Electrical Treeing Morphologies and Behaviors Discovered in Aerospace-Grade Fluorinated Ethylene Propylene

Electrification is on the forefront of research among many industries to mitigate greenhouse gas emissions. To electrify an aircraft, insulation materials are required to handle high operational voltages as well as extreme conditions for the entirety of the aircraft life. Unfortunately, polymer dielectrics are prone to an aging phenomenon called electrical treeing. Electrical treeing can cause electrical breakdown in insulation systems because it propagates through-thickness. This phenomenon has never been studied in aerospace grade dielectric materials before. Not only is it crucial to understand this aging mechanism in aerospace grade materials before service introduction, but it is also imperative to understand how aircraft operating conditions, like temperature and pressure, affect it. This study reveals that commercially available, aerospace-grade, fluorinated insulation material (Fluorinated Ethylene Propylene) is prone to a type of treeing not yet discovered. Additionally, it is shown in this work that the directionality of this dielectric could be leveraged to mitigate electrical tree growth, which would be an elegant, cost-effective solution for preventing electrical treeing in aircraft systems.