A new insight into the mechanical behavior of high-quality RDX in pressed polymer bonded explosives

The compressive strength, shear strength, and tensile strength of three pressed polymer bonded explosives (PBXs) with different formulations were studied to evaluate the mechanical behavior of high-quality RDX (H-RDX, D₅₀ =134.4 µm) in the system. For further investigation, molecular dynamics simulation, scanning electron microscope, and surface energy calculation were used to research the distinction between the results that the smooth, hard particles made. It is revealed that H-RDX doesn't play a constructive role in the system of pressed PBXs. The surface energy (30.9 mJ·m⁻²) of H-RDX verifies that coating agents are harder to spread on H-RDX crystals with “better” surface conditions, leading to the decrease of binding force between binders and crystals. The mechanical strengths of H-RDX-based pressed PBXs thus are weakened, and the loading capacity is reduced by up to 65%. Moreover, higher bulk elastic modulus (16.26 GPa) and Poisson's ratio (0.25) of H-RDX crystal contribute to the reduction during grains' preparation and testing, respectively. It is hoped that this work provides a referential experience for the application of H-RDX and other reduced-sensitivity explosives.