Surface modification of aramid fibers by amino functionalized silane grafting to improve interfacial property of aramid fibers reinforced composite

The 3-aminopropyltriethoxysilane (APS) grafted aramid fibers were prepared by gamma-ray irradiation and chemical treatment to improve the interfacial properties between aramid fibers and epoxy matrix. The functionalization process of aramid fibers was investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrum. After grafted with APS, the surface roughness of aramid fibers increased obviously, and the element content and composition of functional groups changed significantly in the modification process. Dynamic contact analysis indicated the wettability, and surface free energy of the fibers were greatly improved after the APS treatment. Monofilament pull-out measurement showed that the interfacial shear strength of aramid fiber reinforced composite increased by 51.03%, from 36.33 to 54.87 MPa after the surface modification. Moreover, benefited from the appropriate radiation and the APS grafting, the functionalization process did not damage fiber tensile strength.