Mohammad Reza topa esfandiyari; Mohammad Talaei poor; Habibollah Khademi Eslam; Seeyed Ahmad Mirshokraie; behzad baziyar
Abstract
This study uses soda lignin to modify it with furfural as adhesive on the physical and mechanical properties of plywood Poplar wood. Producing plywood, pure Lignin (L.100%), lignin-furfural 30% (L.70-F.30), lignin- furfural 60% (L.40-F.60) were used as the adhesive at three different levels ( 120 140 ...
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This study uses soda lignin to modify it with furfural as adhesive on the physical and mechanical properties of plywood Poplar wood. Producing plywood, pure Lignin (L.100%), lignin-furfural 30% (L.70-F.30), lignin- furfural 60% (L.40-F.60) were used as the adhesive at three different levels ( 120 140 160gm2) accompanied with ammonium chloride (1%) as the hardener and wheat flour (30%) as the filler based on the dry weight of the adhesive. Plates made with urea formaldehyde resin at 160 g/m2 were produced as control samples. characteristics of adhesives included solid material percentage, viscosity, specific weight and PH were measured. After producing the laboratory boards, the physical and mechanical properties of samples, such as thickness swelling after 2 and 24 hours of being soaked in water, shear strength, modulus of rupture, and modulus of elasticity were measured. The results indicate that independent and interactive effects of adhesive and its consumption level on the physical and mechanical properties of plywood are not statistically significant. And in all cases, the control boards had better properties than the lignin adhesives
Physics and Mechanical Wood
Hadi Dashti; Kambiz Pourtahmasi; asghar tarmian
Abstract
In this research, the effect of preheating in nitrogen medium on acoustic properties of walnut and white mulberry’s boards was studied. Sapwood boards of 300×20×20 mm with the green moisture content were prepared. Heat treatments were applied at 140 and 160 oC under pressure of 2 pascal ...
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In this research, the effect of preheating in nitrogen medium on acoustic properties of walnut and white mulberry’s boards was studied. Sapwood boards of 300×20×20 mm with the green moisture content were prepared. Heat treatments were applied at 140 and 160 oC under pressure of 2 pascal for 30 and 60 minutes. Following the heat treatment, the samples were dried in a convectional laboratory kiln of 8% at 50 oC, relative humidity of 50%, and air velocity of 1 m/s to the average final moisture content of 8%. Using the free vibration method on free- free bar, the dynamic modulus of elasticity and damping factor were evaluated. Results revealed that the heat-treatment at 140 oC for 30 minutes did not have a significant effect on vibration properties of the wood samples. On the other hand, the heat-treatment at 160 oC caused a significant increase in dynamic modulus of elasticity and also a reduction in the damping factor of walnut and white mulberry samples. The FTIR spectroscopy and X-ray studies showed that the degradation of cell-wall polymers and increase in the crystallinity of the walnut wood specimens occurred due to heat treatment at 160 0C.
Physics and Mechanical Wood
shahrzad omrani ghahjaverstani; amir lashgari; mahran roohnia
Abstract
Non-destructive tests today play a vital role in human life. Non-destructive evaluation technology is widely used in industries, especially wood based industries and wood based products and has led to advances in Strength grading lumber, determine the disadvantages of wooden materials, Inspection of ...
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Non-destructive tests today play a vital role in human life. Non-destructive evaluation technology is widely used in industries, especially wood based industries and wood based products and has led to advances in Strength grading lumber, determine the disadvantages of wooden materials, Inspection of timber and wooden structures. The purpose of this research was to estimate the flexural strength of dynamic tests and compare them with the results of static standard tests in two Forest Pine species (Pinus sylvestris) and Rush (Fagus orientalis). The results of the comparison of the estimation of the modulus of elasticity and the estimated modulus of rupture by a non-destructive free vibration method in a free supported beam with similar results from the static test showed a very good correlation So, according to calculations done by applying a safety coefficient of 18% for beech species and 11% for pine species, a non-destructive vibration test can be substituted by a static destructive standard test for estimating the factors mentioned in these two species.
Amir Homan Hemmasi; mostafa kohantorabi
Abstract
In this study the relationship between dynamic modulus of elasticity from longitudinal vibration method with static modulus of elasticity and bending strength in two directions: the Parallel machine direction and machine direction have been investigated. For this purpose 4 plates ...
