Analysis and characterization of nitrocellulose as binder optimized by 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Nitrocellulose (NC), a highly energetic compound, is widely used in nitrolacquer, celluloid, binder, propellants, and explosives. Many studies have focused on the inflammability and instability of NC, but few have investigated its use as a propellant binder. To optimize the properties of NC as a propellant binder, this study introduced 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][NTf₂]) as an additive. This study focuses on the thermal pyrolysis behavior and decomposition mechanism of pure NC (NC-P), NC-NTf₂ (i.e., NC mixed with [Bmim][NTf₂]), and NC-NTf₂-eth (i.e., NC mixed with 30% [Bmim][NTf₂] and 70% ethanol). First, the thermal degradation processes of NC and [Bmim][NTf₂] were investigated using thermogravimetric analysis. In addition, the essential thermodynamic parameters of NC-P, NC-NTf₂, and NC-NTf₂-eth were obtained by differential scanning calorimetry, and the apparent activation energies were evaluated using the Starink method and Friedman method. The results show that NC-NTf₂ has low onset decomposition temperature, low activation energy, and high energy release rate. Moreover, NC-P, NC-NTf₂, and NC-NTf₂-eth were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy to verify and interpret the thermal analysis results obtained.