Semra Çolak

A comparative study on some physical and mechanical properties of Laminated Veneer Lumber (LVL) produced from Beech ( Fagus orientalis Lipsky) and Eucalyptus ( Eucalyptus camaldulensis Dehn.) veneers

Laminated Veneer Lumber (LVL) panels made from eucalyptus (Eucalyptus camaldulensis Dehn.) and beech (Fagus orientalis Lipsky.) veneers were tested for physical and mechanical strength properties in this study. Urea formaldehyde (UF) and Polyvinyl acetate (PVA) adhesives were used for eucalyptus LVL panels and UF adhesive for beech LVL panels. The effect of veneer wood species on some physical and mechanical properties was found statistically significant. Also, different glue species caused the differences in strength properties of LVL panels.ZusammenfassungIn diesem Beitrag werden einige physikalische und mechanische Eigenschaften von Schichtholzplatten, hergestellt aus Buchen- (Fagus orientalis Lipsky.) und Eukalyptusfurnieren (Eucalyptus camaldulensis Dehn.) untersucht. Für die Herstellung von Schichtholzplatten wurden die Buchenfurniere mit UF und die Eukalyptusfurniere mit UF und PVA verleimt. Die Ergebnisse zeigen, dass sowohl die Art des Bindemittels als auch die Holzart der Furniere die Eigenschaften der Schichtholzplatten signifikant beeinflussen.

Utilization Potential of Waste from Window Joints for Particleboard

The aim of this study was to determine some technological properties of particleboard made from the waste from window joints. The effect of board density, adhesive amount, and paint presence on the properties of particleboard was investigated. Increasing density and adhesive amount significantly improved their mechanical properties and surface roughness, but negatively affected their thickness swelling. Removing of the paint from the particle resulted in better mechanical properties, but poorer (higher) surface roughness values. This treatment did not statistically affect the thickness swelling. Based on the results, it is proved that the waste of window joints has a potential as raw material for the manufacture of particleboard.

Einfluß der Dämpfung und Trocknung von Furnieren auf deren Acetylgruppengehalt und die Formaldehydabgabe von Sperrholz

ZusammenfassungIn diesem Beitrag wird den Einfluß der Dämpfung von Kiefernholz (Pinus brutia Ten.) und Buchenholz (Fagus oriantalis Lipsky) und der Trocknung der Furniere auf deren Acetylgruppengehalt und die Formaldehydabgabe daraus hergestellten Sperrholzes untersucht. An den Furnieren wurde der Gehalt an Acetylgruppen nach Freudenberg bestimmt. Ferner wurden IR-Spektren aufgenommen. Die Formaldehydabgabe der Furniersperrhölzer wurde nach der Perferatormethode (photometrisch) und der WKI-Flaschen-Methode ermittelt. Durch die Dämpfung der Furnierblöcke und Trocknung der Furniere trat eine erhebliche Veränderung im Acetylgruppengehalt der Furniere ein. Die Formaldehydabgabe aus Buchenfurniersperrholz lag deutlich niedriger als die aus Kiefernsperrholz. Die Sperrhölzer aus acetylgruppenreichen Furnieren weist eine niedrige Formaldehydabgabe auf.AbstractIn this study, the effect of log steaming and veneer drying on acetyl group content of wood and subsequent formaldehyde emission of plywood produced were investigated. This work was carried out on pine (Pinus brutia Ten.) and beech (Fagus oriantalis Lipsky) species. Changes in acetyl group contents were determined by Freudenberg, method and IR-spectra. Formaldehyde emission was determined by WKI-bottle and perferator methods. Pronounced changes were observed in acetyl group contents due to log steaming and veneer drying. Amount of formaldehyde emission occuring in pine plywood was found to be higher than that of the beech plywood. Lower formaldehyde emission was obtained in plywoods produced using veneers with rich acetyl group content.

