Management and Economics wood
Neda Esmaeili; Maryam Ghorbani; Porya Biparva
Abstract
In this study, the mechanical and biological properties of modified poplar wood with glutaraldehyde and paraffin were investigated. Modification was performed with glutaraldehyde at different concentrations of glutaraldehyde, 5, 10 and 20% using magnesium chloride as a catalyst and then subsequently ...
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In this study, the mechanical and biological properties of modified poplar wood with glutaraldehyde and paraffin were investigated. Modification was performed with glutaraldehyde at different concentrations of glutaraldehyde, 5, 10 and 20% using magnesium chloride as a catalyst and then subsequently with paraffin by vacuum-pressure method. Increasing concentration of glutaraldehyde caused to weight gain and bulking wood cell wall, subsequently reduced paraffin penetration into the porous structure of wood. Biological resistance exposed to white rot fungi and mechanical properties were measured according to the standards EN113 and ASTM D143-94, respectively. Scanning electron microscopic images showed bulking of cell walls and paraffin presence in cell cavities. According to results of TGA, increasing of modification intensity decreased mass loss due to cross linking formation between glutaraldehyde and cell wall polymers. Paraffin at combined modification containing 10% and 20% glutaraldehyde improved significantly the modulus of elasticity. Glutaraldehyde reduced bending strength, but paraffin present in the modified samples improved it. The Glutaraldehyde increased compression strength parallel to grain and hardness that the improvement was more obvious in combined modification. Modification with glutaraldehyde enhanced decay resistance exposed to white rot fungi, and this improvement intensified at the presence of paraffin. Inhibitory influence of chemical modification on wood attacking white rot fungi can be attributed to decreases the wood moisture, bulking of cell walls and blocking cell cavities.
Management and Economics wood
Farvahl Sobhani Oskouie; Maryam Ghorbani; Saeid mojtaba Amini nasab
Abstract
The objectives of this research determine for optimum condition modification with effect of 3-(trimethoxysilyl) propyl methacrylate on physical properties of Poplar wood-polymer were performed. Test samples from Poplar species were divided to five levels: control, Acidified Ethanol/Silan/110 ˚C, Acidified ...
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The objectives of this research determine for optimum condition modification with effect of 3-(trimethoxysilyl) propyl methacrylate on physical properties of Poplar wood-polymer were performed. Test samples from Poplar species were divided to five levels: control, Acidified Ethanol/Silan/110 ˚C, Acidified Ethanol/Silan/150 ˚C, Ethanol / Silan / 150°C and Silan/150°C in two levels with and without Benzoyl peroxide. Samples were impregnated with silan compound according to vacuum-pressure method in experimental cylinder. Weight percent gain of Silan/Et/BP/150 ˚C level by 24/40% had the maximum value were determined. Bulking efficiency and OH groups substituted in Silan/AEt/150 level with 6.81 % and 1.10 mol/gr, respectively compared with the other levels.Modification were resulted to improve water absorption and dimensional stability that maximum dimensional stability in contain initiator level were determined. In immersion-dry period test, the highest and lowest bulking efficiency in Silan/AEt/150 and Silan/Et/150 were reported. Maximum of weight loss in immersion-dry test was determined in Silan/AEt/110 with the 3.6% value.Key words: physical properties, 3-(trimethoxysilyl) propyl methacrylate, Asidified Ethanol, bulking efficiency
asghar tarmian; Seaid Alireza Dehghan; Elnaz Trighnoor; Mohammad reza Pyramon; Razyeh Shamsy; Mohammad Layeghi
Abstract
In this research, the performance of a semi-greenhouse solar kiln was evaluated for dying different wood species in different season in Karaj. This study was carried out in two separate parts. In the first part, the flat-sawn boards of oak and fir with a nominal thickness of 50 mm were dried during summer ...
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In this research, the performance of a semi-greenhouse solar kiln was evaluated for dying different wood species in different season in Karaj. This study was carried out in two separate parts. In the first part, the flat-sawn boards of oak and fir with a nominal thickness of 50 mm were dried during summer of the year 2012. In the second part, the flat-sawn boards of beech and poplar with the same thickness were dried in autumn, 2014 and spring, 2015. For both parts, the boards were also air-dried. The temperature measured inside the solar kiln was 35 ºC greater than that outside during daytime and also the kiln temperature ranged from 55 to 75ºC during 10 a.m. to 2 p.m.. In both parts of research, all wood species dried in the solar kiln faster with better quality compared to those air-dried. The severity of casehardening and surface checking in the boards dried in the solar kiln was lower and more homogenous moisture profile was observed. In addition, the final moisture content was lower for the boards dried in the solar kiln.
