The NCO cycle : a two-step complete recycling process for polyurethanes

This thesis investigates new ways to chemically recycle polyurethane (PU), with special attention to the isocyanate-based part of the material, which is often overlooked. While most recycling research focuses on recovering polyols, this work shows that the isocyanate fraction can also be reused effectively in a circular production process. An improved alcoholysis method was developed to break down PU into carbamates while preventing the formation of unwanted amines. These carbamates were then converted back into valuable isocyanates through thermolysis. The study also explored process optimization and an alternative application as glue for the mechanical recycling of PU. Overall, the work demonstrates a practical and flexible pathway toward more sustainable and circular PU recycling.