Preparation and Characteristics of Foamed NC‐Based Propellants

Abstract

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.

Burning Characteristics of Consolidated Gun Propellants

“…The higher burning rates of the consolidated propellants are attributed to the porous grains therein. Porous grains burn faster than the ambient matrix (energetic adhesive) due to their porous structure [8,10]. The micropores in the burning surface, which are generated due to the fast burning of the porous grains, would increase the burning surface and burning depth of consolidated propellant.…”

“…The porous oblate spherical propellants prepared by supercritical fluid foaming exhibit the fast-burning characteristic [7,8] and are used as the fast-burning filler to increase the burning rate of compact consolidated propellants. The energetic adhesive is used for adhering porous propellant grains and stuffing the voids between the propellant grains.…”

“…The double-base oblate spherical propellants (nitroglycerine 30 wt-%, nitrocellulose 70 wt-%) from Sichuan Nitrocell Co., LTD were foamed using CO 2 as the blowing agent by batch foaming process. The detailed foaming process is demonstrated in the literature [8]. NC powders (nitrogen content, 11.8-12.4 %) from Sichuan Nitrocell Co., LTD were used as the ignition material in the quenched combustion experiment and closed vessel experiment.…”

Combustion of Gas-Permeable Gun Propellants

“…The detailed foaming process using CO 2 as the physical blowing agent is demonstrated in the literature [5], and a description and values of the important process parameters are listed in Table 1.…”

“…In addition, results of burning experiments indicate that the internal porous structure exerts an important effect on the fast burning behaviors of porous propellants. In recent years, the foamed nitrocellulose (NC)-based propellants by supercritical fluid foaming have drawn considerable interests due to the simple production process and fast burning characteristics [5][6][7]. Research results on the burning behaviors of the novel porous propellants show that the porosity of foamed propellants exerts an important impact on their burning characteristic.…”