Enhancing interfacial properties of carbon fiber reinforced epoxy composites by grafting MXene sheets (Ti₂C)

MXene (Ti₂C) modified by 3-aminopropyl triethoxysilane was grafted onto carbon fiber (CF) surface in an attempt to improve interfacial properties in continuous CF reinforced epoxy composites. X-ray photoelectron spectroscopy, scanning electron microscopy, and dynamic contact angle test were employed to characterize the effect of the grafted Ti₂C on the interfacial properties. A single fiber fragmentation test together with acoustic emission testing was performed to identify the interface failure mode and also determine the interfacial shear strength (IFSS). The interlaminar shear strength (ILSS) of the laminates was also evaluated with three-point beam testing. It was experimentally observed that Ti₂C sheets were uniformly grafted on the fiber surface with covalent bonding. It could provide not only the increase of the CF surface roughness but also an excellent opportunity to create plenty of the polar functional groups thereby leading to a greater surface energy of the CF. The IFSS and ILSS of Ti₂C modified CF composites were enhanced by ~78% and ~28% increase, respectively, compared to ones of unsized CF composites.