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In this study the relationship between dynamic modulus of elasticity from longitudinal vibration method with static modulus of elasticity and bending strength in two directions: the Parallel machine direction and machine direction have been investigated. For this purpose 4 plates of particleboard with dimensions 124× 90 ×1.6 cm (length× width× thickness) were selected and free longitudinal vibration test in PMD and MD were performed on each plates. After that the primary plates were cut to four plates with dimensions 62× 44 ×1.6 cm (length× width× thickness) and longitudinal vibration test in PMD and MD were performed on each plates again. Finally each plates were cut to the beams with dimensions 36× 1.6 ×1.6 cm and longitudinal vibration test and and static bending test were performed on them. The results show that good correlation between dynamic modulus of elasticity from longitudinal vibration test and static modulus of elasticity and bending strength (result of beams extracted from each plates) in both size of plates in two size (124× 90 ×1.6 and 62× 44 ×1.6 cm) and beams extracted from each plates in two directions (PMD and MD). In addition there was good correlation between dynamic modulus of elasticity of longitudinal vibration from two size plates (124× 90 ×1.6 and 62× 44 ×1.6 cm). When the samples smaller than primary plates, the dynamic modulus of elasticity values were increased, that it due to the diffusion of waves in samples with larger dimensions. In general, according to results of this research it can be concluded that by applying the appropriate correction factors, longitudinal vibration method an efficiency method for calculation of dynamic and static modulus of elasticity and estimate of the modulus of rupture in plates in full sized.
Physics and Mechanical Wood
Ehsan Haji rafiriha; Mehran Roohnia; Ahmad Jahan latibari; Ajang Tajidini
Abstract
The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied by non-destructive free vibration test. 120 samples with nominal dimensions of 2.5×2.5×45 ...
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The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied The effect of lamination and adhesive coverage rate in layered products made from Poplar wood was studied by non-destructive free vibration test. 120 samples with nominal dimensions of 2.5×2.5×45 cm without any obvious deficiencies were selected and free flexural vibration in free-free bars were performed for testing them. Samples were longitudinal cut in three thinner tangential layers and jointed together again using Poly Vinyl Acetate glue. The specimens were divided into four groups according to adhesive coverage rates, which one group was fully glued and 3 groups were carrying some glue deficiencies in different rates. Manipulated samples were tried again in above mentioned test. Results indicated that shear moduli compare to modulus of elasticity is a more sensitive parameter to evaluate glue efficiency in laminated beams but concerns remained due to blind points in flexural vibration nondestructive method.
Hossein Rangavar; Behzad Bazyar; Hamed Akbari
Abstract
Abstract : In this study, the possibility of using Cicer arietinum straw residues for manufacturing three-layer particleboards was studied.The amounts of Cicer arietinum straw in mixture with industrial particles were ( % 25:75),(% 40:60),(% 55:45) respectively.Urea formaldehyde (100%) and Melamin urea ...
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Abstract : In this study, the possibility of using Cicer arietinum straw residues for manufacturing three-layer particleboards was studied.The amounts of Cicer arietinum straw in mixture with industrial particles were ( % 25:75),(% 40:60),(% 55:45) respectively.Urea formaldehyde (100%) and Melamin urea formaldehyde at different ratios of MF / UF were used as binders. The resin were applied at two levls of (% 8,10) in core and two levels of (% 10,12) in surface layers, based on oven dried weight of particles. Mechanical and physical properties of boards ( Modulus of rupture, Modulus of elasticity, Internal bonding and thickness swelling and water absorption after 2, 24 hours soaking in water) were measured and data were analyzed, statistically. The results indicated that increase of Cicer arietinum straw lead to increase of bending strength and Modulus of elasticity. Also the increase of resin content and use of Melamin urea formaldehyde resin caused to improve mechanical and physical properties. In General, the use of Cicer arietinumstraw in mixture with industrial particles up to 55% , and resin content of (10,12%) in core and surface layers, resulted in producing boards with appropriate mechanicals properties which are suitable for interior uses.
Amir Eshraghi; Habib alah Khademeslami; Amir Nourbakhsh; Behzad Bazyar; Mohammad Talaeipoor
Abstract
In this study, aspen chips with OCC (Old Corrugated Container) were used in particleboard production and samples were prepared at two different levels of resin contents (%9 and %10) and three levels of combination:
1- %25 OCC +%75 aspen, 2- %50 OCC + %50 aspen, ...
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In this study, aspen chips with OCC (Old Corrugated Container) were used in particleboard production and samples were prepared at two different levels of resin contents (%9 and %10) and three levels of combination:
1- %25 OCC +%75 aspen, 2- %50 OCC + %50 aspen, 3- %75 OCC +%25 aspen. Indeed in this study these two mentioned factors are variable and other factors such as press temperature: 165 ºC, press time: 5 minute, mat moisture %12, board density 0.75 g/cm3 and press pressure 30 kg/cm2 were constant. After the boards were manufactured according to DIN-68763 standard, were undergone different tests such as: bending strength, modulus of elasticity, internal bonding strength and thickness swelling after 2 & 24 hours immersion in water. The results indicate that second ratio(%50 OCC and %50 aspen chips) is proper for bending applications and the first ratio(%25 OCC and %75 aspen chips) is proper for tensile and thickness swelling applications. Therefore, applying the OCC more than %50 in manufacturing combination; result in decreasing the physical and mechanical properties. Moreover the results show that when the resin content increases, the board features improve.
