Preparation and Characteristics of Foamed NC-Based Propellants

Foaming properties of the three NC-based (nitrocellulose-based) propellants, namely, single-base propellant, NG (nitroglycerine) propellant and TEGDN (triethylene glycol dinitrate) propellant were investigated in the batch foaming process by using supercritical CO2 as the physical foaming agent. Burning characteristics of the foamed NC-based propellants were also investigated in this work. For this study, the CO2 desorption of the three NC-based propellants were plotted by the gravimetric method. The morphology and burning characteristics of these foamed NC-based propellants were characterized by scanning electron microscope (SEM) and closed vessel experiment. The test data revealed that the energetic plasticizer has a considerable effect on the pore formation in the NC matrix although it has little effect on the CO2 solubility in the NC-based propellants. Moreover, the SEM images showed the foaming temperature also plays an important role in the pore parameters of foamed propellants. Furthermore, the data of closed vessel experiment indicated that the burning characteristics of foamed NC-based propellants largely depend on the pore parameters, and the porous structure of foamed propellants would considerably increase the mass conversion rate.