Study on <scp>KH550</scp> ‐Modified Basalt Fiber/Epoxy Resin Film and Its Enhanced Mechanical Properties

ABSTRACT This study investigates the effects of surface‐modified basalt fiber (BF) on the interfacial properties and mechanical performance of epoxy resin (EP) films. Surface modification was achieved using the silane coupling agent γ‐Aminopropyltriethoxysilane (KH550). KH550 was grafted onto the BF surface via the aqueous solution method to establish a “molecular bridge” effect between the fiber and resin. Successful grafting was confirmed through characterization techniques by fourier transform infrared spectroscopy (FT‐IR), X‐ray photoelectron spectrometer (XPS), and scanning electron microscopy (SEM). Results indicate that the interfacial bonding states between BF and EP after KH550 modification were significantly optimized, with no discernible gaps between the BF and EP. The failure mode shifted from interfacial debonding to fiber fracture as the dominant mechanism. Mechanical testing data show that, compared with the EP film, the EP film prepared using KH550‐modified BF increased the shear strength on LY12‐CZ aluminum substrates by approximately 11.5%, the bond strength on 45# steel substrates by approximately 13%, and the peel strength by approximately 10.7%. Overall, KH550 surface modification effectively enhances the interfacial compatibility between BF and EP, significantly improving the EP film's overall mechanical properties. This provides theoretical and technical support for its engineering applications in aerospace, automotive manufacturing, and other fields.