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

摘要

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 C min~(-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 1597 J g~(-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 ± 4.3 kJ mol~(-1), respectively.