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DSC and SEM analysis of Poly(ethylene oxide)/Polyhedral oligomeric silsesquioxanes (POSS) nanocomposites

Poly(ethylene oxide) (PEO) as a semi- crystalline, biocompatible, water-soluble polyether finds considerable application in many different branches of industry. PEO based electrolytes are among the most extensively studied polymer ionic conductors, but high crystallinity of PEO limits ionic conductivity of these electrolytes at room temperatures. One of the possible ways to reduce the crystallinity of PEO is the incorporation of nanoparticles such as polyhedral oligomeric silsesquioxanes (POSSs) in the PEO matrix. The use of POSSs for making polymer composites has grown exponentially since the last few years of the 20th century. In comparison with the other most commonly used fillers, POSSs possess the advantage of being molecules. Thus, this allows us to combine their nano-sized cage structures, which have dimensions that are similar to those of most polymer segments and produce a particular and exclusive chemical composition. These characteristics linked with their hybrid (inorganic–organic) nature allow researchers to modify POSS according to particular needs or original ideas, before incorporating them into polymers. In this work PEO nanocomposites with different hepta isobutyl polyhedral oligomeric silsesquioxanes (hib-POSS) were prepared and the influence of hib-POSS on PEO melting was investigated. It was observed that the glass transition temperature, melting temperature and crystallinity of PEO decrease when hib-POSSs with methyl, fluorine or chlorine substituents on phenyl group are present. Taking into account the mass ratio of the components, values of melting enthalpies suggest decrease of PEO crystallinity in the composites, probably due to the formation of POSS-POSS aggregates. Furthermore, hib-POSSs with methyl, fluoro and chloro substituents on phenyl ring narrow the melting and crystallization regions of PEO.

DSC, SEM, phenyl hepta isobutyl polyhedral oligomeric silsesquioxane (phenyl hib-POSS), poly(ethylene oxide) (PEO)

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