with controlled temperature and humidity to minimise errors due to the effect of CO 2 interferences.…”

“…In such an analysis, the weight remaining as a function of temperature is recorded, 92,98,101,103 with temperature span up to 900 C. Also, thermogravimetric analysis-mass spectroscopy can be conducted under an He atmosphere. 92 Water uptake. AEMs and PEMs require water for normal operation, as an optimal degree of hydration needs to be maintained in order to obtain optimal performance of the membrane.…”

Hydrophobic Effect on Alkaline Stability of Graft Chains in Ammonium‐type Anion Exchange Membranes Prepared by Radiation‐Induced Graft Polymerization

“…The authors have concentrated on developing graft-type PEMs and AEMs by radiation-induced graft polymerization. [28][29][30][31][32][33][34][35][36][37][38] The advantage of radiation-induced graft polymerization is the introduction of ionic groups containing graft polymers into mechanically and thermally tough polymers, such as poly (ethylene-co-tetrafluoroethylene) (ETFE) and poly(ether ether ketone), while maintaining these properties. [31][32][33] Therefore, these graft-type PEMs and AEMs composed of a mechanically and thermally tough crystalline substrate and ionic grafts will solve the problem of low alkaline stability.…”