The Effect of Electro–Thermal Ageing of Polymer–Ceramic Nanocomposite Insulation on Dielectric Endurance

This study investigates the electro-thermal ageing (ETA) behaviour of neat polyamide-6 (PA6) and PA6/barium titanate (BTO) nanocomposites. Time–to–breakdown measurements were performed at 333 K, 353 K, and 373 K at field strengths between 50 and 90 kV/mm to assess the impact of nanofiller level on lifetime to failure. The ageing experiment showed that moderate amounts of nanofiller improved the electro-thermal endurance while excessive filler addition (20 wt.%) led to faster breakdown. The Dissado–Montanari–Mazzanti (DMM) model was used to evaluate the ageing parameters for neat PA6 and PA6/10 wt.% BTO across all three temperatures. Neat PA6 and PA6/10 wt.% BTO both showed nearly identical activation enthalpy (H/k) values, indicating that the intrinsic thermally activated ageing mechanism of PA6 is preserved in the nanocomposite. Variations in the field-sensitivity parameters (C/k and b) align with an interpretation involving changes in charge transport and interfacial trapping introduced by the addition of BTO. Furthermore, analysis of all filler concentrations confirmed that 1–10 wt.% BTO maintains or slightly improves the time to breakdown, while 20 wt.% significantly accelerated the ageing process. This research forms part of the research programme of DPI, project #852.