Synergistic Effect of a Novel Aqueous Sizing Agent to Enhance the Interfacial Properties of CF/PAEK Composites

Sizing agent is a thin layer of resin evenly covering the surface of carbon fibers, which plays an important role in interface and mechanical propertiesin carbon fiber/polyaryl ether ketonecomposites (CF/PAEK). In this study, a novel waterborne phenolphthalein-type polyaryletherketone-poly(styrenesulfonate) sodium (PEKC-NaPSS) sizing was specifically synthesizedby a simple, efficient and environmentally friendly UV induced grafting method, and was sized on CF surface. PEKC-NaPSS exhibits high thermal stability, with a decomposition temperature above 450 °C, meeting the processing temperature of CF/PAEK composite. Relative to desized CF/PAEK composites, the 1 wt% PEKC-NaPSS sized CF/PAEK composites exhibited significant enhancements in flexural strength, flexural modulus, and interlaminar shear strength (ILSS) of 38.03%, 38.2%, and 28.67%, respectively. Furthermore, the mechanism for interface improvement in PEKC-NaPSS sized CF/PAEK composites has been proposed. This study provides a straightforward and eco-friendly approachof producing high-performance CF/PAEK composites.