Exploring mechanisms of enhanced dissipation in nanoparticle-filled rubber using molecular dynamics

Since its discovery in the 1930s, nanoparticle-filled rubber has found wide ranging application for its reinforced toughness compared to neat rubber. Despite being in use for almost a decade, our understanding of the physics behind this reinforcement is incomplete and many active competing theories exist. All theories formulate molecular-scale mechanisms for the origins of enhanced energy dissipation due to the presence of nanoparticles within a polymer network, which leads to a better mechanical response. Here, we describe our novel approach to addressing these theoretical controversies. By leveraging molecular dynamics simulations of filled rubber and their response to shear, we identify locations of enhanced energy dissipation within the melt. These results discriminate between the roles of the various proposed mechanisms of enhanced dissipation in filled rubber. Elucidating the physics of reinforcement of filled rubber will lead to better-informed manufacturing that selects for desirable properties in many important industries, such as better toughness with high electrical conductivity for energy storage.