Chapter 8 – On the friction and wear of carbon nanofiber-reinforced PEEK-based polymer composites

: In the context of establishing novel polymer nanocomposites for successful industrial use, this chapter is aimed at providing a fundamental overview of comprehensive research regarding carbon nanofiber (CNF)-reinforced poly(ether ether ketone) (PEEK) composites for demanding tribological applications. Following a summary overview describing the potential of nanoscale additives for tribological systems in general, the intrinsic structure–property relationships of CNFs are discussed in order to set the frame for the subsequent experimental results regarding their use in PEEK. As demonstrated, successful PEEK–nanofiber composites have been developed, showing a clear enhancement in mechanical properties while minimizing other detrimental effects commonly observed with such nanocomposites. These nanocomposites also reveal a significant beneficial effect on the wear behavior of PEEK under dry sliding conditions. In addition to relating the observed enhancements in the tribological performance to the underlying microstructures and properties of the nanocomposites, evidence for a further optimization of such systems by combining the nanoscale filler with conventional tribological additives and reinforcements such as carbon fibers is provided. Lastly, based on the promising results regarding the wear behavior of such hybrid systems, the performance of advanced nanocomposite hybrid materials for an intended industrial tribological application is introduced and discussed.