Effects of multi-walled carbon nanotube/graphene oxide-based sizing on interfacial and tribological properties of continuous carbon fiber/poly(ether ether ketone) composites

Typical carbon-based nanoparticles, including MWCNTs and GO, are promising candidates for improving the interfacial properties of composites. It is imperative to know which kinds of nanoparticles are more favorable for performance improvement of CF/PEEK composites. In this study, the thermally stable and soluble s-PEEK is synthesized and utilized as the basic part of sizing agent. Amino-functionalized MWCNTs and GO were separately dispersed in the s-PEEK solution to make the complex sizing agents, which were deposited on the surface of CFs respectively. The modified composites presented improved ILSS and tribological performance, simultaneously preserved their high tensile strength. Highly loaded MWCNTs in the interfacial region was more effective to enhance the overall performance of composites. Conversely, dilute GO-based complex sizing agent was beneficial in terms of improved properties. The maximum ILSS of CF/PEEK laminate was 72.8 MPa after 0.05 wt% GO/s-PEEK agent sizing, which was 56.37% higher than that of pristine composites. A lowest friction coefficient was recorded for 1 wt% MWCNTs/s-PEEK sizing laminates, and the wear extent was reduced by 31.71% after modification. Finally, the interfacial reinforcing mechanism disparities of MWCNTs and GO based complex sizing agent were explained by thoroughly analyzing the interfacial structure.