## 2 Review of Influence of Sensitizers on Detonation Properties of Emulsion Explosives
### Chemical Density Reduction
Starting from the obtained magnitudes of maximum overpressures, the authors of papers [18,19,20] estimated the degree of desensitization (S\({}_{\text{d}}\)) (Table 4) of loaded EEs based on Equation (6):  
\[S_{d}=(P_{0}-P_{1})/(P_{0}-P_{\text{d}}) \tag{6}\]  
where \(P_{0}\)--peak overpressure of unloaded EE, \(P_{1}\)--peak overpressure of loaded EE, and \(P_{\text{d}}\)--peak overpressure of the booster. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{5}{c}{**Sensitizer**} \\ \cline{2-5}  & **GMs** & **NaNO\({}_{\text{2}}\)** & **MgH\({}_{\text{2}}\)** & \\ \hline
**Component** & \multicolumn{5}{c}{**[wt.\%]**} \\ \hline Matrix & 96.0 & 99.8 & 98.0 & 99.0 \\ GMs & 4.0 & - & - & - \\ NaNO\({}_{\text{2}}\) & - & 0.2 & - & - \\ MgH\({}_{\text{2}}\) & - & - & 2.0 & 1.0 \\ \hline Distance [mm] & \multicolumn{5}{c}{**Sensitization degree [\%]**} \\ \hline
25 & 100 & 88.12 & 38.97 & 38.97 \\
40 & 86.41 & 84.47 & 18.89 & 18.89 \\
50 & 79.82 & 71.63 & 12.11 & 12.11 \\
60 & 73.67 & 53.47 & 10.45 & 10.45 \\
75 & 63.34 & 15.59 & 11.76 & 11.76 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Compositions and degrees of desensitization of EEs sensitized with various additives [13,14,15,16,17]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{5}{c}{**Sensitizer**} \\ \cline{2-5}
**Component** & **GMs** & **GMs/Al** & **MgH\({}_{\text{2}}\)** & **NaNO\({}_{\text{2}}\)** \\ \cline{2-5}  & \multicolumn{5}{c}{**[wt.\%]**} \\ \hline Matrix & 96.0 & 92.0 & 98.0 & 99.8 \\ GMs & 4.0 & 4.0 & - & - \\ Aluminum dust & - & 4.0 & - & - \\ MgH\({}_{\text{2}}\) & - & - & 2 & - \\ NaNO\({}_{\text{2}}\) & - & - & - & 0.2 \\ \hline Parameter & & & & \\ \hline Density [g/cm\({}^{3}\)] & 1.21 & 1.24 & 1.29 & 1.24 \\ Underwater test & 10.89 & 10.72 & 13.12 & - \\ maximum overpressure [MPa] & & & & \\ Energy [k]/kg] & 2871 & 3187 & 3762 & - \\ Detonation energy [k]/kg] & & & & \\ Theoretical & 3297 & 3684 & 3530 & 3297 \\ Experimental & 2728 & 3028 & 3574 & 2835 \\ Detonation velocity [m/s] & 4434 & 4389 & 5552 & - \\ Brisance [mm] & 16.1 & 16.2 & 19.1 & 16.85 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: EE compositions and parameters [13]. The data summarized in Table 3 clearly demonstrate that EEs sensitized with MgH\({}_{2}\) exhibit the highest energy parameters. This result is attributed to the contribution of hydrogen, generated during the decomposition of MgH\({}_{2}\), to high-energy reactions within the detonation wave zone. Additionally, when assessing the degree of desensitization of EEs with different sensitizers, [PERSON] et al. [13; 14; 15; 16; 17] (Table 4) observed that EEs containing MgH\({}_{2}\) displayed the highest resistance to non-initiation shock waves. However, it is puzzling that the authors of studies [13; 14; 15; 16; 17] reported identical desensitization values for EEs despite using two different MgH\({}_{2}\) contents. Based on the observed relationship between the degree of desensitization and the type of EE, [PERSON] et al. [13; 14; 15; 16; 17] concluded that the process affecting the value of this parameter is not the phenomenon of matrix demulsification. Instead, it is attributed to changes occurring in the \"hot spots\" formed by individual sensitizers. Under the influence of the shock wave, some of the GMs are crushed and lose their sensitizing properties. In contrast, in the case of MgH\({}_{2}\), the hydrogen bubbles are flexible and can return to their original form when squeezed. The authors also believed that when added to the matrix, only part of the MgH\({}_{2}\) reacts. The remaining MgH\({}_{2}\) can react only as a result of exposure to a strong shock wave (temperature increase), in which case, we would be dealing with so-called \"dynamic sensitization\". The gasification method is now increasingly used in the production of EEs, due to the cumbersome handling of either glass or polymer microspheres and their high prices.