一步造粒法制备RDX/PMMA微球及其性能表征

Preperation and characterization of the RDX/PMMA microspheres by one-step granulation process

以环三亚甲基三硝胺(RDX)为主体炸药,聚甲基丙烯酸甲酯(PMMA)为粘接剂,采用超声辅助一步造粒技术,制备了RDX/PMMA微球。利用分子动力学(MD)模拟,对PMMA可作为RDX包覆材料的可行性进行了分析,并用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅里叶变换近红外(FT-IR)和差示扫描量热仪(DSC)对粒子进行性能表征,通过撞击感度对微球的安全性能进行测试。通过模拟,结合能ERDX&PMMA(610.69 k J/mol)>ERDX&F2602(499.93 k J/mol),即PMMA与RDX分子间作用力较强,相容性更好,可作为包覆RDX的粘接剂,与实验结果一致;XRD和FT-IR分析显示RDX/PMMA晶型结构没有发生转变;由DSC分析,与原料RDX相比,RDX/PMMA微球的热爆炸临界温度由220.95℃增加到227.53℃,热稳定性有所改善;RDX/PMMA微球特性落高从22.4 cm上升到了38.6 cm,安全性能明显提高;该方法将普通包覆的工作时间缩短了2.5倍,工作效率明显改善。

By using RDX as the main explosive component, PMMA as a binder, RDX/PMMA was prepared by the ultrasonic assisted one step granulation process. The molecular dynamics （MD） simulation was conducted for the feasibility of PMMA as an explosive coating material. Structural characterizations of the solid spherical RDX/PMMA were systematically studied by scanning e- lectron microscopy （SEM）, X-ray diffraction （XRD）, Fourier-transform infrared （FF-IR） and its thermal durability as well as mechanical sensitivities were measured. The results indicated that by simulating, the binding energy of PBX of ERDX＆PMMA （610.69 kJ/mol） is greater than ERDX＆F2602（499.93 kJ/mol）. It means that there was strong interaction and better compatibility between PMMA and RDX molecules. PMMA can be used as an explosive coating material, which was consistent with the experimental results. The results of SEM showed that the grain of RDX/PMMA was solid spherical and the particle were homogeneous and minor, where the coating brings about a striking effect. The XRD and FT-IR analysis showed that the polymorph of RDX crystal structure did not change during the whole preparing process. Compared with the raw material RDX, the critical temperature of the RDX/PM- MA particles was increased from 221.0 ℃ to 227.5 ℃, showing improved thermal stability. The H5o of RDX/PMMA increased from 22.4 cm to 38.6 cm, indicating significantly improved safety performance. More importantly, the entire coating process eliminates the process of RDX refining and drying, and the working time of the ordinary coating is reduced by 2.5 times, so the work efficiency was obviously improved.