Shockwave properties of SWIFT Silicone Foams

Polymer foams are used extensively as structural supports and shock mitigating materials.  Under shock wave compression, large compressions result in high temperatures, leading to chemical decomposition at low shock pressures.  The high temperature rise is also known to give rise to anomalous compression even at relatively low initial porosities. Furthermore, stochastic porous structures can result in shock wavefront heterogeneities at the microscale.  These features make shockwave measurements of highly porous foams plagued with difficulties in diagnostic data return and large experimental errors.   Here, we report the results of a series of plate impact experiments on SWIFT silicone-based polymer foams using a shockwave transmission configuration, diagnosed with x-ray phase contrast imaging and photonic Doppler velocimetry.  SWIFT foams are produced by a patent-pending Silicon/Water in Familiar Template method, which produces foams by a robust and flexible process, in which variables such as molecular weight, crosslink density, filler, and pore scale can be tightly controlled.  We compare the shock properties of SWIFT foams to other polydimethylsiloxane foams, and will comment on the influence of microstructure on reducing error in measurements of the principal Hugoniot over a range of initial densities.