Rubbery and glassy epoxy resins reinforced with carbon nanotubes

Two epoxy resins with widely different mechanical properties were used as matrices in which functionalized carbon nanotubes were randomly dispersed to produce nanocomposites. In both cases, strong covalent bonds were created as a bridge between the nanotubes and matrix, but due to differences in viscosity, the nanotubes dispersion was much better in the rubbery epoxy resin than in glassy epoxy. A 28% increase in tensile Young's modulus was observed in the rubbery system using 1 wt.% functionalized nanotubes, compared to the unreinforced rubbery epoxy. As to glassy epoxy based composites, no improvement in modulus could be observed but a significant 50% improvement in impact toughness was observed, compared to the unreinforced glassy epoxy resin.