Preparation of MWCNTs/CF/PEEK multi-scale composites with good mechanical and electrical conductivity by a two-step process of AFP and out-of-autoclave tempering

Developing simple and highly automated strategies for manufacturing green, high-performance thermoplastic composite components remains a major challenge. In this paper, multi-walled carbon nanotube (MWCNT) nanofillers are successfully dispersed on the carbon fiber/polyetheretherketone (CF/PEEK) prepreg surface via a simple solution volatilization method. Furthermore, MWCNTs/CF/PEEK multi-scale composites are prepared by the highly automated automatic fiber placement (AFP) in-situ consolidation technology. The in-situ consolidated samples are tempered by an out-of-autoclave (OOA) technique to improve the bonding strength of the MWCNTs with the PEEK substrate. Enhanced adhesion is achieved between the CF and the PEEK substrate by introducing nanofiller modification methods at the interlayer fine-scale. Moreover, the interlocking effect of the nanofiller with the PEEK substrate increases the interlayer strength of the multi-scale composites. Compared to the CF/PEEK composite, the MWCNTs/CF/PEEK multi-scale composite achieved a maximum interlaminar shear strength (ILSS) of 91.49 MPa, i.e., an increase of 25.21%. In addition, due to the excellent electrical conductivity of the nanofillers, the nanofillers form electron channels between the fibers. This increases the conductivity of multi-scale composites by 766% and 323% in the 0° and 90° directions, respectively. This work provides a simple and highly automated method for preparing complex thermoplastic composite components with good mechanical properties and excellent electrical conductivity. Such composites may be employed in aerospace lighting protection.