Molecular dynamics study of binding energies, mechanical properties, and detonation performances of bicyclo-HMX-based PBXs

Abstract

To investigate the effect of polymer binders on the monoexplosive, molecular dynamics simulations were performed to study the binding energies, mechanical properties, and detonation performances of the bicyclo-HMX-based polymer-bonded explosives (PBXs). The results show that the binding energies on different crystalline surfaces of bicyclo-HMX decrease in the order of (0 1 0) > (1 0 0) > (0 0 1). On each crystalline surface, binding properties of different polymers with the same chain segment are different from each other, while those of the polymers in the same content decrease in the sequence of PVDF > F 2311 > F 2314 ≈ PCTFE. The mechanical properties of a dozen of model systems (elastic coefficients, various moduli, Cauchy pressure, and Poisson's ratio) have been obtained. It is found that mechanical properties are effectively improved by adding small amounts of fluorine polymers, and the overall effect of fluorine polymers on three crystalline surfaces of bicyclo-HMX changes in the order of (0 1 0) > (0 0 1) ≈ (1 0 0). In comparison with the base explosive, detonation performances of the PBXs decrease slightly, but they are still superior to TNT. These suggestions may be useful for the formulation design of bicyclo-HMX-based PBXs.