Effects of carbon fillers on the conductivity and tensile properties of polyetheretherketone composites

Abstract

Polyetheretherketone (PEEK)‐based composites are used in aerospace applications due to their high mechanical strengths at temperatures >250°C, excellent chemical resistance properties, and outstanding dimensional stability. In this work, varying amounts of three different carbon fillers (carbon black [CB], graphene nanoplatelets [GNP], and carbon fiber [CF]) were added to PEEK to produce conductive composites for aerospace applications. Researchers extruded, injection molded, and performed electrical and thermal conductivity (TC) and tensile tests on GNP/PEEK, CB/PEEK, CF/PEEK, and CB/CF/PEEK composites. Five formulations could be used for electrostatic dissipative applications: 15 wt% GNP/PEEK, 20 wt% CF/PEEK, 2.5 wt% CB/10 wt% CF/PEEK, and 2.5 wt% CB/20 wt% CF/PEEK. Seven formulations could be used for electrically conductive applications: 30 wt% CF/PEEK, 5 wt% CB/PEEK, 7.5 wt% CB/PEEK, 10 wt% CB/PEEK, 2.5 wt% CB/30 wt% CF/PEEK, 5 wt% CB/30 wt% CF/PEEK, and 7.5 wt% CB/30 wt% CF/PEEK. The most conductive composite produced was 7.5 wt% CB/30 wt% CF/PEEK, which had an electrical resisitivity (1/electrical conductivity) of 0.56 Ω cm, a TC twice that of the neat PEEK, a tensile strength of 145 MPa, and a tensile modulus of 18.4 GPa. Per the authors' knowledge, properties on these GNP/PEEK, CB/PEEK, and CB/CF/PEEK composites have not been previously reported in the open literature. POLYM. COMPOS., 39:E807–E816, 2018. © 2016 Society of Plastics Engineers