Effective amino-functionalization of carbon nanotubes for reinforcing epoxy polymer composites

An effective functionalization method was investigated to take full advantage of the exceptional performance of both carbon nanotubes and epoxy polymer for composite application. Epoxy polymer curing agent, EPI-W, was grafted to the single-walled carbon nanotubes through diazotization. Fourier transformed infrared spectroscopy, Raman spectroscopy, differential scanning calorimetry, dynamical mechanical analysis and thermo-gravimetric analysis were performed to characterize the functionalization effect. The degree of functionalization was estimated to be 1 in 50 carbons in the nanotube framework. The elastic modulus of the nanocomposite was enhanced 24.6% with only 0.5 wt% loading of functionalized carbon nanotubes, in contrast to the 3.2% increase of un-functionalized carbon nanotube reinforced composite. This significant improvement suggested an effective way to realize an industrial application of nanotubes reinforcing epoxy composite.