Research Paper
Mohammad Tasoji; Amir Nourbakhsh; Abolfazl Kargarfard; Hossein Hosseinkhani
Abstract
Physical and mechanical properties wood-plastic composites produced from wheat and rice straw particles, nano-clay, polypropylene and MAPP were investigated. The amount of polypropylene and lignocellulosic materials were selected as 60 wt% and 40 wt% respectively. The Nano-clay was added in three levels ...
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Physical and mechanical properties wood-plastic composites produced from wheat and rice straw particles, nano-clay, polypropylene and MAPP were investigated. The amount of polypropylene and lignocellulosic materials were selected as 60 wt% and 40 wt% respectively. The Nano-clay was added in three levels 0, 2 and 4 wt% and the amount of coupling agent was fixed and set to 2 wt% for all treatments except for the control. The control samples were made from polypropylene and lignocellulosic materials with neither nanoclay nor coupling agent was used. The results showed that the tensile and flexural strengths were decreased by the addition of nanoparticles. For tensile and flexural modulus, adding 2 wt% of nanoclay led to an increase in both moduli. However there was a decrease in both moduli when 4 wt% nanoclay was added. The impact strength decreased adding nanoclay. There was a decrease in 24 hour water absorption when 2 wt% of nanoclay was added but an increase was observed in 4 wt% of nanoclay level. According to the mechanical and physical properties of all the treatments, the samples made of rice straw showed better results compare to wheat straw samples due to their high amount of silica and its compatibility with nanoclay. SEM test was performed.
Research Paper
Hassan Ziaei Tabari; Amir Nourbakhsh; Habibollah Khademi Eslam; behzad baziyar
Abstract
The aim of this study was to investigate the potential of using reed flour and different contents of montmorillonite (nanoclay) nanoparticles on the physical and tensile properties of polypropylener/reed flour/nano clay composite. The amount of coupling agent and reed flour was constant at 5% and 40%, ...
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The aim of this study was to investigate the potential of using reed flour and different contents of montmorillonite (nanoclay) nanoparticles on the physical and tensile properties of polypropylener/reed flour/nano clay composite. The amount of coupling agent and reed flour was constant at 5% and 40%, respectively and nanoclay content, adjusted at four levels of 0, 1, 3 and 5% were considered. The materials were mixed in an internal mixer and the samples were prepared by injection molding method. The specimens were tested in accordance with EN ISO 527 standard test method for tensile properties (tensile strength and module) and elongation at break. Physical properties such as water absorption and thickness swelling were measured. The results of tensile moduli and strengths, elongation at break and physical properties (water absorption) showed improvement by the addition of nanoclay up to 3%.
Research Paper
Vahid Safdari
Abstract
One of the important families of woody species of Irano-Torani region is Chenpodiaceae which comprises of different woody genus and species and Seidlitzia rosmarinus an specie with vast geographical distribution belongs to this family. Irrespective of its vast spread, the anatomical and other properties ...
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One of the important families of woody species of Irano-Torani region is Chenpodiaceae which comprises of different woody genus and species and Seidlitzia rosmarinus an specie with vast geographical distribution belongs to this family. Irrespective of its vast spread, the anatomical and other properties the specie has not been studied. In order to study the anatomical properties, 6 sound shrubs of Seidlitzia rosmarinus in Ardakan (Yazd, Iran) were harvested and the physical, chemical and anatomical properties of the wood were determined. The anatomical features were determined using light microscope and scanning electron imaging (SEM). Results showed that growth rings boundaries are indistinct; Intrexylary phloem (included phloem) is concentric. Vessels are short (100 µm) and gum–like deposit are present and inter-vessel pits are very tiny. The fiber length is short (334 µm) and fiber wall thickness (2d= 8.4 µm) in comparison to lumen (7.5 µm) is thick. Seidlitzia rosmarinus is anatomically and biometrically similar to Atriplex. The density in normal condition is 0.92 gr/cm3 which categorized the wood as heavy wood and its longitudinal shrinkage and ash content were measured as 5% and 5.5%) respectively.
Research Paper
Babak Mirzaei; Mehdi Tajvidi
Abstract
Stress relaxation behavior of milled newsprint/HDPE composite containing coupling agent was studied. Composites containing 25 and 50% filler in weight were produced, and were compared to neat polymer. Melt blending followed by injection molding was the manufacturing process. Results showed that incorporating ...
