Some Chemical Properties of Luffa and Its Suitability for Medium Density Fiberboard (MDF) Production

Chemical composition influences the calorific power of wood, mainly due to the calorific power of structural compounds and extractives. Heat treatment changes the chemical composition of treated wood. This work studies the relationship between chemical composition and calorific power improvement by heat treatment. Samples were heat-treated by the ThermoWood process ^® for 1 h and 2 h. High heating value (HHV) and chemical composition; lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol, and water were determined. The HHV of untreated wood ranged between 18.54–19.92 MJ/kg and increased with heat treatment for all the tested species. A positive linear correlation was found between HHV and Klason lignin (R² = 0.60). A negative trend was observed for holocellulose, cellulose, and hemicelluloses content against HHV, but with low determination coefficients for linear regression. The best adjust for polysaccharides was found for hemicelluloses content. A positive correlation could be found for dichloromethane extractives (R² = 0.04). The same was obtained in relation to ethanol extractives with R² = 0.20. For water and total extractives, no clear positive or negative trends could be achieved. The results showed that the HHV of wood increased with heat treatment and that this increase was mainly due to the increase in lignin content.

In the last few years there has been an increased demand to change the natural color of valuable hardwoods without chemicals for use mainly in indoor parquet floors. In this study, wood samples from oak (Quercus petraea L.), one of the most used species for parquet, were heat treated (ThermoWood method) at 190 °C for 2 h and at 212 °C for 1 and 2 h. Untreated and heat treated wood surfaces were coated following two different applications: type 1, with a single layer of sealer (50 g/m2) and type 2 with two layers (35 g/m2) using a nanolacke varnishing system. The objective of this study was to investigate surface properties including adhesion, glossiness, pendulum hardness, and color (L*, a*, b*, ΔE*, ΔL*, Δa*, and Δb*). With heat treatment the lightness decreases, and its decrease is higher for higher temperatures and treatment times. Type 2 coated wood presented a slightly lower lightness decrease. The experiment showed a slight increase followed by a decrease in redness (lower a*) and a clear decrease in the yellow tone (b*). The total color variation increased with the intensity of the treatment, while the glossiness decreased (more for Type 1 coated wood). The adhesion strength and surface hardness decreased with the heat treatment in both the Type 1 and Type 2 coated wood samples. The decrease in adhesion was higher for Type 2, reaching 67%, while the decrease in surface hardness reached about 18%.

The objective of this study was to investigate the surface properties of a UV-system applied on laminated parquet made with untreated and heat treated wood (ThermoWood). In this study, wood specimens prepared from Scots pine (Pinus sylvestris) wood were heat treated according to ThermoWood method at 190ºC for 2 hours and at 212ºC for 1 and 2 hours adhesion strength, pendulum hardness, surface roughness, colour and glossiness were determined. The UV-system was applied in two different types according to manufacturer recommendations. Results show that lightness and glossiness decreases and red colour tone increases with heat treatment. Pendulum hardness increased initially, decreasing afterwards with the intensity of the heat treatment. Tests showed that adhesion generally decreased with heat treatment. No significant differences were found for the surface roughness although a slight decrease was observed.info:eu-repo/semantics/publishedVersio

Egzotik ağaç türlerine ait keresteler, Türkiye’de de çeşitli alanlarda (mobilya, parke, kapı ve pencere, kaplama, dış mekânda, vb.) kullanılmaktadır. Bu ağaç türlerinden bir tanesi de Ayous kerestesidir. Ayous (Triplochiton scleroxylon K. Schum) ağacının gerek kerestesi gerekse diğer kısımları (kabuk, kök, vb.) önemli alanlarda değerlendirilmektedir. Bu çalışmada, Ayous odununda janka sertlik değeri, yüzey pürüzlülüğü, shore - D sertlik, çivi tutma direnci ve ısıl işlem uygulamasından sonra meydana gelen renk ve parlaklık özelliklerindeki değişmeler araştırılmıştır. Elde edilen araştırma sonuçlarına göre, ısıl işlem uygulaması sonrası renk parametreleri ile parlaklık değerlerinin değiştiği görülmüştür. Shore - D sertlik 37.65, hava kurusu yoğunluğu 384 kg/m3, Janka sertlik değerleri teğet, radyal ve enine yönlerde sırasıyla 21.01 N/mm2, 17.87 N/mm2 ve 28.69 N/mm2, çivi tutma direnci değeri ise teğet, radyal ve enine yönlerde sırasıyla 4.69 N/mm2, 4.39 N/mm2 ve 4.41 N/mm2 olarak belirlenmiştir. Yüzey pürüzlülüğü sonuçlarına göre zımpara numarasının artması ile pürüzlülük değerlerinin azaldığı sonucuna ulaşılmıştır.