Researchers Develop a Bio-Based and Recyclable Alternative to Conventional Polyurethane Foams

How can a foam material be made from bio-based raw materials without using harmful chemicals, while also ensuring that it can be fully recycled? An international research team, including Miķelis Kirpluks, Leading Researcher at the Polymer Laboratory of the Latvian State Institute of Wood Chemistry (LSIWC), has successfully addressed this challenge. The findings, which open up new possibilities for more sustainable furniture and construction industries, have been published in the internationally recognised scientific journal Advanced Functional Materials.

The Challenge with Conventional Polyurethane

Polyurethane foam is found in a wide range of everyday products – from mattresses, upholstered furniture and car seats to building insulation and refrigerators. Although durable, conventional polyurethane foams are produced using isocyanates – toxic compounds that can pose risks to human health. Furthermore, the chemical structure of polyurethane makes end-of-life recycling extremely difficult, meaning that old mattresses and insulation panels often end up in landfills.

An Innovation Based on Vegetable Oils

The research team has developed a new type of foam material – vinylogous urethane foams – based on vegetable oils and produced without the need for hazardous isocyanates.

One of the key achievements of the study is the efficiency of the production process: the foam material can be produced in approximately 60 seconds under relatively mild conditions, ranging from room temperature to 60°C.

The material's properties can be readily tailored during production. By changing the composition of the raw materials, the researchers can produce anything from very soft, flexible foams suitable for comfort mattresses to rigid, hard materials suitable for load-bearing building insulation. Despite being based on vegetable oils, the new material retains the low density characteristic of commercial foams, with a density of just 60–70 kg/m³.

Dynamic Chemical Bonds Enable Recycling

Unlike conventional polyurethane foams, which cannot simply be melted down and reused, the new material incorporates dynamic chemical bonds – a characteristic of materials known as vitrimers. This means that, when exposed to heat and pressure, the material's internal molecular bonds can temporarily break and rearrange.

In laboratory experiments, the researchers demonstrated that ground foam can be hot-pressed into a new, durable, plastic-like film without adding any additional chemicals or catalysts. This opens up the possibility of transforming used foam materials into entirely different, useful products at the end of their service life.

The Next Step – Industrial Production

So far, the material's properties and recycling potential have been demonstrated under laboratory conditions. However, the proposed approach is compatible with existing polyurethane foam production lines, which could significantly facilitate further development and potential industrial implementation of the technology.

The research team includes scientists from the Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Charles University in Prague, and the Latvian State Institute of Wood Chemistry.

Read the full scientific publication in Advanced Functional Materials:

https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.78270

Photo: Institute of Macromolecular Chemistry, Czech Academy of Sciences