TAGS: Sustainability / Natural Coatings Wood Coatings
Researchers are developing bio-based fire-retardant paints based on nanocellulose of the Canary Islands pine to protect wood indoors and outdoors.
Weather-resistant FR Coating
The architecture and chemical composition of the bark of the Canary Islands pine are the inspiration for the development of a weather-resistant fire protection coating.
In the development of a bio-based fire-retardant coating for wooden buildings, nature should now be the inspiration. Under the direction of the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut (WKI), researchers want to develop a wood fire protection coating based on microfibrillated cellulose (MFC) together with partners from Finland and Norway.
The FireCellCoat project is funded by the Federal Ministry of Education and Research from 2020 to 2022 with 450,000 euros as part of the “Bioeconomy in the North” funding measure.
Canary Pine Bark as a Model
The architecture and chemical composition of the bark of the Canary Island pine serve as a model here. Project manager Claudia Schirp explains, “
The pine burns, but lives on after the fire because it has such an impressive bark that can withstand the fire. This bark has a special structure: it is relatively thick and has ingredients that make it resistant to fire.”
According to Schirp, the special feature of the pine bark structure is its multilayered structure. The researchers want to imitate this macroscale multilayer structure and wood coatings based on MFC - those made of cellulose, a main component of wood. The aim of the bio-inspired paints is to improve the fire protection effect of wooden structures.
New Protective Coatings Based on Nanocellulose
Researchers from the VTT Technical Research Center of Finland will build this multi-layer structure as part of the project and modify the MFC using a novel enzymatic process so that the fire-retardant effect in the paint is improved. Like the annual rings of a tree, according to Schirp, layers of microfibrillated cellulose and inorganic material are layered on top of each other.
This new type of nanocellulose is in turn the basis for the work of the Fraunhofer WKI team around Claudia Schirp, whose task it is to incorporate the MFC into classic coatings such as transparent lacquers or pigmented colors.
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On the one hand, I use the cellulose directly in the synthesis of the polymer from the binder, which is the basis for the paint," explains Schirp. This approach has its pitfalls, as wood is a substance that normally interferes with the polymerization process in the reactor and hinders the production of binding agents because the emulsion clumps, coagulates or even breaks.
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The challenge here is that I control the process management in such a way that I stabilize the nanocellulose so that a good dispersion is created and I can also use the binder for my paint,” explains Schirp.
Flame and Weather Protection in One
Fire protection is just one function that the team strives for with the help of bio-inspired wood coating. Because the nanocellulose can absorb and store water like a sponge. The researchers want to take advantage of this property and develop a fire protection coating that, compared to conventional glazes, is permanently weather-resistant and at the same time breathable.
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What we are aiming for is splash protection that lets water vapor through, so that the moisture in the wood comes through the lacquer layer.” “A coating that can do both,” would be a novelty and, according to Schirp, interesting for the industry. At the moment, separate layers must be applied to the wood for flame and weather protection.
The wood coatings of the Fraunhofer team will primarily be used outdoors, while the Finnish partners are aiming for a paint primarily for the interior. All products developed in the project are checked for their properties by the Norwegian project partner, the wood research institute Norsk Treteknisk Institute in Oslo.
Source: Fraunhofer