Enhancement of the ultraviolet resistance and interfacial adhesion of copolymerized aramid fibers with a titanium dioxide coating

Abstract

Copolymerized aramid fibers (CAFs) hold considerable promise as high-performance materials because of their mechanical strength and thermal resistance. However, their low ultraviolet (UV) resistance and poor matrix adhesion limit their applications. In this study, a TiO2 coating is applied to the surfaces of CAFs through a solution-dipping process to enhance their UV resistance and interfacial adhesion. The fibers are dipped in aqueous solutions with varying concentrations of TiCl3, serving as a precursor, at temperatures in the range 50–90 °C. Changes over time are observed in the fibers using scanning, the TiO2 particles grow and completely coat the fiber surfaces. The TiO2-coated fibers demonstrate a high UV resistance, as evidenced by the tensile strength retention rate of approximately 80%, which is significantly higher than the 55% retention rate observed for the untreated fibers after 24 h of light irradiation at 600 W. The TiO2 coating enhances the interfacial strength between the TiO2 layer and CAF surface through hydrogen and physical bonding. Consequently, the interfacial strength is approximately 2.3 times than that of the untreated fibers. These results emphasize the potential of this simple TiO2 dip-coating method for various practical applications, particularly in extreme environments.