Estudo de um novo eletrólito polimérico sólido em forma de filme autossustentável: Poli(óxido de etileno)-tungstato de sódio
Self-sustainable polymeric films based on new solid polymer electrolyte, having the poly(ethylene oxide) (PEO) as host matrix and sodium tungstate as doping agent (Na2WO4), were obtained from different salt compositions (m = 0.20; 0.26; 0.30; 0.40; 0.50 and 1.31 mg). The films were characterized...
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| Formato: | Dissertação |
| Idioma: | por |
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/21476 |
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| Resumo: | Self-sustainable polymeric films based on new solid polymer electrolyte, having the
poly(ethylene oxide) (PEO) as host matrix and sodium tungstate as doping agent (Na2WO4),
were obtained from different salt compositions (m = 0.20; 0.26; 0.30; 0.40; 0.50 and 1.31
mg). The films were characterized through XRD, FTIR, SEM/EDS, TG/DTG, DSC and IS.
X-ray diffraction showed the semi crystalline nature of the polymer and confirmed that the
addition of salt induces reduction in the crystalinity of the films. FTIR data allowed the
identification of the interaction between salt ions and polymer chains and confirmed that these
interactions are of a physical nature. The micrographs obtained through SEM showed
spherulitic morphology interleaved by interlayered bonds for all of the compositions studied.
The TG/DTG study revealed that the thermal decomposition of the electrolyte almost happens
at a single stage with the addition of salt, increasing the thermal stability of the films.
TG/DTG data also allowed the kinetic study of the thermal decomposition of the electrolyte
through Broido (BR), Coats-Redfern (CR) and Horowitz-Metzger (HM) methods, suggesting
a first-order kinetic for the reaction of the thermal decomposition of the films, as well as the
setting of pre-exponential factor, A, and the thermodynamic activation parameters: E*, ΔH*,
ΔS* and ΔG*. The crystallinity degree was determined through DSC data and showed a
reduction after the addition of salt to the polymer. The polymer has its conductivity increased
after addition of the salt with the PEO-Na2WO4 electrolyte exhibiting maximum of ionic
conductivity of 3.24x10-4 S cm-1, to room temperature, for the film with 1.31 mg of salt (F6
film). The impedance data allowed the study on relaxation on PEO chains, even as the
diffusion of salt between these chains. The impedance diagrams, on Bode and Nyquist
formats, enabled the adjustment of the experimental data to equivalent electric circuits, which
facilitated the association of the circuit components to the physical and chemical phenomena
observed for the films and revealed that, after the addition of salt to the polymer, the films
have their electrical properties enhanced. |
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