Hojat Hematabadi; Mehrab Madhoushi; Abolghasem Khazaeian; Ghanbar Ebrahimi
Abstract
This study investigated the bending and shear strength of hybrid cross-laminated timber (CLT) manufactured from beech (Fagus orientalis) and poplar (Populus deltoides) wood using experimental and finite element methods. The CLT panels were manufactured at various span to depth ratios 6, 10, 15, 20 and ...
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This study investigated the bending and shear strength of hybrid cross-laminated timber (CLT) manufactured from beech (Fagus orientalis) and poplar (Populus deltoides) wood using experimental and finite element methods. The CLT panels were manufactured at various span to depth ratios 6, 10, 15, 20 and 25 with width of 30 cm and thickness of 2 cm in both major and minor directions. Then, the bending and shear strength of CLTs were measured using three-point bending test according to ASTM test methods. The results indicated that with the increase of span to depth ratio of the beam from 6 to 25, the averages modulus of elasticity (MOE) and modulus of rupture (MOR) values were increased in both major and minor directions. On the contrary, the averages shear modulus ( ) values of specimens in both directions were decreased. Moreover, the results of finite elements showed that the amounts of stress distributions and their locations were different in major and minor directions of the beam. In the major direction, the surface layers were primarily contributed load-carrying capacity of CLT panels, while in the minor direction the middle layer played the most significant role for load-carrying capacity. In this research, it was resulted that specimens with span to depth ratio greater than 15 based on ASTM D198 can be used for calculating MOE and MOR of CLT panels. Furthermore, due to existence of lower difference than 10% between experimental and numerical results, modules of elasticity of CLTs were predictable according to finite element method
Rahim Kazemi; Farshid Faraji; Hedayatollah Aminian; Vahid Vaziri
Abstract
In this research, the effect of adding waste tire particles on physical and mechanical properties of oriented strand boards (OSB) produced from poplar wood strands was investigated. Constant factors of this research are: Poplar wood strands (Populus deltoides), phenol formaldehyde resin ...
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In this research, the effect of adding waste tire particles on physical and mechanical properties of oriented strand boards (OSB) produced from poplar wood strands was investigated. Constant factors of this research are: Poplar wood strands (Populus deltoides), phenol formaldehyde resin (8 percent for the strands and 10 percent for waste tire on dry weight basis), three layer OSB (25 percent on either top and bottom layers and 50 percent core layer), boards with a thickness of 16 mm, dimensions of 40×40 cm with a nominal density of 0.75 g/cm3.Variable factors are: mixing ratio of waste tire particles to poplar strands at the four levels of 0:100, 5:95, 10:90, 15:85 and particle size of waste tire in three different sizes of 8, 18 and 45 mesh. The physical and mechanical properties of the boards were measured as defined in relevant European standards test methods EN 300. The results showed that changes in the amount and size of waste tire particles have a significant effect on the physical and mechanical properties of OSB panels. Increasing the ratio of waste tire particles decreased the mechanical properties and inversely improved the thickness swelling of the panels. The minimum value of mechanical strength was observed in panels made of 15% waste tire particles and 45 mesh particles. In general, OSB containing waste tire particles can meet the requirements of the EN 300 standard.
Reza Hajihassani
Abstract
The aim of current research was to investigate the effect of hydro thermo-mechanical treatment and also press conditions on the physical and mechanical properties of poplar wood (Populus deltoides). The wood blocks were initially treated hydrothermally at temperatures of 100°C for holding time of ...
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The aim of current research was to investigate the effect of hydro thermo-mechanical treatment and also press conditions on the physical and mechanical properties of poplar wood (Populus deltoides). The wood blocks were initially treated hydrothermally at temperatures of 100°C for holding time of 0, 60, 120 minutes. Afterwards, the densification process was carried out under a hot press at two phases 1- contact and 2- compression press, for temperature of 160, 180 and 200°C for 60 and 90 minutes. The wood compression set was adjusted for 40 percent based on the thickness (radial direction) of the blocks. The samples were physically and mechanically tested as density, springback after press, water absorption, thickness swelling, bending strength and modulus of elasticity. Afterward, the results were analyzed based on a complete randomized design (CRD) under a factorial experiment. Results revealed that physical and mechanical properties of samples were enhanced due to the combined hydro thermo-mechanical treatment. Results revealed that this process causes reduction of springback, water absorption and thickness (radial direction) swelling and also improvement of mechanical properties such as bending strength and modulus of elasticity.
