## 4 Results and Discussions  
DTA measurements (Figure 3) allowed us to determine which of the compositions were more sensitive to temperature. PC1 presented the lowest self-ignition temperature at 329 \({}^{\circ}\)C, while a self-ignition temperature of 363 \({}^{\circ}\)C was determined for PC2 and 381 \({}^{\circ}\)C for PC3. Thus, the powder form of the composition with the lowest self-ignition temperature (PC1) was chosen because the most sensitive component was required to ignite the mixture faster and maintain the smoke in the first period after the device was launched, whereas tablets were shaped from the other two compositions. However, the self-ignition temperatures were relatively high, and they were raised when the mixture was pressed into a tablet shape, so the final smoke charge capsules required an initiation mixture to burn. Every sample had an endothermic transformation observed at 129 \({}^{\circ}\)C that was associated with KNO\({}_{3}\) crystal structure transformation [26]. Additionally, the melting point of paraffin was observed in PC2 and PC3 compositions between 50-60 \({}^{\circ}\)C [27]. Following the combustion of the composition, samples were examined with SEM/EDS to characterize the reaction products and visualize the morphology of the reaction products. According to SEM analyses, the resulting solid was distributed as conglomerations of two types of particles with random arrangement, irregular shapes, and dimensions ranging from 10-100 um. Some regions of the analyzed materials comprise phosphorus, magnesium, potassium, oxygen, and barium (Figure 4a\") and have a porous form (Figure 4a), while some  
Figure 3: DTA thermogram of the smoke compositions. particles contain only phosphorus, carbon and oxygen (Figure 4b\"). All the resulting materials possess cracks in their structure (Figure 4a',b'). The samples taken from the bottom of the enclosed testing chamber were mostly porous particles, and the EDS elemental concentration profiles show that they mostly contain Mg and Ba, which were found in the ignition composition of the SGD (Figure S7 from Supplementary Materials). The samples taken from the chamber walls, on the other hand, show that the phosphorus was uniformly distributed throughout the enclosed smoke chamber volume and mostly formed spherical particles. The presence of phosphorus, barium, and oxygen as basic products of dispersed smoke was confirmed by EDS line profile measurements (Figure S8 from Supplementary Materials). The proportion of binder has no discernible effect on the thermodynamic properties of the mixture. The difference between compositions is a result of the quantity of oxidant used rather than the amount of red phosphorus. Compositions with a high phosphorus ratio, 35-50% (PC2 and PC3), provide a high percentage of gases, whereas compositions with a high oxidant ratio, up to 70%, provide a high combustion heat. The determined heat of combustion and specific volume was: PC1--1165.9 kcal/kg and 209.9 L/kg, PC2--492.3 kcal/kg and 314.1 L/kg and PC3--647.7 kcal/kg and 343.3 L/kg. However, PC3, which contains 50% RP, has a low combustion temperature compared to the other samples. The high RP content also influences the combustion rate, which has  
Figure 4: SEM images of resulting solid particle and the corresponding EDS spectra: (**a**)—porous shape of phosphorus and barium particle; (**a**)—submicron cracks in the phosphorus and barium particle; (**b**)—spherical form of phosphorus and oxygen particle; (**b**)—submicron cracks in the phosphorus and oxygen particle; (**a**)—Phosphorus and barium particle; (**b**)—Phosphorus and barium particle; (**b**)—Phosphorus and barium particle. the lowest value of 0.33 mm/s (Table 2), but offers a long combustion time and continuous smoke emission, up to 10 s. It was observed that increasing the proportion of potassium nitrate increases the combustion rate and temperature while decreasing the smoking time.