Physical and Mechanical Properties of Fir and Poplar Subjected to Tall Oil and Vacuum Heat Treatment

Abstract

Vacuum heat treatment creates an oxygen-free environment, thus positively effects the properties of wood compared to traditional heat treatment. Crude tall oil is a non-biocidal wood preservative, composed of resin and fatty acids and improves some properties of wood such as water uptake and decay resistance. In this study, tall oil dissolved in ethanol (10% and 20%) for impregnation of the fir and poplar samples according to full cell method, followed by subjected to vacuum-heat treatment at 180 ºC and 200 ºC for 1 and 2 h respectively. Water uptake and mechanical tests such as bending and compression strength of untreated and treated samples were investigated. Results showed that weight percent gain (WPG) was about two times higher for tall oil treatment at 20% than 10% of tall oil. Vacuum heat treatment showed similar trend with control samples in terms of water uptake, while combined treatment of tall oil and vacuum heating lowered the water uptake. The results of mechanical tests indicated that bending strength was not affected by tall oil treatment. Combination of tall oil and vacuum heat treatment improved the compression strength.

Keywords

• Tall oil
• vacuum heat treatment
• fir
• poplar
• water uptake
• bending strength.

Tall Yağı Emprenyesi ve Vakum Altında Isıl İşlem Yapılmış Göknar ve Kavak Odunlarının Fiziksel ve Mekanik Özellikleri

Öz

Geleneksel ısıl işlemle karşılaştırıldığında, vakumlu ısıl işlem oksijensiz bir ortam yaratır, dolayısıyla odunun özelliklerini olumlu yönde etkiler. Ham tall yağı, reçine ve yağ asitlerinden oluşan ve odunun su alma ve çürüklük direnci gibi bazı özelliklerini iyileştiren, biyosidal olmayan bir odun koruyucudur. Bu çalışmada, göknar ve kavak odunlarının dolu hücre yöntemine göre emprenyesi için tall yağı etanolde (%10 ve %20) çözündürülmüş, ardından sırasıyla 180 ºC ve 200 ºC' de 1 ve 2 saat süreyle vakumlu ısıl işleme tabi tutulmuştur. Kontrol ve muamele edilmiş numunelerin su alma, eğilme ve basınç direnci gibi mekanik testleri incelenmiştir. Sonuçlar, tall yağının %20 oranında kullanıldığı emprenye işlemlerinde yüzde ağırlık artışı tall yağının %10'una kıyasla yaklaşık iki kat daha yüksek olduğunu göstermiştir. Vakumlu ısıl işlem, su alımı açısından kontrol örnekleri ile benzer bir eğilim gösterirken, tall yağı ve vakumlu ısıl işlem kombinasyonu su alımını azaltmıştır. Mekanik test sonuçları, eğilme direncinin tall yağı emprenyesinden olumsuz etkilenmediğini göstermiştir. Tall yağı ve vakumlu ısıl işlem kombinasyonu basınç direncini artırmıştır.

Anahtar Kelimeler

• Tall yağı
• vakumlu ısıl işlem
• göknar
• kavak
• su alma
• eğilme direnci

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