Construction of environment-friendly core-shell ammonium perchlorate@1,3,5-triamino-2,4,6-trinitrobenzene composites with high safety and excellent thermal decomposition properties

Ping Ye, Pengfei Xu, Hao Guo, Bing Gao, Guangcheng Yang, Bing Huang, Changping Guo
2020 Materials & design  
Modern solid propellants integrated with enviro-friendly, high safety and excellent thermal decomposition properties are highly desired in the aerospace as well as weapon areas, and it also presents significant challenging. For this purpose, a simple ultrasonic synthesis method was proposed to 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) nanoparticles were deposited on the surface of ammonium perchlorate (AP) to obtain core-shell AP@TATB. Since there is no heavy metal involved in the composite,
more » ... t can effectively avoid the pollution of heavy metals to the environment. The prepared samples were analyzed by powder Journal Pre-proof J o u r n a l P r e -p r o o f 2 X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), it has been confirmed that a uniform and complete shell TATB was formed on the surface of AP particles when the content of TATB was 10%, differential scanning calorimetry (DSC) data shows that the shell TATB effectively reduces the high-temperature decomposition (HTD) of AP and significantly increases heat release of AP by 2.67 times. In addition, AP@TATB also showed excellent safety in the sensitivity test. The ease of the synthesis method and the promising feature of the obtained composites exhibit great potential for application in environment-friendly modern solid propellants. [7] [8] . However, it is still an urgent task and great challenge for the solid propellants to achieve this goal. And more importantly, for modern solid propellants, besides improving the thermal decomposition performance of AP, it is also necessary to pay Journal Pre-proof An extremely insensitive explosive, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), is a good candidate, which exhibits excellent impact and friction sensitivity, compared with most of the other explosives with relatively high sensitivity, mixing with AP will reduce the safety and bring potential safety hazards to propellants [19][20]. That is not acceptable. And TATB also has considerable energy [21], and unique synergistic effect that can effectively improve the thermal decomposition properties of AP Journal Pre-proof 2.2. Surface modification of ammonium perchlorate (AP) with Estane The surface of AP needs to be modified before being encapsulated by the TATB nanoparticles. First, 0.05 g Estane was added into the beaker with 20 mL DCE, and then, the solution was heated in a water bath at 50 ℃ until Estane was completely Journal Pre-proof 2.4. Characterization Powder X-ray diffraction (XRD) patterns were acquired by X′Pert Pro diffractometer (Panaco, Netherlands) with Cu Kα radiation (λ= 0.15410 nm, 2θ= 10° Journal Pre-proof core-shell AP@TATB with different shell contents, and the physical mixture AP/TATB. It can be seen that the diffraction peaks of pure AP are located at 15.4°, 19.4°, 22.8°, 23.9°, 24.7°, 25.8°, 27.5°, 30.1°, 30.9°, 34.6° and 41.0°, which is consistent with the standard diffraction data of AP (JCPDS 08-0451). It can be seen Journal Pre-proof surface of AP is smooth (Fig. 3c and d) . It can be seen from Fig. 3e and f that when nano-TATB coats AP at a content of 5%, nano-TATB is partly cover the surface of AP, so that AP@TATB cannot form a complete core-shell structure. when the content of nano-TATB increased to 10%, as shown in Fig. 3g and h, nano-TATB was uniformly Journal Pre-proof J o u r n a l P r e -p r o o f 8 and compactly coated on the surface of AP to form a perfect core-shell structure. The possible reason for this is that after Estane modified AP, the related functional groups between the interface of AP and nano-TATB can well bind together to increase to enhance the mechanical strength of core-shell AP@TATB [29] , [32] . However, when the content of nano-TATB increases to 20%, the surface of AP is covered with a thick layer of nano-TATB, and even some TATB nanoparticles agglomerate together ( Fig. 3i and j). Therefore, the shell formed by TATB at a content of 10% can completely encapsulate the AP without causing agglomeration of nano-TATB. Journal Pre-proof J o u r n a l P r e -p r o o f 9 Fig. 3 . SEM image of the experimental samples: AP (a,b), modified AP by Estane (c,d), core-shell AP@TATB with TATB content of 5% (e,f), core-shell AP@TATB with TATB content of 10% (g,h), core-shell AP@TATB with TATB content of 20% (i,j). Journal Pre-proof As shown in Fig. 5 and Table 1 , the content of nano-TATB in the sample of core-shell AP@TATB 1-5 was 2%, 5%, 10%, 15% and 20%, respectively. After the comparison of the DSC curve of AP, it can be found that shell TATB has no catalytic activity for crystal transformation and LTD, but has a good catalytic activity on HTD, and can make the decomposition temperature of AP advance to below 370 ℃, the best catalytic activity of AP@TATB-2 reduces the HTD peak to 363.8 ℃, which brings Journal Pre-proof Journal Pre-proof J o u r n a l P r e -p r o o f 16
doi:10.1016/j.matdes.2020.108666 fatcat:joqavihkfzhjjpaonvlxbykgqy