A comparative study on the influences of whisker and conventional carbon nanotubes on the electrical and thermal conductivity of polyether ether ketone composites

In this study, the electrical and thermal conductivity of polyether ether ketone (PEEK)/carbon nanotubes (CNTs) with different types, namely whisker CNTs (Wh-CNTs) and conventional CNTs were compared. PEEK/CNTs composites were melt mixed in PEEK via two screw extrusion technology. Moreover, the effects of different methods for mixing of PEEK/Wh-CNTs, namely, dry mixing, wet mixing and melt mixing, were compared. The electrical and thermal properties were analyzed. A high thermal conductivity value of about 0.741 W/(m K) could be obtained upon loading with 10 wt% Wh-CNTs and the PEEK/Wh-CNTs composites had low volume resistivity value of 10.96 Ω cm at 10 wt% loading via melt mixing. Thermal conductivity values of 1.066 W/(m K) (out-of-plane) and 1.50 W/(m K) (in-plane) were achieved with 10 wt% loading by wet mixing. Experimental results of out-of-plane thermal conductivity were more consistent with the Nan model. PEEK/Wh-CNTs composites prepared by wet mixing exhibited higher thermal conductivity than the composites mixed using the two other methods. As the content of Wh-CNTs in wet mixed PEEK/Wh-CNTs nanocomposites increased, electromagnetic interference (EMI) shielding effectiveness (SE) was improved. The PEEK/Wh-CNTs composites were 0.6 mm thick and showed an EMI SE of 21.5 dB.