Molecular dynamics simulation studies of the ε-CL-20/HMX co-crystal-based PBXs with HTPB

Molecular dynamics simulations were carried out to explore a epsilon-CL-20/HMX (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexazaisowurtzitane/1,3,5,7-tetranitro-1,3,5,7- tetrazacyclooctane) co-crystal-based polymer-bonded explosive (PBX) with HTPB (hydroxyl-terminated polybutadiene). The binding energies, pair correlation functions, and mechanical properties of the PBXs were reported. From the calculated binding energy, it was found that the order of the binding energies per unit surface between the crystalline surface and HTPB is (0 1 0) > (1 0 0) > (0 0 1). The pair correlation function revealed that the H center dot center dot center dot O and H center dot center dot center dot N H-bonds exist on the interfaces between the crystalline surfaces and HTPB, and the number of Ha (TM) a (TM) a (TM) O hydrogen bonds (H-bonds) atom pairs is ten times more than that of Ha (TM) a (TM) a (TM) N H-bonds. Additionally, the calculated mechanical data indicated that the stiffness of the co-crystal/HTPB PBX is weaker and its ductility is better than those of the co-crystal.