Synthesis and Characterization of Pressure Resistant Agent with Double‐Layer Core/Shell Hollow‐Structure for Emulsion Explosive

• Published in: Propellants, explosives, pyrotechnics Vol. 45; no. 5; pp. 798 - 806
• Main Authors: Fang, Hua, Cheng, Yang‐Fan, Tao, Chen, Yao, Yu‐Le, Ma, Hong‐Hao, Han, Ti‐Fei, Shen, Zhao‐Wu, Chen, Yuan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.05.2020
• Subjects: Aluminum sulfate; Cenospheres; Dynamic pressure; Emulsion explosive; Explosive compacting; Hot spot; Microspheres; Optical microscopes; Particle size; Pressure resistant; Raw materials; Sensitizer, Microspheres; Sensitizing; Silicon dioxide; Sodium bicarbonate; Underwater explosions
• ISSN: 0721-3115; 1521-4087
• DOI: 10.1002/prep.201900288

A novel pressure resistant agent (PRA) for emulsion explosive was prepared by a high‐speed shear mixer with cenospheres, Al2(SO4)3, NaHCO3 and hydrophobic nano‐silica as the raw materials. The structural features of the PRAs were characterized using a scanning electron microscope, a laser particle size analyzer and an optical microscope, and the experimental results showed that the PRAs were ellipsoidal microspheres with an average particle size of 200 μm and had double‐layer core/shell hollow‐structures. The inner hollow shell of the microsphere could serve as sensitizing bubble when it was undamaged whatever the status of outer shell, and once it was broken, the materials in the outer and inner shells would react with each other and generate new sensitizing bubbles in emulsion explosive. The brisance and underwater explosion experimental results showed that when the addition of PRAs was determined to be 2 mass %, the resistance to dynamic pressure of emulsion explosive sensitized by glass microsphere (GM) would be improved significantly without affecting its power. The lead column compression of GM‐2 mass % PRAs sensitized emulsion explosive was 16.05 mm, which was close to that of GM sensitized emulsion explosive. When compressed by a RDX booster underwater at the distances of 25 and 75 cm, the dynamic pressure resistance ability of GM‐2 mass % PRAs sensitized emulsion explosive would increase by 56.54 and 62.07 %, respectively, compared to that of GM sensitized emulsion explosive at the same compression distance. This novel PRA provided double protections for improving the pressure resistant properties of emulsion explosives, especially in the condition of dynamic pressure compression.