One-step green method to prepare progressive burning gun propellant through gradient denitration strategy

Gradiently denitrated gun propellant (GDGP) prepared by a "gradient denitration" strategy is obviously superior in progressive burning performance to the traditional deterred gun propellant. Currently, the preparation of GDGP employed a tedious two-step method involving organic solvents, which hinders the large-scale preparation of GDGP. In this paper, GDGP was successfully prepared via a novelty and environmentally friendly one-step method. The obtained samples were characterized by FT-IR, Raman, SEM and XPS. The results showed that the content of nitrate groups gradiently increased from the surface to the core in the surface layer of GDGP and the surface layer of GDGP exhibited a higher compaction than that of raw gun propellant, with a well-preserved nitrocellulose structure. The denitration process enabled the propellant surface with regressive energy density and good progressive burning performance, as confirmed by oxygen bomb and closed bomb test. At the same time, the effects of different solvents on the component loss of propellant were compared. The result showed that water caused the least component loss. Finally, the stability of GDGP was confirmed by methyl-violet test. This work not only provided environmentally friendly, simple and economic preparation of GDGP, but also confirmed the stability of GDGP prepared by this method.