Effects of Metal Oxides on the Thermal Decomposition Kinetics and Mechanisms of HAN/PVA Based Propellants

The thermal decomposition processes of HAN/PVA-based propellants have been investigated using a simultaneous thermogravimetric analysis (TGA) - differential scanning calorimetry (DSC), coupled with Fourier-Transform Infrared Spectroscopy (FTIR) and Mass Spectrometry (MS) system. The activation energy (E-a), pre-exponential factor A and reaction mechanism function f(alpha) of the decomposition processes have been determined by non-isothermal and Malek methods. The results showed that the decomposition process of an HAN/PVA sample occurs mainly in the temperature range 202.2 similar to 220.1 degrees C, with a mass loss, heat release and E-a of about 84.8%, 1474.18 and 88.76 kJ.mol(-1), respectively. Of the seven metal oxides studied as catalysts, Al2O3, V2O5 and Fe2O3 have significant catalytic effects on an HAN/PVA-based propellant, in lowering the decomposition temperature, with E-a changing from 88.8 to 83.7, 85.6 and 113.6 kJ.mol(-1), respectively. The f(alpha) of both HAN/PVA and HAN/PVA/Al2O3 samples can be expressed as f(alpha) = (1 - alpha)(2), whereas f(alpha) = alpha or f(alpha) = alpha/2 fit well for the HAN/PVA/V(2)O(5 )and HAN/PVA/Fe2O3 samples.

Automated summary

The thermal decomposition processes of HAN/PVA-based propellants were studied using TGA-DSC, FTIR, and MS techniques. Results showed that Al2O3, V2O5, and Fe2O3 have significant catalytic effects on lowering the decomposition temperature of HAN/PVA-based propellants.