Effect of Ba(Ti_(0.9)Sn_0.1)O₃ ceramic doping on optical, thermal and dielectric properties of polycarbonate host

Abstract

Ba(Ti_(0.9)Sn_0.1)O₃ (BTS) ceramic was prepared by a conventional ceramic processing. BTS-polycarbonate (PC) composites were prepared at different BTS concentrations by weight in order to study their optical and dielectric properties. The absorption coefficient (α) was determined in the wavelength range from 250–600 nm at room temperature for all BTS-PC composites. The optical gap (E _opt) was also determined for BTS-PC composites. The variation of the absorption coefficient (α) and optical gap (E _opt) with BTS content are reported. It was found that BTS ceramic highly enhances the UV absorption of PC host at 300 nm. The optical gap decreases up to the value of 3.93 eV as BTS content increases up to 35 wt% and this was attributed to the formation of localized states in the forbidden gap. The relative dielectric permittivity, dielectric loss and loss tangent were measured at temperature range from room temperature up to 150°C and at frequency values 1 kHz, 10 kHz and 50 kHz. Addition of BTS to PC host, however, will increase relative dielectric permittivity, dielectric loss and loss tangent. Besides, increasing of temperature will also increase relative dielectric permittivity, dielectric loss and loss tangent especially above the glass transition temperature of PC host and this behaviour was attributed to the segmental motion of polymer chains. On the other hand, this study shows that there is a good agreement between SEM, DSC and dielectric results and also between optical gap and a.c. conductivity results. Moreover, SEM and DSC results reveal that addition of BTS ceramic particles to PC host will reduce the physical bond between polymer chains or may be will increase the free volume in the polymer host and consequently will enhance the segmental motion of polymer chains and this behaviour is independent of ceramic phase.