Exploring the Role of Polymer-Filler Interactions in Modulating Elastomeric Reinforcement
ORAL
Abstract
The reinforcement of elastomeric materials through the inclusion of nanoparticles is a critical yet unresolved topic in materials science, with broad applications across various industries. Despite a century of research, key questions remain about the microscopic mechanisms that govern this reinforcement. Molecular simulations offer a powerful tool to tackle this challenge by providing the resolution necessary to disentangle competing hypotheses. Our recent work has established a mechanism for elastomeric reinforcement that is rooted in a Poisson ratio mismatch between filler network and elastomeric matrix, leading to a large internal normal stress buildup and a dominant contribution from the elastomer's bulk modulus. Here we explore how this mechanism is modified and abetted by the presence of strong polymer-particle interactions, which lead to regions of reduced mobility surrounding filler particles – the so-called 'bound rubber' effect. To do so, we sweep a range of filler-particle attraction strengths and temperatures within a bead-spring model, enabling us to connect enhancement of elastomeric reinforcement to the interfacial alterations in glass formation that have been extensively studied in the presence of interfaces. Results provide insight into strategies to rationally modulate the mechanical response of elastomeric nanocomposites by tuning particle interfaces.
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Publication: [1] S. M. Smith and D. S. Simmons, "Poisson ratio mismatch drives low-strain reinforcement in elastomeric nanocomposites," Soft Matter, vol. 15, no. 4, pp. 656–670, 2019, doi: 10.1039/C8SM02333F.<br>[2] S. M. Smith and D. S. Simmons, "Horizons for design of filled rubber informed by molecular dynamics simulation," Rubber Chemistry and Technology, vol. 90, no. 2, pp. 238–263, 2017, doi: 10.5254/rct.17.82668.<br>[3] P. Kawak, H. Bhapkar, and D. S. Simmons, "Central Role of Filler–Polymer Interplay in Nonlinear Reinforcement of Elastomeric Nanocomposites," Macromolecules, vol. 57, no. 19, pp. 9466–9475, 2024, doi: 10.1021/acs.macromol.4c00489.
