Grafting multi-walled carbon nanotubes (MWCNTs) into PIPD fiber for enhancing mechanical and interfacial performance

Surface modification of PIPD (Poly-pyridobisimidazole) fiber by grafting multi-walled carbon nanotubes (MWCNTs) to improve the fiber/epoxy interaction have significant influence on the overall performance of composite material. The functionalization of MWCNTs with polydopamine solution was initially occurred following by the grafted process in the tris-HCl solution (pH = 8.5). The coated MWCNTs has been successfully grafted to the PIPD samples as the scanning electron microscopy (SEM) showed. The Fourier-transform infrared spectroscopy (FTIR) and the X-ray photoelectron spectroscopy (XPS) supports the pervious analysis. A quite interesting improvement of the fiber/epoxy interaction was detected by 62% after the calculation of the interface shear strength (IFSS). Meanwhile, the bulk properties on the PIPD fiber which presented by the tensile strength (TS) was conserved, the degradation after the grafting was only by 5%. The surface energy of the fibers was also increased and that promotes the surface wettability of the grafted samples.