Effects of multi-walled carbon nanotube and nanosilica on tensile properties of woven carbon fabric-reinforced epoxy composites fabricated using VARIM

The effects of multi-walled carbon nanotubes (MWCNTs) and nanosilica on tensile behavior of woven carbon fabric-reinforced epoxy composites have been studied. Multi-scale composites with epoxy matrices modified with different MWCNT and nanosilica contents (0.1, 0.5 and 0.9 wt.%) have been fabricated by vacuum-assisted resin infusion molding (VARIM). The dispersion of the nanoparticles in the epoxy resin has been made using an ultrasound and high-speed shearing method. Incorporation of nanoparticles improved tensile behavior and this effect was more evident in the case of composites reinforced with 0.5 wt.% of MWNCT and nanosilica. Incorporating either of the tow nanoparticles at 0.9 wt.% leads to a decrease in the trend of tensile properties. Examination of fracture surfaces using scanning electron microscopy (SEM) showed that by incorporating 0.9 wt.% of each nanoparticle, there are local MWCNT and nanosilica agglomerations within the composites. These nanoparticle-agglomerates reduced their potential strengthening effect in multi-scale composites containing 0.9 wt.% of nanoparticles. Also, SEM images showed that the MWCNTs and nanosilica enhanced the fiber-matrix interfacial strength and then by toughening the surrounding matrix, improved the strength and stiffness of multi-scale composites.