MWCNT–Polyimide Fiber-Reinforced Composite for High-Temperature Tribological Applications

A hybrid type of polyimide fibers (PIF) grafted with multi-walled carbon nanotubes (MWCNTs) was developed for high-temperature tribological applications. Compared to pure PI samples, the mechanical properties (i.e., Young’s modulus and hardness) of the PIF-based composite were enhanced following a rule of mixture prediction; the onset decomposition temperature of the MWCNT-PIF-based composite was increased by 14.5 °C and the wear rate at 300 °C decreased by 34.5%. To understand the grafting mechanism, Dmol3 simulation was performed, which revealed that the benzene ring and the hydroxyl group of diene-acceptor (DA) donated electrons to the oxygen atom in the nitrogen-containing five-membered ring of PIF and the straight chain structures had higher reactivity than a branched chain structure.