IMPACT SENSITIVITY OF NITROMETHANE-BASED GREEN-PROPELLANT PRECURSOR MIXTURES

Nitromethane is a promising green propellant candidate. However, one potential issue for industrial use may be its high sensitivity to mechanical impact. In this paper, we assess the effect of adding several phlegmatizing substances (or inhibitors as we call them), on the impact sensitivity and the potential propulsive performance of the resulting mixtures. The impact sensitivity of the nitromethane mixtures was characterized using a BAM Fallhammer impact tester. The theoretical rocket performance of the mixtures was calculated utilizing the NASA CEA program. This study resulted in the identification of several nitromethane-inhibitor mixtures, which lack the high impact sensitivity of pure nitromethane but still retain much of its propulsive performance. The most promising approach was the addition of 6 wt.% of dimethyl sulfoxide: the theoretical specific impulse was only decreased by 3%, while the impact sensitivity was significantly lowered (> 10 J vs. < 5 J, as in pure nitromethane).