Effect of polyphenols and ionic liquids as novel stabilizers for nitrocellulose

摘要

Nitrocellulose (NC) spontaneously decomposes even at room temperature and can ignite due to accumulation of the reaction heat. In this study, with the aim of finding novel stabilizers that can prevent the decomposition of NC. we investigated the thermal behavior of NC containing polyphenols (ellagic acid, rutin, gallic acid, and resveratrol) and ionic liquids (I-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF_4]). trihexyl (tetradecyl) phosphonium chloride ([THP][Cl]). trihexyl (tetradecyl) phosphonium dicyanamide ([THP][(NC)_2N]), and tributyl(methyl)ammonium dicyanamide <[TBA][(NC)_2N])) by differential scanning calorimetry (DSC) and heat flux calorimetry (C80). In the polyphenol-containing samples, the exothermic peak temperature (T_p) and apparent activation energy (E_a). measured by DSC under heating conditions, hardly changed, as opposed to those of NC alone. On the other hand. C80 measurements under isothermal conditions in an O_2 atmosphere indicated that the induction period (t_p)-the elapsed time until an exothermic peak appears after the start of the experiment-for NC containing polyphenols was longer than that of NC alone, regardless of the type of additive. In the case of samples containing certain ionic liquids (NC/fTHP[[fCl], NC/[THP][(NC)_2N], and NC/[TBA][(NC)_2N]). E_a was higher and t_p was longer than those for of NC alone, whereas t_p of NC/[bmim][BF_4] was shorter. These results suggested that certain kinds of polyphenols and ionic liquids could prevent the exothermic oxidative decomposition of NC during isothermal storage.