Researchers at Aarhus University have developed a novel method to recycle polyurethane foam from products like mattresses, offering a more sustainable approach for the industry. Polyurethane (PUR) is a versatile material used in a wide range of applications, but its disposal poses environmental challenges as most products end up in landfills or are incinerated. With the global market for PUR expanding, there is a growing interest in chemically recovering its main components, polyol and isocyanate, in order to create new products more cost-effectively.
The research team has devised a process that involves breaking down PUR foam using acidolysis and separating the resulting polyol and isocyanate components in one step. By heating the foam with succinic acid and filtering the mixture, they are able to recover up to 82% of the original material as two distinct fractions. This innovation represents a significant advancement in the recycling of PUR foam, particularly for manufacturers who use it as a raw material in their production processes. The recovered materials can be used in the production of new polyurethane products, offering a viable alternative to virgin materials.
While the method shows promise for scaling up and increasing the recycling of PUR foam waste from industrial processes, challenges remain for consumer waste recovery. Manufacturers in the PUR industry use different formulations to achieve specific material properties, complicating the recycling process. Waste sorting, logistics, and categorizing PUR materials according to type are key obstacles to achieving a more sustainable circular economy for polyurethane. As such, depolymerization is just one piece of the puzzle, and further development is needed to address these challenges.
In addition to recycling flexible PUR foam used in mattresses, the researchers have also successfully tested the method on regenerated and rigid PUR foam, demonstrating its potential for a wider range of polyurethane products. The recycling process has shown promising results in recovering valuable raw materials from polyurethane products, including diamines and polyols. Ongoing research is focused on testing the technology on other types of polyurethane materials and exploring opportunities to reuse dicarboxylic acid, which is part of the process.
A key feature of the research is the use of succinic acid, a natural antioxidant with various industrial applications, as a catalyst for breaking down polyurethane. By utilizing this eco-friendly acid, the researchers have developed a more sustainable approach to recycling PUR foam, reducing the reliance on fossil oil-based materials. The ability to extract high-quality polyol components from PUR foam using this method has significant implications for the industry, offering a more efficient and environmentally friendly solution for processing waste materials. As efforts continue to refine the technology and address logistical challenges, the potential for a circular economy in polyurethane recycling is within reach.