Increasing Oxygen Balance Leads to Enhanced Performance in Environmentally Acceptable High-Energy Density Materials: Predictions from First-Principles Molecular Dynamics Simulations.

Abstract

Environmental concerns have stimulated the development of green alternatives to environmentally pollutive nitramine compounds used for high-energy density materials (HEDMs). The excellent energetic properties of CL20 make it a promising candidate, but its negative oxygen balance limits its efficiency for industrial and military applications. We predict here that CL20-EO formed by introducing ether links into the CC bonds of the original CL20 structure to attain balanced CO2 and H2O production leads to improved performance while minimizing the formation of carbonaceous clusters and toxic gases. To test this concept, we predicted the detonation properties at the Chapman-Jouguet (CJ) state using reactive molecular dynamics simulations with the ReaxFF force field combined with quantum mechanics based moleculear dynamics. We predict that CL20-EO enhances energetic performance compared to CL20 with a 6.0% increase in the CJ pressure and a 1.1% increase in the detonation velocity, which we attribute to achieving the correct oxygen balance to produce fully oxidized gaseous products. After expansion to normal conditions from the CJ state, CL20-EO leads only to nontoxic fully oxidized gases instead of forming the carbonaceous clusters and toxic gases found with CL-20. Thus, CL20-EO is predicted to be environmentally green. These results indicate that oxygen balance plays an important role in both energy availability and end-product toxicity and that balanced CO2 and H2O production systems provide promising candidates for the next generation of environmentally acceptable alternatives to toxic HEDMs while also enhancing the detonation performance.