Clay assisted dispersion of carbon black in epoxy composites
K.C. Etika, L.A. Hess, J.C. Grunlan
Texas A&M University, US
Keywords: carbon black, clay, epoxy, electrical conductivity
Abstract:Carbon nanofillers, such as nanotubes, nanofibers and carbon black, are electrically conductive and useful for improving polymer properties. Carbon black-filled polymers are widely used in industrial applications due to their cost advantage over other fillers. In this study, clay was incorporated into carbon black filled epoxy to simultaneously increase electrical and mechanical properties. A composite containing 2.5 wt% carbon black has an electrical conductivity on the order of 10-6 S/cm. With the addition of 0.5 wt% clay, conductivity increases by an order of magnitude, but no significant improvement was observed for storage modulus. Composites containing equal amounts of carbon black and clay showed significant improvement in storage modulus as compared to those containing an equivalent amount of only one type of filler. Studies of liquid suspensions were performed to investigate the dispersion state of carbon black and clay prior to composite formation. Suspensions containing carbon black and clay showed superior stabilization to those containing only clay or carbon black alone in acetone. These results indicate an interaction between carbon black and clay that influences the dispersion of carbon black in epoxy. Moreover, clay may impart other properties, such as flame retardancy and gas barrier that will make these composites useful for a wide variety of applications.