Novel high‐density polyethylene‐niobium pentoxide dielectric materials

Abstract

This study for the first time reports the processing and properties of high‐density polyethylene (HDPE) reinforced with niobium pentoxide (Nb2O5) up to 40 wt%. In this work, Nb2O5 was chosen as reinforcement because of its advantageous properties such as good dielectric properties, high temperature stability and excellent biocompatible properties. Almost fully dense HDPE–Nb2O5 composites were prepared via hot pressing route. Both the hardness and dielectric properties of the HDPE increased significantly with the addition of Nb2O5. The hardness of HDPE increased from ∼37 to 60 MPa (i.e., by 62%) with the addition of 40 wt% Nb2O5. The dielectric constant and dissipation factor (dielectric loss) were found to increase with the increasing Nb2O5 content. We have achieved highest ever reported dielectric constant (ε') of 14.66 for HDPE–40 wt% Nb2O5 and the dielectric constant of HDPE is enhanced by 237% and shows the potential of Nb2O5 in improving the dielectric and hardness properties of HDPE. With increasing frequency there was slight decrease in the dielectric constant of HDPE–Nb2O5 composites, whereas not much change in the dielectric constant of pure HDPE. The dielectric constant (ε') of HDPE is 4.6 at 1 MHz, while the ε' value for the composite with 40 wt% Nb2O5 ceramic filler was found to be 13.2. The dielectric loss for the HDPE composites is higher than the neat polymer, particularly HDPE–40 wt% Nb2O5 composite measured with maximum dielectric loss (0.08) at 100 Hz. Nevertheless, the dielectric loss of HDPE materials significantly decreased with further increasing the frequency to 1 kHz and the dielectric loss even significantly lowered with increasing frequency to 1 MHz. The experimental values of dielectric constant show much better values than the calculated values based on theoretical models. The newly developed HDPE–Nb2O5 composites are showing much better dielectric properties than the reported literature values of HDPE materials. POLYM. COMPOS., 40:749–757, 2019. © 2018 Society of Plastics Engineers