posted on 2024-01-19, 21:10authored byJyoti
Ranjan Mandal, Sweety Suhag, Prashant Kumar, Khushboo Singh, Vinod K. Shahi
Poly(vinylidene fluoride-co-hexafluoropropylene)
(PVDF-co-HFP) was defluorinated in the presence of
alkali, and 4-vinyl benzyl chloride (VBC) was grafted by free radical
copolymerization in the presence of an initiator to obtain PVDF-co-HFP-g-VBC. Then, 1-methylimidazole-tethered
PVDF-co-HFP-g-VBC was synthesized
for architecting the partial fluorinated anion exchange membrane (AEM).
To improve essential membrane properties such as conductivity and
ion exchange capacity (cation charge density), silica precursor 3-aminopropyl
trimethoxysilane was incorporated in the polymer matrix. Prepared
AEMs with different structural features were studied for morphology,
ion-exchange capacity, water uptake, conductivity, and stability compared
to other commercial AEMs. The reported PVIM-2.5-Si membrane, with
quaternary ammonium and imidazolium groups, was resistant to alkaline
degradation due to the non-availability of β-hydrogen and negligible
chance of nucleophilic (SN2) attack. The suitably assessed
PVIM-2.5-Si AEM shows 1.04 V open circuit voltage, corresponding to
294.15 mW cm–2 power density at 555 mA cm–2 current density, in an alkaline membrane fuel cell application.