Management and Economics wood
Neda Esmaeeli; Maryam Ghorbani; pourya biparva
Abstract
This research was conducted to determine the optimal conditions for chemical modification of poplar wood with glutaraldehyde and its effect on the physical properties of products. Test samples were prepared according to the standard ASTM-D1037 and impregnated in the laboratory cylinders with Glutaraldehyde ...
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This research was conducted to determine the optimal conditions for chemical modification of poplar wood with glutaraldehyde and its effect on the physical properties of products. Test samples were prepared according to the standard ASTM-D1037 and impregnated in the laboratory cylinders with Glutaraldehyde at a concentration of 10% by using vacuum-pressure method. Modification reaction was done in two procedure. Heating first in the laboratory cylinder (Hydrothermal) for 4 hour and second in oven for 4 level 4,12,24,48 and 48hours. Weight percent gain of modified by hydrothermal and oven method was measured 2.10, 9.26, 10.02, 11.40 and 14.15% respectively. Chemical modification with glutaraldehyde by hydroxyl group's substitution, reduced the uptake of water and swelling of poplar wood. So that at the end of soaking in water the heating in the oven for 48 hours with minimum water absorption and dimensional changes in the 57.32 and 12.08 respectively, and highest bulking, ASE and ASE′ in 8.31,67 and 35.51% respectively was selected as the optimal level. This improvement compared to other modification levels demonstrates the forming of permanent Cross-linking of acetal that increased by Prolongation of the heating time.
Management and Economics wood
Reza Oladi
Abstract
One of the main reasons for low treatability of pine wood is pit aspiration during drying in free water domain or heartwood formation. In this research, for opening the aspirated pits in heartwood of loblolly Pine (Pinus taeda), biological incising modification method with bacteria was used and the impacts ...
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One of the main reasons for low treatability of pine wood is pit aspiration during drying in free water domain or heartwood formation. In this research, for opening the aspirated pits in heartwood of loblolly Pine (Pinus taeda), biological incising modification method with bacteria was used and the impacts of different environments and strains of bacteria on the wood gas permeability were studied. Several famous and known strains of Bacillus subtilis UT B96 bacteria in collection of plant protection department of University of Tehran (22, 35, 40, and 96) were supplied in two different culture media of bacteria, namely Nutrient Broth and water bacteria solution. Optical microscopy was used to figure out the qualitative bacterial effect on the tracheid pit pairs. Data analysis revealed that bacteria strain no.22 and water bacteria solution are the most suitable selections to open the aspirated pits and improve the wood permeability. The more destructive effect of the best strain of bacteria may be due to its ability to produce more degrading enzyme. The higher impact of bacteria in the aquatic environment is probably due to their easier mobility, limited access to oxygen or lack of access to an alternative food.
Management and Economics wood
Mohammad Ghofrani
Abstract
In this study, the effect of heat treatment of Alder (Alnus glutinosa), Poplar (Populus nigra) and Spruce (Picea abies) on adhesion strength of clear and acid catalyzed transparent coating was investigated. For this aim, wooden samples were prepared with dimension of 200×100×18 mm (longitudinal, ...
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In this study, the effect of heat treatment of Alder (Alnus glutinosa), Poplar (Populus nigra) and Spruce (Picea abies) on adhesion strength of clear and acid catalyzed transparent coating was investigated. For this aim, wooden samples were prepared with dimension of 200×100×18 mm (longitudinal, tangential, radial) from sapwood on tangential surface. Samples were kept under heat treatment in oven with 150 and 180˚C temperatures for about 3 hours. After treatment, samples’ surfaces were sanded with 120 and 180 grit size sand paper, respectively. Contact angle of water was measured before and after treatment. Samples’ surfaces were covered with a transparent coat in two separate processes which were clear and acid catalyzed. Adhesion strength of coating measured with Pull Off method according to ASTM D-4541 standards. Results showed that the heat treatment increased contact angle. This increase continues as the heat treatment temperature goes higher and it leads to decrease in wettability of samples’ surfaces. Results also indicated that heat treated of wood had significant effect on adhesion strength of coating. Adhesion strength in control samples was more than heat treated samples. lowest coating strength was observed in samples which were heat treated in 180 ˚C.
