Research on the interfacial adhesion properties of carbon fibers modified by sizing agents to polycarbonate using a single-filament fragmentation test

The effects of different sizing agents on the interfacial adhesion between carbon fibers and polycarbonate were investigated using a home-made polycarbonate emulsion, and polyvinyl acetate, polyurethane and polyethylene aqueous emulsions as the sizing agents. The chemical structures of the sizing agents were characterized by FT-IR and TG-MS, the surface characteristics of the modified carbon fibers by SEM, XPS and TGA, and the interfacial shear strength (IFSS) between the coated carbon fibers and the polycarbonate by a single-filament fragmentation test. Results showed that IFSS decreased in the following order:polyurethane (29.19 MPa) > polyvinyl acetate (22.58 MPa) > self-made (20.36 MPa) > polyethylene (14.52 MPa). Hydrogen bonds contribute the most to the interfacial adhesion forces while polar interaction contributes less and dispersion forces the least. The highest IFSS using polyurethane is ascribed to the formation of hydrogen bonds at the interface.