Basalt fiber/epoxy composites improve interfacial adhesion by using epoxy Pickering emulsion sizing agent

Abstract The interface interaction between basalt fiber (BF) and matrix materials directly affects the mechanical properties of composite materials. Improving the interfacial bonding strength of composites is a key challenge. Inspired by organic/inorganic nanohybrid sizing agents and Pickering emulsions, we synthesized a stable epoxy Pickering emulsion and studied the effect of the solid content of the emulsion sizing agent on the surface characteristics of basalt fiber and the adhesion of the BF/epoxy interface. The sizing agent forms a nanoscale film on the fiber surface, where nano‐SiO 2 increases the roughness of the fiber surface. The epoxy group structure participates in the co‐curing of the matrix resin, enhancing the physical interlocking and chemical bonding between the fiber and the matrix resin, thus strengthening the interfacial interaction. When the solid content of the Pickering emulsion sizing agent is 6%, the interfacial shear strength (IFSS) and transverse fiber bundle tensile test (TFBT) strength of BF/epoxy composites reached maximum values of 64.15 and 58.81 MPa, respectively, increasing by 26.2% and 92.6% compared to DBF. This work demonstrates that the epoxy Pickering emulsion sizing agent could regulate interfacial adhesion, providing a new approach to enhance the interface performance of basalt fiber polymer composites. Highlight Stable epoxy Pickering emulsion sizing agent. Enhanced wettability of BF with matrix resin and a strong physical interlock. Enhanced interfacial bonding strength between BF and matrix resin.