Highly effective suppression of accidental combustion and explosion on B/KNO₃ by perfluorohexanone microcapsule

Boron/Potassium Nitrate (B/KNO₃) is used for ignition and detonation in both military and civilian fuel applications as a fuel/oxidant energetic composite. However, during the process of transport and use, the material is highly susceptible to the effects of friction and impact, which can result in accidental combustion and explosion. Such incidents have the potential to result in significant casualties and property damage. In this paper, a novel core–shell perfluorohexanone microcapsule (SHMP-GE/CFO) was prepared to address the safety concerns associated with B/KNO₃. The SHMP-GE/CFO was prepared by coating perfluorohexanone (CFO) with a synthetic condensate of sodium hexametaphosphate (SHMP) and gelatin (GE). The structural characterization was conducted using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), ¹⁹F nuclear magnetic resonance spectroscopy (¹⁹F NMR) and thermal gravimetric (TG). It was found that perfluorohexanone microcapsule were found to be successfully encapsulated with the encapsulation rate of 40%. The thermal release temperature of CFO was increased to 130 °C to achieve the controlled release of CFO. Evaluation of the combustion and explosion suppression efficacy of perfluorohexanone microcapsule against B/KNO₃ by enclosed explosive experiments. The maximum pressure and the rate of pressure rise in the combustion and explosion of B/KNO₃ are significantly diminished, thereby demonstrating that the microcapsule has an exceptional capacity to suppress combustion and explosion in B/KNO₃. The mechanism of B/KNO₃ combustion and explosion suppression by microcapsule was analyzed to include physical heat absorption and chemical suppression of free radical consumption.