Pantea Omrani; Hamideh Abdolzadeh; Ali Adab
Abstract
The aim of this research was investigating the effect of fiber reinforced polymer (FRP) on the strength of T-shaped wooden joints under tension load. In this regard, T-shaped joints were constructed with beech and poplar species and were reinforced with 1 and 2 layer of carbon and glass fibers reinforced ...
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The aim of this research was investigating the effect of fiber reinforced polymer (FRP) on the strength of T-shaped wooden joints under tension load. In this regard, T-shaped joints were constructed with beech and poplar species and were reinforced with 1 and 2 layer of carbon and glass fibers reinforced epoxy and vinylester polymers of composite. Joint members were assembled by used of wooden dowels and polyvinyl acetate adhesive and then withdrawal resistance of reinforced joints were studied. Results of variance analysis showed that the independent effect of species of joint members, resin type and number of fiber layers at FRPs was significant at 5% level. Results have indicated that withdrawal resistance of joints constructed with beech species was more than the poplar species. The investigation of the effect of number of layers showed that the withdrawal resistance of the joints reinforced by two layers of carbon and glass fibers was more than one layer. Results of FRPs investigation indicated that use of epoxy matrix in comparison with vinyl ester matrix exhibited better results. In addition, carbon fibers have shown better performance than glass fiber as reinforcing agents. According to the results the best treatment was the joints of beech wood and reinforced by composites with epoxy matrix and reinforced with two layers of carbon fibers.
soheila izadyar; Roghayeh Hamzezadeh; Davood Efhamisisi
Abstract
The aim of this study was to investigate the effect of poplar wood saturation with nano-wollastonite and nano-wollastonite-styrene mixture on fire resistance and mechanical properties of polymer wood. Populus deltoids with 4% nano-wollastonite and 75% methanolic solution of styrene monomer was saturated ...
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The aim of this study was to investigate the effect of poplar wood saturation with nano-wollastonite and nano-wollastonite-styrene mixture on fire resistance and mechanical properties of polymer wood. Populus deltoids with 4% nano-wollastonite and 75% methanolic solution of styrene monomer was saturated by vacuum-pressure method. Four different wood treatments with nano-wollastonite, styrene, simultaneous nano-wollastonite and styrene (one-step) by 1:1 ratio and finally, the initial wood saturation by nano-wollastonite and then styrene (two-stage treatment) were investigated. In this study, the fire resistance and mechanical properties of the specimens were investigated. The results showed that the weight loss of wood against fire in two-stage treatment (NW+St) was 61.38% and in one-stage treatment (NW/St) was 69.68% better than control. NW/St treatment flame durability was approximately equal to NW treatment and improved by 30% compared to control. The reduction of carbonized area in two-stage (NW+St) and one-stage (NW/St) treatments was 28.53% and 29.06%, respectively, which showed a significant decrease. The results of mechanical tests showed that the NW/St treatment had the highest value due to the presence of condensing material in parallel to the NW/St treatment which showed an increase of 57.41% compared to the control sample. The modulus of elasticity and disruption of NW/St treatment increased by 26.77% and 35.71%, respectively. In addition, resistance to hardness of NW/St treatment increased by 10.07% compared to control. Overall, it can be concluded that mixing nano-wollastonite with styrene, while increasing the polymer wood fire resistance, also improved the mechanical properties of the polymer wood.
Pulp and paper
Hossein Resalati; Mostafa Nikkhah Dafchahi
Abstract
One of the drawbacks of utilizing non-forest fast growing species of Poplar as raw materials to produce newsprint in Mazandran Pulp and Paper Mill is fairly low bulk and opacity of produced paper at the yield of 85% (current CMP yield of the Mill). In this research work, the effect of process parameters ...
