An Experimental Comparison of Selected Blue Flame Pyrotechnics

Optimization of performance and sensitivity: preparation of two Ag(I)-based ECPs by using isomeric ligands

For energetic compounds, their structure determines their performance, and even minor variations in their structure can have a significant impact on their performance. The application scenarios for energetic materials are diverse, and their performance requirements vary as well. To investigate the influence of different substituent positions on the performance of primary explosives, we prepared two Ag(I)-based complexes, [Ag(2-IZCA)ClO4]n (ECPs-1) and [Ag(4-IZCA)ClO4]n (ECPs-2), using structurally isomeric ligands, 1H-imidazole-2-carbohydrazide (2-IZCA) and 1H-imidazole-4-carbohydrazide (4-IZCA). The structures were confirmed using infrared, elemental analysis, and single-crystal X-ray diffraction. Experimental results demonstrate that both ECPs exhibit good thermal stability. However, compared to ECPs-1, ECPs-2 exhibits a lower thermal initial decomposition temperature (Td = 210 °C), lower mechanical sensitivity (IS = 27 J, FS = 84 N), and more concentrated energy output. Although theoretical predictions suggest similar detonation velocities and pressures for both compounds, actual detonation performance tests indicate that ECPs-2 has stronger explosive power and initiating capability, with potential for use as a laser initiator (E = 126 mJ). The simple preparation method and inexpensive starting materials enrich the research on primary explosives.

Thermite reaction driven pyrotechnic formulation with promising functional performance and reduced emissions

Green pyrotechnics/firecrackers reported herein are driven by thermite reactions for self-contained and self-sustained exothermic chemical reactions to make heat and sound by the usage of minimal fuel (aluminum), oxidizer (potassium nitrate), and Sulfur. These firecrackers have the potential for generating less emissions (70%) compared to commercial firecracker-based counterparts due to the presence of additives and are therefore designated as "Green firecrackers" or reduced emissions firecrackers. The functional performance and long-term stability of the composition was investigated through sound measurement and different tests, including ageing, thermal stability, and moisture test. The thermodynamics of the facilitated thermite reaction was cross-checked with experimental and theoretical methods. Prevalent mechanism for a substantial reduction in emissions to the tune of about 70% has been discussed. Cost of the green firecrackers is at par with the commercial firecrackers as cost of raw materials being used to prepare the formulation is comparable to the relatively toxic oxidizer substituted. "Green firecrackers" developed and reported here are environmentally benign in nature with higher business potential as far as a green chemistry-based sustainable solution for the society is required.

Low-perchlorate blue-flame pyrotechnic compositions

An ammonium perchlorate (AP) and copper(II) benzoate pyrotechnic blue-flame composition was gradually “diluted” by adding an experimental perchlorate-free blue-flame composition based on aminoguanidinium nitrate (AGN), malachite, PVC powder and shellac resin. Flame’s luminous intensity and specific luminous intensity were recorded and analyzed. A copper-aminoguanidinium (CuAG) complex was also synthesized and tested as an energetic additive in perchlorate-free blue-flame composition. Green-flame color was observed when testing chlorine-free energetic compositions with CuAG.