Mechanical properties of epoxy nanocomposites reinforced with functionalized silica nanoparticles

Functionalization of silica nanoparticles is needed in order to improve the mechanical performance of epoxy nanocomposites. Previous experience showed that direct dispersion of commercially available silica nanofillers does not improve significantly the mechanical properties of resulting nanocomposites. Fumed silica nanoparticles from Sigma Aldrich (175-225 nm BET) were functionalized carrying exactly 0.28 mmol of phenylazide per 1g of dry particles. During drying they aggregate and their dispersion in epoxy becomes challenging. We use sonication to break agglomerates and obtain adequate dispersion. Different methods of fabrication are presented along with comments on the resulting tensile composite behavior.