Molecular dynamics simulations for CL-20/TNT co-crystal based polymer-bonded explosives

Abstract

Molecular dynamics (MD) simulations were carried out to study the polymer-bonded explosives (PBXs) where the explosive base was the well-known high energy co-crystal compound, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexazaisowurtzitane/2,4,6-trinitrotoluene (CL-20/TNT), and the polymer binders were fluorine rubber (F[Formula: see text], fluorine resin (F[Formula: see text], polyvinyl acetate (PVAc) and polystyrene (PS), respectively. The binding energies, pair correlation functions (PCFs) and mechanical properties of the PBXs were reported. According to our theoretical results of binding energies, the compatibility of the PBXs is predicted to be in the following order: CL-20/TNT/PVAc[Formula: see text] CL-20/TNT/F[Formula: see text] [Formula: see text] CL-20/TNT/PS [Formula: see text] CL-20/TNT/F[Formula: see text]. The binding energies of the PBXs on three crystalline surfaces, (100), (001), (010), of the CL-20/TNT co-crystal were also compared: CL-20/TNT(100)[Formula: see text]CL-20/TNT(001)[Formula: see text]CL-20/TNT(010) for F[Formula: see text], F[Formula: see text], and PS; CL-20/TNT(001)[Formula: see text]CL-20/TNT(100)[Formula: see text]CL-20/TNT(010) for PVAc. The PCF analysis reveals that there exist H-bonds between H and O, F, and N atoms on all three interfaces and among all H-bonds, N H-bond has the fewest number. For the CL-20/TNT co-crystal, the moduli can be reduced by adding a small amount of the polymer binders but the ductility can be prolonged only by F[Formula: see text] and F[Formula: see text].