Molecular dynamics and experimental study on DAP-4/TNT melt-cast composites: interfacial interactions, structural...

To reduce the mechanical sensitivity of the high-energy molecular perovskite material DAP-4 and broaden its application scope, a DAP-4/TNT melt-cast explosive was developed using TNT as the melt-cast carrier. This study combined molecular dynamics simulation and experimental characterization to systematically investigate the interfacial interactions, multi-scale structural evolution, and overall performance of the DAP-4/TNT melt-cast explosives. Simulation results show that as the mass fraction of TNT increases, the binding energy and cohesive energy density of the system increase monotonically. At a DAP-4:TNT mass ratio of 20:80, the binding energy and cohesive energy density reach 183.55 kcal·mol^-1 and 4.136 × 10⁵ kJ·m^-3, respectively, with significantly improved interfacial compatibility. Experimental results indicate that TNT effectively reduces the sensitivity of DAP-4. When the TNT content increases from 60% to 80%, the impact detonation probability decreases from 50% to 28%, and the critical friction load increases from 160 N to 360 N, which is comparable to that of pure TNT. In terms of detonation velocity, the DAP-4:TNT ratio of 40:60 maintains a detonation velocity of 7201 m·s^-1, only 8.5% lower than that of pure DAP-4, while the 20:80 ratio achieves an 18.4% increase compared to pure TNT. This work elucidates the structure-property relationship in composite energetic materials from molecular to macroscopic levels, demonstrating that rational compositional design can effectively balance energy output and safety. The findings provide a chemical engineering perspective for the development of advanced molecular perovskite energetic materials with tunable performance.