Zheng Baohui, Liu Tao, Gao Dayuan, Zhu Qing, Li Shangbin, Luo Guan, Gao Xia
Institute of Chemical Materials, China Academy of Engineering Physics Mianyang 621900 China
RSC Adv. 2018 Mar 22;8(21):11478-11488. doi: 10.1039/c7ra13393f. eCollection 2018 Mar 21.
Promoting the ignition of boron powders in propellants, explosives and pyrotechnics has been a promising research direction. In this paper, a new strategy for covalently bonded energetic boron powders was designed. Specifically, 2,4-toluene diisocyanate (TDI) and 3-amino-1,2,4-triazole (ATZ) were used as grafting molecules, and then acidification, carbamation and ureylene addition were performed serially on the surface of the boron particles. The reaction conditions were optimized using infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). At lower temperatures, the addition of carbamation or ureylene can improve the yield and stability of isocyanate and urea groups. The chemical composition, microstructure and surface properties of the boron powders were analyzed with nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and contact angle (CA) analysis, respectively. The covalent bonding type was confirmed by the typical peaks at 155.7 and 157.5 ppm in the C NMR spectra of the intermediate isocyanate-grafting boron powders (TB) and target product triazole-grafting boron powders (TTB). The static water contact angles on the surfaces of TB and TTB were 148.3° and 37.0°, respectively. Influences of surface modification of boron powders on the rheological properties of boron/hydroxyl-terminated polybutadiene (HTPB) composites were investigated. Moreover, the prepared samples were characterized by thermogravimetry (TG) and differential scanning calorimetry (DSC) to investigate the thermal stability and reaction activity, and the results showed that this grafting strategy could significantly reduce the critical reaction temperature of B/KNO. Consequently, it is anticipated that the modified boron powders can potentially be used in propellants, explosives and pyrotechnics with high impulses.
促进推进剂、炸药和烟火中硼粉的点火一直是一个很有前景的研究方向。本文设计了一种用于共价键合含能硼粉的新策略。具体而言，使用2,4-甲苯二异氰酸酯（TDI）和3-氨基-1,2,4-三唑（ATZ）作为接枝分子，然后在硼颗粒表面依次进行酸化、氨基甲酰化和亚脲基加成。利用红外（IR）光谱和X射线光电子能谱（XPS）对反应条件进行了优化。在较低温度下，氨基甲酰化或亚脲基加成可以提高异氰酸酯和脲基团的产率和稳定性。分别用核磁共振（NMR）光谱、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和接触角（CA）分析对硼粉的化学成分、微观结构和表面性质进行了分析。通过中间异氰酸酯接枝硼粉（TB）和目标产物三唑接枝硼粉（TTB）的碳核磁共振谱中155.7和157.5 ppm处的典型峰确认了共价键合类型。TB和TTB表面的静态水接触角分别为148.3°和37.0°。研究了硼粉表面改性对硼/端羟基聚丁二烯（HTPB）复合材料流变性能的影响。此外，通过热重分析（TG）和差示扫描量热法（DSC）对制备的样品进行表征，以研究其热稳定性和反应活性，结果表明这种接枝策略可以显著降低B/KNO的临界反应温度。因此，预计改性硼粉有可能用于高冲量的推进剂、炸药和烟火中。
