Nitroplasticizer (NP) is composed of a mixture of bis-2,2-dinitropropyl acetal (BDNPA) and bis-2,2-dinitropropyl formal (BDNPF) or (BDNPA/F). NP is used in practice as a BDNPA:BDNPF 1:1+/-0.1 (mass:mass) mixture as a component of the binder material in energetic material applications. The literature contains conflicting results for the melt temperature for the eutectic point of BDNPA/F. With this work, we intend to resolve the discrepancies in melt temperature and also better define the eutectic phase diagram for these two materials. To determine BDNPA/F phase diagram, a series of heat-cool-heat differential scanning calorimetry (DSC) and modulated DSC (MDSC) experiments was conducted. The experimental parameters were tuned to the material response to optimize the expression of thermal transitions, which are related to phase transitions in many cases. The thermal transitions expressed are: enthalpic relaxation, glass transition (Tg), onset of cold crystallization (Tx), cold crystallization (Tc), melt temperature (Tm), and crystal perfection. The positions and magnitudes/areas of these transitions correspond to phase boundaries in many cases and will be presented in this work. To illustrate some of the preliminary work, the correlation between Tg and the BDNPA/F ratio is presented in Figure 1. From this strong correlation (R2=0.984 with a linear fit), one can deduce the transition between various states with a known BDNPA/F ratio.

Eutectic phase diagram of BDNPA and BDNPF

2019 Fall National Meeting

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