Two series of rigid polyurethane-polyisocyanurate foams (RPU/PIR) modified by cinnamon extract (series C_0t and CU_0t) were obtained. One RPU/PIR series contained a commercial flame retardant (C_0t) in the formulation. The other was produced without its participation (CU_0t). The basic properties of obtained foams, e.g., apparent density, brittleness, water absorption, compressive strength, flammability were examined. Afterwards, both series of foams (C_0t and CU_0t) were subjected to degradation in the climatic chamber, acting on samples of foams a defined temperature, humidity and UV radiation for a seven days. In this way, two successive series of RPU/PIR foams were obtained, which were designated, respectively, C_1t and CU_1t, Chosen properties of degraded foams such as: compressive strength, cellular structure by scanning electron microscopy (SEM) and changes of chemical structure by FTIR spectroscopy were determined. Compressive strength and the aging resistance was also determined (against the coefficient of compressive strength variation (CV). The possible replacement of a commercial flame retardant in polyurethane formulations by the antioxidant raw material (cinnamon extract) was evaluated.

Four types of rigid polyurethane-polyisocyanurate foams (RPU/PIR) were obtained. Three of them were modified by powder fillers, such as cinnamon extract (C10 foam), green coffe extract (KZ10), and cocoa extract (EK10) in an amount of 10 wt %. The last foam was obtained without a filler (W foam). The basic properties and thermal properties of obtained foams were examined. All foams were subjected to degradation in the climatic chamber acting on samples of foams in a defined temperature, humidity, and UV radiation for 7, 14, and 21 days. The physico-mechanical properties of foams were tested. The compressive strength of degraded foams after 7, 14, and 21 days was compared with the compressive strength of nondegraded foams (0 days). The chosen properties of degraded foams, such as cellular structure by scanning electron microscopy (SEM) and changes of chemical structure by FTIR spectroscopy were compared. The obtained foams were also subjected to degradation in a circulating air dryer in an increased temperature (120 °C) for 48 h. Additionally, W, C10, ZK10, EK10 foams were placed in a soil environment and subjected to 28 days biodegradation process. The biochemical oxygen demand (BOD), the theoretical oxygen demand (TOD), and the degree of biodegradation (D_t) of foams were determined in this measurment. Test results showed that the compressive strength of foams decreased with the longer time of foam degradation in the conditioner. The foam subjected to degradation darkened and became more red and yellow in color. The addition of natural compounds of plant origin to foams increased their susceptibility to biodegradation.

Waste of foam containing tri( N, N ′-dimethyleneoxy-3-hydroxypropyl)urea as a polyol was subjected to glycolysis process. After glycolysis, a liquid tea-coloured product, with high viscosity of 17,040 mPa·S, density of 1529 kg/m³, water content of 0.4% and boron and nitrogen content of about 14%, was obtained. New rigid polyurethane–polyisocyanurate foams containing glycolysis product of foam waste with reduced flammability were obtained. It was used as a polyol raw material, simultaneously fulfilling the role of flame retardant in the new foams.