INVESTIGADORES
CASTRO Miriam Susana
congresos y reuniones científicas
Título:
Dielectric measurements of epoxy resin/BaTiO3 fiber composites
Autor/es:
H. ÁVILA; L. RAMAJO; M.M. REBOREDO; M. CASTRO; R. PARRA
Reunión:
Simposio; International Symposium on Applications of Ferroelectrics (Isaf); 2012
Resumen:
Integrating
the advantages of polymer and ceramic materials, composites can offer enhanced
performances compared to those of the individual constituents. Varieties of
ceramic/polymer composites have been developed. Among them, composites with
dielectric and ferroelectric properties have attracted much attention recently.
In
this work, composite materials composed of epoxy resin and BaTiO3(BT)
nanofibers obtained by electrospinning, were prepared. Nanofibers were
synthesized from a sol based on barium acetate, titanium isopropoxide and
poly(vinyl pyrrolidone). Fibers were calcined at different temperatures and
characterized by X-Ray diffraction, field-emission scanning electron microscopy
and Raman spectroscopy. Mats of BT fibers heat-treated at 800°C were embedded in epoxy
resin inside suitable moulds. The resulting epoxy resin/BT composites were cured
and subsequently analyzed by SEM and impedance spectroscopy analyses. The
dielectric constant and hysteresis loops of epoxy resin/BT-fibers were measured
for two types of samples with the electrodes parallel and perpendicular to the
BaTiO3 fiber layers.
Samples
with electrodes perpendicular to the array of fiber mats showed higher real
permittivity values and ferroelectric behavior, whereas samples with parallel
electrodes showed permittivities similar to that of epoxy
resin. Additionally, the dielectric results of epoxy/BT fibers composites
confirmed predictions of the Hashin-Shtrikmans series and parallel mixing model.