Dielectric properties of castor oil derived polymer filled with sol‐gel derived strontium barium niobate (Sr_0.3Ba_0.7Nb₂O₆) ferroelectric powder

Abstract

Sol‐gel derived strontium barium niobate (Sr0.3Ba0.7Nb2O6) (SBN) nanocrystalline powder was homogeneously dispersed in castor oil derived resinous polymer to develop a polymer nanocomposite. The main objective of this work was to develop a large surface area flexible polymeric material having desired mechanical, dielectric, and pyroelectric properties for use in pyroelectric detectors. Sol‐gel synthesized nanocrystalline SBN powder was characterized using X‐ray diffraction, FTIR, and Raman spectroscopy to study their structure. These powders were used to fabricate a ceramic as well as a polymer nanocomposite, which were then characterized for their morphological, thermal, and dielectric behavior using SEM, DSC‐TGA, and Agilent LCR meter, respectively. Dielectric constant of unfilled polymer at room temperature and at all frequencies was found to be around 16–18, which steadily increased with increasing temperature. However, when filled with SBN powder, the resulting polymer nanocomposite showed an increase in the dielectric constant and attained a value of 20–30 at room temperature, which further increased with increasing temperature. For SBN ceramic, the value obtained for ε′max (dielectric constant at Tc = 250°C) was around 600 (at 1 kHz) and ∼2000 (at 100 Hz). POLYM. COMPOS., 38:2119–2127, 2017. © 2015 Society of Plastics Engineers