Sinteza fenolne smole ojačane nanočesticama TiO2 i njezin utjecaj na gorivost lamelirane drvne građe (LVL)

In this study, phenol-formaldehyde (PF) resin has been modified with titanium dioxide nanoparticles (nano-TiO2) at a varying ratio from 0.05 wt.% to 1.5 wt.% to enhance the thermal properties and combustion performance of the resins. The effect of the nano-TiO2 modification on the properties (chemical or thermal) of the resins was determined by Fourier to transform infrared (FT-IR) and thermal analysis (TGA) techniques. In addition, the combustion performance of laminated veneer lumber (LVL) samples bonded with the PF resin modified with nano-TiO2 was tested. The result of the FT-IR analysis indicated that the modified PF resins had match peaks to the reference PF resin. These similarities of the peaks supported that the modified PF resins were successfully synthesise with phenol, formaldehyde, and nano-TiO2. The PF resins modified by nano-TiO2 demonstrated better thermal stability than the reference resin. The nano-TiO2 modified PF resin exhibited a favourable influence on the combustion characteristics of LVL. In consequence, PF resin modified with nano-TiO2 could be used as a combustion retardant adhesive in the wood industry.U ovom je istraživanju fenol-formaldehidna smola (PF) modificirana nanočesticama titanijeva dioksida (nano-TiO2) u različitim omjerima, od 0,05 tež.% do 1,5 tež.% kako bi se poboljšala njezina toplinska svojstva i svojstva gorivosti. Utjecaj modifikacije nanočesticama TiO2 na svojstva smola (kemijska i toplinska) određen je Fourierovom transformiranom infracrvenom spektroskopijom (FT-IR) i termogravimetrijskom analizom (TGA). Osim toga, ispitana je gorivost uzoraka lamelirane drvne građe (LVL) lijepljene PF smolom modificiranom nano-česticama TiO2. Rezultati FT-IR analize pokazali su da modificirane PF smole imaju jednake vrhove kao referentna PF smola. Te sličnosti vrhova potvrđuju da su modificirane PF smole uspješno sintetizirane s fenolom, formaldehidom i nanočesticama TiO2. PF smole modificirane nanočesticama TiO2 pokazale su bolju toplinsku stabilnost od referentne smole i povoljno su utjecale na gorivost LVL-a. Stoga zaključujemo da bi se PF smola modificirana nanočesticama TiO2 mogla upotrebljavati kao ljepilo za usporavanje gorenja u drvnoj industriji

Physical Characterization and Bonding Performance of Phenol-Formaldehyde/Waste Tyre Pyrolytic Oil Blend Adhesive

Several million tons of waste tyres are generated every year all over the world. Many researches have been conducted on the use of recycled tyre products in the industrial area including chemical feedstock. In this study, the bonding performance of commercial phenol-formaldehyde (PF) adhesive containing different amounts of waste tyre pyrolytic oil (10-40 wt%) was investigated. The chemical structure of the waste tyre pyrolytic oil was analysed using Fourier transform infrared spectroscopy (FT-IR). The effect of the substitution level of the tyres pyrolytic oil on the physical characteristics of the PF adhesive was determined. In addition, the shear strength of single lap-joint wood samples bonded with the blended PF adhesives was determined for indoor and outdoor conditions. It was found that the solid content of the blended PF adhesives decreased with increasing amount of the pyrolytic oil. The bonding performance of the wood samples bonded with the PF adhesives containing up to 20 wt% pyrolytic oil were about the same as that of commercial PF adhesive. Finally, pyrolytic oil could be partially blended with commercial PF adhesive

Effects of scarf joints on bending strength and modulus of elasticity to laminated veneer lumber (LVL)

WOS: 000243121000055The role of geometry on the mechanical performance of scarf joints in laminated veneer lumber (LVL) bonded with phenol formaldehyde and melamine formaldehyde (MF) adhesives was investigated. Model joints consists of 3, 4 and 5 mm veneer thicknesses at 30 degrees, 45 degrees and 60 degrees of varying scarf joints for LVL produced from brutia pine (Pinus brutia Ten) and elm (Ulmus compestris 1.) woods. However, there is little information available concerning the bending strength and modulus of elasticity for LVL, and in particular, scarf joints in these field. In this study, it was aimed to determine the bending strength and modulus of elasticity for LVL. For this purpose, samples were tested according to TS EN 3 10 standard. It was observed that the highest bending strength (291.5 N/mm(2)) and modulus of elasticity (28 101 N/mm(2)) were obtained in control (solid wood) samples having three layered LVL, jointed with 30 degrees angle and bonded with MF adhesive. As a result of the effects scarf joints on bending strength and modulus elasticity test, if the scarf angle decreases, the properties of LVL increase. (c) 2006 Elsevier Ltd. All rights reserved

The effects of screw and back panels on the strength of corner joints in case furniture

