Interfacial enhancement of CF/PEEK composites by modifying water-based PEEK-NH2 sizing agent

In this study, a series of soluble aminated polyether-ether-ketone (PEEK-NH2) with good compatibility were designed. Novel water-based sizing agents were then prepared by emulsion/solvent evaporation method, which were selected as CF surface modifiers to improve the interfacial properties of CF/PEEK composites. TGA and DSC results showed that PEEK-NH2 exhibit excellent thermal properties, and the Tg was increased by up to 30.9 °C. The particle diameters of sizing agents range from 54.3 to 73.6 nm, and the contact angles of modified CF were significantly decreased. According to the interfacial properties results, PEEK–NH2–35 presented the most effective reinforcing effect, the interlaminar shear strength and flexural strength were increased by 43.1% and 62.2%, as compared to un-sized CF composites. Moreover, the interfacial strengthening mechanisms of sizing agent was investigated. The improved interfacial adhesion benefits from PEEK-NH2 which performs as effective stress transfer bridge at the interface.