Boron Nitride Nanocomposites for Thermal Management of Aircraft Propulsion System

Electric aircraft propulsion, utilizing either turbine engines or energy storage systems, is a rapidly advancing aviation technology
showing great promise. NASA’s Next Generation Air Transportation System (NextGen) initiative is working toward creating a safer, more reliable, and efficient aviation system while minimizing its environmental impact. Thermal management plays a critical role in the design of aircraft propulsion systems. This study examines the effects of varying the form, size, concentration, and processing of boron nitride (BN) fillers on the thermal conductivity (TC) and dielectric strength (DS) of polyimide (PI) films. Multiple forms of BN were investigated to improve the properties of electric cable insulation materials, including hexagonal BN (h-BN), BN nanotubes (BNNT), and BN nanosheets (BNNS). Findings indicate that BNNS produced by the compressible flow exfoliation (CFE) method not only significantly improved the TC of the baseline material (>2×) with an acceptable dielectric breakdown strength (>150 kV/mm) compared with the neat PI, but they also produced a flexible nanocomposite film. This report presents results and discusses the effect of the BN material forms on the TC and DS parameters of BN/PI nanocomposites.