Perfluoroalkoxy alkane (PFA) is a promising candidate for onbaord high-voltage cable insulation due to its superior dielectric properties, chemical resistance, and high thermal stability. Understanding the thermal aging behavior of PFA is essential for ensuring the long-term reliability of insulation materials in hybrid-electric aircraft, where high thermal fluctuations are common. This study investigates the chemical, structural, mechanical, and dielectric properties of PFA aged at 280 °C for up to 1000 h, simulating real-world aerospace operational environments. Results show that PFA undergoes chain scission and chemicrystallization in the early aging stages (0-480 h), leading to an increase in crystallinity. However, at longer aging times e.g. (>480 h), oxidative degradation becomes dominant, resulting in chemical and structural changes correlated with microstructural damage, including crack formation, tie-chain loss, and lamellar disruption. Dynamic mechanical analysis and tensile results show a significant decrease in molecular rigidity with a reduction in glass transition temperature (T_g), indicating a loss of material stiffness and a reduction in tensile strength (42.16%) and elongation (30.2%) after long term exposure (1000 h). Dielectric characterization demonstrates monotonic increase in dielectric constant (from 1.90 to 2.15), dissipation factor, and AC conductivity, attributed to the formation of polar oxidation products and defect-assisted interfacial polarization. The dielectric strength also decreases from 95.2 kV/mm to 87.1 kV/mm after 1000 h of aging. Molecular dynamics simulations (MDS) are also performed to study the temperature effect on PFA, revealing that at high temperatures, the PFA molecular structure is increasingly destroyed by thermal chain scission. These findings provide valuable insight into the degradation mechanisms governing PFA performance and contribute to evaluating its reliability as an insulation material for high-voltage cable systems in hybrid-electric aircraft.

Electric aircraft represent a promising low-emission alternative to conventional fuel-powered aviation, driving the demand for lightweight and reliable electrical powertrain architectures. This study presents a design process for an electrical power system with an emphasis on the cabling system and battery in all-electric aircraft (AEA). Design considerations for the cabling system in power distribution architectures are discussed, including cable insulation material selection, conductor choice, sizing, and weight reduction methods. The influence of different system voltages and operating temperatures on cable weight is analyzed to identify optimal design tradeoffs. A comparison of polytetrafluoroethylene (PTFE) and perfluoroalkoxy (PFA) insulation materials, as well as aluminum and copper conductors, highlights their impact on weight and reliability, with PFA offering weight advantages under typical aerospace operating conditions. The batteries are sized based on the energy and power demands of a 90-seater AEA as a case study. After designing the components of the aircraft’s electrical power system, the electrical architectures are presented. Furthermore, a framework for evaluating the electrical power system architectures of AEAs is proposed, using two key criteria: reliability and weight. The weight of the electrical power system is then estimated based on aircraft performance requirements. The proposed framework provides practical guidelines for cable selection and architecture optimization in future AEAs.