Study on synthesis and characterization of spherical copper(I) 5‐nitrotetrazolate (DBX‐1)

Abstract

Traditional primary explosives often contain heavy metals, especially toxic lead, such as lead azide (LA) and lead styphnate (LS) that can cause environmental pollution problems. Copper(I) 5‐nitrotetrazolate (DBX‐1) is a green primary explosive without toxic heavy metals, which is considered as one of the most promising alternatives to LA. DBX‐1 is usually synthesized from sodium 5‐nitrotetrazolate dihydrate (NaNT ⋅ 2H2O) and copper(I) chloride (CuCl). However, most of the synthesized products are irregular flakes with poor flowability, which affects the loadability. In this study, dextrin was used as a crystal shape modifier to improve the morphology of the synthesized product. Taguchi analysis method was used to determine the optimal experimental conditions for obtaining the spherical DBX‐1 with smaller particle size. The synthesized products were characterized by SEM, FTIR, UV‐Vis, STA TG‐DSC and VST, and their sensitivity was determined by BAM fallhammer, BAM friction tester and electrostatic spark sensitivity tester. The experiment results showed that the optimal combination of synthesis parameters was the NaNT ⋅ 2H2O concentration of 4.4 wt.%, the reaction temperature of 100 °C, the reaction time of 75 min and the additional dextrin solution of 5.0 mL. The average particle size of the synthesized spherical DBX‐1 was 33.0 μm. The decomposition activation energy was calculated by Kissinger method and Ozawa method to be 178.5 and 178.8 kJ/mol, respectively. The compound had good chemical stability. In addition, the sensitivity of spherical DBX‐1 was lower compared to that of flaky DBX‐1 and LA.