Formulation and Characterization of a New NitroglycerinFree Double Base Propellant

Double base propellants composed of nitrocellulose (NC) and nitroglycerine (NG) are widely used. However, the inclusion of liquid NG presents both stability and performance problems: the NG may migrate from the propellant in storage, and it softens the propellant at high inclusion levels. In this work, the novel nitrate ester 1,4-dinitrato-2,3-dinitro-2,3bis(nitratomethylene) butane (SMX) is considered as a replacement for NG in a double base propellant. Thermochemical calculations indicate improved performance when compared with the common double base propellant JA2 at SMX loadings above 40wt-%. Also, since SMX is a room temperature solid, migration may be mitigated. Both unplasticized and plasticized propellants were formulated to enable the study of the interaction of SMX with nitrocellulose. Thermal analysis of unplasticized propellant showed a distinct melt-recrystallization curve, which indicates that a solid phase solution is being formed between SMX and NC, and that SMX would not act as plasticizer. Analysis of propellant prepared with diethyleneglycol dinitrate (DEGDN) plasticizer indicates that the SMX is likely dissolved in the DEGDN. The plasticized material also showed similar hardness and modulus to JA2. Safety characterization showed that sensitivity is similar to JA2. In short, replacing NG with SMX results in a new family of propellants with acceptable safety characteristics and which may also offer improved theoretical performance.