1 The effect of van der Waals-based interface cohesive law on carbon nanotube-reinforced composite materials

The nonlinear cohesive law derived from the weak van der Waals force for carbon nanotube/polymer interfaces is incorporated in present study of CNT-reinforced composites. Carbon nanotubes can indeed improve the mechanical behavior of composite at the small strain, but such improvement disappears at relatively large strain because the completely debonded nanotubes behave like voids in the matrix and may even weaken the composite. The increase of interface adhesion between carbon nanotubes and polymer matrix may significantly improve the composite behavior at the large strain