## 3 Results and Discussion
### RPU/PIR Foam Structure  
Foam structure was analyzed by using SEM. The density of foams affected on the thickness of the cell walls (and thus the strength of the foams) [50; 51]. The structure of foams with cells smaller than 0.25 mm in diameter is referred to as small cells [42]. Cells with a diameter above 0.5 mm are referred to as large. The small-cell structure gives porous materials more favorable mechanical strength. In flexible foams, a decrease in the diameter of the foam cells was observed after the addition of flame retardant halogen-free organophosphorus compound (Fyrol PNX) [52]. The addition of cinnamon extract caused a slight decrease in density of these foams (Table 8). This could affect the opening of modified foam cells. A specialized program for measuring cells in the SEM method allowed the measurement of foam cell width and length. Based on the width and height of the cells, the anisotropy coefficient was calculated according to Equation (13). \[Anisotropy\;coef\;ficient=\frac{height\;cells}{width\;cells} \tag{13}\]  
The anisotropy factor \(>\) 1 means the elongation of cells in the vertical direction. The highest strength parameters are characterized by foams with anisotropy coefficient equal to 1 (not elongated neither vertically nor horizontally) [27]. The anisotropy of analyzed foams was about 1. The cell walls were destroyed during conditioning (Figure 5b,d,f) (under given conditions) and additional holes were formed. In the SEM study, these additional holes were interpreted and measured by the program as cells (and not as holes created as a result of wall destruction). On a given surface (in \begin{table}
\begin{tabular}{l c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Peak P1**} & \multicolumn{3}{c}{**Peak P2**} & \multicolumn{3}{c}{**Peak P3**} \\ \cline{2-13}
**Foam** & **T\({}_{\text{mact}}\)** & **T\({}_{\text{KL}}\)** & **H\({}_{1}\)** & **T\({}_{\text{mact}}\)** & **T\({}_{\text{m2}}\)** & **T\({}_{\text{KL}}\)** & **H\({}_{2}\)** & **T\({}_{\text{onset}}\)** & **T\({}_{\text{m3}}\)** & **T\({}_{\text{k3}}\)** & **H\({}_{3}\)** \\  & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)D/g)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** \\ \hline WU\_0t s & 29.6 & 78.1 & 129.6 & 33.1 & 227.8 & 325.6 & 354.0 & 76.6 & 354.0 & 374.7 & 391.6 & 5.71 \\ CU1\_0t & 47.6 & 81.2 & 121.8 & 14.2 & 213.5 & 261.3 & 322.0 & 93.7 & 327.9 & 356.7 & 392.3 & 37.1 \\ CU5\_0t & 37.1 & 82.5 & 129.6 & 27.4 & 219.3 & 279.6 & 315.3 & 136.7 & 315.3 & 348.7 & 394.2 & 46.1 \\ CU15\_0t & 35.6 & 84.1 & 138.0 & 55.0 & 221.3 & 282.3 & 320.0 & 116.0 & 307.1 & 336.2 & 395.1 & 10.1 \\ WU\_1t & 54.7 & 91.1 & 179.8 & 41.6 & 271.5 & 289.0 & 314.4 & 19.0 & 318.2 & 323.6 & 342.2 & 4.4 \\ CU1\_1t & 37.8 & 82.8 & 136.1 & 49.6 & 221.3 & 308.1 & 326.9 & 147.6 & 326.9 & 352.0 & 391.6 & 36.8 \\ CU5\_1t & 35.6 & 84.1 & 141.4 & 54.9 & 218.6 & 287.3 & 320.0 & 146.0 & 320.0 & 346.3 & 386.2 & 20.6 \\ CU15\_1t & 38.3 & 91.0 & 150.9 & 82.9 & 279.9 & 325.2 & 355.8 & 49.2 & 354.7 & 368.7 & 390.5 & 4.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Values of thermal transformations of foams series CU (without flame retardant) by using the DSC. 0t—foams before degradation, 1t—foams after one week degradation. this case 1 mm\({}^{2}\)) additional holes were interpreted as a smaller cells (not as a real cells). In fact, the results in Table 12 relate to measurements of holes created after destruction and not measurements of real cells. Measurements proved that foams conditioning (series 1t) were destroyed (the thinnest fragments of the walls were broken); see Figure 5b,d,f). Based on results in Table 12, it was read that cinnamon extract increased the destruction of foams. It was evidenced by the increased number of holes per 1 mm\({}^{2}\) of surface.