Effects of Steaming, Drying Temperature, and Adhesive Type on Static Bending Properties of LVL made of Picea orientalis and Abies nordmanniana veneers

Abstract

The modulus of elasticity (MOE) and modulus of rupture (MOR) were evaluated for laminated veneer lumber (LVL) in static bending. The studied species were spruce (Picea orientalis) and fir (Abies nordmanniana) originated from the Eastern Black sea region and prepared with phenolformaldehyde and melamine-urea-formaldehyde. The effect of wood species, steaming, drying temperature, and type of adhesive on static bending MOE and MOR were determined. According to the experimental results, the bending strength of spruce wood (Maçka) treated with phenol formadehyde adhesives is the highest for the specimens steamed for 6 h at a drying temperature of 110 ºC. Furthermore, the modulus of elasticity for spruce wood (Maçka) treated with phenol formadehyde adhesive is the highest for the specimens steamed for 12 h and subjected to a drying temperature of 150 ºC.

Optimization of Press time and Properties of Laminated Veneer Lumber Panels by Means of a Punching Technique

“…Considering the aesthetic beauty of natural wood, LVL technology encourages extensive usage of timber. However, unlike sawn timber, LVL can be produced in any size and length (depending on the dimensions of the press machine) and simultaneously offers the advantages of higher reliability, which can be achieved through the process of defect removal (Nzokou et al 2005;Xue and Hu 2012), higher dimensional stability (Keskin 2001;Hayashi et al 2005;Deam et al 2008), and higher strength properties in certain directions (Kurt 2010;Kiliç 2011;Peker et al 2015). The production process of LVL is very similar to that of plywood composite boards.…”

“…Apart from the mechanical and physical characteristics of wood materials and the type of adhesive used, the hot pressing characteristics (press time, pressure, press temperature, etc.) are among the most important factors that directly affect the properties of LVL panels (Döngel 1999;Kamdem 2008, 2009;Bal and Bektaş 2012;Peker et al 2015). In this context, hot press time is known as a bottle-neck for most wood-composite manufacturing factories (Doosthoseini 2001).…”

“…The press time could be simply reduced if the pressing temperature was increased. However, even slight increases in the optimum press temperature can negatively affect the surface quality (as a result of temperature degradation on the board surface) and strength properties of LVL panels (Xue and Hu 2012;Peker et al 2015). Hence, an alternative solution is to establish new techniques to reduce press duration without changing the optimum pressing temperature.…”