Science and Technology of Energetic Materials

Vol.81, No.3 (2020)

Research paper

Degradation mechanism of BCN in GN/BCN/water system and the effect of degradation on the thermal behavior of the system
Yosuke Nishiwaki and Mieko Kumasaki


Degradation decreases the quality and safety of pyrotechnic compositions. To reduce pyrotechnic degradation, a better understanding of the mechanism of degradation is required. Previously, our work revealed that exposure to water caused degradation of a guanidine nitrate (GN) and basic copper nitrate (BCN) mixture, a major component for gas-generating agents in pyrotechnics. Our previous study detected only one degradation product: copper oxide (CuO). Herein, we aim to identify other degradation products and reveal the degradation mechanism of BCN. We also study the effect of GN/BCN degradation on thermal stability. Modified accelerating aging tests and X-ray powder diffraction analysis revealed two degradation products: CuO and copper nitrate trihydrate [Cu(NO3)2⋅3H2O, CuNite]. CuNite was not observed in experiments involving heating or contact with CuO during drying. CuO was detected in each degradation. Degradation behavior in water was observed using UV-Vis spectroscopy. Quantitative spectroscopic analysis revealed a ratio of Cu2+ to NO3- of 1:2 in water during the accelerating aging test with BCN, consistent with CuNite but not with BCN. Differential thermal analysis of simulated aged GN/BCN revealed the effect of aging on thermal stability. Two degradation products, CuO and CuNite, decreased the thermal stability of GN. GN/CuO showed higher thermal stability than GN/BCN. The thermal stabilities of GN/CuO/CuNite and GN/BCN were the same, but the former showed a decrease in mass at around 100 ℃ due to dehydration. These results indicate thermal stability changes in GN/BCN due to aging.

> Full text (Open access*)


aging, degradation, basic copper nitrate, guanidine nitrate, thermal stability

© Copyright 1999-2017 Japan Explosives Society. All right reserved.