Management and Economics wood
Mehdi Jonobi; Shabo Salehpoor; zhreh Araaznia; Yahya Hamzeh
Abstract
This study was carried out to investigate the effect of storage time on the color and chemical compounds of bagasse particleboard made. For this purpose, the three levels of stored and fresh bagasse from karoon particleboard Company were used. In addition, the chemical compositions ...
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This study was carried out to investigate the effect of storage time on the color and chemical compounds of bagasse particleboard made. For this purpose, the three levels of stored and fresh bagasse from karoon particleboard Company were used. In addition, the chemical compositions were determined according to the TAPPI test methods and also biometrical (slenderness ratio) was done using the fiber dimension measured by Franklin method. The results showed that the amount of lignin was different in the stored samples at three levels, but the difference in the amount of cellulose and extractive was not observed. The results illustrated that the color changes in the stored bagasse were more than fresh sample. Identification of the microorganisms in stored samples was done and results showed that most of microorganisms were bacteria and yeast. The results showed that the storage time can significantly effect the color and physical properties of stored bagasse.
Management and Economics wood
shahram tahmasebi; behzad bazyar; habibolah Khademi Islam; mohammad Ghofrani
Abstract
In this study, structural performance of corner joint reinforced by fiber reinforced polymers (FRP) at the area of maximum tension stress was investigated under diagonal tension loading. Therefore 1 to 3 layers of unidirectional woven Glass, Carbon and Kevlar fibers were used ...
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In this study, structural performance of corner joint reinforced by fiber reinforced polymers (FRP) at the area of maximum tension stress was investigated under diagonal tension loading. Therefore 1 to 3 layers of unidirectional woven Glass, Carbon and Kevlar fibers were used and hand lay-up was done by vinyl ester and epoxy resins. Results of load-displacement curve at yield point exhibited capability of the reinforcing layers in preventing joint opening to some extent under load. However, failure was observed at the joint due to picking fibers from wood surface or members fracture near the interface when loading increased. Since the reinforced zones of the joints by FRP show the maximum shear stress, consequently the separation of fibers from wood surfaces increased at these locations. The adhesion of FRP layers to joint surface was not appropriate due to difficult process of layering at right angle of joints followed by probable formation of air bubbles. The results of assessing FRPs reinforcing behaviour indicated that application of vinyl ester in comparison with epoxy as matrix exhibited better performance. In addition, glass and carbon fibers showed better performance than Kevlar fibers as reinforcing agents.
Management and Economics wood
Saeed Khojasteh Khosro; Mohammad Ghofrani; Morteza Ganjaei sari
Abstract
In this study the effect of adding zinc oxide nanoparticles (ZnO) on color change and adhesion strength of polyurethane clear coat in Elm wood species (Ulmus glabra) investigated. ZnO nanoparticles with concentration of 0, 0.25, 0.50, 1, 1.50 and 2 wt% were dispersed in coating. TEM (Transmission electron ...
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In this study the effect of adding zinc oxide nanoparticles (ZnO) on color change and adhesion strength of polyurethane clear coat in Elm wood species (Ulmus glabra) investigated. ZnO nanoparticles with concentration of 0, 0.25, 0.50, 1, 1.50 and 2 wt% were dispersed in coating. TEM (Transmission electron microscopy) images were used for investigate the dispersion of nanoparticles in coatings matrix. Results of investigate the dispersion of nanoparticles in polyurethane coating indicated that the best dispersion of nanoparticles obtained in coating with 1 wt% nano. Increasing concentration of nanoparticles to 2 wt%, reduced dispersion of nanoparticles and aggregates of nanoparticles observed in coating. Investigation adhesion strength of coating showed that the highest value of adhesion was in nanocomposite coating with 1 wt% nano but increasing nanoparticles more than this content, had negative effect on coating adhesion. Results also revealed that adding ZnO nanoparticles, changed color of samples coated with nanocomposite coating but it was not significant in low content of nanoparticles.
Management and Economics wood
abdollah zamnai; Mohammad reza Mastari farahani
Abstract
In this research, the effect of oil heat-treated on the outdoor performance of coatings namely, transparent resin stain, alkydi paint, semi- transparent cellulosic stian, acrylic paint coated on eastern cotton wood was investigated. For this purpose, sound specimens with the dimensions of 50×50×2 ...