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One of the drawbacks of utilizing non-forest fast growing species of Poplar as raw materials to produce newsprint in Mazandran Pulp and Paper Mill is fairly low bulk and opacity of produced paper at the yield of 85% (current CMP yield of the Mill). In this research work, the effect of process parameters (cooking yield and freeness) on the optical and mechanical properties of chemi-mechanical pulp was investigated. The chemi-mechanical pulps of poplar was prepared at four various levels of cooking yield, through changing the cooking time, and their properties at different level of freeness were evaluated in comparison with the control sample of Mazandran Pulp and Paper Mill (75% hornbeam and 25% beech). Strength properties of the paper pulps stemmed from the cooking yields of 85.25% to 90.4% were higher and more favorable than the control sample. By contrast, the strength properties of the produced paper pulp from the cooking yield of 94.6% were inferior to prepared paper pulp from the control sample. According to the results, there is the possibility of significant improvement of the strength properties, opacity and bulk of the chemi-mechanical pulps of poplar trough controlling the process parameters like cooking yield and freeness to utilize it as raw material of newsprint production in Mazandran Pulp and Paper Mill.
Management and Economics wood
Mehrab Madhoushi; Vajihe Mojerian Galogahi; Mohammadreza Masteri Farahani
Abstract
Radiography is a method of non-destructive for evaluating the quality of wood construction machinery in order to detect the defects due to natural degradation. The objective of this study was to investigate the assessment of Poplar (Populus deltoides) and beech (Fagus orientalis) wood defects arising ...
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Radiography is a method of non-destructive for evaluating the quality of wood construction machinery in order to detect the defects due to natural degradation. The objective of this study was to investigate the assessment of Poplar (Populus deltoides) and beech (Fagus orientalis) wood defects arising from the decaying by using x-ray non-destructive method. In this study, for each of species, uncolored (no coating) and colored samples by acid catalyzed lacquers and nitrocellulose lacquers were used. Decay resistance test based on modified ASTM D1413 standard was performed. The decay process was done in the periods of 1, 2 and 3 months with use of Coriolus versicolor fungus at laboratory condition. After each of these periods, for the decay of the samples, x-ray imaging by using an imaging at the lateral, tangential and radial direction was done. Results of weight loss confirmed the presence of decay in the radiographic images. The results showed that after 1, 2 and 3 months of exposure to fungus, fungal degradation leads to weight loss in the painted and unpainted samples. So that, the weight loss caused by decay in beech was less than poplar samples. As well, the weight loss of unpainted was less than painted samples, which was also statistically significant. The x-ray results of unpainted and painted samples at the cross, tangential and radial directions indicate that decay has a more impact on beech in comparison to poplar wood structure. The study as well showed that the protective layer has partly a barrier for decay destruction in these samples.
Physics and Mechanical Wood
Mohamad ali Sadatnia; noshin sattari; mehran roohnia; mohsen bahmani
Abstract
The goal of this study was to determine the modulus of elasticity and modulus of rapture of two kinds of date palm (Khasi and Hajmohammadi) using static bending and dynamic (flexural vibration) techniques. To reduce the difference between static and dynamic stiffness values, the static bending modulus ...
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The goal of this study was to determine the modulus of elasticity and modulus of rapture of two kinds of date palm (Khasi and Hajmohammadi) using static bending and dynamic (flexural vibration) techniques. To reduce the difference between static and dynamic stiffness values, the static bending modulus of elasticity was modified by taking into account the value of the shear deflection. In addition to, for better understanding of the mechanical properties of date palm, values were compared with those measured for poplar samples. The results showed that, in Khasi the mean values of the modulus of elasticity obtained by flexural vibration, the static modulus of elasticity, the modified static modulus of elasticity and as well as the modulus of rapture were 47, 67,68 and 38% less than those measured for Hajmohammadi respectively. In comparing with date palm, values measured for poplar samples were more pronounced. The difference between dynamic and static values of modulus recorded for Khasi, Hajmohammadi and poplar samples were 63, 40 and 19% respectively. After modification of the static values, the difference was reduced in to 3% for Khasi, 6% for Hajmohammadi and 7 % for poplar experimental samples. Finally the significant correlation coefficients were found between the static and the dynamic modulus of elasticity for both two kinds of date palm.
