THERMOLYSIS OF HIGH-NITROGEN ENERGETIC COMPOUNDS USING FTIR SPECTROSCOPY AND TIME OF FLIGHT MASS SPECTROMETRY
Open Access
- Author:
- Shah, Kaushal Jayesh
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 03, 2011
- Committee Members:
- Stefan Thynell, Thesis Advisor/Co-Advisor
Stefan Thynell, Thesis Advisor/Co-Advisor - Keywords:
- Rapid Thermolysis
TAGzT
GzT - Abstract:
- Thermal decomposition of high-nitrogen energetic materials was studied using Fourier transform infrared spectroscopy (FTIR) and time-of-flight mass spectrometry (ToFMS) at high heating rates. The information obtained from these studies will be used in formulating detailed chemical reaction mechanisms for further use in predicting the burn rate of solid propellants from comprehensive modeling tools. The decomposition studies were conducted using an existing confined rapid thermolysis chamber, to which the FTIR and ToFMS systems were interfaced to allow in situ measurements of the evolved gas-phase species. The evolved gas-phase species were also allowed to condense on a glass plate. This residue, as well as the residue that remained on the foil in the confined region, were pressed into KBr pellets and examined ex situ using FTIR transmission spectroscopy. The experiments were conducted in an inert environment at atmospheric pressure. Small quantities of the sample were subjected to heating rates of 2000 K/s. The energetic material of interest is triaminoguanidinium azotetrazolate (TAGzT). To understand its behavior, guanidinium azotetrazolate (GzT) was also examined. The decomposition of GzT and TAGzT begins within the azotetrazolate dianion, releasing nitrogen. GzT decomposition produces chain-branching reactions resulting in a nearly explosive event. Once the explosive event has occurred, the remaining products continue to release gaseous ammonia via secondary reactions. Decomposition of TAGzT on the other hand, occurs at a much slower rate than GzT and at lower temperatures. The early phase of TAGzT decomposition involves release of hydrazine, but it ends when the AzT dianion is completely consumed. The TAGzT decomposition produces the 5-azido-tetrazole as one of the major decomposition products, in addition to NH3 and N2. Small amounts of HCN are also released.