The effect of annealing of milled carbon fibers on the mechanical and tribological properties of solid-lubricant thermoplastic polyimide-based composites.

The mechanical and tribological properties of polyimide (PI)-based composites loaded with polytetrafluoroethylene (PTFE) and milled carbon fibers (MCF) in the as received and annealed states were studied in order to increase adhesion to the polymer matrix. It has been shown that loading with micron-range MCF (200 μm) doubles elastic modulus of the composites while all other physical and mechanical properties remain at neat PI levels. The three-component composite loaded with annealed MCF and PTFE has possessed the highest wear resistance. In comparison with neat PI, its wear rate has decreased by 312 times for the metal-polymer tribological contact and by 286 times for the ceramic-polymer one. Based on the obtained experimental data, the most preferential conditions for their implementation (load-speed modes for the given types of the tribological contacts) have been determined using a developed computer algorithm. The designed solid-lubricant "PI + 10 wt% PTFE + 10 wt% MCFannealed" composite has been recommended for both metal-polymer and ceramic-polymer tribological units. [ABSTRACT FROM AUTHOR]