Kinetic Parameters of PBX Based on Cis‐1,3,4,6‐tetranitroocta‐hydroimidazo‐[4,5‐d] imidazole Obtained by Isoconversional Methods using Different Thermal Analysis Techniques

Abstract

The thermal decomposition kinetics of the interesting polycyclic nitramine cis-1, 3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole (BCHMX) and its polymer bonded explosive (PBX) based on polyurethane matrix, have been investigated using different thermal analysis techniques and methods. The used polyurethane matrix is based on hydroxyl-terminated polybutadiene (HTPB) cured by hexamethylene diisocyanate (HMDI). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used nonisothermally, whereas the vacuum stability test (VST) was used isothermally. Kinetic parameters were determined by using isoconversional (model-free) methods. Furthermore, the Advanced Kinetics and Technology Sol-ution (AKTS) software was used to determine the kinetic parameters of the studied samples in order to provide a comparison. It was found that the decomposition temperature of BCHMX/HTPB is lower than that of pure BCHMX. All the applied techniques as well as computational results showed that BCHMX/HTPB has a lower activation energy than pure BCHMX. The different methods used, Kissinger, Ozawa, Flynn, and Wall (OFW) and Kissinger-Akahira-Sunose (KAS) methods presented activation energies in the same range of the AKTS software results. Also the results proved that VST technique could be a useful tool to present results suitable for calculation of the kinetic parameters of explosives.

Environmentally safe (chlorine-free): new green propellant formulation based on 2,2,2-trinitroethyl-formate and HTPB

“…As commonly suggested in literatures, the mean values of activation energy using OFW and KAS methods were calculated in the interval of (a ¼ 0.3-0.7) due to the large inuence of the experimental conditions specially in case of TG/DTG on the data quality of the process "tails". [47][48][49][50] Conclusions 2,2,2-Trinitroethyl-formate (TNEF) is a new interesting (chlorine-free) green high-energy dense oxidizer (HEDO), which can be easily prepared from 2,2,2-trinitroethanol (TNE). The burning characteristics calculated for the new green propellant formula based on TNEF with HTPB was higher than that of traditional propellant based on AP/HTPB.…”

Thermal Behavior and Decomposition Kinetics of Bis(2,2,2‐trinitroethyl)‐oxalate as a High Energy Dense Oxidizer and its Mixture with Nitrocellulose

“…The mean values of effective activation energy using OFW and KAS methods were calculated in the interval of (a = 0.3-0.7) as commonly suggested in literatures [13,14,20,40] due to the large influence of the experimental conditions specially in case of TG/DTG on the data quality of the process "tails". Figure 8 shows the relation between the pre-ex- Note: T ot : onset temperature of decomposition; T oe : onset temperature of the end decomposition; T i : initial thermal decomposition temperature; T p : the peak temperature of mass loss rate; Mass Loss: from initial temperature to end temperature of DTG peak 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 ponential factor A and the effective activation energy at each step of conversion and the effect of adding the oxidizer BTNEOx to the NC matrix which improve the normal distribution of the effective activation energy during each a that gives a homogeneous burning for the new propellants formula.…”

“…Usually, thermal analysis is considered the best process of studying the thermal decomposition of energetic materials. The most common thermal analysis techniques such as thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) have been used isothermally and non-isothermally in the study of the decomposition kinetics [13][14][15][16][17][18][19][20][21][22][23][24].…”

The effect of glycidyl azide polymer on the stability and explosive properties of different interesting nitramines

“…In addition, a thermoanalytical study of these PBXs was conducted by Yan et al [17][18][19] The penetration performance of the advanced nitramines has been studied, [20][21][22] while different relationships have been presented and discussed by Zeman et al [23][24][25][26] based on the reactivity and sensitivity of the studied PBXs. BCHMX as part of a low sensitivity composition was studied by Hussein et al [27][28][29] From the previously mentioned research, it was concluded that the polymeric matrices have a signicant inuence on the different explosive properties of the studied PBXs.…”