Behavior of phenolic resins shocked to chemistry-relevant pressures

We study the shock response of phenolic polymers from 0.3 GPa up to 66.5 GPa using classical molecular dynamics (MD). Using the ReaxFF potential in combination with the constant stress Hugoniostat approach, we compare phenolic systems with molecular structures representative of phenolics at different stages in the curing process. We find that the shoulder or “cusp” in the Hugoniot in density-pressure space, also observed by Carter and Marsh, appears over a finite period of time on the order of 10s to 100s of picoseconds above 40 GPa in our simulations. The cusp is associated with finite rate chemistry that ultimately leads to a dense, highly crosslinked, carbonaceous solid. Chemical mechanisms that lead to this state will be explored and compared to cases where the cusp does not form.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.