WOS: 000251487900026This study was carried out to determine the effects of screw and back panel on the corner joints in case furniture produced from medium density fiber board MDF, and particle board (PB). For this purpose, the different test panels, the edges of which were covered or uncovered with solid wood or massive and back rebated, not back rebated samples, were used and the types of "L corner joints" were manufactured. Also, the plywood used for back panel had a thickness of 4 mm. Compression and tension strength tests were applied on the corner joints in accordance with ASTM-D 143-83 standards. As a result, the highest tension strength was obtained in covered edges of MDF as 181.7 Nm, the lowest in rebated and uncovered samples as 78.7 Nm, the highest compression strength was obtained in rebated and covered samples as 178.7 Nm, and the lowest was observed in unrebated and uncovered samples as 79.5 Nm. In conclusion, the edges of cupboard panels should be rebated and covered with solid wood or massive wood in Case furniture. (c) 2007 Elsevier Ltd. All rights reserved

Determination of modulus of rupture and modulus of elasticity on flakeboard with fuzzy logic classifier

In this study, a model based on fuzzy logic classifier was created in order to determine the values of modulus of elasticity (MOE) and modulus of rupture (MOR) of flakeboards. MOR and MOE are the most important mechanical features of wood-composite panels. The most appropriate mixture ratios to be used in production of wood based boards were determined experimentally. These experiments are very expensive for the manufacturers and require time. For this purpose, MOE and MOR values were measured depending on flakes mixture ratios of manufactured boards. Using these values, input and output values and rule base of fuzzy logic classifier were created. With the fuzzy logic classifier model prepared in Matlab Simulink, MOR and MOE values for flakes mixture ratios were predicted. It was observed that the fuzzy logic classifier predicted MOR and MOE values with 95-97% accuracy. With this system, for the manufacture of wood-composite materials, the most appropriate chip mixture amount required by the manufacturer could be determined. (C) 2008 Elsevier Ltd. All rights reserved

Effect of Tenon Geometry, Grain Orientation, and Shoulder on Bending Moment Capacity and Moment Rotation Characteristics of Mortise and Tenon Joints

Bending moment capacity and moment rotation characteristics of mortise and tenon joints as a function of tenon geometry, grain orientation, length, and shoulder fit were examined. Bending moment capacity of all joints in which tenons were fully inserted in mortises was 54% greater than for joints in which tenons were not fully inserted. Jointswith 25.4-mm-long diamond-shaped tenons had greater moment capacity than either rectangular or round tenon joints, whereas joints with 38- or 51-mm-long rectangular tenons had greater capacities than jointswith diamond or round tenons. Similarly, for joints inwhich tenonswere not fully inserted, rectangular tenons had the greatest moment capacity regardless of grain orientation or length

THE EFFECT OF GRAIN ANGLE AND SPECIES ON THERMAL CONDUCTIVITY OF SOME SELECTED WOOD SPECIES

In this study the thermal conductivity of different wood materials was determined. For this purpose, Scots pine (Pinus sylvestris L.), Uludag fir (Abies Bornmülleriana Matff), Oriental beech (Fagus orientalis L), Oak (Quercus robur L.), and Chestnut of Anatolia (Castanea sativa Mill.) woods were used. In the test, the thermal conductivity of the woods was measured according to procedure of ASTM C 1113-99 standards. The lowest thermal conductivity was obtained in the perpendicular direction of Scots pine samples as 0.156 Kcal/mh°C. The highest thermal conductivity was obtained from perpendicular direction of samples in Oriental beech as 0.331 Kcal/mh°C

THE EFFECTS OF ADHESIVE RATIO AND PRESSURE TIME ON SOME PROPERTIES OF ORIENTED STRAND BOARD

This study was carried out to determine the effects of adhesive ratio and pressure time on thickness swelling (TS), internal bond (IB), modulus of rupture (MOR), and modulus of elasticity (MOE) properties of oriented strand board (OSB). For this purpose, 80 mm long strands made of Scots pine (Pinus sylvestris L.) were bonded with phenol-formaldehyde resin at three different ratios (3, 4.5, and 6\%) to produce three-layer cross-aligned OSBs. Strands used for the production of OSB panels were made up 40\% of core layer and 60\% of outer layers. The panels were pressed for three different press times, from 3, 5, to 7 minutes, under 0.4 MPa pressure, aiming for a target density of 0.70 g/cm3. TS, IB, MOR, and MOE properties of OSB panels were evaluated according to the standards (TSE EN 117-319-310). Results showed that MOR and MOE values were changed in the ranges 25.31 to 42.27 N/mm(2), and 2848.90 to 6545.63 N/mm(2), respectively. Also, the results showed that as adhesive ratio and pressure time increased, the TS, MOR, and MOE values increased too

Technical Note: Static Versus Cyclic Load Capacity of Side Chairs Constructed with Mortise and Tenon Joints

The effect of cross-sectional tenon geometry on static and cyclic load capacity of side chairs constructed with round-, rectangular-, and diamond-shaped mortise and tenon joints was investigated. Cyclic load capacity averaged about two-thirds of static load capacity for the joint configurations tested. For the configurations included in the test, chairs with mortise and tenon joints constructed with round-, rectangular-, and diamond-shaped tenons had static load to cyclic passing load ratios of 56.5, 66.8, and 69.2% for rectangular-, round-, and diamond-shaped tenons, respectively. These results indicate that useful relationships existed between static and cyclic performance of round mortise and tenon joints, which may simplify the design process for chairs that must pass cyclic performance tests