Theoretical investigations on stability, sensitivity, energetic performance, and mechanical properties of CL-20/TNAD cocrystal explosive by molecular dynamics method

The crystal models of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD), hexanitrohexaazaisowurtzitane (CL-20), and CL-20/TNAD cocrystal explosive with different component ratios were established. Molecular dynamics (MD) method was applied to predict the stability, sensitivity, energetic properties, and mechanical properties. The effect of component ratio on properties of CL-20/TNAD cocrystal explosive was investigated and estimated. Results show that the cocrystal model with component ratio in 1:1 exhibits the highest binding energy and it is more stable. In CL-20/TNAD cocrystal explosive, the interaction energy of trigger bond is increased by 0.8 similar to 15.0 kJ/mol, implying that the mechanical sensitivity of CL-20/TNAD cocrystal explosive is lower than CL-20 and the safety is effectively improved. Compared with raw CL-20, the crystal density of cocrystal explosive is declined by 0.014 similar to 0.193 g/cm(3), detonation velocity is declined by 39 similar to 755 m/s, and detonation pressure is declined by 0.95 similar to 11.40 GPa; namely the energy density of CL-20/TNAD cocrystal explosive is lower than CL-20. The cocrystal explosives with component ratio in 10:1 similar to 1:1 still exhibit desirable detonation performance and can be regarded as high energy density explosives. The values of tensile modulus, shear modulus, and bulk modulus of CL-20/TNAD cocrystal explosive are decreased by 0.448 similar to 10.285 GPa, 0.195 similar to 4.189 GPa, and 0.194 similar to 6.292 GPa, respectively, Cauchy pressure is increased by 0.990 similar to 5.704 GPa, meaning that the rigidity, fracture strength, and hardness of cocrystal explosive are declined, while the plastic property and ductility are increased and the mechanical properties are improved. The cocrystal model with component ratio in 1:1 has the best mechanical properties. Consequently, the CL-20/TNAD cocrystal explosive with component ratio in 1:1 is more stable and insensitive; it also has high energy density and the best mechanical properties and may be an attractive candidate for high energy explosives.

Automated summary

This study establishes crystal models of different component ratios of three explosives and predicts their properties using molecular dynamics method. The results show that CL-20/TNAD cocrystal explosive with a component ratio of 1:1 has the highest binding energy, greater stability, lower mechanical sensitivity, and lower energy density. The cocrystal explosives with component ratios ranging from 10:1 to 1:1 exhibit desirable detonation performance. The cocrystal explosive with a component ratio of 1:1 has the best mechanical properties.