Accessible Requires Authentication Published by De Gruyter January 11, 2019

Effect of hardening parameters of wood preservatives based on tannin copolymers

Lukas Sommerauer, Marie-France Thevenon, Alexander Petutschnigg and Gianluca Tondi
From the journal Holzforschung


Amongst polyphenols, tannins belong to the most effective chemical protection systems against biological attack on trees. Tannins are water-soluble and are thus leached out easily when used for wood protection. In situ polymerized tannin-hexamine wood preservatives have better leaching resistance (LR), but they do not resist weathering. In this study, tannin copolymer formulations were prepared with hexamine, formaldehyde, furfural, glyoxal, furfuryl alcohol and maleic anhydride, impregnated in wood, and cured at higher temperatures. The wood samples treated with these formulations were tested for their anti-swelling efficiency (ASE), leaching behavior, mechanical properties, and their resistance against fire, weathering and biological attack. Several tannin-treated specimens showed improved hardness and enhanced leaching and fire resistance. Some formulations also responded well to artificial weathering cycles, but natural weathering cycles deteriorated their performance. Samples treated with maleic anhydride showed improved leachability and high biological resistances, even without the addition of inorganic biocides. These organic and bio-friendly products can be considered as promising alternatives to heavy metal-based wood preservatives.

  1. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: The study was financed for one part by the European Union with the ERA-Net Wood Wisdom program and namely to the project “BIOCOPOL – Enhancing wood durability and physical properties through innovative bio-based sustainable treatments”.

  3. Employment or leadership: None declared.

  4. Honorarium: None declared.


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Supplementary Material

The online version of this article offers supplementary material (

Received: 2018-06-06
Accepted: 2018-11-21
Published Online: 2019-01-11
Published in Print: 2019-05-27

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