Effect of multi-type oxides on the catalytic pyrolysis behaviors of 5-amino-1H-tetrazole

Abstract

5-Amino-1H-Tetrazole (5AT), as a novel energetic material, has been widely applied in propellant, airbags, and fire extinguisher areas due to its excellent combustion properties. However, suboptimal combustion performance limits its extensive application. Thermal behaviors investigation could provide guidance on the control of combustion performance, which can be effectively optimized by adding catalysts. Therefore, exploring the thermal decomposition behaviors of 5AT is more beneficial to its combustion performance optimization, management and applications. Traditional catalysts for 5AT, such as coolants (CaCO3), hydrohalide salts (HCl), and guanidine (CH4N4O2) are easy to release harmful gas to destroy the environment when they catalyze the pyrolysis and combustion process. Moreover, different catalysts can play various catalytic mechanism. Therefore, a highly effective catalysts that are not easy to be occurred for pyrolysis on their own are required. In this study, three kinds of catalysts (acid oxide (SiO2), alkaline oxide (PbO), amphoteric oxide (MnO2)) are mixed with 5AT by means of ball milling, which is for the purpose of investigating the effect of multi-type oxides on the catalytic pyrolysis behaviors about 5AT. The TG test is conducted to analyze the thermal behaviors and the isoconversion method (Advanced Vyazovkin) is applied to evaluate the thermal activation energy ranging from 100 ∼ 300 ℃. The results reveal that the catalyst PbO embodies the best catalytic effect. The Criado method is employed to determine the pyrolysis model. The results indicates that the pyrolysis model is not governed by a specific model but all followed by Fn model when the conversion is below 0.5 while the model is mainly charged by F3/2 model when the conversion is over 0.5 with the addition of catalysts. Moreover, the TG-FTIR technology is also employed to capture the evolved gas products and further to infer the most likely pyrolysis route of 5AT. The conclusions in this study will provide a theoretical support for the storage, transportation, application, management, combustion investigation and the computer simulation of 5AT-based solid propellant.