Structure and dielectric properties of a thermoplastic blend containing dispersed metal |
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Authors: | Haralampos Zois Yevgen P. Mamunya Lazaros Apekis |
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Affiliation: | 1. National Technical University of Athens, Department of Physics, Zografou Campus, 157 80 Athens, Greece;2. Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Kharkovskoe shausse 48, Kiev 02160, Ukraine |
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Abstract: | In the present work broadband dielectric relaxation spectroscopy measurements were employed to investigate the dielectric properties of polymer composites. A polyethylene/polyoxymethylene (PE/POM) thermoplastic blend was used as a matrix, while the inclusions were iron (Fe) particles. For comparison, the two pure polymers- PE and POM- were used as a matrix, too. In the PE/POM-Fe composites, the polymer matrix is two-phase and the filler particles are localized only in the POM phase, resulting in an ordered distribution of the dispersed filler particles within the blend. In PE-Fe and POM-Fe composites, the filler spatial distribution is random. The behaviour of all the composites studied is described in terms of the percolation theory. The PE/POM-Fe composites, based on the PE/POM blend, demonstrate different electrical behaviour compared to that of POM-Fe and PE-Fe systems. The percolation threshold value of the PE/POM-Fe composites was found much lower than that of the other two systems. The results were related to the microstructure of the composites. A schematic model for the morphology of the composites studied has been proposed. This model explains the peculiar behaviour of the PE/POM-Fe composites by taking into account the ordered distribution of the filler particles in a binary polymer matrix. Optical microscopy photographs confirm this model. |
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Keywords: | composite materials dielectric properties morphology percolation |
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