Preparation and characterization of polyimide-modified carbon fiber-reinforced polyetheretherketone composites

Thermoplastic sizing agents, which are primarily composed of thermoplastic polymers, are functional coating materials used to improve the surface characteristics of fibers or fabrics. They are frequently employed in aerospace applications and can increase the fatigue resistance of carbon-fiber composite panels. However, carbon fiber (CF) sizing agents present new challenges due to the high molding temperature and inert nature of thermoplastic resins. This study used the thermal imidization technique and polyamide acid (PAA) synthesis to create PI, a carbon fiber sizing agent. Up to 370°C, the PI sizing agent exhibits outstanding thermal stability; at 390°C, it decomposes by just 3.86%. To improve the mechanical and interfacial qualities of CF/PEEK composites, PI was set up as an aqueous solution for carbon fibers and sizing treatments based on the solubility of its ammonium polyamides. According to the mechanical test findings, the B-DCF/PEEK composites’ flexural strength and ILSS were 540.14 MPa and 40.45 MPa, respectively. These values were 69.92% and 76.10% greater than those of the CF/PEEK. Additionally, based on the microscopic morphology of the composites at the fracture, the sizing agent can enhance their interfacial properties. This paper offers technical support for the use of high-performance CF/PEEK composites in high-temperature and high-load industries like aerospace.