Correlations between mechanical, structural, and dynamical properties of polymer nanocomposites

TL;DR

This study uses molecular dynamics simulations to explore how structural and dynamical factors influence the reinforcement of polymer nanocomposites, highlighting the importance of filler size and interface interactions.

Contribution

It reveals the correlation between mechanical reinforcement and structural/dynamical properties, emphasizing the effectiveness of small fillers and strong polymer-filler interactions.

Findings

Small fillers maximize reinforcement by increasing polymer-filler interactions.

Stress at failure correlates with filler loading and interface surface area.

Minimized filler mobility is linked to enhanced structural reinforcement.

Abstract

We study the structural and dynamical mechanisms of reinforcement of a polymer nanocomposite (PNC) via coarse-grained molecular dynamics simulations. In a regime of strong polymer-filler interactions, the stress at failure of the PNC is clearly correlated to structural quantities, such as the filler loading, the surface area of the polymer-filler interface, and the network structure. Additionally, we find that small fillers, of the size of the polymer monomers, are the most effective at reinforcing the matrix by surrounding the polymer chains and maximizing the number of strong polymer-filler interactions. Such a structural configuration is correlated to a dynamical feature, namely, the minimization of the relative mobility of the fillers with respect to the polymer matrix.