Carbon nanotube (CNT)-epoxy nanocomposites: a systematic investigation of CNT dispersion

A systematic investigation of the dispersion of carbon nanotubes (CNTs), 1-6 nm in diameter and a few microns in length, in a bisphenol F-based epoxy resin has been presented. Several dispersing techniques including high-speed dissolver, ultrasonic bath/horn, 3-roll mill, etc. have been employed. Optical microscopy has been extensively used to systematically characterise the state of CNT dispersion in the epoxy resin during the entire processing cycle from mixing CNT with resin to adding and curing with hardener. Complimentary viscosity measurements were also performed at various stages of nanocomposite processing. A method to produce a good CNT dispersion in resin was established, but the state of CNT dispersion was found to be extremely sensitive to its physical and chemical environments. The cured nanocomposites were further tested for their thermo-mechanical properties by dynamic mechanical thermal analysis (DMTA), and for flexural and compressive mechanical properties. The measured properties of various nanocomposite plates were then discussed in view of the corresponding CNT dispersion.