Efficient Degradation and Optimization of Waste Polyisocyanurate by La-Ni Perovskite Catalysts

Polyisocyanurate (PIR) foams cannot be processed quickly and efficiently due to their thermophysical properties. To address this challenge, this work investigates the alcoholysis degradation process of waste PIR foams, aiming at the high-value utilization of resources. With respect to the chemical recovery method of polyurethane, the effects of catalyst type, dosage, and ratio on the effect of alcoholysis were investigated. The results showed that the performance of the resulting recycled PIR tubular shells was superior to that of commercially available products when an alcoholysis agent with a butylene glycol to diethylene glycol ratio of 43:57 was used. The mixture was reacted at 180 °C for 2 h, and a combination of 0.100% LaNiO₃ and 0.200% NaOH catalysts was used. The lowest viscosity of degradation product obtained under this scheme was 2201.6 mPa·s, and the thermal conductivity of the regenerated PIR foam was 0.025 W/(m·K) with a compression strength of 239 kPa. This study provides an efficient and feasible process route for the resource utilization of used PIR foams.