AbstractThe effect of nanosilica on the tensile stress-strain response of Epikote 828 epoxy polymer was studied. A 40 wt% nanosilica/epoxy masterbatch was used to prepare a series of nanocomposites with 5–25 wt% nanosilica content. Static uniaxial tensile tests were conducted to investigate the tensile stress–strain response and tensile properties of unmodified and nanomodified epoxy polymers. In addition, the degree of dispersion of the silica nanosphere particle in the epoxy matrix was investigated using transmission electron microscopy. It was found that the incorporation of a well-disperse nanosilica improved the tensile properties of the polymer. The addition of 25 wt% nanosilica enhanced the tensile modulus and strength of about 38% and 24%, respectively, compared to the neat polymer without sacrificing the failure strain.