Effects of nano-silica contents on the properties of epoxy nanocomposites and Ti-epoxy assembles

Abstract In order to get a strong Ti-epoxy bond, nano-silica was added to epoxy as the reinforcement, and the effects of the presence of nano-silica on the properties of epoxy nanocomposites and Ti-epoxy assembles were investigated. The results showed that, although glass transition temperature of nanocomposites decreased with the increase in silica addition, mechanical properties of the nanocomposites such as flexural strength, fracture toughness, and hardness rose to the highest values when silica content was 15 wt%. However, the shear strength of the Ti-epoxy assemble was 45.38 MPa when the silica content was 2.5 wt%, from a low of 31.75 MPa for pure epoxy bonded assemble, increasing by 42.9%. With further increase in silica content, the shear strength decreased gradually. The remarkable increase in the shear strength with 2.5 wt% silica addition should be attributed to the improved wettability between epoxy and Ti surface, which resulted in much higher bonding strength between them.