Bio‐based hyperbranched poly (aryl ether ketone) sizing agent to enhance the interfacial property of carbon fiber/poly ether ether ketone composites

Abstract Despite the considerable advancements in poly aryl ether ketone (PAEK) sizing agents for carbon fiber (CF)/poly ether ketone (PEEK) composites, the majority of reported studies have focused on linear architectures, with a paucity of proposals employing hyperbranched poly aryl ether ketone (HPAEK). The present study discloses a CF sizing agent capitalizing on bio‐based hyperbranched poly aryl ether ketones (Bio‐H‐PAEK) capitalizing on a three‐dimensional monomer derived from vanillin and guaiacol. The substance displays excellent dispersibility, high thermal stability, a high glass transition temperature, and good solubility. The structural similarity between the PAEK sizing agent and the resin matrix, coupled with the favorable solubility and low melt viscosity of the HPAEK, enables this approach to enhance the overall performance of the CF/PEEK composite. The T_g and T_5% of Bio‐H‐PAEK‐F were determined to be 125°C and 420°C, respectively. Following the Bio‐H‐PAEK‐F sizing treatment, the flexural strength and interlaminar shear strength of the composites exhibited increases of 705.19 MPa (47.26%) and 64.91 MPa (60.43%), respectively, in comparison to untreated CF/PEEK composites. This study provides an efficient and environmentally friendly method to enhance the interfacial properties of CF/PEEK composites. Highlights The Bio‐H‐PAEK resin is introduced for the first time into CF sizing agents. The Bio‐H‐PAEK sizing agent significantly fortified the surface energy of CF. This work broadens the application range of CF/PEEK composites. The ILSS and flexural strength were increased by 60.43% and 47.26%.