(367d) Insights into the Dependence of Elastomeric Nanocomposite Mechanics on Nanoparticulate Properties

A frequent challenge in multifunctional composites is the need to simultaneously maintain high mechanical strength while optimizing some secondary physical property. A major barrier to this goal in elastomeric nanocomposites is the longstanding lack of understanding of the microscopic mechanistic origins of nanoparticulate-based mechanical reinforcement of these systems under nonlinear deformation. As a consequence, it is not clear how mechanical reinforcement depends on an array of molecular and structural properties including nanoparticle structure, dispersion state, and interactions.

Work by multiple groups over the last several decades has suggested that mechanical percolation of filler particles is central to mechanical reinforcement. This naturally implicated the structural and chemical variables above in playing a central role in reinforcement. At the same time, particulate percolation can play a central role in determining other key properties, such as thermal and electrical conductivity, raising the possibility of substantial trade-off and interplay between particle-mediate mechanical reinforcement and enhancement of other properties. In practice, the variables above are commonly empirically tuned in an effort to optimize mechanical properties. However, co-optimization of mechanical strength with any other property will require a much more predictive understanding of their roles in determining polymer mechanical response.

Here we employ molecular dynamic simulations to determine how nonlinear mechanical reinforcement of elastomeric nanocomposites are controlled by these nanoparticulate structure, dispersion state, and interactions. We specifically describe results probing local and global mechanical properties in elastomeric nanocomposites over a matrix of these variables. Results provide new insight into the rational design and optimization of elastomeric nanocomposites with targeted mechanical response.

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award Number DE-SC0022329.