Circular Design of Coatings and Composites

Circular solutions for complex products

The chemical industry has committed to the ambition of making its products fully circular in the years to come. This certainly brings challenges where coatings and composites are concerned. These complex products are optimised for superior barrier and/or structural performance. They need to be mechanically strong and withstand long-term environmental influences such as moisture, sunlight and varying temperatures. To achieve these high-performance properties, they are engineered for strong bonding to a substrate or reinforcing filler. As a result of this design, both coatings and composites are difficult to repair, reuse or recycle after their functional use. This is especially the case for petrochemical-based products, many of which are made on the basis of persistent carbon bonds. Wageningen Food & Biobased Research is working on concrete solutions to meet these challenges.

Circularity without compromise

Wageningen Food & Biobased Research has extensive experience in the development of biobased performance materials and the biodegradability of chemicals. Within the research themeCircular design of coatings and composites, we are specifically working on the development of biobased technologies that enable a circular end-of-life scenario, without compromising the performance of these products. Think of new biobased resins with reversible bonds or enabling chemical or enzymatic hydrolysis. This could improve chemical recyclability and/or biodegradability. UV-sensitive components that improve the biodegradability of products are also being studied. Furthermore, biobased alternatives often deliver new unexplored functionalities such as a reduced accumulation in nature and improved visual and haptic characteristics. Our vision is to make all materials fully renewable and biodegradable, closing the loop at the end of their lifecycle.

Mild and reversible chemistry

In several projects, Wageningen Food & Biobased Research is developing safe and circular alternatives for coatings and composites:

• In the European project ESTELLA (2021-2024) we are developing bio-based composite resins that have thermo-reversible chemical bonds. This means that the materials can be repaired and reprocessed by heating, thereby significantly improving the circularity of the products.
• In the European CHAMPION project (2020-2024) we are working with industry on biobased coatings, adhesives and household products. They are based on mild and reversible chemistry, using amines, a specific class of nitrogen-containing chemicals. With these, materials can be made that are sufficiently strong for their lifetime, but not persistent afterwards. At the end of their lifetime, they can be taken apart again. Moreover, they are biodegradable.
• Together with Nemho-Trespa we developed a resin system in which 50% of the toxic phenol was replaced with lignin, a renewable and environmentally benign aromatic polymer. A substantial reduction in the process’ ecological footprint was achieved without negative performance impact of the resulting materials. Currently, we are striving for full phenol replacement. In the TKI More Reactive Lignin project, we aim to mildly extract and fractionate lignin to make it more amenable for higher-value applications such as resins.