Investigation of dielectric behavior of the PVC/BaTiO₃composite in low-frequencies

Abstract

Polyvinyl chloride (PVC) is widely used as insulator in electrical engineering especially as cable insulation sheaths. In order to improve the dielectric properties, polymers are mixed with ceramics. In this paper, PVC composites with different weight percentages 2 wt.%, 5 wt.%, 8 wt.% and 10 wt.% were prepared and investigated. Loss index ([Formula: see text]) and dielectric constant ([Formula: see text]) have been measured using an impedance analyzer RLC. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) have been used as characterization techniques. The incorporation of BaTiO3 does not modify the crystallinity and the morphology of the PVC but reduces the space charges, therefore the dielectric losses. The frequency response analysis has been followed in the frequency ranges (20–140 Hz and 115–1 MHz). Relaxation frequencies have been evaluated in each frequency range. Experimental measurements have been validated using Cole–Cole’s model. Experimental results show well that BaTiO3 as a filler improves the dielectric properties of PVC.

Effect of BaTiO3 on the Properties of PVC-Based Composite Thick Films

“…SEM images indicated that the pure PVC acted as a host matrix material and BaTiO 3 particles are almost evenly distributed with minimum agglomeration. Figure 3 a for pure PVC revealed smooth surface morphology consistent with previous studies [ 18 , 19 , 20 , 21 ]. The distribution of fillers in 30% of BT content is more obvious than that of 10% and 20% of BT content in the host PVC matrix.…”

“…The FTIR absorption spectra of BT, PVC and PVC/BT composite thick films with various BT content as fillers are shown in Figure 4a. For pure PVC, the characteristic absorption peaks of CH 2 deformation mode were observed at 1332 cm −1 , CH rocking mode at 1253 cm −1 , trans CH-wagging mode at 958 cm −1 , C-Cl stretching mode at 833 cm −1 and C is CH-wagging mode at 610 cm −1 , consistent with previous reports [18,21]. For pure BT, a broad peak is observed at 544 cm −1 due to the O-Ti-O vibration [28].…”

“…Figure 4 b shows that the relative intensities of peaks are decreased with the decrease in PVC content in the composite films. The peaks at 1332 cm −1 , 1253 cm −1 , 959 cm −1 and 833 cm −1 did not shift in composite films, which indicates that there is no chemical reaction taking place between the two phases [ 21 ]. The peak at 610 cm −1 has changed from a sharp peak at a lower wave number to a broader peak at 544 cm −1 with increasing BaTiO 3 content.…”

“…The piezoelectric coefficients d 31 of PVC has been reported in the range of 0.5 to 1.3 pC/N with a glass transition temperature of 80 • C [16,17]. PVC possess low dielectric constant (ε r = 4) and can be modified by adding various piezoelectric ceramic powders [18][19][20][21][22]. Funt has put forward the microwave dielectric properties of PVC under radio frequencies [23].…”

Experimental Study of Electric and Dielectric Behavior of PVC Composites

“…Novel polymeric composites containing ceramic powders have been utilized in order to improve insulators' performance [8,[19][20][21][22]. After the doping process in the samples a broadening of the peak in the BF region occurs [23] (Figures 2 and 3). A peak appears in the curve of the dielectric constant and in parallel an inflection in the curve of the loss index under around 50Hz.…”