THERMAL CONDUCTIVITY VALUES OF SOME WOOD SPECIES USED IN PLYWOOD INDUSTRY

Thermal conductivity is one of the most important properties for construction materials. The aim of the study was to determine the thermal conductivity values of veneers from common wood species used in plywood industry. For this aim, Scots pine, maritime pine, black pine, poplar, beech, alder, spruce, birch, plane tree, tetra, okoume, ozigo were used as wood species in this study. Thermal conductivity values of the veneers were determined according to ASTM C518 by means of The Fox 314 instrument. It was determined from the study that there were differences among the thermal conductivity values of the veneers obtained from wood species in plywood industry. It was also concluded from the study that some manufacturing parameters such as veneer drying temperature affect the thermal conductivity values of veneers

Predviđanje optimalne gustoće ekspandiranog polistirena za najbolje performanse toplinske izolacije polistirenske kompozitne iverice primjenom umjetne neuronske mreže

The objective of this study is to predict the optimum expanded polystyrene (EPS) densities for the best insulation properties of the particleboards manufactured with waste EPS instead of formaldehyde-based adhesives used in particleboard production with artificial neural network (ANN). For this purpose, the waste EPS particles of five different densities were used in the production of composite particleboards. The experimental dana used in the study were obtained from the previous study. Half of the beech, poplar, alder, pine and spruce chips were dried in a drying oven and the other half were naturally conditioned at room temperature, and then 18 mm thick three-layer composite particleboards were produced. The thermal conductivity of panels was determined according to ASTM C 518. The prediction model with the best performance and acceptable deviations was determined by using statistical and graphical comparisons between the experimental data and the prediction values obtained as a result of ANN analysis. Then, using this prediction model, the thermal conductivity coefficient values were estimated for the intermediate EPS densities that were not experimentally tested. According to the analysis findings, the thermal insulation performance for both beech and spruce polystyrene composite particleboards (PCP) panels increased with using of waste EPS foams with a density of 30 kg/m3. The lowest thermal conductivity values were obtained from the EPS waste foams with the density of 18, 13 and 22 kg/m3 for the PCP panels produced with poplar, alder and pine in the natural drying, respectively. In the technical drying, these values were found to be 15, 14 and 11-13 kg/m3, respectively. Technical drying showed much better thermal performance than natural drying while poplar indicated the best performance among the wood species.Cilj je ove studije primjenom umjetne neuronske mreže (ANN) predvidjeti optimalne gustoće ekspandiranog polistirena (EPS) radi postizanja najboljih izolacijskih svojstava iverice proizvedene s otpadnim EPS-om umjesto s ljepilom na bazi formaldehida, kakvo se rabi u proizvodnji iverice. Stoga je za proizvodnju iverice upotrijebljen otpadni EPS pet različitih gustoća. Eksperimentalni podatci primijenjeni u studiji dobiveni su prijašnjim istraživanjem. Jedna je polovica iverja bukovine, topolovine, johovine, borovine i smrekovine osušena u sušioniku, a druga je polovica iverja kondicionirana na sobnoj temperaturi. Od osušenoga i kondicioniranog iverja proizvedene su troslojne kompozitne iverice debljine 18 mm. Toplinska vodljivost ploča određena je metodom ASTM C 518. Predikcijski model najboljih svojstava i prihvatljivih devijacija određen je statističkom i grafičkom usporedbom eksperimentalnih podataka s vrijednostima predviđenima ANN analizom. Potom su primjenom predikcijskog modela procijenjeni koeficijenti toplinske vodljivosti za one gustoće ekspandiranog polistirena koje nisu eksperimentalno ispitane. Prema toj analizi, termoizolacijska svojstva polistirenske kompozitne iverice (PCP) od bukovine i smrekovine poboljšana su pjenom od otpadnog EPS-a gustoće 30 kg/m3. Najniže vrijednosti toplinske vodljivosti za polistirensku kompozitnu ivericu od prirodno osušene topolovine, johovine i borovine dobivene su uz uporabu pjene otpadnog ESP-a gustoće 18, 13 i 22 kg/m3. Za polistirensku kompozitnu ivericu od tehnički osušenog iverja te su vrijednosti bile 15, 14 i 11-13 kg/m3. Tehničkim sušenjem iverja postignuta su znatno bolja toplinska svojstva polistirenske kompozitne iverice nego prirodnim sušenjem, a topolovina je pokazala najbolja svojstva od svih ispitivanih vrsta drva

