Ionic polymers VI. Chemical stability of strong base anion exchangers in aggressive media

Neagu, Violeta; Bunia, I.; Plesca, I.

doi:10.1016/s0141-3910(00)00142-7

Cited by 76 publications

(49 citation statements)

References 2 publications

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“…11) for the short period of time that sample was available in the boiling water; this was expected as any displacement of the NMe 3 or Me groups by the OH -ions would occur faster at elevated temperatures (both processes would give a reduced IEC when measured using the procedure described in this study). 38 The decay of IEC at both temperatures appears to follow a curve, with a rapid initial drop in IEC, which then stabilises; more data would be required for any firm conclusions on the mechanism of decay to be established. A drop in IEC of approximately 18% of the initial IEC over a period of 119 days (2856 h) was observed with F2NOH.…”

Section: Long-term Temperature Stability Of F2nohmentioning

confidence: 96%

Alkaline anion-exchange radiation-grafted membranes for possible electrochemical application in fuel cells

2003

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This submission was created using the RSC Article Template (DO NOT DELETE THIS TEXT) (LINE INCLUDED FOR SPACING ONLY -DO NOT DELETE THIS TEXT)Vinylbenzyl chloride was grafted onto PVDF and FEP polymer films using the radiation-grafting methodology. Subsequent reaction with trimethylamine and ion-exchange with potassium hydroxide yields alkaline anion-exchange membranes that are capable of conducting hydroxide ions; such membranes may be suitable for use in low temperature direct methanol fuel cells for portable devices. The PVDF based materials underwent an undesirable degradation and were found to be less suitable for this class of membrane. FEPbased materials exhibited superior structural stability, conductivities up to 0.02 S cm -1 at room temperature, and good retention of ionexchange capacities when treated in water at 60°C.

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Section: Long-term Temperature Stability Of F2nohmentioning

confidence: 96%

Alkaline anion-exchange radiation-grafted membranes for possible electrochemical application in fuel cells

2003

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“…Typically, the AAEMs are synthesized via chloromethylation of the pristine polymers and subsequent exposure to trimethylamine (TMA) to form the desired benzyltrimethyl-type quaternary ammonium (QA) head-groups [9][10][11]. However, there are three potential disadvantages with the use of AAEMs: (1) The commonly used chloromethyl methyl ether, used for the chloromethylation step, is a carcinogen and highly harmful to human health (its use has been restricted since 1970s) [12]; (2) The poor stability of the QA head-groups (the most commonly encountered) in alkaline environments is caused by the attack on the quaternary ammonium groups by the strongly nucleophilic OH -anions via direct nucleophilic displacements, Hofmann elimination reactions, and/or minor side-reactions involving ylide-intermediates [1,[13][14][15]; (3) The lower ionic conductivities observed are due to the weak alkalinity of QA hydroxides (cf. the strong acidity of the perfluorosulfonic acid groups in PEMs) and resultant poor self-dissociation capability (e.g.…”

Section: Introductionmentioning

confidence: 99%

Alkali resistant and conductive guanidinium-based anion-exchange membranes for alkaline polymer electrolyte fuel cells

Lin

Liu

et al. 2012

Journal of Power Sources

153

100

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“…However, if none of the groups on a hetero atom bears a b-hydrogen, the nucleophilic substitution S n 2 is the only possible reaction, see Fig. 1b [9][10][11]. The two different mechanisms of S n 2 displacement of the trialkylammonium groups by hydroxide anions can occur simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Polymer anion selective membranes for electrolytic splitting of water. Part I: stability of ion-exchange groups and impact of the polymer binder

et al. 2011

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In this study, the chemical stability of three types of the anion-exchange functional groups in an alkaline environment was tested. The following groups were selected for the test: trimethylbenzylammonium, methyl pyridinium, and tributhylbenzylphosphonium. A KOH solution with various concentrations and temperatures was used as the environment. The trimethylbenzylammonium group showed the highest stability of the materials tested under conditions relevant to water electrolysis. In the next step, four types of polymeric binders, including ethyleneco-methacrylic acid, linear polyethylene, linear polyethylene blended with poly(ethylene-co-vinylalcohol), and low-density polyethylene, were selected to determine their impact on the resulting electrochemical properties of a heterogeneous membrane. This study reveals the morphology of the membrane, ion-exchange capacity, ionic conductivity, and performance in alkaline water electrolysis conducted on a laboratory scale. The material showing the most promising properties was selected for further optimization and testing.

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Ionic polymers VI. Chemical stability of strong base anion exchangers in aggressive media

Cited by 76 publications

References 2 publications

Alkaline anion-exchange radiation-grafted membranes for possible electrochemical application in fuel cells

Alkaline anion-exchange radiation-grafted membranes for possible electrochemical application in fuel cells

Alkali resistant and conductive guanidinium-based anion-exchange membranes for alkaline polymer electrolyte fuel cells

Polymer anion selective membranes for electrolytic splitting of water. Part I: stability of ion-exchange groups and impact of the polymer binder

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