Improving the mechanical properties of epoxy using multiwalled carbon nanotubes functionalized by a novel plasma treatment

Achieving both uniform dispersion and good interfacial adhesion have been long-term challenges in optimizing the properties of carbon nanotube reinforced polymer nanocomposites. A novel and effective plasma method, which combines continuous and pulsed plasma modes in a nitrogen and hydrogen gas mixture (15% H2), has been developed to better meet this need. It has yielded high levels of primary amines on the surface of multiwalled carbon nanotubes which improved their dispersion and interfacial bonding with an epoxy resin. By adding just 0.1 wt% of these nanotubes to Bisphenol F epoxy resin, the mechanical properties of the nanocomposites, from nano to macro, were significantly improved. Nanoindentation tests showed that the hardness and elastic modulus increased by 40% and 19%, respectively, using the functionalized nanotubes. Macro-mechanical properties from thermo-mechanical and flexural analysis were also enhanced, with a nearly 40% improvement in toughness.