Management and Economics wood
Samira Porbar; Omid Hosseinzadeh; Marzieh Hajjarian
Abstract
Wood industries need abundant resources of wooden raw material and these industries could continue to productive activities with poplar consumption attitudes. Given the size and importance of poplar farming and its role in the economy of Kurdistan, study for evaluation of its value chain is essential. ...
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Wood industries need abundant resources of wooden raw material and these industries could continue to productive activities with poplar consumption attitudes. Given the size and importance of poplar farming and its role in the economy of Kurdistan, study for evaluation of its value chain is essential. Since improving of the poplar value chain is a factor for the development of poplar farming given the current situation in Kurdistan providence value chain, in this research suitable value chains was identified for development. According to the study objectives, the effective criteria to prioritize research alternatives were identified through library studies and with the help of questionnaires were completed and confirmed, according to the experts. The experts were used to identify the interrelations between criteria. After completing the paired comparison questionnaire, weight of each criterion was measured and priorities were found by the ANP. Ultimately, the final results of alternatives ranking showed the most weight is related to the MDF chain with weight of 0.259. The next priorities were paper, straw and cellulose with respectively weights of 0.135, 0.134 and 0.115. The next priorities were furniture, particle board, plywood and matches, pallets, boxes, lumber and boards, with weights of 0.096, 0.077, 0.075, 0.073 and 0.019 respectively. Results of group decision-making using ANP showed that in the current situation with regard to the suitable market for MDF, proper future demand, appropriate market for processed products from MDF, condition of infrastructure in Kordestan province and feasibility of use of poplar wood in production of MDF, this industry is more important to develop in Kordestan province.
Management and Economics wood
Aisona Talaei; Mohammad Hadi Rezvani
Abstract
In this research the effect of chemical modification with Polycrease ECR on the functional performance of poplar wood to use as wood polymer were investigated. Polycrease ECR the modified dimethyloldihydroxy-ethyleneurea (DMDHEU) was used for chemical modification of wood by impregnation method. Specimens ...
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In this research the effect of chemical modification with Polycrease ECR on the functional performance of poplar wood to use as wood polymer were investigated. Polycrease ECR the modified dimethyloldihydroxy-ethyleneurea (DMDHEU) was used for chemical modification of wood by impregnation method. Specimens prepared according to the ASTM standard and treated in two levels of 30 and 50%. Modification process of specimens were performed at 24 hours in temperature of 120°C. Functional performance including Weight percent gain (WPG), bulking, long term water absorption and volumetric swelling in 8 weeks, bending strength (MOR) and modulus of elasticity (MOE), compression strength parallel to the grain, shear strength and withdrawal resistance of screw parallel to the grain was measured. Two-way analysis of variance (ANOVA) was used for statistical analysis. Obtained results of modified specimens were compared with untreated control. Results showed that modification with Polycrease ECR had significant effects on physical and mechanical properties in treated specimens. Chemical modification in 30% level, lead to reduce long term water absorption and volumetric swelling. Reduction in mechanical properties were not considerable. Chemical modification with Polycrease ECR in 30 % level compared to 50 % level, showed better physical and mechanical properties. Generally, influence of chemical modification on the physical properties (long term water absorption and volumetric swelling) were dominant.
Composite wood products
Abbas Tamjidi; Mohammad Mehdi Faezipour; Kazem Doosthoseini; Ghanbar Ebrahimi; Habibollah Khademieslam
Abstract
In this study, the effects of mat moisture content and press temperature on physical and mechanical properties of three layered oriented strand boards were evaluated. Two levels of mat moisture content 7% and 10% and three levels of press temperature 180 ˚c , 200 ˚c and 220 ˚c were applied and 12 ...
