Nitrocellulose (NC), or cellulose nitrate, is an essential ingredient in both gun powder and solid propellants (Niehaus 2000; Pourmortazavi et al. 2009; Trache et al. 2016, 2019; Rodrigues et al. 2019; Trache and Tarchoun 2019a; Benhammada et al. 2020; Cieślak et al. 2020; Wu et al. 2020). Since the thermal degradation characteristics, have a substantial impact on the combustion behaviour of compositions based on nitrocellulose (Wei et al. 2010; Chelouche et al. 2020; Yao et al. 2020; Zhao et al. 2021), research into its thermal stability has garnered a great deal of interest. Furthermore, it is well known that the decomposition behaviour of NC is closely related to the burning efficiency of solid propellants. Therefore, one may regulate the combustion characteristics of propellants containing NC by manipulating the thermal degradation of NC. Incorporating nanoparticles into NC has been shown to effectively enhance its thermal characteristics by modifying the degradation process and/or the activation energy without sacrificing thermal safety and compatibility factors (Guo et al. 2019; Yao et al. 2020; Akhter and Hassan 2021) in recent years. Numerous metal oxide nanoparticles (NPs) have been studied for their potential use as NC additives. In fact, excellent results have been found from studies on the thermal degradation of nitrocellulose in the presence of copper oxide, iron (III) oxide, manganese (IV) oxide, nano boron, nickel (II) oxide, and bismuth (III) oxide (Wei et al. 2010; Li et al. 2017; Zhang et al. 2017; Maraden et al. 2018; Rodrigues et al. 2019; Benhammada et al. 2020; Yao et al. 2020; Zhao et al. 2021). However, to the best of our knowledge, research on NC's thermal decomposition properties and compatibility when coupled with barium oxide (BaO) has never been conducted.
As a result of the O-NO2 rupture of NC under normal circumstances, nitrocellulose-based compositions may exhibit poor chemical stability, reducing their important qualities and, in turn, their performance and reliable service life (Pourmortazavi et al. 2009; Rodrigues et al. 2019; Chelouche et al. 2020, 2021). This constant breakdown may be traced back to the CH2–O–NO2 functional group's poor bonding energy (Chelouche et al. 2019). This results in the release of gaseous chemicals, most notably nitrogen oxides. This issue may be sidestepped by using chemical agents called stabilizers. In order to put NC and other energetic materials to practical use, it is essential to improve their safety properties, including their chemical stability (Krabbendam-La Haye et al. 2003; Trache and Tarchoun 2018, 2019a; Chelouche et al. 2019). Without the addition of any stabilizers, these produced compounds have a catalytic influence on the degradation processes (Rodrigues et al. 2019; Chelouche et al. 2021). A nitrate ester's degradation cannot be stopped, but stabilizers may slow it down and lessen the catalytic effect of by-products such nitrogen oxides and nitrous and nitric acids (Chelouche et al. 2019; Cieślak et al. 2021).
The fact that metal oxides nanoparticles have been shown in the literature to be capable of trapping nitrous vapors (NOx) (Bijgner et al. 1995; Fridell et al. 1999; Rodriguez et al. 2001; Cant and Patterson 2002; Schmitz and Baird 2002; Tsami et al. 2006; Desikusumastuti et al. 2008) suggests that this type of material can also assist conventional stabilizer (diphenyl amine, centralite, etc.) for energetic formulations based on nitrate esters. In agreement with the above observations and what has been published previously (Krabbendam-La Haye et al. 2003; Trache and Tarchoun 2018), Fig. 1 displays the possible stabilizing mechanism of nitrocellulose by barium oxide (BaO), which may effectively interacts with the breakdown products (NOx) of nitrocellulose. Bonding configurations show that nitrogen dioxide may be adsorbate on oxygen sites and metal centers of BaO (Broqvist et al. 2002; Schmitz and Baird 2002; Desikusumastuti et al. 2008). The autocatalytic process may be inhibited and the NC's useful life can be prolonged by using a metal oxide, which may also have a good effect on free radical scavenging activity. Metal oxide may have an effect on NC's chemical stability, but to our knowledge, no study has examined this.
Thus, the purpose of this study is to determine the dual influence of barium oxide NPs on the thermal degradation reaction kinetics and chemical stability of nitrocellulose. To create the NC-based composite, synthetised barium oxide (BaO) nanoparticles by the precipitation method were mixed with nitrocellulose (NC). Differential scanning calorimetry (DSC) coupled with different isoconversional kinetic approaches, namely iterative Kissinger-Akahira-Sunose (It-KAS), iterative Flynn-Wall-Ozawa (It-FWO), and Vyazovkin's nonlinear integral with compensation effect (VYA/CE), were used to investigate the thermal decomposition kinetics of the NC-based composite (Touidjine et al. 2021a, b, 2022; Akbi et al. 2022; LOUAFI et al. 2022). The impact of BaO NPs on the chemical stability of NC was investigated using both qualitative (methyl violet and Abel tests) and quantitative (Bergmann-Junk test (BJ) and Vacuum Stability Test (VST) tests. Stability tests based on microcalorimetric measurement (HFC) were also performed.