The Effect of UV Radiation on the Properties of Rigid PUR-PIR Foam

Rigid polyurethane-polyisocyanurate (PUR-PIR) foams modified with tris(5-hydroxypentyl)-2-hydroxypropane-1,2,3-tricarboxylate (THHT) were synthesized. Selected foams were subjected to degradation in an aging oven for 168, 346, and 504 h, respectively. These foams have been exposed to UV radiation. FTIR analysis, TGA, and DSC of the foams were conducted (after radiation and before). Properties of foams radiated with UV rays were compared with the original not radiated foams. The results showed that the degradation time has an effect on the intensity of ranges of bonds related to isocyanurate and hydroxyl bonds. In SEM pictures, the differences in structures between degraded and not degraded foams are clearly visible. The examination with the SEM method showed the disappearance of the heat effect connected to the isocyanurate bond. The degradation time does not affect the anisotropy coefficient of the foams. Foam thermal stability is mostly dependent on the degradation time and in lesser degree on the amount of THHT used.