Hüseyin PELIT

Isıl işlemli ahşap malzemelerin yüzey renk özelliklerine farklı ahşap verniklerinin etkisi

Bu çalışmada, ısıl işlemli ahşapların yüzey renk özelliklerine farklı ahşap verniklerinin etkisi araştırılmıştır. Doğu kayını (Fagus oriantalis L.) ve sarıçam (Pinus sylvestris L.) odunundan hazırlanmış örneklere 190, 200 ve 210 °C sıcaklıkta 2 saat süresince ısıl işlem uygulanmıştır. Daha sonra örnek yüzeyleri selülozik (SZ), sentetik (ST), poliüretan (PU) ve su bazlı (SB) ahşap vernikleri ile kaplanmıştır. Örneklerin renk özellikleri üç boyutlu CIEL*a*b* renk uzayına göre belirlenmiştir. Araştırma sonuçlarına göre, ısıl işlem sonrası işlem sıcaklığına bağlı olarak örneklerde L* değeri %64, b* değeri %70 oranında azalmıştır. a* değeri ise sarıçam örneklerde %96’ya kadar artarken, kayın örneklerde %56 oranına kadar azalmıştır. Isıl işlemli örneklerin renk değerleri vernik uygulamalarından sonra önemli derecede değişmiştir. Verniksiz örneklere göre tüm örneklerin L* değeri azalmış ve örnekler daha da koyulaşmıştır. Vernikleme sonrası, ısıl işlemli sarıçam örneklerin a* değeri önemli oranda artarken, yüksek sıcaklıkta (200 ve 210 °C) ısıl işlemli kayın örneklerde genellikle azalmıştır. b* değeri ise PU ve ST vernik uygulanmış her iki ağaç türünde önemli oranda azalmıştır. Verniklenmiş örneklerdeki toplam renk değişimi (ΔE*) değeri genel olarak 200 °C’de ısıl işlemli örneklerde daha yüksektir. Ayrıca, renk değişiminde ST vernik en fazla etkiye sahip iken, SB vernik en az etkiye sahiptir. Isıl işlem sonrası kayın ve sarıçam odunlarında elde edilen ahşap renginin maksimum düzeyde korunması arzu ediliyor ise SB vernikler tercih edilebilir.

The effect of different wood varnishes on surface color properties of heat treated wood materials

This study investigates the effects of different wood varnishes on the surface color properties of heat treated wood. Samples prepared from Oriental beech (Fagus orientalis L.) and Scots pine (Pinus sylvestris L.) are subjected to heat treatment at 190, 200, and 210 ° C for 2 h. Sample surfaces are then covered with cellulosic (SZ), synthetic (ST), polyurethane (PU), and water-based (SB) wood varnishes, and the color properties of samples are determined according to the three-dimensional CIEL*a*b* color space. Results show a decrease in the L* and b* values of samples by 64% and 70%, respectively, depending on the process temperature after heat treatment. The a* value increases by up to 96% for Scots pine samples and up to 56% for beech samples. Color values of heat treated samples change significantly after varnish is applied; L* values of all samples are reduced compared to unvarnished samples and samples are seen to darken. However, the a* value of heat treated Scots pine samples increases significantly after varnishing, while that of heat-treated beech samples at high temperatures (200 and 210 °C) generally decreases. Nevertheless, the b* value decreases significantly in both wood species subjected to application of PU and ST varnishes, and the total color change (ΔE*) of varnished specimens is generally higher for samples heat-treated at 200 °C. Results show that ST varnish has the largest effect on color change and SB varnish has the smallest effect. The use of SB varnishes is thus preferable when it is necessary to preserve the color of samples from either species following heat treatment.

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