Molecular Dynamics Simulations for Pure epsilon-CL-20 and epsilon-CL-20-Based PBXs

摘要

Molecular dynamics has been employed to simulate the well-known high energy density compound epsilon-CL-20 (hexanitrohexaazaisowurtzitane) crystal and 12 epsilon-CL-20-based PBXs (polymer bonded explosives) with four kinds of typical fluorine polymers,i.e.,polyvinylidenedifluoride,polychlorotrifluoroethylene,fluorine rubber (F_(2311)),and fluorine resin (F_(2314)) individually.The elastic coefficients,isotropic mechanical properties (tensile moduli,bulk moduli,shear moduli,and poission's ratios),and bonding energy are first reported for epsilon-CL-20 crystal and epsilon-CL-20-based polymer bonded explosives (PBXs).The mechanical properties of epsilon-CL-20 can be effectively improved by blending with a small amount of fluorine polymers,and the whole effect of the adding fluorine polymers to improve mechanical properties of PBXs along the three crystalline surfaces of epsilon-CL-20 is found to be (100) (001) > (010).The interaction between each of the crystalline surfaces and each of the fluorine polymers is different,and the ordering of binding energy for the three surfaces is (001) > (100) > (010); F_(2311) always has the strongest binding ability with the three different surfaces.F_(2314) can best improve the ductibility and tenacity of PBX when it is positioned on epsilon-CL-20 (001) crystal surface.The calculations on detonation performances for pure epsilon-CL-20 crystal and the four epsilon-CL-20-based PBXs show that adding a small amount of fluorine polymer into pure epsilon-CL-20 will lower detonation performance,but each detonation parameter of the obtained PBXs is still excellent.