Multi-Scale Carbon (Micro/Nano) Fiber Reinforcement of Polyetheretherketone Using High Shear Melt-Processing

Abstract

Fiber-reinforced polymer matrix composites offer lightweight, high mechanical performance but have required much effort to achieve good fiber–matrix adhesion and uniform distribution, and generally suffer from low impact resistance. In this work, a uniform, high shear melt-processing method was used to prepare carbon fiber (CF) reinforced polyetheretherketone (PEEK), carbon nanofiber (CNF) reinforced PEEK, and multi-scale CF and CNF reinforced PEEK composites. Scanning electron microscopy images show good fiber distribution and fiber–matrix interaction, as well as surface crystallization of PEEK from the fiber surfaces. Tensile modulus and strength increase most significantly with the addition of CF but with a loss in ductility. The multi-scale composite of CF–CNF-PEEK displays the stiffening effect from the CF and retains more ductility due to the CNF. Further, the CF–CNF-PEEK composite displays the highest impact energy absorption. This study shows that good mixing of CFs and CNFs is achievable in PEEK using a uniform, high shear processing method that can easily produce intricate shapes and provides a stiff, high impact energy absorption multi-scale carbon fiber-reinforced composite.