Tannic acid and aminopropyltriethoxysilane modified basalt fiber/epoxy resin composites with enhanced interfacial and mechanical properties

Abstract In the present study, a mild and eco‐friendly method is adopted to co‐deposit tannic acid (TA) and aminopropyltriethoxysilane (APS) onto the surface of basalt fibers (BFs) in an aqueous medium. Stiffness and strength assessments have been performed on the prepared BF‐TA/1APS/epoxy samples. The obtained results show that the fiber‐matrix interfacial shear strength (IFSS) of modified basalt fiber‐reinforced polymer (BFRP) composites increases by 65.3%, contributing to increases of 38.1%, 31.6%, and 20.9% in the composite flexural strength, flexural modulus, and interlaminar shear strength, respectively. These enhancements in the mechanical properties are attributed to improved fibers' surface roughness and wettability, leading to stronger chemical bonding, hydrogen bonding, and ππ interaction between the fibers and matrix. Furthermore, Finite Element Analysis (FEA) reveals that the maximum stress inside the material decreases with the increasing thickness of the interfacial transition zone, demonstrating a maximum decrease of about 33.9%. Highlights A mild and eco‐friendly method is adopted to modify BFs in an aqueous medium. Interfacial shear strength between fiber and matrix increased by 65.3%. Enhanced mechanical properties of BFRP are attributed to improved interface. FEA reveals the relation between internal stresses and interfacial thickness.