Thermal behavior and decomposition kinetics of Viton A bonded explosives containing attractive cyclic nitramines

• Published in: Thermochimica acta 2013-06, Vol.562, p.56-64
• Main Authors: Yan, Qi-Long, Zeman, Svatopluk, Elbeih, Ahmed
• Format: Article
• Language: English
• Subjects: Activation energy; Autocatalysis; Binders; Bonding; Conversion; Cyclic nitramines; Decomposition; Differential scanning calorimetry; PBX; RDX; Thermal decomposition; Viton A
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2013.03.041

•The effects of Viton A binder on the thermal behavior of cyclic nitramines have been investigated by using non-isothermal techniques.•The decomposition kinetics parameters have been calculated by modified Kissinger-Akahira-Sunose method.•As a thermostable polymer, Viton A could inhibit the initial autocatalysis effect of cyclic nitramines.•It would improve the thermal stability of corresponding PBXs containing RDX, β-HMX and ε-CL-20. The thermal behavior and decomposition kinetics of Viton A bonded PBXs containing some attractive cyclic nitramines were investigated by means of nonisothermal TG and DSC techniques. It has been shown that only a single decomposition process has been observed for RDX-VA, CL-20-VA and HMX-VA while an obvious two-step process for BCHMX-VA under 1.0°Cmin−1. The exothermic onset temperatures of RDX-VA, BCHMX-VA, HMX-VA and CL-20-VA were found as 212.6, 241.3, 277.6 and 237.8°C with the peak maximum of 234.1, 242.6, 278.7 and 238.6°C, respectively. Their corresponding heat releases were determined as 1552, 1263, 1302 and 1597Jg−1, which are much lower than that of the pure cyclic nitramines. It has been proved that Formex polymer is not good binder for BCHMX, while Viton A is better than C4 and Formex as the binder of cyclic nitramines for the sake of greater thermal stability. Viton A has a significant effect on the activation energy distribution of cyclic nitramines, and the initial autocatalysis effect for RDX and BCHMX was weakened or inhibited. The activation energies for thermolysis of RDX-VA, BCHMX-VA, HMX-VA and CL-20-VA were found almost independent on the extent of conversion at interval of 0.3–0.7 with the mean values of 174.4±3.1, 183.3±1.3, 285.8±11.7 and 184.0±4.3kJmol−1, respectively.