Hybrid approach for wood modification: Characterization and evaluation of weathering resistance of coatings on acetylated wood
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2021-06
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Language
en
Pages
16
Series
Coatings, Volume 11, issue 6
Abstract
Wood, as a biological material, is sensitive to environmental conditions and microorgan-isms; therefore, wood products require protective measures to extend their service life in outdoor applications. Several modification processes are available for the improvement of wood proper-ties, including commercially available solutions. Among the chemical treatments, acetylation by acetic anhydride is one of the most effective methods to induce chemical changes in the constitutive polymers at the cellular wall level. Acetylation reduces wood shrinkage-swelling, increases its durability against biotic agents, improves UV resistance and reduces surface erosion. However, even if the expected service life for external cladding of acetylated wood is estimated to be 60 years, the aesthetics change rapidly during the first years of exposure. Hybrid, or fusion, modification includes processes where the positive effect of a single treatment can be multiplied by merging with additional follow-up modifications. This report presents results of the performance tests of wood samples that, besides the modification by means of acetylation, were additionally protected with seven commercially available coatings. Natural weathering was conducted in Northern Italy for 15 months. Samples were characterized with numerous instruments by measuring samples collected from the stand every three months. Superior performance was observed on samples that merged both treatments. It is due to the combined effect of the wood acetylation and surface coating. Limited shrinkage/swelling of the bulk substrate due to chemical treatment substantially reduced stresses of the coating film. Hybrid process, compared to sole acetylation of wood, assured superior visual performance of the wood surface by preserving its original appearance.Description
Funding Information: The authors gratefully acknowledge the European Commission for funding the InnoRenew project (grant agreement #739574 under the Horizon 2020 Widespread-2-Teaming program), the Republic of Slovenia (investment funding from the Republic of Slovenia and the European Regional Development Fund) and infrastructural ARRS program IO-0035. Part of this work was conducted during project BIO4ever (RBSI14Y7Y4), funded within call SIR by MIUR-Italy; the project Multi-spec (BI-IT/18-20-007), funded by ARRS-Slovenia; Archi-BIO (BI/US-20-054) funded by ARRS-Slovenia, BI-AT/20-21-014 funded by ARRS-Slovenia, J7-9404 (C) funded by ARRS-Slovenia, and CLICK DESIGN, ?Delivering fingertip knowledge to enable service life performance specification of wood?, (No. 773324) supported under the umbrella of ERA-NET Cofund ForestValue by the Ministry of Education, Science and Sport of the Republic of Slovenia. ForestValue has received funding from the European Union?s Horizon 2020 research and innovation programme. The experimental samples were provided by Accsyss The Netherlands and coated by Teknos/Drywood The Netherlands, ICA Italy, and Renner Italy. Authors would also like to thank Ferry Bongers for valuable comments and discussion. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
Acetylation, Aesthetic, Coatings, Natural weathering, Service life performance, Wood modification
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Citation
Sandak, A, Földvári-Nagy, E, Poohphajai, F, Herrera Diaz, R, Gordobil, O, Sajinčič, N, Ponnuchamy, V & Sandak, J 2021, ' Hybrid approach for wood modification: Characterization and evaluation of weathering resistance of coatings on acetylated wood ', Coatings, vol. 11, no. 6, 658 . https://doi.org/10.3390/coatings11060658