Facilitating polymorphic crystallization of HMX through ultrasound and trace additive assistance

作者：Jie Li, Shichun Li, Shiliang Huang, Jinjiang Xu, Qi‐Long Yan, Shaohua Jin, Yu Liu · 发表于：Ultrasonics Sonochemistry · 年份：2024 · DOI：10.1016/j.ultsonch.2024.106946 · 被引用次数：14 · 研究领域：Crystallization and Solubility Studies、Crystallography and molecular interactions、Energetic Materials and Combustion

Low sensitivity octahydro-1,3,4,7-tetranitro-1,3,5,7-tetrazocine (HMX) has garnered significant attention from researchers due to its reduced shock sensitivity. However, the crystallization process poses challenges due to the high solidity and viscosity of the metastable α phase. Despite efforts to address this with additional energy sources like ultrasonic irradiation, prolonged exposure duration often results in small particle sizes, hindering the production of HMX with a consistent particle size distribution, thus limiting its applicability. To overcome these challenges, a method combining ultrasonic irradiation and trace H+ additive was proposed and investigated for their impact on the polymorphic transformation of HMX. The H+ additive was found to modify barriers, thus there was a lack of competitive driving force for the nucleation or growth of the metastable α form, thereby shortening the transformation pathway and duration. Moreover, the H+ additive significantly accelerated the nucleation rate of the β form (67.7 orders of magnitude faster with 0.10 wt ‰ H+) and the growth rate of β form HMX (5.8 orders of magnitude faster with 0.10 wt ‰ H+). While H+ additive alone was insufficient to induce spontaneous nucleation of the β form, combining it with short-duration ultrasonic irradiation further promoted β nucleation and shortened the polymorphic transformation duration (almost 20 orders of magnitude shorter). This rational approach led to effective control of the trans...