Preparation of polyether ether ketone (PEEK) based polymer composites and improving their properties

In this study, carbon fabric (CF)-reinforced polyether ether ketone (PEEK) composites were developed for use in aerospace applications. Due to the low surface energy of carbon fibers and their weak interfacial bonding with the PEEK matrix, the carbon fabrics were modified using nitric acid, Meldrum's acid, and polyetherimide-silica (PEI-SiO2) nanofibers. Surface coating with PEI-SiO₂ nanofibers via electrospinning was subsequently applied to the CFs. The mechanical and chemical properties of the composites, produced with 13 layers via compression molding, were comprehensively examined. The morphology of the composites was investigated using Scanning Electron Microscopy (SEM), while their chemical structures were analyzed by X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The temperature-dependent mechanical properties were measured using Dynamic Mechanical Analysis (DMA). The variation in interlaminar adhesion due to CF modifications was investigated through Interlaminar Shear Strength (ILSS) tests. Mechanical properties were further assessed through tensile, three-point bending, and impact tests. Thermal stability was examined using Thermogravimetric Analysis (TGA), and melting/crystallization behaviors were studied using Differential Scanning Calorimetry (DSC). PEEK-CF composites reinforced with silica-modified PEI, produced via electrospinning and compression molding, exhibited high tensile strength and storage modulus, as well as superior impact resistance, interlaminar shear strength (ILSS), and degree of crystallinity. The results indicate that the modified CFs significantly improve the interfacial bonding within the composite, thereby enhancing the mechanical strength of PEEK while maintaining its thermal stability. This study represents a significant step toward broadening the potential applications of PEEK-CF composites in the aerospace industry.