Breakthrough in safe and circular performance materials

The Netherlands and Europe are aiming for a 100% circular society, but this is not always possible. For example, how does one recycle paint that is chipping off a garden gate, or the ingredients of a detergent after the laundry is done? This requires materials that were designed to be recycled: they should be circular by design, safe by design, preferably made from biobased resources and should degrade if they end up in nature.

Wageningen University & Research and the University of York have made a breakthrough in the research into such materials within the European CHAMPION project. The scientists from Wageningen and York worked together with Circa Sustainable Chemicals and AVA Biochem on developing bio-based chemical building blocks and polymer materials while focusing both on the materials’ performance as well as on closing the cycle and the end of their useful life.

“Within CHAMPION, we are developing a reversible chemistry”, says Daan van Es, research associate and project leader at Wageningen Food & Biobased Research. “At the same time, we aim to get rid of the toxic components that are usually used in demanding applications, such as isocyanates and epoxy in resins, coatings and glues.”

Mild chemistry

To make this possible, the scientists are using mild (“click”) chemistry, without applying any aggressive chemicals, high pressures or high temperatures. “We are applying what are called aza-Michael reactions. In short, we are using amines, a specific class of nitrogen containing chemicals. These react under mild conditions, from room temperature to just above 100 degrees Celsius. Using these chemicals, we can produce materials that are sufficiently strong for the duration of their useful life and not persistent thereafter. At the end of their useful life, they can be broken down again. They are also biodegradable. If they end up in the environment, they will easily decompose instead of accumulate.”

Designing materials that have all these properties and are durable proved to be challenging. Rolf Blaauw, research associate at Wageningen Food & Biobased Research: “Until recently, the results were soft, sticky and rubbery. However, our industrial partners require hard and tough materials, for applications such as office furniture lacquers or adhesives for wind turbine blades, for example. By adjusting the ingredients of the formulation, we managed to create a condensed three-dimensional network of polymers. The tighter the network is, the harder and tougher the materials become. This means that our toolbox has become more flexible, and we can more easily meet the demands from industry.”

Materials transition

To facilitate a running start of the research, some of the chemical building blocks currently used within CHAMPION are commercially available. For the time being, they are fossil-based. However, the scientists are also hard at work on developing renewable, biobased alternatives with comparable chemical properties. Daan van Es: “In the medium term, we will be able to produce materials that are partially renewable. This will allow industry to actually start producing them within two to five years. Our vision for the longer term is for all materials to become fully renewable.”