β secondary transition of nitrocellulose-containing gun propellants

The β secondary transition of 4 nitrocellulose-containing gun propellants is investigated by means of dynamic viscoelastic grapher DDV-VIII-EA. It is found that single-base, double-base, nitramine and nitroguanidine-based propellants all give an corresponding peak of β secondary transition. Compared with single-base propellant, the peak tanδ of double-base propellant at its β secondary transition apparently increases, while those of nitramine-based and NGU-based propellants decrease at their β secondary transition. The experimental frequency shows little influence on the tanδ at their β secondary transition. During aging test, the tanδ at β secondary transition of nitramine-based propellant is larger than that of NGU-based, and the former decreases rapidly than the later, but after 600h, both tanδ peaks are nearly closed to each other. The relationship of β secondary transition with impact fracture strength of the gun propellants is briefly discussed.