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In this research, the effect of oil heat-treated on the outdoor performance of coatings namely, transparent resin stain, alkydi paint, semi- transparent cellulosic stian, acrylic paint coated on eastern cotton wood was investigated. For this purpose, sound specimens with the dimensions of 50×50×2 mm (Longitudinal × tangential × radial) were prepared from sapwood. Test samples were treated with canola oil at temperatures of 180, 200 and 220 ° C for 4 hours. The coatings were the wet film thickness of 150µm were applied on the specimens using an applicator. The coating adhesion was measured according to ASTM D 4541 standard, and the color characteristics of the coating were measured according to ASTM D 2244 before and after a natural weathering for 180 days. The statistical analysis of the color change data showed that the effect of the oil heat-treatment on the color change depended on coating type. The statistical analysis of the adhesion strength data showed that the adhesion strength depended on the combination of weathering, oil heat-treatment and coating type.
Management and Economics wood
Saeed Hasani; Seid Khalil Hosseini Hashemi; Ramin Farsi; Ahmad Jahan Latibari
Abstract
AbstractAmong the forest diseases, fungi are the most important factors that cause irreparable losses to the wood in standing trees and logs. Fungi are the cause of contamination and decay of trees and timbers in forest or in the stock of factories. Decayed woods are one of the biomass resources and ...
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AbstractAmong the forest diseases, fungi are the most important factors that cause irreparable losses to the wood in standing trees and logs. Fungi are the cause of contamination and decay of trees and timbers in forest or in the stock of factories. Decayed woods are one of the biomass resources and a great amount of decayed woods in the forests are not viable. In this study some experiments were conducted in order to investigate the effect of Coriolus versicolor decay on compounds obtained from beech wood (Fagus orientalis L.) pyrolysis and preparation of various and valuable chemicals. Separation and identification of chemical compounds in sound wood and decayed wood of beech was conducted by using pyrolysis method at 500° C and in nitrogen atmosphere. Separation and identification of extracted chemical compounds was carried out using sailylation of these compounds by N, O-bis (trimethylsilyl) trifluoroacetamide and also using Gas Chromatography and Mass Spectrometry method. Totally, 23 compounds were identified in sound beech wood which most of these compounds, in this temperature, are related to 2,6-dimethoxyphenol and 3-hidroxy-4-methoxy benzoic acid; and 31 compounds were detected in decayed beech wood that most of them are related to Cyclononasiloxane octadecamethy and 4-(3,4-Dimethoxybenzylidene)-1-(4-nitrophenyl) and also 17 compounds were detected the same in sound and decayed wood.
Management and Economics wood
Reza Oladi; Saeideh Nasiriani; Afshin Danekar
Abstract
From a long time ago, researchers in the fields of wood science, dendroclimatology and tree physiology were interested in variation of tree-ring width and vessel features within a tree. However, mutual relationship and interplay between these anatomical features were less studied. In this regard, the ...
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From a long time ago, researchers in the fields of wood science, dendroclimatology and tree physiology were interested in variation of tree-ring width and vessel features within a tree. However, mutual relationship and interplay between these anatomical features were less studied. In this regard, the main question is whether the pattern of adjustment in wood anatomical traits (tree-ring width and vessel features) is similar in all hardwoods and in every site? Or may the same species chose different strategies in different sites? To answer these questions, two growing sites of black alder (Alnus glutinosa) with completely different micro-climates (dry and brackish) were selected near Astara city. In each site, a few trees were selected, cut or cored. After preliminary treatments, wood cross sections were prepared from the bark to the pith of each tree. These sections were scanned and by using an image analysis software, tree-ring width (TRW), average vessel lumen area (AVLA), number of vessel in the unite of an area (VF), and the porosity (Porosity) of a tree ring were measured in the last 20 annual rings of each tree. To study the inter-relations between variables at each site, they were analyzed using different statistical tests. The results showed that the inter- and mutual-relations between tree-ring width and vessel features were similar in tow studied sites. In brief, it can be concluded that regardless of site and climatic condition, in alder trees, wider tree rings leads to fewer vessels and these two anatomical traits are controlled by the same component but AVLA is affected by a different component and is not associated with the tree-ring width.
Management and Economics wood
Elham Hatamzadeh; Maryam Ghorbani; Poria bi parva
Abstract
In this research, effect of the alkaline precursors of soda and ammonia as reagent deposition of zinc oxide nanoparticles using hydrothermal method in structure and physical properties of poplar wood were investigated. The samples of physical test were prepared with dimensions of 2*2*2 cm3 according ...
