Dielectric response characteristics of low density polyethylene/TiO ₂ nanocomposites

In this study, the low density polyethylene based samples filled with different loadings of titanium oxide nanoparticles were electrically characterized by a broadband dielectric spectrometer at different temperatures. Neat LDPE and nanofilled LDPE samples up to 10 wt% weight have been studied. From experimental results, it indicated that a new relaxation loss peak was observed in the low frequency region at high nanoTiO₂ loadings (>1 wt%). This new loss peak shifts to high frequency with increase in nanoTiO ₂ loadings and it has gradually widened at high particle loadings. It indicated that the observed loss peak in low density polyethylene/TiO ₂ nanocomposite initially shifts to high frequency and then moves to the low frequency zone with increasing temperature for samples with 5 wt% and 10 wt% nanoparticles. Through analyzing dielectric properties of samples, these phenomena were close related to the absorbed water in nanocomposite. The cole-cole plots of samples of 1 wt% and 2 wt% also presented two peaks existed in dielectric spectra. One is the intrinsic peak of LDPE, the other is the new peak. In addition, this new peak did not caused by Maxwell-Wagner interfacial polarization. The interfacial region affected the dielectric response properties of nanocomposites.