The Effect of Press Temperature and Duration on the Bonding Strength of American Poplar Laminated Veneer Lumber

Abstract

In this study, the effect of press temperature and duration on bonding strength of laminated veneer lumber (LVL) was investigated. For this purpose, LVLs were produced from I 77/51 American poplar clone (Populus deltoides) by using 2 different press temperatures (140 and 170⁰C) and 3 press duration (10, 15 and 20 minutes). Phenol formaldehyde (PF) adhesive was used for bonding of poplar veneers. The bonding strength and wood failure rate of produced LVLs were determined according to TS EN 314-1 standard. According to experimental results, the LVLs pressed at 170⁰C showed better bonding strength compared to LVLs pressed at 140⁰C. On the other hand, a decrease was observed in the wood failure rate due to the increase in temperature. The highest bonding strength was obtained by press duration of 10 minutes at press temperature of 170⁰C and a significant decrease in bonding strength was observed when press duration was extended.

Keywords

• Press temperature
• press duration
• bonding strength
• laminated veneer lumber
• American poplar
• phenol formaldehyde

Pres Sıcaklık ve Süresinin Amerikan Kavağı Tabakalı Kaplama Kerestenin Yapışma Dayanımı Üzerine Etkisi

Öz

Bu çalışmada, tabakalı kaplama kereste (TKK) üretiminde pres sıcaklığı ve pres süresinin yapışma direnci üzerine etkisi incelenmiştir. Bu maksatla I-77/51 Amerikan Kavağı klonu (Populus deltoides) kaplamaların, fenol formaldehit (FF) yapıştırıcısı kullanılarak 140⁰C’de 10 dakika, 170⁰C’de 10, 15 ve 20 dakika süreyle preslenmesiyle TKK’ler üretilmiştir. Elde edilen TKK’lerin yapışma dirençleri ve odun kırılma oranları TS EN 314-1 standardına göre belirlenmiştir. Deney sonuçlarına göre 170⁰C’de preslenen numunelerin yapışma direnci 140⁰C’de preslenenlere göre daha yüksek bulunmuştur. Diğer yandan, pres sıcaklığındaki artış sonucunda odun kırılma oranında düşme gözlemlenmiştir. Pres süresi incelendiğinde en yüksek yapışma direnci 170⁰C’de 10 dakika preslenerek üretilen TKK’lerden elde edilmiş ve pres süresi uzatıldığında yapışma direncinde düşüş gözlemlenmiştir.

Anahtar Kelimeler

• Pres sıcaklığı
• pres süresi
• yapışma direnci
• tabakalı kaplama kereste
• Amerikan kavağı
• fenol formaldehit

Kaynakça

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