Preparation and characterization of core–shell structured FOX-7/F2602 PBX with improved thermal stability and reduced sensitivity
Yue Yang, Xiaodong Li, Yue Zhao, Yuanqi Han, Yantao Sun, Jingyu Wang
Abstract
To improve thermal stability and security of energetic materials, the core–shell structured FOX-7 (1,1-diamino-2,2-dinitroethylene)/F2602 (fluoroelastomer) PBX (polymer bonded explosive) was prepared from recrystallized FOX-7 by a spray drying strategy. The morphology and crystal form of the recrystallized FOX-7 were retained, and the mean particle size of the FOX-7/F2602 PBX was apparently reduced from 39.72 µm of raw FOX-7 to 1.50 µm. SEM, TEM, and XPS analysis showed that F2602 was deposited on the surface of FOX-7 to form a core–shell structured composite. The formation mechanism of the core–shell composite was proposed. Compared with the recrystallized FOX-7 grains, the prepared FOX-7/F2602 PBX had higher apparent Ea and Tb, which signifies improved thermal stability and thermal safety. The impact sensitivity test showed that the critical height value (H50) of the FOX-7/F2602 composite had remarkable enhancement, indicating better mechanical security. This work provides a simple and effective method to prepare the core–shell structured energetic composite with enhanced safety performance.