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In this research, effect of the alkaline precursors of soda and ammonia as reagent deposition of zinc oxide nanoparticles using hydrothermal method in structure and physical properties of poplar wood were investigated. The samples of physical test were prepared with dimensions of 2*2*2 cm3 according to ASTM-D4446-05, and divided to three levels; control, Zncl2/NH3 and Zncl2/Naoh at 0.05M concentration and pH=10. Test samples were impregnated with salty precursor in the experimental cylinder using vacuum-pressure method, and in order to adjust the pH, soda and ammonia added. Due to the electron microscope images, change the type of precursor deposition, caused the different structure of ZnO nanoparticle. Retention of zinc oxide nanoparticles, density changes, water absorption, swelling and anti-swelling efficiency (ASE) were determined after synthesis. Retention of zinc chloride precursor with ammonia and soda acidity regulator was determined 4.43 and 1.71kg/m3 respectively. Water absorption increased at first hours of immersion, and then decreased. These treatments increased water absorption of wood. Least swelling and water absorption, and maximum ASE were measured in Zncl2/NH3 level.
Management and Economics wood
Azadeh Nikkhah Shahmirzadi; Maryam Ghorbani; Seyed Mojtaba Amininsab
Abstract
This research was conducted to investigate the effect of modification with maleic anhydride and methyl methacrylate on mechanical properties and decay resistance of poplar wood. Samples of mechanical and biological resistance tests were prepared according to ASTM D143-94 and EN113 standards. Treatment ...
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This research was conducted to investigate the effect of modification with maleic anhydride and methyl methacrylate on mechanical properties and decay resistance of poplar wood. Samples of mechanical and biological resistance tests were prepared according to ASTM D143-94 and EN113 standards. Treatment levels were divided into 4 groups; control, methyl methacrylate, maleic anhydride and combined of maleic anhydride/ methyl methacrylate. Samples were impregnated with maleic anhydride and monomer using vacuum- pressure method with experimental cylinder. Maleic anhydride treated samples were heated in oven for 4 and 24 hours at 150 and 103ºC. For polymerization, methyl methacrylate monomer treated samples were heated in oven at 90ºC for 24 hours, consequently at 103ºC for the same time. Methyl methacrylate polymer coating formed on the cell wall, causing 22.57% improvement in the lateral stability under pressure parallel to grain. Highest value in modules of rupture, elasticity and hardness were measured in combined level with 24.13, 47.13 and 45.53% improvement compared with the control, respectively. Maleic anhydride in the presence of methyl methacrylate, with decreasing polarity of the wood and create a good distribution of the particle and the polymer, resulting in the cross linking formation and transmission of uniform tension that would lead to improved mechanical properties. Also, decay resistance was improved in all levels of modification, so that weight loss declined from 80.4% in control to 4.29% in combined level. Modified with maleic anhydride because of the wood composition change, reduction in moisture absorption ability of cell wall and bulking effect, and the presence of methyl methacrylate in the cell cavities as a physical barrier to the movement of fungi mycelium and moisture, were leading to improved decay resistance.
Management and Economics wood
Mohammad Saleh Hosseini Fard; Saeed Khojasteh Khosro; Behbod Mohebby
Abstract
In this research the effect of oil-heat treatment of Fir species (Abies spp) on contact angle and adhesion strength of organic solvent based and water based coating (acid catalyzed and acrylic water based coating) were investigated. Soy oil was used for the heat treatment modification. Modification process ...
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In this research the effect of oil-heat treatment of Fir species (Abies spp) on contact angle and adhesion strength of organic solvent based and water based coating (acid catalyzed and acrylic water based coating) were investigated. Soy oil was used for the heat treatment modification. Modification process of samples were done at two time, 12 and 15 hours with temperature of 180°C. Control and modified samples were covered with acid catalyzed and acrylic water based coating. Contact angle of water was measured before and after treatment. Adhesion strength of coating was determined according to ASTM 4541 standard. Obtained results of contact angle and adhesion strength were compared with the control samples. The results showed that modification process of oil-heat treatment increased contact angle. This increase continued by increasing treatment time. Increasing contact angle reduced wettability of samples’ surface. On the other hand oil-heat treatment of wood, decreased adhesion strength of coating. The lowest value of adhesion strength was observed in the modification process of 15 hours. Results of comparing coating revealed that acid catalyzed coating had higher adhesion strength than acrylic water based coating but generally no significant differences was observed between these coating.
