Principles for designing sustainable and high-strain rate stress wave dissipating materials

Abstract

Dynamic covalent networks serve as effective tools for dissipating high-strain rate mechanical energy throughout reversible bond exchange reactions. Despite their potential, a gap exists in understanding how polymer chain mobility and the kinetics of bond exchange reactions impact the energy dissipating capabilities of dynamic covalent networks. This study presents an optimal strategy to enhance energy dissipation by controlling the side chain structures and bond exchange rates of dynamic covalent networks. Lipoic acid-derived polymers are chosen as our model system due to their easily tunable side chains and disulfide-rich backbones. High-strain rate stress waves are subjected to the polymers using a laser-induced shock wave technique. A strong correlation is observed between the energy dissipation capability and the glass transition temperature of the poly(disulfide)s. Furthermore, the addition of a catalyst to accelerate the disulfide exchange reaction improves energy dissipation. Leveraging the inherent nature of cyclic disulfides, our polymers exhibit self-healing and chemical recycling to monomers. The principles observed in this study provide a rational framework for designing sustainable and efficient energy dissipating materials.