Surface characterization and paint bonding quality on chemically and thermally modified short rotation teak wood

Abstract

Chemical and thermal modification can change the hydrophilic properties of wood, and thus affect their coating performance. This study determined the surface characteristics of chemically and thermally modified short rotation teak wood. The characteristics studied were surface roughness, surface free energy (SFE), contact angle, wettability, and coating bonding quality. Results show that the surface of short rotation teak became smoother after chemical and thermal modifications; however, surface roughness increased after furfurylation. The total SFE of chemically and thermally modified teak wood decreased after treatment. The decrease in the total SFE caused the decrease in the constant contact angle change rate (K-value). The K-values for water-dispersed polyurethane and acrylic paints were nearly 0, which indicated their lower wettability. The paint bonding quality decreased after accelerated weathering. Short rotation teak with Glycerol-Maleic Anhydride (GMA)-thermal treatment can be considered for exterior applications with a proper selection of paint.

Improving the Technical Characteristics of Untreated and Heat-Treated Ayous Wood against Accelerating Ageing by Testing Two Application Modalities of an Innovative Polyurethane Coating for Outdoor Uses

“…On the contrary, the untreated uncoated wood experiences little variation in surface contact angle, which exhibits an increase in this parameter that leads to a decrease in wettability [46]. This result is consistent with those of other works found in the literature [48][49][50][51], and it was demonstrated to be associated with a decrease in the polarity of the wood surface due to an increase in carbon and a decrease in the oxygen percentage, which points towards greater hydrophobicity [49,52,53].…”

“…On the contrary, the untreated uncoated wood experiences little variation in surface contact angle, which exhibits an increase in this parameter that leads to a decrease in wettability [46]. This result is consistent with those of other works found in the literature [48][49][50][51], and it was demonstrated to be associated with a decrease in the polarity of the wood surface due to an increase in carbon and a decrease in the oxygen percentage, which points towards greater hydrophobicity [49,52,53]. The change in the wettability of the coated samples mainly depends on the thermal treatment, depending less considerably on application modality, though, in all cases, a decrease in the contact angle can be observed because of artificial ageing.…”

The Influence of the Initial Treatment of Oak Wood on Increasing the Durability of Exterior Transparent Coating Systems

“…UV radiation can cause cleavage of covalent bonds in lignin, resulting in the formation of reactive radicals [17][18][19]. These reactive radicals may penetrate deeper into the wood, initiating chain reactions that can extend up to a depth of 2500 µm [30]. While the use of pigments can prevent photodegradation, it is often undesirable from an aesthetic perspective as they cover the natural grain and color of the wood [6].…”