Physics and anatomy
vahidreza safdari; shadman Pourmosa
Abstract
The Avicennia tree genus was named in honor of Ibn Sina, a 10th century Persian philosopher and physician known more commonly as Avicenna. In this paper wood anatomical property of Avicennia marina (Acanthaceae) which is one of the most important species of Iranian Mangrove forest has been investigated. ...
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The Avicennia tree genus was named in honor of Ibn Sina, a 10th century Persian philosopher and physician known more commonly as Avicenna. In this paper wood anatomical property of Avicennia marina (Acanthaceae) which is one of the most important species of Iranian Mangrove forest has been investigated. Wood samples were taken from trunk of three adult trees, and and micro -sectioned and dyed by Astrablue and Safranin O and finally mounted by Canada balsam. Also Wood chips (match size) were placed in equal parts of glacial acetic acid and hydrogen peroxide and were put in the oven at 60°C for 48 hours, then counted and stained on microscope slides. The presence of concentric included phloem which is surrounded by lignified conjunctive parenchyma (axial parenchyma) and scleroid bands are the most important anatomical characteristics of Avicenna marina. The variability of anatomical characteristics of Avicennia marina in different references can be attributed to grwoing site condition (altitude and latitude).
Zibab Frozan; asghar tarmian; Reza Ghamari; hamed matini behzad
Abstract
In this research, the effect of wetwood and blue stain on the drying rate and fluid transport coefficients of poplar (P. nigra) was evaluated. For this purpose, five boards with dimensions of 150 × 35 × 45 mm were cut from wet wood, normal wood and stained -wood areas of freshly cut ...
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In this research, the effect of wetwood and blue stain on the drying rate and fluid transport coefficients of poplar (P. nigra) was evaluated. For this purpose, five boards with dimensions of 150 × 35 × 45 mm were cut from wet wood, normal wood and stained -wood areas of freshly cut lumbers in Taleghan region and then dried to the final moisture content of 8 percent inside a laboratory dryer at temperature of 50 °C, relative humidity of 60% and air velocity of 1 m/s. Overall, drying time was 120 h. After drying, the transverse permeability and diffusion coefficients were measured. The results showed that the wetwood had no decreasing effect on the drying rate of poplar wood; however, it reached to the final moisture content slower due to higher initial moisture content. َAlso, the wetwood had no significant effect on the transverse permeability but reduced the diffusion coefficient. In contrast to the wetwood effects, the drying rate, permeability and diffusion coefficients were increased due to the blue stain.
Chemistry of wood
milad tajik; ramin vaysi; majid kiaei
Abstract
This research was carried out to identification and comparison of organically chemical component in the wood / bark extractives Eucalyptus camaldulensis. Three healthy trees were cut down from Nowshahr forest and samples were converted into the wood flour. The extractives was prepared with acetone solvent ...
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This research was carried out to identification and comparison of organically chemical component in the wood / bark extractives Eucalyptus camaldulensis. Three healthy trees were cut down from Nowshahr forest and samples were converted into the wood flour. The extractives was prepared with acetone solvent according to TAPPI standard, then transfer to the ballon and then the BSTFA catalyst was added and transfer to the GC / MS injections. Identification of components was done according to the retention time curve, calculation of Kovats correlation and Adams table. Out of 13 components in the bark of Eucalyptus and 18 components in that wood, 2 constituents such as Bis (2 - ethyl hexyl) phthalate and hexadecanoic acid was detected as the same. The most important of chemical component in the bark is (2 _ ethyl hexyl) phthalate (98.72 %). 2 - Pentanone (57.41 %) was important component in the eucalyptus wood .
Management and Economics wood
Reza Hajihassani; seyedeh masoomeh
Abstract
Abstract In this research, the effects of acetylation on the prevention of white-rot and brown-rot fungi deterioration in medium density fiberboard (MDF) were investigated. Sample boards were made from acetylated poplar fibers, which were treated at different times (0, 30, 90 and 270 minutes) to obtain ...
