Influence of chemical surface treatment of basalt fibers on interlaminar shear strength and fracture toughness of epoxy-based composites

In our study, the effect of chemically treated basalt fibers on the mechanical interfacial properties of basalt fibers reinforced epoxy composites was investigated. The surface properties of the basalt fibers were determined by Fourier Transform Infrared (FT-IR) spectroscopy. The surface structure of the basalt fibers was analyzed Atomic Force Microscopy (AFM). The acid and alkali chemical treatments led to significant changes in the surface characteristics of the fibers. The chemically treated fibers improved the mechanical interfacial properties, interlaminar shear strength (ILSS) and fracture toughness (KIC) of the composites. Composites treated with H₂SO₄ had higher values of ILSS and KIC than the KOH-treated composites. These results are attributed to the improvement of interfacial bonding strength, which was caused by an increase of the surface roughness of basalt fibers.