Shock Wave Energy Dissipation in Catalyst-Free Poly(dimethylsiloxane) Vitrimers

TLDR

Materials that absorb shock wave energy from blasts and high‑speed impacts are critical for protecting structures, vehicles, and people, yet prior work on dynamic bonds in polymers has focused on slower time scales and lower forces than those of shock waves. The study designs vitrimers—polymer networks with dynamic covalent bonds—to explore reversible exchange reactions as a mechanism for shock wave energy dissipation. The authors create vitrimers by incorporating dynamic covalent bonds that enable reversible exchange reactions, allowing the material to dissipate shock wave energy. Increasing the density of dynamic bonds systematically raises shock wave energy dissipation, as shown by reduced peak pressure, while a permanent polymer network shows no such dependence; moreover, vitrimers can absorb multiple shocks without performance loss due to bond exchange and self‑healing, marking the first demonstration of vitrimers as effective high‑frequency, high‑pressure energy‑dissipating materials.

Abstract

Materials that absorb shock wave energy from blasts and high-speed impacts are critical for protection of structures, vehicles, and people. Incorporating dynamic bonds into polymers has enabled precise control over the time-dependent response and energy-dissipating modes, but this work has focused on much slower time scales and lower forces than those associated with shock waves. Here, we design polymers networks with dynamic covalent bonds, called vitrimers, where reversible exchange reactions provide a potential mechanism for shock wave energy dissipation. Increasing the density of dynamic bonds leads to a systematic increase in energy dissipation, measured by the drop in peak pressure of a laser-induced shock wave. An analogous permanent polymer network shows no dependence of dissipation on cross-link density. The vitrimers can absorb shock multiple times while maintaining performance, attributed to bond exchange and the intrinsic self-healing ability of the polymer. Our results are the first to demonstrate that vitrimers are an effective route to the design of energy-dissipating materials, particularly at the high frequencies and pressures associated with shock waves.