Dielectric properties OF 40SiO(2)-40P(2)O(5)-20ZrO(2) /sulfonated styrene-ethylene-butylene-styrene hybrid membranes for proton exchange membrane fuel cells
[EN] The dielectric spectra of a series of hybrid membranes prepared with sulfonated styrene-ethylene-butylenestyrene (sSEBS) as the polymeric matrix, and zirconia-modified phosphosilicate (40SiO2-40P2O5-20ZrO2), as inorganic filler through direct infiltration, was analysed. All the membranes displa...
| Authors: | , , , |
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| Format: | article |
| Publication Date: | 2023 |
| Country: | España |
| Institution: | Universitat Politècnica de València (UPV) |
| Repository: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Language: | English |
| OAI Identifier: | oai:riunet.upv.es:10251/210783 |
| Online Access: | https://riunet.upv.es/handle/10251/210783 |
| Access Level: | Open access |
| Keyword: | Proton Exchange Membrane Fuel Cell (PEMFC) Dielectric properties Sulfonated SEBS MAQUINAS Y MOTORES TERMICOS |
| Summary: | [EN] The dielectric spectra of a series of hybrid membranes prepared with sulfonated styrene-ethylene-butylenestyrene (sSEBS) as the polymeric matrix, and zirconia-modified phosphosilicate (40SiO2-40P2O5-20ZrO2), as inorganic filler through direct infiltration, was analysed. All the membranes displayed characteristic sSEBS spectra, consisting of three molecular relaxations: A non-cooperative (beta) relaxation and two cooperatives (alpha EB, alpha PS) ones ascribed to the glass transition of the ethylene-butylene and the polystyrene blocks, respectively. As a result of the infiltration of the inorganic component (40SiO2-40P2O5-20ZrO2), the dielectric spectra were considerably modified. Accordingly, the formation of dynamic crosslinking (M-O-M ' bonds, with M = P, Si, Zr) difficulties the motion of the alpha EB process, thus shifting it towards higher temperatures. Moreover, a significant plasticisation effect was found at high temperatures, which facilitates the activation of the alpha PS process. Furthermore, the decreasing values of the fragility parameter, due to the infiltration of the inorganic filler, revealed that all hybrid membranes displayed an arrangement of molecular chains and a strong behaviour. Thus, higher resistance to sudden temperature changes is expected. The optimum infiltration time (tau inf) is between 10 and 20 min since it provides acceptable values of electric permittivity, and the induced dynamic crosslinking brings the glass transitions of both blocks closer. Consequently, a complete characterisation of the molecular mobility by studying the spectrum of dielectric relaxations enables to fine-tune the membranes for an optimum design focused on its application in a proton exchange membrane fuel cell (PEMFC). |
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