Construction of flexible 1D core-shell Al2O3@NaNbO3 nanowires/poly-(p-phenylene benzobisoxazole) nanocomposite with stable and enhanced dielectric properties in an ultra-wide temperature range

Polymeric dielectrics with high-temperature resilience are of critical importance in developing advanced electrostatic capacitors. Poly-(p-phenylene benzobisoxazole) (PBO) is a polymer with excellent thermal stability. However, the poor processability and low...

An Improved Physical-Stochastic Model for Simulating Electrical Tree Propagation in Solid Polymeric Dielectrics

The dielectric breakdown of solid polymeric materials is due to the inception and propagation of electrical trees inside them. The remaining useful life of the solid dielectrics could be determined using propagation simulations correlated with non-intrusive measurements such as partial discharges (PD). This paper presents a brief review of the different models for simulating electrical tree propagation in solid dielectrics. A novel improved physical-stochastic model is proposed, which allows quantitatively and qualitatively analyzing the electrical tree propagation process in polymeric dielectrics. Simulation results exhibit good agreement with measurements presented in the literature. It is concluded that the model allows adequately predicting the tree propagation behavior and additional experimental analyses are required in order to improve the model accuracy.

Experimental Characterization of Polymer Surfaces Subject to Corona Discharges in Controlled Atmospheres

Polymeric dielectrics are employed extensively in the power transmission industry, thanks to their excellent properties; however, under normal operating conditions these materials tend to degrade and fail. In this study, samples of low-density polyethylene, polypropylene, polymethyl methacrylate, and polytetrafluorethylene were subjected to corona discharges under nitrogen and air atmospheres. The discharges introduced structural modifications over the polymer surface. From a chemical perspective, the alterations are analogous among the non-fluorinated polymers (i.e., polyethylene (PE), polypropylene (PP), and polymethyl methacrylate (PMMA)). A simulation of the corona discharge allowed the identification of highly reactive species in the proximity of the surface. The results are consistent with the degradation of insulating polymers in high-voltage applications due to internal partial discharges that ultimately lead to the breakdown of the material.