Thermal Behavior and Decomposition Kinetics of RDX and RDX/HTPB Composition Using Various Techniques and Methods

Abstract

Abstract:In this paper, the thermal behavior and decomposition kinetics of trinitrohexahydrotriazine (RDX) and its polymer bonded explosive (PBX) containing a hydroxyl-terminated polybutadiene (HTPB) based polyurethane binder in the ratio 80% RDX/ 20% HTPB were investigated using various experimental techniques and analytical methods. The HTPB polyurethane matrix contains other additives and was cured using hexamethylene diisocyanate (HMDI). Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Vacuum Stability Test (VST) and Ignition Delay Techniques were applied both isothermally and non-isothermally. The kinetic parameters were determined using both the isoconversional (model free) and the model-fitting methods. For comparison, Advanced Kinetics and Technology Solution (AKTS) software was also used. It was found that the addition of an HTPB-based polyurethane matrix to pure RDX decreased its decomposition temperature. It was also found that RDX/ HTPB has a lower activation energy than pure RDX. The polyurethane matrix had a significant effect on the decomposition mechanism of RDX resulting in different reaction models. It was concluded that the activation energies obtained using the Ozawa, Flynn, and Wall (OFW) and Kissinger-Akahira-Sunose (KAS) methods were very close to the results obtained via the AKTS software lying in the range 218.3-220.2 kJ·mol −1. The VST technique yielded kinetic parameters close to those obtained using TG/DTG. On the other hand, the Ignition Delay Technique yielded different and inconsistent kinetic parameters.

Studies on Sheet Explosive Formulation Based on Octahydro-1,3,5,7-Tetranitro-1,3,5,7-Tetrazocine and Hydroxyl Terminated Polybutadiene

“…Thermal characterisation and analysis of energetic materials and their formulations are important not only for understanding the kinetics of their thermal decomposition, but also for assessing the effect of their exothermic decomposition on the potential hazards in their handling, processing, and storage 15,16 . Thermal characterisation of PBX containing RDX or HMX with HTPB-binder has been reported by different authors [17][18][19][20][21] . The performance, sensitivity and thermal analysis data obtained from HMX-based sheet explosive formulation have been compared in this paper with the existing conventional RDX-based sheet explosive formulation 13,14 .…”

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

“…These advanced explosives have been studied in comparison with traditional nitramines by several researchers. [1][2][3][4]9 The detonation parameters of these explosives bonded by several polymeric matrices were determined.…”

Thermal decomposition and shelf-life of PETN and PBX based on PETN using thermal methods

“…The polymeric binder coating, that binds the explosive granules, can absorb impact impulse, reducing the sensitivity of explosives to mechanical shocks. In addition, it can also improve the mechanical and chemical properties of explosive [5,6].…”

“…Compared to single high explosives (e.g. PETN), the thermal decomposition behavior and kinetics of PBXs are more complicated due to the addition of binders and other additives [3,5,6]. Nevertheless, similar to single explosives, these vital parameters of PBXs can be evaluated using the Arrhenius kinetic constants of their thermal decomposition reactions [7][8][9][10].…”