The Mechanical Performance and Thermal Resistance of Carbon Fiber–Reinforced Polyetherether Ketone Composites Are Improved by the Polyetherketone‐Imide Sizing Agent

ABSTRACT Carbon fiber–reinforced polyetherether ketone (CF/PEEK) requires molding at over 300°C, which thermally degrades conventional sizing agents and weakens the interfacial adhesion between PEEK resin and carbon fiber (CF). To address the issues of the sizing agent's thermal resistance and interfacial strength, a high‐temperature‐resistant polyether ketone imide sizing agent (PATT) was synthesized to enhance thermal stability and compatibility between the sizing agent and the resin matrix. Compared with epoxy‐sized CF, the PATT sizing agent increased the flexural strength and interlaminar shear strength (ILSS) of CF/PEEK by 58.8% and 55.9%, respectively, and the tensile strength and modulus by 52.0% and 14.3%, respectively. It also raised the heat resistance temperature to 567.3°C. Experimental results indicate that PATT significantly improves the high‐temperature stability and mechanical strength of CF/PEEK composites. This improvement provides broader application prospects for CF/PEEK composites in aerospace, transportation, and high‐end manufacturing fields.