New Insight toward Dynamic Impedance Optimization in Glass/Polymer Composites: The Role of Segmental Dynamics of Interlayers
Abstract
Recent observations on the influence of high-rate deformation-induced glass transition affecting the dynamic impact response in poly(urethane urea) (PUU) elastomers has inspired a new inquiry into whether enabling molecular mechanisms could also benefit dynamic impedance optimization at the interface of a glass/polymer bilayer, particularly at the moment of target/impulse interaction. In this work, we investigated the molecular influence on dynamic stiffening and strengthening observed under microballistic measurements of two bulk elastomersa PUU and a polyurea. Upon impact at strain rates of approximately 10(exp 8)/s, PUU exhibited a moderate improvement over polyurea in resistance against penetration that is more pronounced at higher speeds. The variation in dynamic stiffening corroborates well with the corresponding segmental dynamics data determined via broadband dielectric relaxation. Meanwhile, we calculated the shock impedance from the shock velocity data derived from the respective shock Hugoniot. Results strongly indicate the efficacy of dynamic impedance optimization between PUU and glass, which is greatly desired for mitigating reflective tensile stress waves and limiting the propensity of further fracture in the glass. New insight on molecular attributes of hierarchical elastomers will guide the glass/polymer interface designs for integration into advanced lightweight transparent armor with multihit performance capability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2018
- Accession Number
- AD1056778
Entities
People
- Alex J. Hsieh
- Daniel F. Miranda
- David Veysset
- James Runt
- Keith A. Nelson
- Steven E Kooi
Organizations
- United States Army Research Laboratory