Isothermal decomposition kinetics and possible decomposition process of pentaerythritol tetranitrate

The isothermal decomposition kinetics of pentaerythritol tetranitrate (PETN) was studied through a self-established isothermal thermal decomposition gas metering device. The pressure versus time curves of the gas generated by PETN decomposition under different temperature conditions were divided into two parts, showing the remarkable effect of temperature and melting point on PETN decomposition. Model-fitting calculation result showed that the decomposition of PETN at 90–110°C conformed to the No. 8 model, namely, the anti-Jander equation, and a corresponding activation energy Ea of 107.1 kJ·mol−1 with ln(A/s−1) = 6.97. Within a temperature range of 112–130°C, the decomposition model of PETN conformed to the No. 28 model with reaction order n = 4. The device was simultaneously used to predict the time of PETN to reach a certain decomposition extent. Results showed that the time of PETN was extrapolated to 54.4 years when the extent of reaction reached 0.1% at ambient temperature (25°C). Furthermore, Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize PETN decomposition residues with different decomposition depths to understand the decomposition process.