Impact-induced glass-to-rubber transition of polyurea under high-velocity temperature-controlled microparticle impact
Author(s)Sun, Yuchen; Kooi, Steven E; Nelson, Keith Adam; Hsieh, Alex J; Veysset, David Georges
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Deformation-induced glass transition in segmented elastomers has been proposed to allow highly desirable enhanced energy dissipation. In this study, we investigate the temperature-dependent microscale impact response of polyurea at a fixed impact velocity. We observe a local elevated impact energy absorption around 115 °C, which is attributed to the glass-to-rubber transition temperature under the present high-rate dynamic loading. Dielectric spectroscopy was performed, and the soft-segmental α2-relaxation was extracted and fit with a Havriliak-Negami function. The α2-relaxation frequency at 115 °C correlates well with an order-of-magnitude estimate of the equivalent frequency of deformation. This work further supports the importance of the dynamical Tg as an important consideration in the design of impact resistant materials.
DepartmentMassachusetts Institute of Technology. Department of Chemistry; Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies
Applied Physics Letters
Sun, Yuchen et al. "Impact-induced glass-to-rubber transition of polyurea under high-velocity temperature-controlled microparticle impact." 117, 2 (July 2020): 021905 © 2020 Author(s)
Author's final manuscript