The Effects of Natural Weathering on Color Stability of Impregnated and Varnished Wood Materials

Turkay Turkoglu,Hilmi Toker,Ergun Baysal

doi:10.1155/2015/526570

Turkay Turkoglu, Hilmi Toker + Show 1 more

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https://doi.org/10.1155/2015/526570

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Abstract

The aim of this study was to investigate effects of natural weathering on color stability of Scots pine (Pinus sylvestrisL.) and Oriental beech (Fagus orientalisL.) impregnated with some chemicals [tanalith-E (TN-E), adolit-KD5 (AD-KD5), and chromated copper arsenate (CCA)] and then varnished [synthetic varnish (SV) and polyurethane varnish (PV)]. While applying varnish increased lightness, impregnation decreased lightness of the wood specimens before natural weathering. Natural weathering caused greenish, bluish, and dark color tones of the wood surface. Total color change was increased with increasing exposure times in natural weathering. Untreated (control) wood specimens exhibited higher color changes than the other wood specimens in all the stages of natural weathering. The total color changes of untreated Oriental beech specimens were less than untreated Scots pine specimens. The color stability of impregnated and varnished wood specimens gave better results than untreated and solely varnished wood specimens after natural weathering. The best color stability was obtained from both Oriental beech and Scots pine wood impregnated with TN-E before PV coating.

Highlights

Wood is one of the most important natural materials used for aesthetic, engineering, and structural applications [1, 2]
This study investigates the effect of natural weathering on color stability of Scots pine and Oriental beech wood impregnated with copper-based wood preservatives including TNE, AD-KD5, and Chromated copper arsenate (CCA) and applied with polyurethane varnish (PV) or synthetic varnish (SV)
The highest retention amounts determined in Scots pine and Oriental beech treated with TN-E were 35.5 kg/m3 and 28.8 kg/m3, respectively

Summary

Introduction

Wood is one of the most important natural materials used for aesthetic, engineering, and structural applications [1, 2]. Weathering is the general term used to define the degradation of materials exposed to the weather [13], initially causing changes in the wood surface’s color [14]. Yalinkilic et al investigated the outdoor performance of Scots pine and chestnut wood treated with chromium-copper-boron (CCB) and applied with polyurethane varnish (PV) or alkyd-based synthetic varnish (SV). They reported that CCB impregnation greatly stabilized the surface color and reduced mass loss of wood. Another research about outdoor weathering durability of obeche, red beech, spruce, and fir wood treated with CCB was carried out by Sell and Feist They found that CCB-coated wood has high resistance and protective effect against weathering [26]. The comparison of new copperbased wood preservatives with CCA and their performance testing is important in determining consumer expectation of these new products

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