Utjecaj materijala za oblaganje na svojstva posmičnog zida od furnirske ploče

Wooden buildings are intensely preferred especially in earthquake regions due to their many advantages such as lightness, durability, environmental friendliness, insulation and aesthetics. Shear walls provide the lateral resistance needed for light-frame wood structures to withstand earthquake loads. When sheathed with wooden structural panels such as plywood, shear walls can be strong, stiff, and ductile. This study focuses on the effects of production factors (wood species, thickness of panels) of plywood and fibre direction of sheathing material on the racking performance of the shear wall. The displacement at ultimate load decreased with increasing the thickness of plywood panels. It was also concluded that the black pine plywood panels were the best sheathing materials for the shear walls among wood species in terms of ductility. Scots pine plywood panels are the best sheathing materials for the shear walls among wood species in terms of load carrying capacity. Moreover, it was found that the wall formed perpendicular to fibre direction of sheathing materials could carry more load than the wall formed parallel to fibre direction.U potresnim su područjima osobito zastupljene drvene građevine zbog njihovih brojnih prednosti kao što su lakoća, trajnost, ekološka prihvatljivost, izolacija i estetika. Posmični zidovi osiguravaju bočnu otpornost kako bi lagane drvene konstrukcije izdržale potresna opterećenja. Kada su obloženi drvenim strukturnim pločama kao što je furnirska ploča, posmični zidovi mogu biti jaki, kruti i duktilni. Ovo je istraživanje fokusirano na učinke proizvodnih čimbenika furnirske ploče (vrstu drva, debljinu ploče) te na smjer vlakanaca materijala za oblaganje na svojstva posmičnog zida. Pokazalo se da se s povećanjem debljine furnirske ploče smanjuje pomak pri krajnjem opterećenju. Također je zaključeno da su sa stajališta duktilnosti furnirske ploče od drva crnog bora bolji izbor za oblaganje posmičnih zidova nego furnirske ploče od ostalih istraživanih vrsta drva. Sa stajališta nosivosti, za oblaganje posmičnih zidova najboljima su se pokazale furnirske ploče od drva bijelog bora. Osim toga, utvrđeno je da zid formiran okomito na smjer vlakanaca materijala za oblaganje može nositi veće opterećenje nego zid formiran paralelno sa smjerom vlakanaca materijala za oblaganje

YONGALEVHA ÜRETİMİNDE KONTRPLAK ATIKLARININ KULLANILMASI

Bu çalışmada çam kontrplak atıklarından üretilen yongalevhaların bazı teknolojik özelliklerinin araştırılması amaçlanmıştır. Bu amaçla çam kontrplak atıklarından ve çam odunundan elde edilen yongalar farklı oranlarda (%25, %50, %75, %100) karıştırılarak yongalevhalar üretilmiştir. Üretilen yongalevhaların mekanik özelliklerinden EN 319’ a göre yüzeye dik çekme direnci, EN 310’ a göre eğilme direnci; fiziksel özelliklerinden EN 323’ e göre yoğunluk, EN 322’ ye göre denge rutubet miktarı ve EN 317’ ye göre kalınlığına şişme ve su alma değerleri belirlenmiştir.Sonuç olarak; üretilen yongalevhaların eğilme direnci ve yapışma direnci değerleri tüm gruplar için EN’nin ilgili standartlarında genel kullanım amaçlı yongalevhalar için öngörülen değerleri karşılamıştır

