Effect of POSS-NH ₂ functionalization of MWNTs on reinforcing properties in epoxy nanocomposites

Abstract

The research focuses on multiwalled carbon nanotubes (MWNTs) functionalization with aminoethyl aminopropyl polyhedral oligomeric silsesquioxane to increase their compatibility with epoxy polymers and enhancement of interface adhesion. Functionalization of MWNTs consisted of a three-stage reaction by oxidation and further amidation through acylation with thionyl chloride. The new nanomaterials were dispersed as reinforcing agent in a weight ratio of 0.3% related to the epoxy matrix, which was further cured with an aromatic polyamine. Characterization of functionalized MWNTs by infrared spectroscopy revealed the presence of POSS cages bonded to the MWNTs through the formation of amide groups, these findings were also proved by transmission electron microscopic images. Although catalytic influence of the reinforcing agent on the curing reaction was not significant at this level of reinforcement, scanning electron microscopic images of the nanocomposites fracture surface revealed strong interfacial adhesion and crack retardant effect of POSS-functionalized MWNTs.