Improvement of the interphase between basalt fibers and vinylester by nano-reinforced post-sizing

Abstract

Basalt fiber reinforced composites are innovative materials which may be used as an alternative to glass fiber-based composites in civil engineering applications. They exhibit high temperature resistance, corrosion resistance, low cost and excellent mechanical properties. However, according to previous studies, weak interfaces between the basalt fiber and the thermoset resin, such as polyvinylester, could be a problem for the use of basalt fibers reinforced polymers (BFRP) for civil engineering applications. To solve this problem, this study investigates the improvement of properties of basalt fibers coated with silica nano-reinforced epoxy resin. Three types of coatings were tested: epoxy resin, epoxy resin treated with fumed silica, and epoxy resin treated with silane-treated fumed silica. Silica nanoparticles were characterized by Fourier Transform Infrared Spectrometry (FTIR), Thermal Gravimetric Analysis (TGA) and micro-electrophoresis (Zeta-Nanosizer). Basalt fibers were dip-coated in diluted solutions/suspensions of epoxy coatings in acetone and analyzed using Scanning Electron Microscopy (SEM). Basalt fibers/vinylester (VE) composites were then prepared by compression molding. Tensile tests and interlaminar shear tests (ILSS) were performed on the different molded BFRP. Preliminary results show a 5–25 % improvement in mechanical properties depending on the type of coating. The presence of nanosilica at the interface between the basalt fiber and VE matrix leads to a significant enhancement of interlaminar and ultimate tensile strength.