The Role of Particle Size on the Combustion of Boron Carbide/Sodium Periodate Biocidal Formulations

摘要

The ever‐present threat of biological weapons has encouraged the development of novel pyrotechnicformulations. These formulations release gaseous iodine upon combustion that acts as a potent activeagent capable of countering bio‐agents (e.g. anthrax). Typical reactive material formulations contain aniodate and a metal fuel, usually aluminum powder. However, the percentage of free iodine generated isrelatively low and aging of these formulations remains an issue. In this work, boron carbide based biocidalformulations with NaIO_4 serving as the primary oxidizer are explored and the role of particle size on thecombustion velocities, iodine output, and combustion products are detailed. Formulations are studiedwith and without the addition of binder and the role of particle size detailed toward developing 3‐Dprintable energetics. It was shown in this study that the effect of changing the boron carbide particle sizehad nominal effects on both the combustion velocity and iodine recovery. However, promising resultshave been established by reducing the particle size of the oxidizer, NaIO_4. The NaIO_4 was milled to an D90value of 30.30 μm resulting in iodine recovery close to 90%, much higher than any formulation seen thusfar. By reducing the particle size even farther to under 25 μm while maintaining the same fuel content,iodine recovery was close to 100%. Iodine quantification was done using UV‐VIS, simultaneous differentialscanning calorimetry and thermogravimetric analysis (DSC/TGA), heat of reaction, X‐ray diffraction (XRD)and combustion characteristics will be discussed.