Preparation and Safety of Well-Dispersed RDX Particles Coated with Cured HTPB

Abstract

HTPB/IPDI (hydroxyl terminated polybutadiene & Isophorone diisocyanate) and TNT (2,4,6-trinitrotoluene) were successively coated on RDX (hexogen) particles by solvent evaporation and aqueous slurry melting, respectively. When HTPB coated on RDX particles cured completely, TNT was removed by solvent dissolution and the well-dispersed RDX particles coated with cured HTPB were obtained successfully. SEM (scanning electron microscopy), TEM (transmission electron microscopy), XPS (X-ray photoelectron spectrometry), and laser granularity measurement were employed to characterize the coated samples, and the mechanical sensitivity and thermal stability were measured and analyzed. Results show that TNT on the outer layer effectively hinders the adhesion among the particles resulting from the curing of inner layer (i.e., HTPB and IPDI). The final coating particles disperse well and their mechanical sensitivity decreases significantly. When the covering amount of HTPB is 2 wt.%, drop height (H₅₀) of RDX increases from 37.2 to 66.5 cm and explosion probability (P) decreases from 92 to 16%. Compared with that of uncoated samples, the activation energy and self-ignition temperature of coated samples do not vary.