Thermal decomposition of fluorinated polymers used in plasticized explosives and munitions

Abstract

A number of military explosives and munitions employ fluorinated polymers as binders or components, e. g., PBXN‐5. To determine potential environmental releases during disposal operations, the thermal decomposition of the fluorinated polymers Viton A, Kel‐F, and Teflon were examined alone and in combination with the explosive HMX. Although PBXN‐5 only contains 5 % by weight Viton A, laboratory prepared analogs were made with 5 % polymer as well as with 50 % polymer to ensure polymer decomposition products could be detected. Under air and under nitrogen decomposition was examined by SDT [simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)], TGA‐infrared (IR) spectrometry, and pyrolysis gas chromatography with mass spectrometric analysis (GC‐MS). All three techniques, SDT, TGA‐IR, and pyrolysis GC‐MS, suggest that decomposition of HMX could be completed at low temperature before polymer decomposition ensues. To confirm this observation, pyrolysis GC‐MS was performed at temperatures below 350 °C since above this temperature all three polymers exhibited some fluorinated decomposition products.