Establishing TA-Pb/Cu and SA-Pb/Cu interface catalyst shells on HMX surfaces via in situ coprecipitation to ameliorate the performances of HMX

Lead/copper tannate (TA-Pb/Cu) and lead/copper salicylate (SA-Pb/Cu) interface catalyst shells are established on the surface of 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) via in situ coprecipitation to prepare HMX@TA-Pb/Cu and HMX@SA-Pb/Cu composites. The structures and properties of the obtained HMX@TA-Pb/Cu and HMX@SA-Pb/Cu composites are characterized in detail. Molecular dynamics simulations are performed to study the adsorption mechanism of TA-Pb/Cu and SA-Pb/Cu on HMX surface. The residues after HMX@TA-Pb/Cu and HMX@SA-Pb/Cu combusted in air are collected and characterized to study the catalytic effect of TA-Pb/Cu and SA-Pb/Cu on combustion. The study results show that TA-Pb/Cu shells are coated on HMX surface due to the excellent membrane-forming properties of TA, while SA-Pb/Cu shells are embedded in the gullies and holes of HMX surface. TA-Pb/Cu and SA-Pb/Cu shells can decrease the mechanical sensitivities and catalyze the decomposition and combustion of HMX, and the catalytic effects of in situ coprecipitation are better than that of physical mixing. In addition, the phase transition temperature of HMX in HMX@TA-Pb/Cu is increased while that of HMX@SA-Pb/Cu is decreased, illustrating that TA-Pb/Cu can enhance the thermal stability of HMX while SA-Pb/Cu can catalyze the phase transition of HMX.