Effects of wood species and adhesive types on the amount of volatile acetic acid of plywood by using desiccator-method

ZusammenfassungThe effects of wood species and adhesive types on the amount of volatile acetic acid and pH values of plywood panels were investigated using high performance liquid chromatography (HPLC). The plywood panels bonded with PF resin emitted more volatile acetic acid than those bonded with UF resins. According to the pH measurement carried out in the absorption solutions for volatile acetic acid emissions, the pH values of beech plywood panels were found to be higher than those of alder plywood panels.

Effects of hardener on some technological properties of particleboard produced from MUF adhesive with low melamine content

Subject Earlier studies indicated that increasing the melamine/urea (M/U) mole ratio from 45:55 to 50:50 improves the water durability of particle. The thickness swelling of the particleboard produced with this resin is considerably reduced. However, the high melamine content in MUF would increase the price of resin. In this study, particleboards were produced at industrial conditions by using MUF resin with M/U ratio 23:77 and with two different hardener types according to the EN 312-5 standards. Tensile strength perpendicular to the surface, thickness swelling, formaldehyde emission (according to the EN 120 and JIS A 5908 Desiccator Method), and volatile acid content of this panels were determined.

The effects of waiting time of alder (Alnus glutinosa subsp. barbata) veneers before drying on shear and bending strength of plywood

(Alnus glutinosa subsp. barbata) veneers before drying, on some properties of plywood, were investigated. Veneers produced at laboratory conditions were divided into four groups considering their waiting time before the drying process. pH and 1% NaOH solubility of these four groups of veneers were determined. No significant differences were found in solubility and pH values obtained from test groups. In addition bending strength, shear strength and formaldehyde emission values of plywood, produced from these veneers, were investigated. While bending strength and formaldehyde emission values of the plywood showed no differences, the shear strength of the plywood produced from veneers immediately dried after production was significantly higher than the one of other groups.

Effects of plasma surface treatment on bending strength and modulus of elasticity of beech and poplar plywood

This is a study on the effect of plasma treatment with different gases and plasma intensity on the bending strength and modulus of elasticity of plywood manufactured from beech and poplar. Oxygen (O2) and ammonia (NH3) plasma were applied on the veneer sheets; two plasma intensities were applied on the veneers with 150 and 300 W in the plasma chamber during one minute. Phenol formaldehyde resin was applied on one surfaces of each veneer with approx. 160 g/m2. Bending strength and modulus of elasticity were determined according to EN 310.The effects of plasma surface treatment on chemical structure of the panels were determined with FTIR-ATR analysis. Bending strength of all tested panels slightly and partly increased without statistical significance when applying oxygen plasma. The effect of ammonia plasma treatment on bending strength and was determined by the wood species and the plasma intensity, and it was not uniform. Modulus of elasticity of the panels with oxygen plasma treatment showed in most cases improvement, whereas ammonia plasma pretreated veneers caused lower values compared to the control panels.

BUHARLAMA İŞLEMİ YAPILMIŞ LADİN (Picea orientalis L.) ODUNUNUN BAZI FİZKSEL VE MEKANİK ÖZELLİKLERİNDEKİ DEĞİŞMELER

Bu cali s manin ana amaci hidro-termik i l sem olarak 12 saat sureyle buharlama yapilan ladin ( Picea orientalis L.) odunun fiziksel ve mekanik ozelliklerindeki de g i s melerin belirlenmesidir. Bu maksatla, a g actan alinan tomruk ikiye bolunerek biri kontrol, di g eri ise test icin kullanilmi s tir. Orneklerin denge rutubet miktari, ozgul a g irlik, daralma ve geni s lemeleri yaninda mekanik ozelliklerinden liflere paralel basinc direnci, statik ve dinamik e g ilme direncindeki de g i s meler belirlenmi s tir. Sonuc olarak; hava kurusu ozgul a g irlik, denge rutubet miktari ve radyal yondeki daralma ve geni s leme oranlari buharlama yapilmi s orneklerde daha du s uktur. E g ilme ve s ok direncinde daha fazla olmak uzere buharlanmi s orneklerin mekanik direnc ozelliklerinde azalma olmu s tur.