Reinforcing efficiency of nanoparticles: A simple comparison for polymer nanocomposites

The mechanical reinforcing efficiencies of two types of nanoparticles, nanotube and nanoplatelet, are compared from a micro-mechanics perspective. Additionally, the interphase zone created by altered dynamics of host polymer molecules in the vicinity of the nanoparticles is addressed. The results indicate that nanotubes generally have superior mechanical reinforcement potential beyond that of nanoplatelets for aligned orientations, while the high in-plane isotropic modulus of nanoplatelets allows better reinforcing in random orientations. However, at the same volume fraction, under the assumption of identical degree of dispersion and extent of influence on the surrounding polymer molecules, the nanotubes generate a significantly larger amount of interphase than the nanoplatelets. The interphase effects can then overwhelm the basic nanoparticle influence and lead to higher stiffnesses for all configurations of nanotube composites. These simple yet insightful comparisons may provide guidance in the design of nanocomposites.