Chestnut Tannin/Furfuryl Alcohol Copolymers for Beech Wood Chemical Modification

Author: mycolabadmin
4/24/2025
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Summary

Researchers developed a new way to protect beech wood by combining natural tannins extracted from chestnut with furfuryl alcohol. This treatment makes the wood more resistant to rot-causing fungi while making it more water-resistant and thermally stable. The innovation is significant because it replaces half of the chemical compound (furfuryl alcohol) with a natural plant extract, making the wood treatment more sustainable and environmentally friendly.

Background

Tannins are abundant polyphenols present in all plants with potential as wood preservative agents. Previous studies demonstrated the potential of tannins combined with furfuryl alcohol (FA) for wood modification, but prior research used low concentrations and did not explore hydrolysable tannins. This study focuses on using large quantities of hydrolysable tannins from chestnut to maximize biomass substitution for synthetic FA.

Objective

To evaluate the use of large quantities of hydrolysable tannins from chestnut (Castanea sativa) mixed with furfuryl alcohol to chemically modify beech wood (Fagus sylvatica L.), replacing as much FA as possible while maintaining or improving wood properties. Properties analyzed included weight percent gain, leachability, dimensional stability, thermal stability, wettability, and durability against fungal decay.

Results

Replacing 50% of FA mass with tannins significantly increased weight percent gain (up to 55%) while maintaining comparable leachability and dimensional stability to standard furfurylation. The tannin-FA copolymer treatments demonstrated superior resistance to wood-degrading fungi, improved thermal stability with higher char content, and increased hydrophobicity. Treatment (50)TH(1)FA(1) achieved durability class D1 against both rot types with only 2.7% degradation by Trametes versicolor after leaching.

Conclusion

Hydrolysable chestnut tannins can successfully replace up to 50% of furfuryl alcohol in wood modification while maintaining or improving protection against fungi and thermal stability. This bio-based modification approach offers an ecologically responsible alternative to conventional furfurylation by substituting chemically transformed fossil-based materials with naturally extracted polyphenolic compounds. Further studies are needed to evaluate mechanical properties and termite resistance of the modified wood.

Published in:Polymers (Basel),
Study Type:Experimental Study,
Source: 10.3390/polym17091159, PMID: 40362943