Novel polyimide-hexagonal boron nitride nanocomposites for synergistic improvement in tribological and radiation shielding properties

Polyimide (PI), a high-performance polymer with a high strength-to-weight ratio, thermal stability up to 330 degrees C, and chemical resistance, is a candidate material for aerospace and automotive applications. However, the poor tribological performance at elevated temperatures and radiation-induced brittle fracture threaten the durability of PI materials. To counter these challenges, novel hexagonal boron nitride (h-BN) based PI nanocomposites were prepared at 2 wt% and 5 wt% h-BN using direct forming. The dispersion of h-BN in the PI matrix was facilitated using ball milling. The glass transition temperature (Tg) of PI-2 wt% and 5 wt% h-BN increased by 18 degrees C and 20 degrees C, respectively, compared to neat PI. Tribological characterization using dry ball-on-disk sliding revealed an improvement in wear rate of-56 % and-70 % for PI-2 wt% and 5 wt% h-BN compared to neat PI at room and high temperatures (300 degrees C). PI-hBN nanocomposites were subjected to a neutron radiation source. The linear and mass absorption coefficient of PI-2 wt% and 5 wt% h-BN enhanced significantly by 1.9 and 2.2 times, respec-tively, compared to neat PI. The developed nanocomposites, with their excellent tribological behavior and neutron shielding capacity, have great potential as multifunctional materials for aerospace applications.