Maximizing the toughness of polymer nanocomposites based on the radial strength of carbon nanotubes

Similarity in the mechanical properties of a matrix and an inclusion is key to designing tough nanocomposites. Matching the matrix and inclusions with similar mechanical strengths prevents stress perturbation at the interface, enabling nanocomposites to withstand higher loads as a homogeneous material. We tabulate the chirality-dependent radial buckling properties of multi-walled carbon nanotubes (MWCNTs) and present a design methodology for providing optimal strengthening properties for poly(p-phenylene terephthalamide) matrices. The structural orientation effect of the aromatic rings of polymer chains surrounding MWCNTs provides a strong support against transverse loading. The effect of the interfacial area of different materials on the toughness of the entire continuum system is characterized through a nonlinear finite element model. MWCNT buckling and polymer yielding occur simultaneously under conditions selected by the proposed methodology, thereby maximizing the reinforcing effect of the nanocomposites by creating a continuous stress field at the interface.