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Abstract In this research, the effects of acetylation on the prevention of white-rot and brown-rot fungi deterioration in medium density fiberboard (MDF) were investigated. Sample boards were made from acetylated poplar fibers, which were treated at different times (0, 30, 90 and 270 minutes) to obtain different weight percent gains (WPGs of 0, 4.85, 9.1, and 15.8 %). Totally twelve samples boards at three replication for every treatment were made.. The results were analyzed based on a complete randomized design (CRD) under a factorial experiment. Results revealed that the acetylation decreased the deterioration effect of white-rot and brown-rot fungi. As it was determined, the weight reduction of acetylated boards with the highest WPG (15.8 %) after 16 weeks were measured as 1.605 % and 16.93 % for white and brown-rot fungi, respectively. It was also determined that the weight loss of the control (untreated boards) samples was measured as 39.96 and 49.31% in the same period. The research results showed that the acetylation enhances biologic resistance in medium density fiberboard.
Management and Economics wood
Aliakbar Aenayati; Hamid Hatefnia
Abstract
Microbiological degradation of wood and wood products is one of the most important of disadvantage which reduce its useful life. There are various methods to increase the natural durability of wood and wood products and most of them using chemical reagents. In the past, the thermal ...
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Microbiological degradation of wood and wood products is one of the most important of disadvantage which reduce its useful life. There are various methods to increase the natural durability of wood and wood products and most of them using chemical reagents. In the past, the thermal modification has been used as a ecofriendly method in many times. In this research the effects of steam pretreatment on the fungal durability of particleboard were studied. Steam pre-treatment was applied on the poplar wood particles using a stainless steel reactor at four temperature levels (155, 165, 175 and 185 ºc) and three retention times (15, 30 and 45 min). The amount of hemicelluloses, acetone extractives of wood particles as well as EMC and Mass loss of test panels were measured.The results indicated that the steam pretreatment significantly decreased the amount of hemicelluloses of wood particles, EMC and mass loss of test samples where as the amount of extractives of wood particles increased.According to the results, the variation of Mass loss of particleboard test samples showed a significant correlation to the variation of EMC of test samples, hemicelluloses and extractives amount of wood particles when the wood particles thermally pre-treated at 165ºC for 30 minutes
Management and Economics wood
Lila Asadi khoramabadi; Abolghasem Khazaeian; Mohammad reza Masteri Farahani; Alireza Shakeri
Abstract
Heat treatment is one of the processes used to modify the properties of wood. The investigation of thermal treatment of wood has led to the improvement of heat treatment with vegetable oils. Heat treatment improves the dimensional stability and biological durability, but reduces the mechanical properties ...
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Heat treatment is one of the processes used to modify the properties of wood. The investigation of thermal treatment of wood has led to the improvement of heat treatment with vegetable oils. Heat treatment improves the dimensional stability and biological durability, but reduces the mechanical properties of wood. In this research, to improve the mechanical properties with other properties of wood, soybean oil modified with maleic anhydride was used for thermal treatment. Wood speciments were subjected to heat treatment soybean oil modified with maleic anhydride at two temperature (180 and 200° C ) and three time (2, 4 and 6 hours). Untreated beech was used as comparison for each treatment conditions. In this study, the effects of heat treatment on physical properties )water absorption and volumetric changes) and mechanical properties such as Bending strength) ISO 3133-1975(, Compression strength Parallel to grain) ISO 3787-1976 (and Impact bending) DIN 52189( were examined. The test results of heat-treated with modified soybean oil and control samples showed that physical and mechanical properties increases with heat treatment.
Composite wood products
Ghonche Rassam; Hamid Reza Taghiyari; Bratali Keshtegar
Abstract
Wood-composites are susceptible to fire due to their nature. Some research projects were therefore carried out to investigate potentiality of bentonite nanoparticles in improving fire-retarding properties in medium-density fiberboards (MDF); the present complimentary study aimed at determining the effects ...
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Wood-composites are susceptible to fire due to their nature. Some research projects were therefore carried out to investigate potentiality of bentonite nanoparticles in improving fire-retarding properties in medium-density fiberboards (MDF); the present complimentary study aimed at determining the effects of nanobentonite on physical and mechanical properties of MDF. Ten percent of urea-formaldehyde resin was used as adhesive in the matrix. Nano bentonite was added at 5 levels (%0 ,% 5 ,% 10 , %15 and %20) g/kg based on the dry weight of fibers. Bentonite nanoparticles were sprayed on the fibers after being mixed with the resin solution. Mats were hot-pressed for 4, 5, and 6 minutes at temperature of 170°C. Density was kept constant (75 g.cm-3) for all treatment. Results revealed that nano Bentonite did not improve the physical properties of water absorption, thickness swelling and mechanical properties of internal bonding (IB), modulus of elasticity (MOE), modulus of rupture (MOR). As to the other treatments, nano Bentonite consumption level of % 5 showed the lowest negative effect on the physical properties (water absorption, thickness swelling ) and treatment of 5% and %10 also less negative effect on the Mechanical properties (Modulus of rupture, Internal Bonding ). Treatment 20% is not recommended because it weakens the properties; moreover, the surface of fiberboards is not suitable. It was concluded that due to the fire-retarding improving effects, %5 of nano Bentonite is recommended as the optimum level for the industry.
