## 3 Results and Discussion
### Organoleptic Assessment of RPUP/PIR Foams  
An organoleptic analysis was performed comparing the appearance of non-degraded foams (series 0t on photographs in Figure 2a) with foams aged in a dryer at 120 \({}^{\circ}\)C for 48 h (C and CU, WU and WU series 48h on photographs in Figure 2b) and with foams degraded in the climatic chamber (1t series in Figure 3). The external appearance of the foams and the possible color change were compared. It was determined whether the surface of the foams are crumble or not. Foams after thermostating in the dryer had a slight change in their color (foams in Figure 2b) in relation to the non-thermostated foams (Figure 2a). Aging at temperature (120 \({}^{\circ}\)C) caused a light yellow foams color (Figure 2b). Their roughness also increased.  
Figure 2: Photography of foam series: (**a**) C_0t and CU_0t not degraded; and (**b**) C_48h and CU_48h aged in a hot air dryer (48 h, 120 \({}^{\circ}\)C).  
The surface color of foams, which were irradiated by UV rays in the climate chamber, was changed from light yellow to orange (series C_1t on Figure 3. After that, the surface was exposed to UV radiation, humidity, and temperature. The surface of C_1t and W_1t foams became brittle after degradation than the surface of CU_1t and WU_1t foams. The following dependence was observed: CU_0t foams not contained the flame retardant (FR) were more brittle than the C_0t foams that contained FR. Degradation caused the opposite effect. Crumbling of the surface of a series of foams (CU_1t, without flame retardant after one week of degradation) slightly increased. Surface of C_1t foams subjected to one week of degradation was much more destroyed than the surface of foams from before degradation (C_0t). Based on the organoleptic assessment, it could be assumed that the removal of flame retardant from cinnamon-based foams should improve the strength of the bonds responsible for reducing the crumbling of CU_1t foams in relation to the C_1t series subjected to aging in the climatic chamber. The color change can be caused by thermal-oxidation degradation of the foams surface, hence, the color change in the case of thermostating (foams on Figure 3).  
[PERSON] [29] reports that PU obtained from aromatic MDI turn yellow under the influence of light. Colorful quinonoimide groups are formed on its surface. Yellowing does not affect the strength properties, it only decreases the properties of coatings.  
A different color (yellow, orange) was observed on the surface of conditioned foams (Figure 3) depending on whether the foam contained a flame retardant (yellow) or not (orange). This dependence was already observed in reference foams (W_1t and WU_1t) even before the addition of cinnamon extract. Soft segments of the foams, which are aliphatic polyethers and aliphatic polyesters, are more susceptible to oxidation and affect discoloration (change of color) [12]. Aromatic amines are produced in the reaction of the isocyanate with water. They are easily oxidized to chromophores could make to contribution towards change of color of foams. The changed color on the surface of C_0t series can be caused by presence of phosphate flame retardant. These compounds can decompose giving hydrogen halide.