One-step functionalization of carbon fiber using in situ generated aromatic diazonium salts to enhance adhesion with PPBES resins

In the present study, we developed a novel approach to introduce amino group (-NH2), hydroxyl group (-OH) and sulfhydryl group (-SH) onto carbon fibers (CFs) using aromatic diazonium salts. Fourier transform infrared spectroscopy, Raman spectra, X-ray photoelectron spectroscopy, scanning electron microscope and single fiber tensile testing were performed to characterize the functional CFs. Interlaminar shear strength (ILSS) and flexural strength were carried out to investigate the interfacial properties of CFs/PPBES composites. Experimental results showed that -NH2, -OH and -SH were grafted on the CFs surface and increase the fibers surface roughness. The functionalization did not lead to any discernable decrease in the fibers tensile strength. It was obvious that ILSS and flexural strength were enhanced. Dynamic mechanical analysis and hydrothermal aging tests revealed that CF-NH2/PPBES had excellent high temperature mechanical properties and hydrothermal aging resistance. Additionally, the reinforcing mechanisms were also analyzed.