Chemical functionalization for improving dispersion and interfacial bonding of halloysite nanotubes in epoxy nanocomposites

The effects of chemical functionalization of halloysite nanotubes (HNTs) on dispersion, interfacial interaction, and mechanical properties of epoxy nanocomposites were investigated. HNT-filled epoxy nanocomposites were fabricated and their morphology and mechanical properties were systematically studied; the results were compared with those for neat epoxy resin. Transmission electron microscopic micrographs revealed uniform morphologic dispersion of functional HNTs in the epoxy matrix. The interfacial interaction between functional HNTs and the epoxy matrix was shown by differential scanning calorimetry and scanning electron microscopy analyses. The reaction between the functional amine--terminated groups of HNTs and epoxy monomers improved the dispersion of HNTs and the interfacial adhesion between HNTs and epoxies. The functional HNT-filled epoxy nanocomposites showed improved mechanical properties compared with the as-received HNT-filled nanocomposites. This was attributed to better dispersion and stronger interfacial interaction.