Reactive Materials with Staged Release of Energy and Biocidal Products

This study is conducted jointly by New Jersey Institute of Technology (NJIT) and the University of Cincinnati (UC). Reactive materials that are stable at low temperatures and release biocidal species upon ignition are being developed and characterized. Burning materials reach and maintain high temperatures and release biocidal species leading to their effective mixing with aerosolized bio-agents. This work builds on the previous effort, where Al-I2 and other Al-based reactive composites were prepared by cryomilling. Here, the focus is on halogen-bearing materials based on reactive metals other than aluminum, e.g., Mg or B. Other biocidal materials, such as sulfur are also explored. The reactivity of the prepared materials is improved by including oxidizers and gas generating additives. A set of new materials is being synthesized and characterized. Stability of new materials upon their heating is characterized using thermo-analytical measurements. Further characterization includes both combustion dynamics and biocidal performance. The latter includes a time-resolved study of the bioaerosol inactivation. Reactive material powders are fed into an air-acetylene flame. Spores of Bacillus anthracis (B. a.) surrogates, B. thuringiensis kurstaki [Bt(k)] and B. thuringiensis Al Hakam [Bt(AH)], are prepared, aerosolized and exposed for 0.05–5 s to the combustion products of the new materials. The state-of-the-art Bioaerosol Research and Evaluation Facility developed at UC through DTRA-supported efforts has been modified and used. Present result suggest that boron and iodine containing reactive materials offer the most effective biocidal performance. In an effort to understand the mechanism of biocidal effects, samples of exposed spores are being examined for mutational DNA damage and subjected to other analyses. The results are expected to lead to a kinetic model capable of describing and predicting the interaction between aerosolized spores and combustion products of reactive materials at different exposure times and temperatures.