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In this study, the effects of mat moisture content and press temperature on physical and mechanical properties of three layered oriented strand boards were evaluated. Two levels of mat moisture content 7% and 10% and three levels of press temperature 180 ˚c , 200 ˚c and 220 ˚c were applied and 12 mm in nominal thickness laboratory boards were made from mixture of three clones of ten-year-old hybrid poplar ( populous euramericana vernirubensis, p. e. I-214, P. e. 561/41) while the strands on the surface layers are aligned in the long direction of the board and the middle layer strands are cross aligned to the surface layers. In all treatments, board targeted density of 0/7 g/cm3 and press time of 8 min and phenol-formaldehyde resin (PF) content of 7% based on the oven dry weight of the strands were held constant. The mechanical and physical properties of the boards were measured as defined in relevant European standards EN 300 for OSB/1 and OSB/2. Overall results showed that all boards made from above mentioned conditions exceed the EN 300 standards for MOR, MOE, IB and TS24. The bending properties (MOR and MOE) of boards were significantly improved as the mat moisture content increased from 7 to 10%. The highest MOR was achieved at 10% mat moisture content and 220 ˚c press temperature and the highest MOE was achieved at 10% mat moisture content and 180 ˚c press temperature. The Modulus of Rupture (MOR) and Thickness swelling (TS24) were significantly improved as the press temperature increased from 180 ˚c to 220 ˚c. The lowest TS24 was achieved at 7% mat moisture content and 220 ˚c press temperature and the highest IB was achieved at 7% mat moisture content and 200 ˚c press temperature.
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.
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.
Sarveh Hosseinzadeh; Maryam Ghorbani; Porya Biprva
Abstract
This research was conducted to determine the physical properties of poplar wood treated with silica colloidal nanoparticles prepared from rice husk using ash making and alkaline digestion. Test samples were prepared according to ASTM-D1037 standard with the dimension of 2×2×2 cm and then ...
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This research was conducted to determine the physical properties of poplar wood treated with silica colloidal nanoparticles prepared from rice husk using ash making and alkaline digestion. Test samples were prepared according to ASTM-D1037 standard with the dimension of 2×2×2 cm and then were impregnated ina cylinder according to Bethell method applying five concentration levels of soluble colloidal silica nanoparticles (0, 1.2, 1.7, 2.2 and 3.2%). Nanoparticle retention and absorption, density changes, water absorption, and anti-swelling efficiency (ASE) were determined. Nano silica absorption was determined as 119.8, 169.5, 196.3 and 214.7 % corresponding to 1.2, 1.7, 2.2 and 3.2 % nanoparticle addition, respectively. Nano-silica retention in the lowest and the highest treatment level were 1.2 and 9.3%. Results showed that the density increased from 0.37g/cm³ in control samples to 0.40 g/cm³ at the highest level of nano-silica absorption. Water absorption increased by increasing nano-silica absorption. However, dimensional stability of impregnated samples increased. After the longest immersion time, average swelling volume of the sample impregnated with nano-silica was decreased in comparison with the control sample. With increasing nano-silica absorption, anti-swelling efficiency of impregnated samples treated at the 1.2, 1.7, 2.2 and 3.2 % level and immersed for 168h was 36.5, 42.9, 34.7 and 26.8 %, respectively.
Shima Ramezani; Mohammad Talaeipoor; Misam Aliabadi; Asghar Tabeai; Behzad Bazyar
Abstract
Samples were prepared from the native poplar species (Populus alba) grown in Mehnan, a region in Bojnourd at the ages 5 and 25 and the anatomical, biometrical and chemical characteristics of the samples sections in three directions (cross section, radial and tangential) of the tree were measured. ...
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Samples were prepared from the native poplar species (Populus alba) grown in Mehnan, a region in Bojnourd at the ages 5 and 25 and the anatomical, biometrical and chemical characteristics of the samples sections in three directions (cross section, radial and tangential) of the tree were measured. Dioxan and Klason lignin were measured. Structural similarities in vascular cavities or impacted vessels in the form of binary, tripple or tetraploidy groups in juvenile and mature wood was observed primarily in radial direction. Fiber length and cell wall thickness variation in the juvenile and mature wood was significantly different and as the age of the tree increases, such difference is more significant. This point need to be considered by cellulose industries. As the age of the tree increase and the wood matures, significant change in vessel size in samples from 5 or 25 years old trees was not detected. The result showed that the older wood contains lower content of extractive and lignin and higher content of cellulose
Kazem Dosthosseini; robab ghafari
Abstract
In this research, the effect of increasing content of urea to urea-formaldehyde adhesive on physical and mechanical properties of poplar wood particleboard was investigated. The content of urea added to the adhesive four levels (zero, 4.1, 8.2 and 16 % based on the solid content of adhesive) and ...
