Polycarbonate diol-silane sizing agent for enhanced interfacial adhesion of 3D-printed polycarbonate/carbon fiber composites

Enhancing the interfacial bonding performance between carbon fibers (CF) and thermoplastic resins is extensively researched. In this study, we propose a novel method for the synergistic surface modification of carbon fibers using a silane coupling agent and poly-carbonate diol (PCDL), which significantly improves the interfacial compatibility between CF and polycarbonate (PC). Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) confirmed the successful grafting of silane onto the surface of CF and subsequent PCDL sizing. Mechanical characterization showed that the modified carbon fiber composites exhibited a 47.3% increase in interlaminar shear strength (ILSS) relative to the unmodified system. Notably, with a loading of 10 wt%, the modified fibers improved the tensile strength, flexural strength, and notched impact toughness by 36.2, 38.5, and 39.6%, respectively. The impact fracture surfaces exhibited typical characteristics of ductile fracture, with a dense and gap-free interfacial layer forming between the fiber and the matrix, indicating that the efficiency of stress transfer was effectively enhanced. The findings of this study are expected to provide a valuable technical reference for the fabrication of carbon fiber–reinforced thermoplastic composites.