Effect of water vapor on the ion transport in polymer films of PVOH/LiH2PO4/H2O

Vargas, R.A.; Zapata, V.H.; Delgado, Miguel Iban; Palacios, I.

doi:10.1016/j.ssi.2003.10.022

Cited by 11 publications

(14 citation statements)

References 5 publications

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“…These results agree with the literature reports [3,4,18,19] for the glass transition temperature of PVAL, related to its sensitivity to doping level. The X-ray diffraction spectra shows a peak around 20 °C which can be interpreted by considering the Hodge et al criterion [20], establishing a correlation between the height of this peak and the degree of crystallinity of PVAL, e.g.…”

Section: Discussionsupporting

confidence: 93%

“…This finding, as well as the observation that the temperature of the anomalies shifts upward show that the alumina stabilized the polymer. These results agree with the literature reports [3,18,19]; in other words, the glass transition temperature of PVAL is strongly sensitive to doping. characteristics of the water removal: The onset of liberation of superficial water is around 50 °C (provided that the atmosphere is dry) and the process continues up to 95 °C.…”

Section: Experimental Methodssupporting

confidence: 93%

“…The T g of pure PVAL is around 80 o C [17]. The plastification effect of water on PVAL is well known [18], but the addition of LiOH/water causes a further drop of T g in PVAL [4]. The melting point of the complex is around 150 o C and the decomposition begins around 195 °C.…”

Section: Experimental Methodsmentioning

confidence: 99%

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New polymer electrolyte based on PVAL‐LiOH‐Al₂O₃‐H₂O

Fernández

Diosa

Vargas

et al. 2007

Phys. Status Solidi (c)

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In this work we report the preparation of membranes based on poly (vinyl alcohol) (PVAL), lithium hydroxide, alumina, and water with different alumina concentrations. The samples were characterized by impedance spectroscopy, differential scanning calorimetry (DSC), thermogravimetry, and x-ray diffraction. The DSC thermograms show three anomalies after the first thermal treatment, the first one as a downward jump at around 20 °C, associated to the glass transition of the polymer, the second one as an endothermic peak around 210 o C associated to the polymer melting point, and the third one as an endothermic peak around 235 o C associated to the decomposition process. The results show that the glass transition temperature is strongly sensitive to the alumina content. Impedance results show a dielectric relaxation that disappears with increasing alumina concentration. The X-ray diffraction shows that the amorphous part of the composite increases as the alumina concentration increases, indicating an approximation effect of the dispersed ceramic nanoparticles in the polymer matrix. These results can be interpreted by considering the Hodge et al. criterion, which establishes a correlation between the height of this peak an the degree of crystallinity of PVAL.

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Section: Discussionsupporting

confidence: 93%

Section: Experimental Methodssupporting

confidence: 93%

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New polymer electrolyte based on PVAL‐LiOH‐Al₂O₃‐H₂O

Fernández

Diosa

Vargas

et al. 2007

Phys. Status Solidi (c)

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“…Water contents in the membranes favor their proton transport [16] and promise a wide range for the composites to operate as PEM at higher temperatures [9]. Although a high water content in the membrane is desirable, in the fuel cell can block reactant access to the catalyst layer, reducing the overall cell performance [17].…”

Section: Thermal Analysismentioning

confidence: 99%

“…The proton transport properties of a membrane can be improved by enhancing the hydrophilicity of the membrane, since it raises the selectivity of water toward organic [9] and inorganic [10] aqueous solution. For example, PVOH interacts with inorganic salts and acid to form an ionic conductor in a polymer matrix.…”

Section: Introductionmentioning

confidence: 99%