Surface Coating of Cyclotetramethylenetetranitramine (HMX) Particles and Its Property Investigation
Guo Yan1, Shi Xiaobing2, Pang Weiqiang2,3, Qin Zhao3, Xu Huixiang2,3, Li Huan2 and Fan Xuezhong2
1School of Computer Science, Northwestern Polytechnical University, Xi’an 710072; 2Xi’an Modern Chemistry Research Institute, Xi’an 710065 China 3Science and Technology on Combustion and Explosion Laboratory, Xi’an 710065 China
Abstract: To improve the safety of cyclotetramethylenetetranitramine (HMX) particles, the polymer thermoplastic polyurethane elastomer (TPU) and nitrocellulose (NC) were introduced to coat HMX powder by water-solution suspension method and internal solution method, respectively. Scanning electron microscope (SEM) and X-ray photo-electron spectrometry (XPS) were employed to characterize the HMX samples and the role of NC and TPU in the coating processes were discussed. The impact sensitivity, friction sensitivity, and the thermal decomposition of coated HMX particles were investigated, and compared to the unprocessed ones. The results indicate that both TPU and NC can improve the wetting ability of the coating materials on HMX surface and reinforce the connection between HMX and the coating materials. The impact sensitivity and friction sensitivity of HMX samples decrease obviously after they have been surface coated; the drop height (H50) is increased from 35.24 cm to 50.08 cm, and the friction probability is reduced from 93.2 % to 58.3%. The activation energy (Ea) and the self-ignition temperature increase by 10.46 KJ·mol-1 and 1.8, respectively.
Keyword: Material chemistry, Surface coating, Thermoplastic polyurethane elastomer, HMX, Safety properties, Thermal decomposition.