Abstract:

As the key functional component of solid propellant, the burning rate inhibitor plays an important role in regulating the burning rate of solid propellant. In this paper, the quaternary ammonium and aldehyde-based structures with combustion suppression effect are precisely designed and evaluated. The high nitrogen triaminoguanidine glyoxal two-dimensional copolymer(TAGP) is used as an energetic ligand. It is complexed with alkaline earth metal ions, such as K⁺, Ba²⁺ and Ca²⁺, to prepare a series of novel energetic burning rate inhibitors(so called TAGP-M). The morphologies, structure and thermal stability of the as-prepared compoundsare characterized by X-ray diffraction,X-ray photoelectron spectroscopy, scanning electron microscope/energy dispersive spectrometer, and differential scanning calorimetry and thermogravimetric analysis techniques. The negative catalytic effect of energetic burning rate inhibitor on ammonium perchlorate (AP) decomposition is analyzed. It shows that TAGP-K has obvious inhibitory effect on the crystal transition of AP. In presence of TAGP-K, the endothermic peak temperature of AP crystal transition is increased by 5.9℃, whereas the first peak decomposition temperature is increased by 28.7℃. More importantly, the use of 10 wt% TAGP-K could reduce the maximum thermal decomposition rate of AP by 58%. The corresponding energy release of AP is focused to high-temperature decomposition(HTD) process. The heat release of AP/TAGP-Ca is more than 50% higher than that of pure AP during HTD process. It shows that TAGP-Ca and TAGP-Ba increase the energy release efficiency of AP while inhibitingits decomposition. The TAGP-M burning rate inhibitors release NH₃ during the decomposition process and combine with HClO₄(AP decomposition product) to form $\mathrm{M}\left(\mathrm{ClO}_{4}^{-}\right)_{n}$ which is more difficult to decompose.The HTD process of AP is inhibited by the strong electrostatic interaction between alkaline earth metal ions and $\mathrm{ClO}_{4}^{-}$, which inhibits the decomposition of $\mathrm{ClO}_{4}^{-}$ to generate an oxidizing atmosphere and prevent theoxidative exotherm of the adsorbed NH₃.

Key words: energetic burning rate inhibitor, in-situ cross-linking coordination, thermal stability, structure optimization, burning rate reduction mechanism