Cheetah calculations of GA BAMO candidate compositions

Norway’s main objective in the EDA project No B-0585-GEM2-GC “Formulation and Production of New Energetic Materials” was to synthesize different new energetic binders built of GA and BAMO polymers. Before starting experimentally work, Cheetah calculations with both BKWC and BKWS product libraries at standard conditions were performed to study what effects energetic binder/binder system had on the performance on different types of compositions. Two classes of pressed compositions, one with filler content of 96 wt. % RDX or HMX and one with 92 wt. % RDX or HMX, have been studied to replace PBXW-11 and PBXN-9. The energetic binders we wanted to synthesize were GA/BAMO with different ratio between GA and BAMO. Calculations have been performed with both GAP and BAMO and of a mixture of these two binders. In addition, calculations with energetic binder and inert plasticizer have been performed. Obtained detonation pressures and velocities for compositions with GAP, BAMO or GA/BAMO are both equal for these compositions. The ratio between GA/BAMO has only minor effect on both detonation velocity and detonation pressure. Changes occur first when an inert plasticizer is introduced. With inert plasticizer the detonation pressure drops by 1.6 GPa for the 96 wt. % HMX compositions and by 3 GPa for the 92 wt. % HMX compositions with the BKWS product library. With the BKWC product library the drop is 2.3 and 4.2 GPa respectively. The detonation velocity drops are 150 m/s and 300 m/s with BKWS and 240 m/s and 450 m/s with the BKWC product library for the respective compositions. A composition with 92 wt. % HMX and energetic binder/plasticizer has equal or better performance than PBXW-11 (96 wt. % HMX, inert binder). Use of energetic binder in combination with inert plasticizer has only minor influence on detonation velocity and pressure for compositions with 96 wt. % filler. For compositions with 92 wt. % filler and energetic binder/inert plasticizer the detonation pressure increases by 1 GPa and the detonation velocity by +100 m/s. This trend is independent of filler. For 87 wt. % HMX or RDX cast-cure compositions the effect of changing the binder system in PBXN-110 to energetic binders gives larger differences. The detonation pressure increases with 7.32 GPa (BKWC) and 4.94 GPa (BKWS) for HMX and slightly less (6.48/4.39) with RDX. The detonation velocity increase by 820 m/s (BKWC) and 508 m/s (BKWS) for HMX and 784/468 m/s for RDX. Compositions with energetic binders and inert plasticizer (DOA) have properties between those for PBXN-110 and compositions containing energetic binder systems. The calculations have shown that compositions having energetic binder/binder systems increase the performance for both cast-cure and pressed compositions. The increased performance may also be used or utilized to reduce the filler content and thus reduce the sensitivity. For pressed compositions, the choice of ratio between GA and BAMO for the new polymers to be synthesised will be governed by the ability to coat crystals and give the press powder the required properties rather than the energy content, since the energy content is independent of the ratio.