Thermal Behavior and Decomposition Mechanism of Ammonium Perchlorate and Ammonium Nitrate in the Presence of Nanometer Triaminoguanidine Nitrate

Yi Wang; Xiaolan Song; Fengsheng Li

doi:10.1021/acsomega.8b02515

Thermal Behavior and Decomposition Mechanism of Ammonium Perchlorate and Ammonium Nitrate in the Presence of Nanometer Triaminoguanidine Nitrate

ACS Omega. 2019 Jan 4;4(1):214-225. doi: 10.1021/acsomega.8b02515. eCollection 2019 Jan 31.

Authors

Yi Wang¹, Xiaolan Song¹, Fengsheng Li²

Affiliations

¹ School of Materials Science and Engineering and School of Environment and Safety Engineering, North University of China, Taiyuan 030051, China.
² School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.

Abstract

Nanometer triaminoguanidine nitrate (TAGN) with mean size of 218.7 nm was fabricated, and its structures were characterized by scanning electron microscopy, X-ray diffraction, IR, and X-ray photoelectron spectroscopy analyses. As an energetic accelerator for thermal decomposition of ammonium perchlorate (AP) and ammonium nitrate (AN), 10% nano TAGN blended with AP and AN, and samples "[90% AP + 10% (nano TAGN)]" and "[90% AN + 10% (nano TAGN)]" were obtained, respectively. Differential scanning calorimetry (DSC) analyses were employed to investigate the decomposition kinetics and thermodynamics of the samples. The results indicated that [90% AP + 10% (nano TAGN)] presented a higher activation energy (152.34 kJ mol^-1) than pure AP (117.21 kJ mol^-1) and [90% AN + 10% (nano TAGN)] possessed a lower activation energy (147.51 kJ mol^-1) than pure AN (161.40 kJ mol^-1). All activation free energies (ΔG ^≠) were positive values. This means that activation of the molecules was not a spontaneous process. The decomposition peak temperature of AP decreased from 478.5 °C (for pure AP) to 287.2 °C (for [90% AP + 10% (nano TAGN)]). The decomposition peak of AN also advanced via doping with nano TAGN. Using DSC-IR analysis, the decomposition products of nano TAGN, pure AP, [90% AP + 10% (nano TAGN)], pure AN, and [90% AN + 10% (nano TAGN)] were investigated, and their decomposition mechanisms were proposed. The key factors, i.e., the formation of hydrazine in the decomposition of nano TAGN, were speculated, which substantially promoted the consumption of HNO₃, HClO₄, and their decomposition products in kinetics. Additionally, the energy performances of AP- and AN-based propellants doping with TAGN were evaluated. It is disclosed that the introduction of TAGN would not result in improvement in the energy performance of propellants, but due to its energetic property and high hydrogen content, proper introduction of TAGN will not reduce the energy performance of propellants in a large degree compared with the introduction of inert catalysts.