Polyurethane foams are notoriously difficult to recycle and end up in landfills or in lower value products, such as synthetic carpets. Source: Northwestern UniversityA team from Northwestern University and the University of Minnesota has devised a new technique for repurposing polyurethane foams, which are typically difficult to recycle.

To repurpose polyurethane foams, which typically cannot be melted and recycled due to chemical bonds that won’t melt, researchers mixed post-consumer polyurethane foam waste from products such as mattresses, insulation, shoes and cushions with a catalyst solution.

Once mixed with the catalyst solution, the material became pliable and a “twin-screw” extrusion process was applied wherein two intermeshing, co-rotating screws simultaneously mixed and remolded the foam, eliminating air within the foam.

The end result is a new foam material that can be shaped into new products such as high quality rubbers, hard plastic shoe cushioning components, watch wristbands, automobile bumpers, and shopping cart or skateboard wheels, for instance.

The article "Reprocessing Postconsumer Polyurethane Foam Using Carbamate Exchange Catalysis and Twin-Screw Extrusion" appears in the journal ACS Central Science.