Composite wood products
Amineh Behzadi Shahrebabak; Mehrab Madhoushi; Mohammad reza MastriFarahani
Abstract
In this study, the effect of nanoclay and coupling agent on decay resistance and physical properties (including water absorption and thickness swelling) of nanoclay- Polyethylene- MDF sanding- powder composite were investigated. For this aim, MDF sanding dust and polyethylene were used as lignocellulose ...
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In this study, the effect of nanoclay and coupling agent on decay resistance and physical properties (including water absorption and thickness swelling) of nanoclay- Polyethylene- MDF sanding- powder composite were investigated. For this aim, MDF sanding dust and polyethylene were used as lignocellulose and thermoplastic material respectively. Also, Maleic anhydride grafted polyethylene (MAPE) was used in different weight percentages; 3% and 6% as a compatibilizer and nanoclay .Cloisite®15A was used in different weight percentages 2%, 4% and 6%.At first, raw materials were producted to fabricate granules by using twin-screw extruder. Then 36 panels (12 treatments by 3 repetitions) were made by hot pressing with 1 g/cm3 nominal density at dimensions by 30 cm × 28 cm × 1 cm. Then, water absorption and thickness swelling and decay resistant (loss weight) were investigated. Specimens were exposed to Trametes versicolor for 3 months, according to ASTM-D1413 standard. The results shown, water absorption and thickness swelling reduce with increasing MAPE significantly. While, at the time when nanoclay was added 2% (phr), water absorption and thickness swelling reduced significantly and then increased. Also, decay resistance was improved with increasing coupling agent and nanoclay.
Management and Economics wood
Kazem Dost Hosseini; Maryam Ghorbani kobandeh; Samira Mohammad ali bighi; Alinaghi Karimi
Abstract
This research was conducted to evaluate the effects of acetylation and the resin type on three layered populus particleboard against white-rot fungus, Trametes versicolor. Populus particles were acetylated at three levels of acetyl content (WPG of 0, 8.39% and 17.27%). In manufacturing of single and ...
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This research was conducted to evaluate the effects of acetylation and the resin type on three layered populus particleboard against white-rot fungus, Trametes versicolor. Populus particles were acetylated at three levels of acetyl content (WPG of 0, 8.39% and 17.27%). In manufacturing of single and three layered boards with acetylated particles two type of resin, urea formaldehyde and isocyanate( as adhesives) were employed.
The results indicated positive role of acetylation in reducing decay rate. Weight loss of boards made from isocyanate was less than the boards containing urea formaldehyde resin. Also, three layered boards showed higher resistance against the fungus compared with single layered boards.
Management and Economics wood
Mohammad mehdi Parhizkari; asghar tarmian; Hamid Reza Taghiyari; Alinaghi Karimi
Abstract
The longitudinal gas permeability of tension wood and normal wood of Populus nigra dried by two different drying conditions was measured. Board specimens were dried under mild conditions (50ºC, and ٪63 relative humidity) to reach ٪11.8 MC, and under severe conditions (62ºC, and ٪35 RH) to ...
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The longitudinal gas permeability of tension wood and normal wood of Populus nigra dried by two different drying conditions was measured. Board specimens were dried under mild conditions (50ºC, and ٪63 relative humidity) to reach ٪11.8 MC, and under severe conditions (62ºC, and ٪35 RH) to reach ٪7 MC. After drying, dowel specimens of 14 mm in diameter and 40 mm length were prepared. Epoxy resin was applied all around each specimen to prevent fluid passing through lateral direction. Results showed that under both moisture conditions, longitudinal gas permeability values in normal wood were greater than those in tension wood. Furthermore, the permeability of both tension and normal wood decreased by increasing of drying intensity and decreasing of final moisture content.
