TAGS: Environmentally Friendly Coatings
Chemists from the University of Groningen, together with colleagues from AkzoNobel have developed a new process to convert biomass into a high-quality coating.
The process works with only visible light, oxygen and UV light and combines renewable raw materials with green chemistry. This approach can eventually replace raw materials from petroleum, such as acrylic, with sustainable building blocks to produce coatings, resins and paint.
Using Lignocellulose as a Basis
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You can crack lignocellulose with acid into the chemical building block furfural, but you then have to adjust that to make coatings with it," says Hermens, PhD candidate in Feringa's group. He used a process developed by the Groningen group in recent decades to convert furfural into a compound called hydroxybutenolide, which resembles acrylate.
Only light, oxygen and a simple catalyst are needed for the chemical conversion. There is also no waste. The only by-product is methyl formate, which in turn is useful as a replacement for chlorofluorocarbon, the CFCs, in other processes.
Part of the structure of the hydroxybutenolide is very similar to acrylate, but because the part of the hydroxybutenolide molecule that is highly reactive is contained in a ring structure, it is less reactive than acrylate. So, the challenge was to further adapt the molecule to make usable polymers. This was done by linking various green alcohols or alcohols made from bio-raw materials to the hydroxybutenolide. This resulted in four so-called alkoxybutenolide monomers.
Coatings Tailored to Different Applications
These monomers are relatively easy to convert into polymers and coatings with the aid of a starter compound and UV light. Coatings consist of cross-linked networks of polymer chains. By combining different monomers, they were able to create such networks with different properties.
For example, all coatings adhered to glass, but only a combination did so on plastic. And by using stiffer monomers, a harder coating was created, with properties similar to those used on cars. In this way, the coatings can be tailored to different applications.
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We have succeeded in making coatings from a sustainable raw material, lignocellulose, via green chemistry,” Hermens concludes. 'And the quality is comparable to existing acrylate-based coatings.' AkzoNobel has applied for a patent for two different steps in the process. Hermens is now working on the production of another building block, derived from furfural, to make other types of coatings.
The program comprises all steps from fundamental scientific discoveries to the development of industrial processes and products. It is a long-term collaboration, in which universities and the chemical industry work together on the green chemistry of the future.
Source: University of Groningen