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Previous issue date: 2016-02-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Filmes polim?ricos autossustent?veis baseados em um novo eletr?lito polim?rico s?lido (EPS), tendo como matriz hospedeira o poli(?xido de etileno) (POE) e como agente dopante o tungstato de s?dio (Na2WO4), foram obtidos para diferentes composi??es do sal (m = 0,20; 0,26; 0,30; 0,40; 0,50 e 1,31 mg). Os filmes foram caracterizados por DRX, FTIR, MEV/EDS, TG/DTG, DSC e EI. Os difratogramas de raios X confirmaram a natureza semicristalina do pol?mero e sugeriram que a adi??o do sal provoca uma redu??o na cristalinidade dos filmes. Os dados de FTIR permitiram a an?lise da intera??o entre os ?ons do sal e as cadeias polim?ricas. As micrografias obtidas por MEV demonstraram morfologia esferul?tica intercaladas por liga??es interlamelares para todas as composi??es estudadas. O estudo de TG/DTG mostrou que a decomposi??o t?rmica do eletr?lito ocorre em uma ?nica etapa com a adi??o do sal aumentando a estabilidade t?rmica dos filmes. Os dados de TG/DTG permitiram, ainda, o estudo cin?tico da decomposi??o t?rmica do eletr?lito por meio dos m?todos de Briodo (BR), Coats-Redfern (CR) e Horowitz-Metzger (HM) sugerindo uma cin?tica de 1? ordem para a rea??o de decomposi??o t?rmica dos filmes, assim como, a determina??o dos par?metros termodin?micos de ativa??o: E*, ?H*, ?S* e ?G*. O grau de cristalinidade foi determinado atrav?s dos dados de DSC e mostrou uma redu??o ap?s a adi??o do sal ao pol?mero. O eletr?lito POE/Na2WO4 exibiu um m?ximo de condutividade i?nica de 3,24x10-4 S.cm-1, a temperatura ambiente, para o filme com 1,31 mg do sal. Atrav?s dos dados de imped?ncia foi poss?vel o estudo de relaxa??o das cadeias do POE, assim como, a difus?o do sal entre estas cadeias. Os diagramas de imped?ncia, nos formatos Bode e Nyquist, permitiram o ajuste dos dados experimentais ? circuitos el?tricos equivalentes o que facilitou a associa??o dos componentes dos circuitos aos fen?menos f?sicos e qu?micos observados para os filmes e revelaram que, ap?s a adi??o do sal ao pol?mero, os filmes t?m suas propriedades el?tricas melhoradas. / 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*, ?H*,
?S* and ?G*. 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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21476 |
| Date | 05 February 2016 |
| Creators | Lima, Gilberto de |
| Contributors | 13893734449, Fernandes, Nedja Suely, 44420773472, Correia, Adriana Nunes, 32343272387, Silva, Cassia Miriam Lucas da, 03713149410, Cavalcante, Maria Gorette, Silva, Djalma Ribeiro da |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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