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In this research, the effect of increasing content of urea to urea-formaldehyde adhesive on physical and mechanical properties of poplar wood particleboard was investigated. The content of urea added to the adhesive four levels (zero, 4.1, 8.2 and 16 % based on the solid content of adhesive) and two press temperatures of 170 and 180° C as the variable factors were selected. Boards with density of 0.63 gr/cm3 and 10% of the adhesive dosage were made. Mechanical properties including modulus of rupture (MOR), internal bond (IB) and physical properties including water absorption and thickness swelling were measured. Results showed that urea addition to urea formaldehyde adhesive improved the mechanical strengths of the board especially internal bonding reduced the water absorption and thickness swelling. Also, the impact of press temperature on mechanical and physical properties of boards was noticeable and boards produced applying press temperature of 170° C were superior.
Pulp and paper
Amir hooman Hamasi; Mehdi Sabor; Mohammad Talaeipoor; Mohammad Azadfallah
Abstract
The aim of present study was to investigate the effects of xylanase enzyme obtained from Trichoderma viride on APMP pulp from Populus nigra wood. Treatment temperature, time, enzyme dosage and pulp consistency were varied. The results demonstrated that treating by xylanase has considerable effects on ...
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The aim of present study was to investigate the effects of xylanase enzyme obtained from Trichoderma viride on APMP pulp from Populus nigra wood. Treatment temperature, time, enzyme dosage and pulp consistency were varied. The results demonstrated that treating by xylanase has considerable effects on pulp. Paper brightness improved in average 2.5% ISO and the highest gain was 4.5%. Also, using enzyme resulted in enhancement of tear and burst indices. Breaking length of paper from enzyme treated pulp was increased to 4098 meters. Further treatment by xylanase reduced the pulp yield by 2.78% as compared to sample without enzyme treatment. The impact of other treatment such as washing by distilled water and alkaline extraction revealed that these treatments did not have significantly effect on the results of enzyme treatment. The optimum temperature, time, enzyme dosage and pulp consistency were 40-50° C, 70 minutes, 10 U/g of oven dried pulp and 10% respectively.
Composite wood products
Ali akbar Enayati; Farnaz Eslah
Abstract
This study was conducted to investigate the effect of mixing great size wood particles of poplar with appropriate size particles of the same species, on density profile and physical -mechanical properties of the made particleboard, this study was carried out. One layer boards were made by use of appropriate ...
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This study was conducted to investigate the effect of mixing great size wood particles of poplar with appropriate size particles of the same species, on density profile and physical -mechanical properties of the made particleboard, this study was carried out. One layer boards were made by use of appropriate and great size residue particles on a 7mm pores screen with the ratio of 0/100, 15/85, 30/70, and 45/55 respectively. The results obtained from measured physical and mechanical properties showed that increasing great particles ratio had no negative effect on properties of boards. Increasing the amount of this particles in boards composition, caused increasing internal bonding and decreasing water absorption and thickness swelling levels. In addition, there were no significant differences within boards made from different treatments MOR and MOE properties. Regarding results of this study, when %15 great particles was used with appropriate particle ones, boards had minimum reduction of mechanical strength. Investigation of density profile showed the same result. But all properties of the boards were over the determined limit in terms of relevant standard values even in the case of using 45% great particles.
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.
Management and Economics wood
Asghar Taremian; Mahdi Shahverdi; Saeid Eshaghi; Hadi Dashti
Abstract
In this study, the susceptibility of poplar (P. nigra) tension and normal wood to collapse during drying was investigated. Thus, the poplar boards with nominal dimensions of 100 × 50 × 25 mm (L×T×R) were dried using three different drying schedules. In schedule A, the boards were ...
