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Durability and wettability of varnishes on the modified and aged surfaces of short rotation teak wood

Efrida Basri (Department of Forest Product, Institut Pertanian Bogor (IPB) University, Bogor, Indonesia and Research Center for Biomass and Bioproducts, National Research and Innovation Agency (BRIN), Cibinong, Indonesia)
Resa Martha (Laboratoire d’Etudes et de Recherche sur le Matériau Bois (LERMAB), Université de Lorraine, Nancy, France)
Ratih Damayanti (Research Center for Biomass and Bioproducts, National Research and Innovation Agency (BRIN), Cibinong, Indonesia)
Istie Rahayu (Department of Forest Products, Institut Pertanian Bogor (IPB) University, Bogor, Indonesia)
Wayan Darmawan (Department of Forest Products, Institut Pertanian Bogor (IPB) University, Bogor, Indonesia)
Philippe Gérardin (Laboratoire d’Etudes et de Recherche sur le Matériau Bois (LERMAB), Université de Lorraine, Nancy, France)

Pigment & Resin Technology

ISSN: 0369-9420

Article publication date: 27 December 2022

22

Abstract

Purpose

The surface characteristics of thermally and chemically modified wood, such as surface roughness, surface free energy (SFE) and wettability, are important properties that influence further manufacturing processes such as gluing and coating. The aim of this paper was to determine the influence of the surface roughness of thermally and chemically modified teak wood on their SFE, wettability and bonding quality for water-based acrylic and solvent-based alkyd varnishes. In addition, durability against subterranean termites in the field of these modified teak woods was also investigated to give a valuable information for their further application.

Design/methodology/approach

The woods tested in this study were fast-growing teak woods that were prepared in untreated and treated with furfuryl alcohol (FA), glycerol maleic anhydride (GMA) and thermal. SFE values were calculated using the Rabel method. The wettability values were measured based on the contact angle between varnish liquids and wood surfaces using the sessile drop method, and the Shi and Gardner model model was used to evaluate the wettability of the varnishes on the wood surface. The bonding quality of the varnishes was measured using a cross-cut test based on ASTM 3359-17 standard. In addition, durability against subterranean termites in the field of these modified teak woods was also investigated according to ASTM D 1758-06.

Findings

The results showed that furfurylated and GMA-thermal 220°C improved the durability of teak wood against termites. The furfurylated teak wood had the roughest surface with an arithmetic average roughness (Ra) value of 15.65 µm before aging and 27.11 µm after aging. The GMA-thermal 220°C treated teak wood was the smoothest surface with Ra value of 6.44 µm before aging and 13.75 µm after aging. Untreated teak wood had the highest SFE value of 46.90 and 57.37 mJ/m2 before and after aging, respectively. The K values of untreated and treated teak wood increased owing to the aging treatment. The K values for the water-based acrylic varnish were lower than that of the solvent-based alkyd varnish. The untreated teak wood with the highest SFE produced the highest bonding quality (grades 4–5) for both acrylic and alkyd varnishes. The solvent-based alkyd varnish was more wettable and generated better bonding quality than the water-based acrylic varnish.

Originality/value

The originality of this research work is that it provides evaluation values of the durability and SFE. The SFE value can be used to quantitatively determine the wettability of paint liquids on the surface of wood and its varnish bonding quality.

Keywords

Acknowledgements

The authors would like to thank the Ministry of DIKBUD RISTEK of the Republic of Indonesia for its financial support under grand number 3787/IT3.L1/PT.01.03/P/B/2022. The authors also thank IPB University, Bogor for the assistance in this research work. The authors want also to thank BRIN for the PhD grant allowing her to study at IPB University and to LERMAB the University of Lorraine for its kind support in some testing.

Citation

Basri, E., Martha, R., Damayanti, R., Rahayu, I., Darmawan, W. and Gérardin, P. (2022), "Durability and wettability of varnishes on the modified and aged surfaces of short rotation teak wood", Pigment & Resin Technology, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/PRT-09-2022-0110

Publisher

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Emerald Publishing Limited

Copyright © 2022, Emerald Publishing Limited

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