CHEMICAL RECYCLING OF POLYURETHANE WASTE VIA SPLIT- PHASE GLYCOLYSIS

Abstract

This study explores the chemical recycling of polyurethane waste via split-phase glycolysis, using glycerine as the glycolysing agent and sodium hydroxide (NaOH) as catalyst. Polyurethane widely used in foams, furniture, mattresses and coatings. It is resistant to natural degradation and contributes significantly to environmental pollution through traditional disposal methods like landfilling and incineration. To overcome this issue, glycolysis was performed at a temperature range of 170°C to 190°C, resulting in a clear phase separation of the degraded product into three distinct layers. The top layer was a light-yellow viscous liquid rich in polyol, the middle layer was semi-solid containing partially degraded fragments and the bottom layer consisted of excess glycerine. The top polyol-rich layer was further characterized using FTIR and NMR spectroscopy. FTIR results confirmed the breakdown of urethane bonds with the appearance of hydroxyl functional group, while NMR spectra revealed proton signal typical of polyol structures, validating the successful recovery of reusable polyol. These recovered polyols have potential to be blended with virgin materials and repurposed into new polyurethane products, thus promoting material circularity. The use of glycerine, a biodegradable and non-toxic glycol, along with the cost-effective catalyst like NaOH, ensures the process remains economically and environmentally sustainable. This method is simple, efficient and suitable for adoption in both academic and industrial settings, offering a promising solution to polyurethane waste management while aligning with the principles of green chemistry and circular economy.