Compatibility Assessment of Liquids with High Explosives by Ampoule and Titration Heat Flow Calorimetry (HFC)

摘要

Traditionally, compatibility assessment with high explosives has been carried out using vacuum stability testing, however this test is not suitable for low boiling point liquids. Alternative thermal techniques, such as Differential Scanning Calorimetry (DSC) and Thermo-gravimetric Analysis (TGA), are also used for compatibility assessment. Standard ramped methods are not suitable for low boiling temperature liquids as evaporation occurs prior to degradation of the explosive and can invalidate the test. These techniques are also not considered sufficiently sensitive to conduct low temperature isothermal investigations. HFC allows lower temperature investigations to be undertaken and, due to its larger samples size, has improved sensitivity when compared to DSC and TGA. HFC is a well-established technique for propellant compatibility and stability assessment; however the technique is considered less mature for high explosive formulations. Additional developments in the technology, such as the titration calorimeter cells allow for higher scrutiny into the chemistry of incompatibility including zero time data capture. A method combining ampoule and titration Heat Flow Calorimetry is currently under development at AWE to assess the compatibility of high explosives with low boiling liquids. Initial findings and proposed sentencing criteria are discussed here.