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Licensed Unlicensed Requires Authentication Published by De Gruyter November 6, 2020

Effect of phenol-formaldehyde (PF) resin oligomer size on the decay resistance of beech wood

  • Vladimirs Biziks EMAIL logo , Sascha Bicke , Gerald Koch and Holger Militz
From the journal Holzforschung


Treating wood with water-soluble resins is a well-known and effective method to improve the durability of wood. However, there has been no systematic work to date related to the influence of average molecular size of phenol-formaldehyde (PF) resin on the decay resistance of wood, especially of hardwoods. Therefore, the goal of this study was to investigate the effect of average molecular size of PF resin treatment on the resistance of beech wood against brown- and white-rot fungi. Four different average molecular weights (Mw) of resol type resin oligomers (297, 421, 655 and 854 g/mol) were examined. Different weight percent gains (WPGs) in European beech (Fagus sylvatica) wood blocks (15 × 20 × 50 mm3) were attained through vacuum impregnation using various concentrations of aqueous-PF solutions. Afterwards treated wood blocks passed the leaching and were exposed to brown-rot fungi (Gloeophyllum trabeum; Coniophora puteana) and white-rot fungi (Trametes versicolor) for 16 weeks. No effect of oligomer size on the resistance against G. trabeum decay of wood blocks was observed, resulting in resin loadings of 7–8%. The required WPG for resistance to brown-rot decay by C. puteana increased slightly with increasing oligomer molecular size: 6, 7, 10 and 11% for wood treated with 297, 421, 655 and 854 g/mol, respectively. The extent of white-rot fungal decay resistance of treated wood was affected by the molecular size of oligomers. Resin loadings of 8% and of 17% against T. versicolor were required to attain similar durability levels for beech wood treated with Mw = 297 and 854 g/mol, respectively.

Corresponding author: Vladimirs Biziks, Department of Wood Biology and Wood Products, Georg August University Goettingen, Büsgenweg 4, 37077Göttingen, Germany, E-mail:

Funding source: Pollmeier Massivholz GmbH & Co. KG


The authors extend their sincere thanks to Daniela Nissen, Tanja Potsch, and Johann Heinrich from the Thünen-Institut, Institute of Wood Research, Hamburg, for assistance in the UMSP analysis. The authors also express their appreciation to Dr. Elke Fliedner from Prefere Resins Germany GmbH for her outstanding help on the resin characterization.

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

  2. Research funding: The authors express their appreciation to Pollmeier Massivholz GmbH & Co. KG for financial support.

  3. Conflict of interest statement: The authors declare to have no conflicts of interest regarding this article.


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Received: 2020-01-17
Accepted: 2020-09-23
Published Online: 2020-11-06
Published in Print: 2021-06-25

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