Abstract
Polymers and foams are pervasive in everyday life, as well as in specialized contexts such as space exploration, industry, and defense. They are frequently subject to shock loading in the latter cases, and will chemically decompose to small molecule gases and carbon (soot) under loads of sufficient strength. We review a body of work—most of it performed at Los Alamos National Laboratory—on polymers and foams under extreme conditions. To provide some context, we begin with a brief review of basic concepts in shockwave physics, including features particular to transitions (chemical reaction or phase transition) entailing an abrupt reduction in volume. We then discuss chemical formulations and synthesis, as well as experimental platforms used to interrogate polymers under shock loading. A high-level summary of equations of state for polymers and their decomposition products is provided, and their application illustrated. We then present results including temperatures and product compositions, thresholds for reaction, wave profiles, and some peculiarities of traditional modeling approaches. We close with some thoughts regarding future work.
Highlights
Polymers, polymeric composites, and polymeric foams are used extensively as cushioning, insulation, structural support, and for shock mitigation
The concepts discussed above will be used to interpret results obtained for the following materials: solid and porous polyurethane [6,13,47,48,57,58], Epon- and Jeffamine-based epoxies [59,60], carbon fiber-filled phenolic (CP) and cyanate ester (CE) composites [5,60,61], and filled polydimethylsiloxane foam (SX358) [62,63]
Data for all of the polymers recorded in Carter and Marsh (CM) display structure in their principal Hugoniots, its degree varies widely
Summary
Polymeric composites, and polymeric foams are used extensively as cushioning, insulation, structural support, and for shock mitigation As such, they are frequently exposed to impact or dynamic (high strain rate) loading conditions, their response to which is complex and distinct from that of other material classes. 107 /s−1 ), the volumetric and deviatoric components of their response often are not in equilibrium, and viscoelasticity plays an important role [1,2] Their elastic moduli and strength can be strongly strain rate- and temperature-dependent [2]. Most undergo order-disorder phase transitions, such as the glass transition separating “glassy” from “rubbery” regimes [3] Even when complications such as viscoelasticity or phase transitions are neglected, the complexity of polymer response places high demands on equation of state (EOS) models [4,5,6].
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