Effect of veneer drying process on some technological properties of polystyrene composite plywood panels

• Published in: Drvna industrija Vol. 70; no. 4; pp. 369 - 376
• Main Authors: Ozturk, Hasan, Demir, Aydin, Demirkir, Cenk, Colakoglu, Gursel
• Format: Journal Article
• Language: English
• Published: 01.12.2019
• ISSN: 0012-6772; 1847-1153
• DOI: 10.5552/drvind.2019.1844

The aim of study was to determine the effect of veneer drying process on some technological properties of polystyrene composite plywood panels. For this reason, 2 mm-thick rotary cut veneers were obtained from beech (Fagus orientalis, Lipsky), Alder (Alnus glutinosa subsp. Barbata) and Scots pine (Pinus sylvestris L.) logs. The veneers obtained from three different wood species were divided into two groups to produce polystyrene composite plywood (PCP) and traditional plywood. While PCP was produced both air dried (at 20 °C) and oven dried (at 110 °C), the veneer sheets for production of traditional plywood were dried at 110 °C until reaching 7 % equilibrium moisture content. Two different types of polystyrene with high density (30 kg/m3) and low density (16 kg/m3) were used as bonding material for PCP panel production. The urea-formaldehyde adhesive was used as a bonding material for traditional plywood panels. Bonding shear strength, bending strength, modulus of elasticity and density of plywood and polystyrene composite plywood panels were investigated. It was found that the technological properties observed in the study of composite plywood panels manufactured with natural dried veneers gave similar results compared to those of composites produced with technical dried veneers. Cilj ovog istraživanja bio je utvrditi utjecaj procesa sušenja furnira na tehnološka svojstva kompozitnih uslojenih drvnih ploča vezanih polistirenom. Ljušteni furniri debljine 2 mm pripremljeni su od trupaca drva bukve (Fagus orientalis, Lipsky), drva johe (Alnus glutinosa subsp. Barbata) i drva običnog bora (Pinus sylvestris L.). Furniri od tri različite vrste drva podijeljeni su u dvije skupine kako bi se proizvela kompozitna uslojena ploča vezana polistirenom (PCP) i tradicionalna uslojena ploča. Za proizvodnju PCP ploča rabljeni su furniri sušeni na zraku (na 20 °C) i u sušioniku (na 110 °C), a za proizvodnju tradicionalne uslojene ploče upotrijebljeni su furniri sušeni pri 110 °C sve do postizanja ravnotežnog sadržaja vode od 7 %. Kao vezivo za PCP ploče uporabljene su dvije vrste polistirena – polistiren velike gustoće (30 kg/m3) i polistiren male gustoće (16 kg/m3). Za proizvodnju tradicionalne uslojene ploče kao vezivo je služilo urea-formaldehidno ljepilo. Istraživani su smična čvrstoća lijepljenog spoja, čvrstoća na savijanje, modul elastičnosti te gustoća uslojene i kompozitne uslojene ploče vezane polistirenom. Utvrđeno je da kompozitne uslojene drvne ploče proizvedene od prirodno sušenih furnira imaju slična promatrana tehnološka svojstva kao i kompoziti proizvedeni od tehnički sušenih furnira.