Mechanical conversion of wood and wooden fittings
Abdolah Najafi; Mehdi Faezipoor; Habibalah Khademi eslam; Saeid Kazemi; Amir homan Hamasi
Abstract
In this study flexural properties Wood-plastic composites(WPCs), the composites made from high density polyethylene(virgin, recycled and mix of them) and four types lignocellulosic fillers (wood sawdust, sanding of MDF, particleboard sawdust and rice hull) at %60 by weight fiber loadings were manufactured ...
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In this study flexural properties Wood-plastic composites(WPCs), the composites made from high density polyethylene(virgin, recycled and mix of them) and four types lignocellulosic fillers (wood sawdust, sanding of MDF, particleboard sawdust and rice hull) at %60 by weight fiber loadings were manufactured using a dry blend/hot press method. Nominal density and dimensions of the panels were 1g/cm3 and 35Î35Î1cm, respectively. After conditioning, flexural properties of the panels including flexural modulus and flexural strength were determined. The results show the flexural modulus and strength wood plastic composites containing sanding MDF and particleboard sawdust were higher than those made from other fillers. The flexural modulus and strength were affected by kind of high density polyethylene (virgin or recycled
Composite wood products
Saeid Kazemi najafi; Ali Shalbafan; Majid Charmahali
Abstract
Density profile of three types of medium density fiberboard (MDF) panels used in Iran market was studied through direct method and gradually removing of layer. Modulus of elasticity, bending strength, internal bond, water absorption and thickness swelling were also determined. The results show that the ...
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Density profile of three types of medium density fiberboard (MDF) panels used in Iran market was studied through direct method and gradually removing of layer. Modulus of elasticity, bending strength, internal bond, water absorption and thickness swelling were also determined. The results show that the shape of density profiles in all types of panels is nearly symmetric and normal, but the profil density in one was deeper, so it showed higher modulus elasticity and bending strength. No significant difference in internal bond was observed between different types of panels.
Composite wood products
Amir Nourbakhsh; Taghi Tabarsa; Abolfazl Kargarfard; Fardad Golbabaei
Abstract
Laminated veneer lumber (L. V. L) manufactured from Maple and Alder wood is investigated. Three levels of layer thicknesses of 2, 3 and 4mm. were investigated. Bending strength (MOR and MOE), CompressionThe results of this investigation indicated that laminated wood strength of samples produced from ...
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Laminated veneer lumber (L. V. L) manufactured from Maple and Alder wood is investigated. Three levels of layer thicknesses of 2, 3 and 4mm. were investigated. Bending strength (MOR and MOE), CompressionThe results of this investigation indicated that laminated wood strength of samples produced from Alder layers are superior to Maple. Statistical analysis of the results showed that the effect of wood species on strength properties was significantly different at 99% level. Layer thicknesses also showed significant effect on strength increasing layer thicknesses from 2 to 4 mm. caused a reduction on MOE and improved impact properties.The results of this investigation also showed that Alder layers at 4 mm. Is superior to Maple layers in impact properties.
Composite wood products
Ahmad Jahan latibari; Habibalah Arabtabar; Fardad Golbabaei; Abolfazl Kargarfard; Amir Nourbakhsh; Abbas Fakhryan roghani
Abstract
Laminated beam ( LB.) and laminated veneer lumber ( LVL) manufactured from maple, hornbeam and beech wood is investigated. Three levels of press pressures at 30, 35, 40 kg/cm2, three levels of layer thicknesses of 2, 3, 4 mm and tangential and radial layers are investigated. Bending strength (MOR and ...
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Laminated beam ( LB.) and laminated veneer lumber ( LVL) manufactured from maple, hornbeam and beech wood is investigated. Three levels of press pressures at 30, 35, 40 kg/cm2, three levels of layer thicknesses of 2, 3, 4 mm and tangential and radial layers are investigated. Bending strength (MOR and MOE) and shear strength were measured according to ASTM 1186 and 905 respectively.The results of this investigation indicated that laminated wood strength of samples produced from hornbeam layers is superior to beech and beech is superior to maple. Statistical analysis of the results showed that the effect of wood species on strength properties is significantly different at 99% level. Press pressure also showed significant effect on strength. Increasing press pressure improved bending properties, but the highest shear strength was observed at 30 kg/cm2. Cutting direction did not influence bending strength and only influenced the shear strength. Even though the initial anticipation was the fact that thinner layer will produce stronger laminated wood. But the results or this study showed that layer thickness did not significantly affect strength properties.
