Rapid thermal decomposition of Viton A

Viton A, when used as a binder in energetic formulations, typically decomposes on millisecond time scales. Characterization of this reaction, however, has been traditionally carried out using conventional thermal analysis (TA), on time scales of minutes to hours. Here, the decomposition of thin films of Viton A in an inert environment is studied using fast scanning calorimetry with heating rates up to 20,000 K/s. Thus, the decomposition occurs within tens of milliseconds. The measurements are complemented by visual observation of the sensor, making it possible to correlate details of the heat flow signal with processes occurring at different parts of the sensor. Conventional TA measurements are also performed. In both fast and conventional TA experiments, the heat flow signal does not return to an identifiable baseline, making interpretation of the results challenging. Nevertheless, it is observed that the volatilization is accompanied by an exothermic heat effect of 150.3 ± 16.7 J/g that slightly precedes the removal of the material, or mass loss in conventional thermal analysis. Kinetic processing shows an activation energy of 218 ± 2 kJ/mol, broadly consistent with literature data.