Fabrication and Characterization of PMMA/HMX-based Microcapsules via in situ Polymerization

Abstract

Abstract:Microcapsule technology was applied with nitramine explosives to improve their performance. Polymethyl Methacrylate (PMMA) was selected for the fabrication of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) based microcapsules. The PMMA/HMX-based microcapsules were prepared via a facile in situ polymerization of PMMA on the surface of the HMX crystals. Structural characterization of the PMMA/HMX microcapsules was studied systematically by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fouriertransform infrared (FT-IR) spectroscopy, and their thermal durability as well as their mechanical sensitivities were measured. The results indicated that spherical microcapsules were formed, with PMMA as the capsule wall and HMX as the core material. The SEM results showed that the grains of the PMMA/HMX microcapsules were spherical and that the particle distribution was homogeneous. XRD and FT-IR analyses indicated that the HMX polymorph was preserved in the optimal β-form during the whole preparative process. The DSC results showed that the PMMA/HMX microcapsules had better thermal decomposition performance, and that the apparent activation energy of the microcapsules had increased by 47.3 kJ/mol compared to the recrystallized HMX, and its thermal stability had greatly improved. In addition, the drop height (H50) had increased from 30.45 cm to 58.49 cm, an increase of 65.81%. Thus, microcapsule technology will have a very wide range of applications in reducing the sensitivity of high energy materials in the future.

Effective Insensitiveness of Melamine Urea-Formaldehyde Resin via Interfacial Polymerization on Nitramine Explosives

“…Interestingly, the three samples prepared by the interfacial polymerization exhibit the lowest friction sensitivity. More importantly, compared to previous reports [7, 18, 26], the safety performance of GPBX fabricated by interfacial polymerization is optimal. The desensitization effect is amazing.…”

“…This can be attributed to the “isotropic” physical properties of the amorphous MUF, resulting in an irregular arrangement for the resultant explosive/MUF particles in spatial distribution. Such periodic arrangement weakens the diffraction intensity of the explosive [26]. Most importantly, the diffraction peak of MUF is also present in the diffraction peak of the explosive/MUF composite particles.…”

Green Preparation, Spheroidal, and Superior Property of Nano-1,3,5,7-Tetranittro-1,3,5,7-Tetrazocane

“…As illustrated in Figure 8, compared with the raw material, the H50 of nano-HMX particles gradually increases with the increase of the shearing time. This can be explained by the hotspot theory [23][24][25]. On the one hand, as the shearing time increases, the appearance of the HMX particles gradually becomes smoother, and the internal defects gradually decrease, so that the heat transfer rate between the particles increases.…”

Design and Characterization of a Cook‐Off Resistant High‐Energy Booster Explosive Based on CL‐20/FOX‐7

“…The characteristic peak diffraction intensity of CL-20/FOX-7 powder was significantly lower than FOX-7. It is considered that EVA and ACM have obvious amorphous characteristics, and it exhibits irregular periodic arrangement in spatial distribution, which weakens the diffraction characteristic peak intensity of FOX-7 [23].…”