Novel high‐density polyethylene‐niobium pentoxide dielectric materials

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