Effects of Micro‐Encapsulation Treatment on the Thermal Safety of High Energy Emulsion Explosives with Boron Powders

Abstract The effects of micro‐encapsulation technology on the thermal safety of boron‐containing emulsion explosives were experimentally studied. Micro‐structures of additives, demulsification states and thermal characteristics of boron‐containing emulsion explosives were characterized by the laser particle size analyzer, scanning electron microscope and thermal analysis equipment, respectively. The storage experiments showed that emulsion explosives with boron powders would be demulsified in a short time, while those with micro‐encapsulated boron powders were not demulsified and had good surface morphologies and structures. The results of TG‐DSC experiments showed that the thermal stability of emulsion explosive with polymethyl methacrylate (PMMA) micro‐encapsulated boron powders was higher than that of other samples with boron powders, and the order of thermal stability was as follows: PMMA/Boron sensitized emulsion explosive > Paraffin/Boron‐Glass microspheres (GMs) sensitized emulsion explosive > Boron‐GMs sensitized emulsion explosive. The experimental data of accelerating rate calorimeter (ARC) tests showed that the addition of boron powders would significantly increase the risk of thermal explosion of emulsion explosives under the adiabatic condition, and PMMA micro‐encapsulation for boron powders could largely reduce the thermal explosion risk of boron‐containing emulsion explosives compared with paraffin coating. The coating effect of micro‐encapsulation technology was much better than that of traditional paraffin coating method, and the compatibility and thermal safety of boron‐containing emulsion explosives were also improved.