Structural transition, dielectric properties and functionality in epoxy resin—barium titanate nanocomposites

Epoxy resin/ceramic barium titanate nano- and micro-composites were prepared and studied. Investigation of morphological characteristics was conducted by means of x-ray diffraction spectra and scanning electron microscopy images, while the dielectric response of the composite systems was examined via broadband dielectric spectroscopy in the frequency range of 10−1–107 Hz and over the temperature range of 30–160 ° C, varying the content and the type of ferroelectric particles. Functional behaviour of the composites is attributed to the structural transition occurring at the critical Curie temperature of the ferroelectric inclusions. Embedded micro- and nano-inclusions are considered to be a dispersed network of capacitors where energy can be stored. The energy storage efficiency of the systems is examined via the variation of dielectric permittivity and polarization with frequency, temperature and filler content, while the dielectric reinforcing function is introduced and exploited in determining the optimum functional behaviour and energy storing capability. (paper)