The stabilizers currently used in solid propellants efficiently capture nitrogen oxides released during nitrocellulose and nitroglycerin decomposition, preventing autoignition. However, these reactions produce a mixture of chemicals that includes potentially carcinogenic N-nitrosamines and nitroaromatics. This project addresses the potential human health and environmental challenges caused by these compounds during the propellant lifecycle, including production waste disposal, surveillance, and demilitarization activities. The project team will use green chemistry and biological synthesis to produce new, environmentally friendly stabilizers inspired by nontoxic, natural antioxidants that do not form N-nitrosamines.

The project team will use a workflow similar to a drug discovery funnel to screen a large molecular space of potential biological antioxidants, applying computational chemistry methods to identify biochemicals that are predicted to tightly binding nitrogen oxides released during propellant decomposition. The lead candidate biochemicals will be produced in microorganisms using synthetic biology and bioprocess engineering to develop efficient and flexible production platforms. Small-scale nitrosation assays on the purified biochemicals will test predictions and inform preliminary assessments of environmental health and human impacts. project team will test whether the most promising candidates effectively stabilize a double-base propellant formulation during quantitative accelerated aging tests. A baseline lifecycle will be developed for the most successful stabilizer to quantify potential benefits during the in-service life of the new propellant formulation.

This project expects to identify biochemicals that react efficiently with nitrogen oxide radicals and acids, stabilizing propellant formulations without forming hazardous N-nitrosamine products. The anticipated scientific discoveries will inform the applied chemistry of nitrogen oxide reactivity in propellants and address the physiological question of how organisms scavenge reactive oxygen and nitrogen compounds in natural biological and environmental systems. project team expects that biochemical stabilizers developed in this project can be produced at large scale without organic solvents, using renewable feedstocks, and assuring a secure supply chain for propellants.