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In this study, the susceptibility of poplar (P. nigra) tension and normal wood to collapse during drying was investigated. Thus, the poplar boards with nominal dimensions of 100 × 50 × 25 mm (L×T×R) were dried using three different drying schedules. In schedule A, the boards were dried under constant conditions (dry-bulb temperature of 600C and wet-bulb temperature of 440C); in schedules B and C, they were dried under a time-based schedule, consisting of 4 and 2 steps, respectively. The initial dry-bulb temperature in schedules A, B and C were selected as 60, 60 and 820C, respectively. After drying, the severity of collapse in the cross section of boards was determined by scanning electron microscope (SEM). The results revealed that collapse did not occur in the boards dried by schedule A. Collapse occurred slightly in the boards dried by schedule B and severe collapse and cell wall degradation developed in the boards dried by schedule C. In the latter, gelatinous layer of tension wood was separated from fiber cell walls. Tension wood was more sensitive to collapse than normal wood. Based on the results, it can be concluded that the occurrence of collapse is influenced by initial dry-bulb temperature rather than wet-bulb depression.
Management and Economics wood
Sohrab Rahimi; Mohammad mehdi Faezipoor; Saeid Eshaghi; Asghar Taremian
Abstract
Poplar lumbers with nominal thickness of 5 cm from Taleghan region, located in west of Karaj were dried under three different schedules including T8-F4 (recommended schedule by F.P.L for poplar), T8-F5 and T9-F4. The purpose of this research was to study the effects of the kiln’s rows (upper, middle, ...
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Poplar lumbers with nominal thickness of 5 cm from Taleghan region, located in west of Karaj were dried under three different schedules including T8-F4 (recommended schedule by F.P.L for poplar), T8-F5 and T9-F4. The purpose of this research was to study the effects of the kiln’s rows (upper, middle, lower) on the quality of the dried boards. Dry bulb temperatures for the schedules were adjusted at 54, 54 and 60 °C, while the final temperatures were adjusted at 82, 82 and 71 °C, respectively. The severity of warping, internal checking and surface checking in kiln dried lumbers were measured and analyzed. The results indicated that the boards in upper, middle and lower rows of the kiln, in all three schedules, did not have any significant difference in 95% confidence interval. Also, the final moisture content of the boards in all three rows and all three schedules were in acceptable quality.
Composite wood products
masoudreza habibi; Hossein Hosseinkhani; Saeed Mahdavi; Sayed javad Sepidehdam
Abstract
In this study, particleboard was produced by Eucalyptus and Poplar wood mixture. Variations of this study were as follow: - Combinations of Eucalyptus and Poplar wood were (%100 , %0) , (%66.5 ,% 33.5) , (%33.5 ,% 66.5) and (%0 ,% 100) respectively. ...
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In this study, particleboard was produced by Eucalyptus and Poplar wood mixture. Variations of this study were as follow: - Combinations of Eucalyptus and Poplar wood were (%100 , %0) , (%66.5 ,% 33.5) , (%33.5 ,% 66.5) and (%0 ,% 100) respectively. - Resin content ( %8 and %10) Physical and mechanical properties of boards such as MOR, MOE, IB TS2 and TS24 were tested according to EN standard. The effects of raw materials combinations on bending properties were significant. Maximum of MOE and MOR were observed in %66.5 of Poplar wood and % 33.5 of Eucalyptus wood. As expected, Physical and mechanical properties of boards were improved by increasing of resin content. Results indicated that TS2 and TS24 were increased with increasing of Poplar wood in combinations. Also the minimum of these properties were obtained in combinations of Eucalyptus and Poplar wood, %100, %0 respectively.
Composite wood products
masoudreza habibi; Hossein Hosseinkhani; Saeid Mahdavi; Fardad Golbabaei
Abstract
In this study Medium Density Fiberboard was produced from 4 year old Poplar clones (P.e. costanzo, P.e. 564.41, P.e. vernirubensis). Fibers length of P.e. costanzo, P.e. 564.41, P.e. vernirubensis were measured 805, 751 and 764 micron respectively. Also fibers diameter of these clones were determined ...
