The mechanical behavior of CNT reinforced nanocomposites assuming imperfect interfacial bonding between matrix and nanoparticles and percolation of interphase regions

The effective inverse aspect ratio (αeff) and volume fraction (φeff) of nanoparticles in polymer/CNT nanocomposites are defined accounting imperfect interfacial adhesion between polymer matrix and nanoparticles and percolation of interfacial regions as interphase percolation. After that, the tensile modulus and strength of nanocomposites are expressed by Halpin-Tsai and Pukanszky models to show the effects of radius (R) and length (l) of nanoparticles as well as the interphase thickness (t) and interfacial shear strength (τ) on the mechanical properties of nanocomposites. The best levels of “αeff” and “φeff” are obtained by the thinnest and the longest nanotubes as well as the highest values of “t” and “τ” factors. The best relative modulus of 8 is calculated by R < 13 nm and l > 6500 nm, while the strength slightly improves by R < 17 nm. Likewise, the relative modulus of 9 is calculated at t > 20 nm and τ > 170 MPa, while the best relative strength of 4.5 is shown at the highest levels of t = 25 nm and τ = 300 MPa. Conclusively, the interphase properties further affect the mechanical properties of nanocomposites compared to material parameters.