Atomistic Modeling of Binder Adhesion Properties for Novel Insensitive High Explosives

High explosives (HEs) have historically been formulated by combining a base HE with a polymer binder. In this respect, a computational model that can predict favorable HE-polymer pairs based on fundamental chemical information would help narrow the design space for new formulations. We implement and refine classical all-atom molecular dynamics (MD) force fields (FFs) and workflows for modeling crystal-polymer interfaces. We first validate a published FF for a novel insensitive HE against experimental vibrational spectra, high-pressure equation of state and crystal lattice parameters, thermal expansion data, and the sublimation enthalpy. To accurately model interfaces, we combine the HE FF with a general polymer FF, fitting the HE-polymer cross interactions to electronic structure calculations. A numerically robust workflow is developed to construct MD simulations of crystal-polymer interfaces that builds on the generalized crystal-cutting method. This enables rapid generation of amorphous films in triclinic cells at experimental density, and respects each chain’s excluded volume. We apply the validated MD FFs and workflow to assess polymer adhesion on the most morphologically relevant facets of the insensitive HE.



Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-2002317