Development, dielectric response and functionality of SrTiO₃/epoxy nanocomposites

Composite systems of epoxy resin and SrTiO₃ nanoparticles have been prepared and studied in different filler concentrations. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that there was a successful filler integration and fine dispersion in the polymer matrix. Moreover, Broadband dielectric spectroscopy (BDS) was employed for the determination of the dielectric response of all manufactured systems. Dielectric results divulge three relaxation processes which are referred to: (a) glass to rubber transition of the polymer matrix (α-mode), (b) re-arrangement of polar side groups of the polymer matrix (β-mode) and (c) interfacial polarization between systems’ components. It was found that all nanodielectric systems exhibit enhanced dielectric properties which are mainly attributed to the semiconductive nanoinclusions and to the extended interface between the polymer matrix and the nanofiller. Finally, dynamic analysis of the relaxation processes was also performed. Vogel–Fulcher–Tammann equation describes the α-mode’s loss peak dependence on temperature, whereas the β-mode follows the Arrhenius expression. In case of β-mode it was found that the presence of the nanoinclusions hinders the orientation of the matrix’s polar side groups.