Mechanistic tradeoffs between low-strain reinforcement and high-strain cavitation in elastomeric nanocomposites

Nanoparticles dispersed in elastomeric matrices can to enhance the mechanical properties of composites by up to an order of magnitude. For this reason, they are widely employed in applications such as carbon black–reinforced rubber tires. However, the underlying physics of this reinforcement, and microscopic mechanisms by which these composites ultimately fail via cavitation and void growth, remain poorly understood.

Here, we report on molecular dynamics simulations providing new insights into these mechanisms. Our results demonstrates that in the linear and intermediate strain regimes, a mismatch in the Poisson ratios of the elastomer and nanoparticles leads to a competition over nanocomposite volume, invoking contribution from the bulk modulus to the tensile response. In the high-strain regime, we show how this competition leads to cavitation and failure at earlier strains. This leads to a tradeoff wherein the most highly reinforced elastomeric nanocomposites at low strain tend to cavitate and fail earlier under high-strain deformation.