Utjecaj procesa sušenja furnira na tehnološka svojstva kompozitnih uslojenih drvnih ploča vezanih polistirenom

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

MÜF TUTKALI İLE ÜRETİLEN ÇEŞİTLİ AĞAÇ TÜRÜ KONTRPLAKLARINDA PRESLEME SÜRESİNİN FORMALDEHİT EMİSYONUNA ETKİLERİ

Odun esaslı levha ürünlerinin üretiminde çeşitli avantajları nedeniyle önemli ölçüde kullanılan formaldehit esaslı reçineler üretim esnasında ve sonrasında insan sağlığı ve çevre için zararlı olan formaldehit ayrışmasına neden olmaktadır. Bu çalışmada 2 mm kalınlığındaki doğu kayını (Fagus orientalis Lipsky), sarıçam (Pinus sylvestris L.) ve sakallı kızılağaç (Alnus glutinosa subsp. Barbata), soyma kaplamalarından melamin-üre formaldehit tutkalı kullanılarak üretilen 3 tabakalı kontrplakların formaldehit emisyonu üzerine presleme süresinin etkileri araştırılmıştır. Bu amaçla üretilecek kontrplaklar için 5 farklı (4, 5, 6, 7 ve 8 dk.) presleme süresi seçilmiştir. Çalışma sonuçlarına göre, pres süresindeki artışa bağlı olarak kontrplak levhalarından ayrışan formaldehit miktarlarında doğrusal bir azalma meydana gelmiştir. En fazla formaldehit emisyonu miktarı sarıçam kontrplaklarda belirlenirken, en düşük emisyon değerleri sakalı kızılağaç kontrplaklar için elde edilmiştir. 

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

Thermal insulation properties of hybrid textile reinforced biocomposites from food packaging waste

Due to the significant and harmful effect of the global warming on our communities, health, and climate, the usage of thermal insulation material in building is must to decrease the energy consumption and to improve energy efficiency. On the other hand, the utilization of waste and biomass resources for developing new bio-based composite materials is attracting much attention for the environmental and socioeconomics. Therefore, in this study, thermal insulation bio-based composite panels from Tetra Pak (R) waste and wool fiber waste with different ratios were manufactured. Likewise, other sandwich bio-based composite panels were manufactured using Tetra Pak waste as a core material with glass woven fabric and jute wove fabric as skin materials. Thermal conductivity and thermal resistance results showed a significant improvement on thermal insulation properties of the developed biocomposite panels compared to the control samples made of plain Tetra Pak (R)

Influence of Aging Procedure on Bonding Strength and Thermal Conductivity of Plywood Panels

Wood and wood composite materials have been used in house, school, and office construction throughout the world. Wood composite materials are superior to other building materials in terms of thermal conductivity due to its porous structure. Bonding strength and thermal conductivity are two of many other significant properties of composite panels used in construction. It was essential to determine the effect of ageing process on the properties of panels used in structural applications. This study evaluates thermal conductivity and bonding strength of Scots pine and black pine plywood panels manufactured from rotary cut veneers dried at three different temperatures: 110 degrees C, 140 degrees C, and 160 degrees C. Phenol formaldehyde (PF) and melamine urea formaldehyde (MUF) were used as adhesives for plywood manufacturing. Panels were exposed to ageing process according to ASTM C 481-99 standard. Plywood panels with five plies and 10 mm thickness were manufactured for each group. Thermal conductivity and bonding strength values of plywood panels were determined. Thermal conductivity of the panels decreased with increase of the drying temperature. It was also found that the thermal conductivity of test panels decreased after the ageing process. Shear strength mean values obtained from the samples of all plywood panels were above the limit value (1.0 N/mm(2)) indicated in TS EN 314-2 standard but those of the panels with MUF after ageing process