Abstract

FERNANDEZ, M. E. et al. Improvement of Proton-Exchange Membranes Based on (1 − x )(H ₃ PO ₂ /PVA)- x TiO ₂. ing.cienc. [online]. 2017, vol.13, n.25, pp.153-166. ISSN 1794-9165.  https://doi.org/10.17230/ingciencia.13.25.6.

Using impedance spectroscopy (IS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and infrared spectroscopy (IR) techniques to study the polymer electrolyte membranes based on poly(vinyl alcohol) (PVA) and hypophosphorous acid (H3PO2) with different titanium oxide nanoparticles (TiO2) concentrations. The polymer systems (1-x)(H3PO2/ PVA) + xTiO2 were prepared using the sol-casting method and different weight percent of TiO2, x ≤ 10.0%. The DSC results show that the glass transition for molar fraction P/OH = 0.3 appears around 75 ºC and for the samples doped with TiO2 around 35 ºC; the melting point for all membranes appear around 175 ºC. The FTIR spectra show changes in the profiles of the absorption bands with the addition of H3PO2 and the different concentrations of TiO2. The IS results show dielectric and conductivity relaxations as well as a change in DC ionic conductivity with the TiO2 content. The order of the ionic conductivity is about 10 − 2 S/cm for 5.0% of TiO2. The TGA in the heating run shows water loss that is in agreement with DC conductivity measurements.

Keywords : Composite polymer membranes; PVA; Hypophosphorous acid; Proton conduction, DC conductivity.

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