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In this study Medium Density Fiberboard was produced from 4 year old Poplar clones (P.e. costanzo, P.e. 564.41, P.e. vernirubensis). Fibers length of P.e. costanzo, P.e. 564.41, P.e. vernirubensis were measured 805, 751 and 764 micron respectively. Also fibers diameter of these clones were determined 25.76, 25.44, 25.23 micron respectively. Three steaming times (5, 10, 15 minutes) were used for fibers preparation. Also three press times (3, 4, 5 minutes) and two resin contents (9%, 11%) were applied for MDF production. Thus physical and mechanical properties of boards such as MOE, MOR, IB and Thickness Swelling after 2 and 24 hours were investigated. The physical and mechanical properties of boards were tested in based on EN standard. The measurements of bending properties and IB of MDF revealed that increasing steaming time caused to decrease MOE, MOR and IB. The highest of MOE, MOR and IB were obtained in 5 minutes steaming time. Also the lowest values of Thickness Swelling after 2 and 24 hours were obtained in 15 minutes steaming time. The influence of press time on bending properties was not significant. The highest of IB was obtained in 5 minutes press time. As expected, boards demonstrated better properties at higher resin content.
Management and Economics wood
Hamideh Abdolzadeh; Kazem Doost hosseini
Abstract
The capability of acetylated poplar particles with isocyanate resinin manufacturing particleboard was investigated. The acetylation degrees at high, medium, and zero (control) levels and type of resin (isocyanate and urea formaldehyde) were considered as variables. Then the effects of these variables ...
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The capability of acetylated poplar particles with isocyanate resinin manufacturing particleboard was investigated. The acetylation degrees at high, medium, and zero (control) levels and type of resin (isocyanate and urea formaldehyde) were considered as variables. Then the effects of these variables on practical properties of manufactured boards were investigated. The results indicated that use of isocyanate resin in board with acetylated particles not only caused to improve dimensional stability of manufactured boards but also caused to increase its mechanical Strength in comparison with blank with urea formaldehyde resin. Increasing acetylation degree caused to decrease the studied boards of the mechanical properties and enhance their dimensional stability. Although on board with isocyanate resin, increasing dimensional stability in comparison with blank is the highest. Particleboards with isocyanate resin indicated less water absorption and thickness swelling in comparison with blanks with urea formaldehyde resin after immersing in water for 2 and 24 hours.
Composite wood products
masoudreza habibi; Hossein Hosseinkhani; Saeed Mahdavi
Abstract
In this study , MDF was produced from three clones of poplar (P.e. vernirubensis, P.e. costanzo, P.e.561.41). Age clones of poplar were 4 and 12 years. In addition to age variation , the influence of three production variables (steaming time , press time and resin content on MDF properties were investigated. ...
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In this study , MDF was produced from three clones of poplar (P.e. vernirubensis, P.e. costanzo, P.e.561.41). Age clones of poplar were 4 and 12 years. In addition to age variation , the influence of three production variables (steaming time , press time and resin content on MDF properties were investigated. Variations of each variable were as follow:
- Steaming time (5, 10, 15 minutes)
- Press time (3, 4, 5 minutes)
- Resin content (9%, 11%)
Fiber length and fiber diameter of 4 and 12 years old poplar clones (P.e. vernirubensis, P.e. costanzo, P.e.564.41) were measured 746, 25.23, 805, 25.76,751, 25.44 and 902, 31.62, 995, 29.23, 899, 26.83 micron respectively.
MOR, MOE, IB, TS2, TS24 were determined according to DIN standard.
Increasing steaming time decreased board's internal bond and bending properties. As expected, boards demonstrated better properties at higher resin consumption. Minimum of boards thickness swelling were obtained at 15 minutes steaming time because of fiber hydrophilic properties were decreased. There are no significant differences between 4 and 12 years old of clones for bending properties and IB of boards. The effect of age variation is only significant difference on thickness swelling of boards which it is lower for 4 years old clones.
