Effect of Filler–Polymer Interface on Elastic Properties of Polymer Nanocomposites: A Molecular Dynamics Study

Abstract

A coarse-grained model has been built to study the effect of the interfacial interaction between spherical filler particles and polymer on the mechanical properties of polymer nanocomposites. The polymer is modeled as bead-spring chains, and nano-fillers grafted with coupling agent are embedded into the polymer matrix. The potential parameters for polymer and filler are optimized to maximally match styrene-butadiene rubber reinforced with silica particles. The results indicated that, to play a noticeable role in mechanical reinforcement, a critical value exists for the grafting density of the filler-polymer coupling agent. After reaching the critical value, the increase of grafting density can substantially enhance mechanical properties. It is also observed that the increase of grafting density does not necessarily increase the amount of independent polymer chains connected to fillers. Instead, a significant amount of increased grafting sites serve to further strengthen already connected polymer and filler, indicating that mechanical reinforcement can occur through the locally strengthened confinement at the filler-polymer interface. These understandings based on microstructure visualization shed light on the development of new filler polymer interfaces with better mechanical properties.

Interface binding and mechanical properties of MXene-epoxy nanocomposites

“…Coarse-grained MD simulations of polymer networks and composites were performed using the standard bead-spring "Kremer-Grest" model [42], which has proven to be a great technique to study microscopic structural and mechanical properties of a broad range of polymer materials, including polymer nanocomposites [43,44] and highly cross-linked polymer networks [45,46].…”

Coarse-grained molecular dynamics simulation of cis-1,4-polyisoprene with silica nanoparticles under extreme uniaxial tension

“…It is also more reasonable to consider the effect of other factors in the models than those with a single filler particle [21]. For polymer models with multiple filler particles, their structures are closest to the real polymer structures, and the research issues are more comprehensive [22]. Hagita et al [4] compared the cases of 'aggregated' and 'dispersed' nanoparticles (NPs) for repulsive and attractive interactions among the NPs and polymers.…”

“…Such a model will deviate from the specific material being studied. In order to alleviate the contradiction between the fine molecular simulation and the large model size, we established a new vulcanized CG model containing multiple NPs, the potential functions of which are completely derived from the atomic potential functions without making equivalent assumptions like the Lennard-Jones potential function [4,22].…”