Interactions and physical properties of energetic poly-(phthalazinone ether sulfone ketones) (PPESKs) and ε-hexanitrohexaazaisowurtzitane (ε-CL-20) based polymer bonded explosives: a molecular dynamics simulations

Abstract

Molecular dynamic (MD) simulations were employed to investigate the hexanitrohexaazaisowurtzitane (CL-20) crystal, seven designed energetic poly-(phthalazinone ether sulfone ketones) (PPESKs) and PPESKs/e-CL-20 polymer–bonded explosives (PBXs). Cohesive energy density (CED) and solubility parameters (δ) were predicted for PBXs, the results indicated that stability of PBXs are related to their cohesive energy density (CED). Mechanical properties of seven polymer-bonded explosives (PPESKs/e-CL-20) were found improved in comparison with that of e-CL-20 by adding polymer binders. Young’s modulus (E), Shear modulus (G), and Bulk modulus (K) declined compare with e-CL-20. K/G ratio and Cauchy pressure C12-C44 of PBXs indicate that they have certain ductility. Radial distribution function (RDF) was utilized for analyzing the interactions between PPESKs and e-CL-20, and results demonstrate that hydrogen bond and van der Waals interactions exist between polymers and e-CL-20. The calculated oxygen balance of polymer-bonded explosives (PBXs) is lower than that of pure e-CL-20 by nearly about − 24%. Detonation properties of the polymer-bonded explosives (PBXs) were predicted based on e-CL-20 values. Detonation velocity (D) for these PBXs was predicted almost at about 8300 m s−1, and the detonation pressure (P) for these PBXs was all predicted nearly at 38 GPa.