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