Characteristics of a Protective Layer on Oil Heat-Treated Scots Pine and Fir Wood

Abstract

Effects of natural weathering were studied relative to the adhesion strength, surface hardness, and color change of coated heat-treated and untreated Turkish fir and Scots pine wood. For this study, water-based coatings (varnish and paint) were applied on heat-treated samples. The coated heat-treated, and untreated samples were naturally weathered for one year. The difference between several properties such as adhesion strength, hardness, and color were measured before and after weathering. The test results showed that varnished heat-treated samples had good performance as compared to those of the untreated samples.

Coating Performance on Exterior Oil-Heat Treated Wood

“…The color change of samples after 18 months of natural weathering of both wood species are shown in Figure 3. Although there is not much difference between the color change of heat-treated and untreated wood for uncoated samples, it is clearly apparent that coated-heat-treated wood samples had much less color change than coated untreated woods as reported previously for the effect of stain on heat-treated wood [20]. It seems that the coating significantly enhanced the performance of heat-treated wood, regardless of wood species.…”

“…Hydroxyl functional groups in wood are responsible for attracting water molecules by creating hydrogen bonds with water, either from moisture in the air or by absorbing liquid water through rain and snow. Higher dimensional stability of wood translates to less swelling, less checking, and cracking; thus, in general, they should create fewer stresses for a coating's film [17][18][19][20].…”

“…Their results showed that the degradation was not due to the coating adhesion loss but rather it was related to the degradation of heat-treated wood under the coating layer. Kesik et al [20] investigated the weathering performance of one varnish and one paint formulation when applied on heat-treated scots pine and fir during one year of natural weathering in Turkey. They reported that varnished heat-treated wood had better performance (color change and hardness) than varnished untreated wood samples, while painted samples had similar performance on both heat-treated and untreated wood.…”

Thermal treatment of wood using vegetable oils: A review

“…Therefore, it is very suitable for outdoor above ground applications. However, coatings on the oil heat treated are always recommended for exterior applications as it is very effective against weathering [134]. As the oil heat treatment reduced the wettability of the wood surface, selection of appropriate coating systems is vital to ensure an acceptable adhesion between the coating and the hydrophobic wood surface.…”

Встановлення Ефективності Захисту Термомодифікованої Деревини Граба Від Дії Ультрафіолету

“…Виявле-но, що деградація пов'язана з руйнуванням термообробленої деревини під шаром покриття. Проведено дослідження на стійкість до вивітрювання лаку та фарби в разі нанесення на термічно оброблену деревину сосни та ялини [15]. Встановлено, що покрита лаком термомодифікована деревини мала кращі показники (зміна кольору та твердість), ніж лаковані зразки необробленої деревини.…”