Glycolysis Recycling of Waste Polyurethane Rigid Foam Using Different Catalysts

Dramatically increasing waste polyurethane rigid foam (WPRF) draws the attention of the world. A mixture of ethylene glycol (EG) and diethylene glycol (DEG) is used as glycolysis agents. WPRF was subjected to alcoholysis using different catalysts which are titanium ethylene glycol and potassium hydroxide to obtain recycled polyol, respectively. The effect of a different catalyst on the viscosity and hydroxyl value of recycled polyol is discussed. The regenerated polyurethane (RPU) is performed using the recycled polyol. Infrared spectrum, compressive strength, apparent density, water absorption, scanning electron microscope, and thermogravimetric analysis are carried out to investigate the effect of WPRF degradation using different catalysts. The results show that titanium glycol is more efficient than potassium hydroxide in almost all conditions. The viscosity of the recycled polyol is relatively low, and the hydroxyl value meets the requirements of industrial use. When the titanium glycol titanium addition amount is 0.05%, the prepared RPU has a compressive strength of 0.24 MPa, an apparent density of 41.75 kg/m³, and a good foam structure. Besides, the water absorption rate of the RPU under the two catalytic systems is not much different, and the thermal stability is good. The recycled polyol can generally partially replace traditional polyols to prepare polyurethane rigid foams with good comprehensive properties.