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Stress relaxation behavior of milled newsprint/HDPE composite containing coupling agent was studied. Composites containing 25 and 50% filler in weight were produced, and were compared to neat polymer. Melt blending followed by injection molding was the manufacturing process. Results showed that incorporating filler to polymer increases the flexural strength and modulus. It was observed that higher stress is needed to maintain higher strain levels. Furthermore, comparing the stress ratio patterns revealed that the difference among relaxation of different samples develops over time. Power law computed parameters showed that higher strain level results in higher stress relaxation amplitude (A) and lower time exponent (t). It was also found that, almost complete linear relationship could be established between strain level and parameter A, and the effect of strain level on parameter A is more pronounced at higher filler contents.
Research Paper
Amir Nourbakhsh
Abstract
To improve the mechanical properties of wood plastics composites, four lignocellulosic materials (bagasse, rice straw, wheat straw and poplar wood powder) was used as the reinforcing material. The amount of nano-clay at different levels (0, 3 and 6%) were examined on the performance of wood plastic composites. ...
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To improve the mechanical properties of wood plastics composites, four lignocellulosic materials (bagasse, rice straw, wheat straw and poplar wood powder) was used as the reinforcing material. The amount of nano-clay at different levels (0, 3 and 6%) were examined on the performance of wood plastic composites. Tensile, flexural and impact properties were measured in accordance with ASTM standard test methods. Scanning electron microscope imaging (SEM) and transmission electron microscope imaging (TEM) were performed to interpret the results. The applocation of bagasse and poplar wood powder compared with wheat and rice straws increased the strength of wood plastics composites. Using 3% nanoclay particles increased the strength properties to the maximum values. Imaging the morphology of nanoclay by X-ray diffraction and electron microscopy showed the distribution of nanoclay particles in polymer structure. With increasing the amount of nanoclay to 3%, the distance between layers increased.
Research Paper
Vahid Delnavaz; Ahmad Jahan latibari; Ahmad Mirshokraei; Sead Javad Sepide dam
Abstract
Soda - oxygen pulping of old corrugated container to produce totally chlorine free bleached pulp was investigated. In order to reach the optimum delignification condition; four levels of sodium hydroxide (9, 11, 13, and 15 %), three cooking times (90, 120, and 150 minutes) and two cooking temperatures ...
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Soda - oxygen pulping of old corrugated container to produce totally chlorine free bleached pulp was investigated. In order to reach the optimum delignification condition; four levels of sodium hydroxide (9, 11, 13, and 15 %), three cooking times (90, 120, and 150 minutes) and two cooking temperatures (120, and 150 ºC) at 6 bar oxygen pressure were studied. Yield and kappa number of pulps were measured. Results showed that the pulp obtained applying 9% sodium hydroxide, 150 minute delignification time and 150 ºC delignification temperature which produced the pulp with the yield and kappa number of 72.44% and 24.72 respectively was suitable for further bleaching. Strength of selected pulp including burst strength, tensile strength, and tear strength indices were measured as 2.27 kPa.m2/g, 29.19 Nm/g and 10.24 mN.m2/g respectively. The pulp was bleached applying 3% H2O2 and 2% NaOH to reach the final brightness of 57.97% ISO.
Research Paper
Physics and anatomy
Neda Sakhavati; Moslem Akbari nia; Hoshangh Zanganeh
Abstract
Cerasus mahaleb (L.) Mill is among the important broad-leaved trees in Zagros forests. Good bending property and the pleasant aroma helped the tree species to find a long history of rural and local uses. Wood consumption is closely influenced by the physical, biometric and other engineering properties. ...
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Cerasus mahaleb (L.) Mill is among the important broad-leaved trees in Zagros forests. Good bending property and the pleasant aroma helped the tree species to find a long history of rural and local uses. Wood consumption is closely influenced by the physical, biometric and other engineering properties. Three sound trees were harvested and tested according to ASTM-D143 standards testing procedures. Results showed that Cerasus mahaleb (L.) Mill has semi-heavy wood with high bending ability. Its compression strength parallel strain was measured as 48.45 MPa. The average fiber length and fiber diameter was 0.71 mm and 19.85 m respectively. Mean volume shrinkage and swelling was measured as 6.09% and 6.69% respectively. The radiant and tangent shrinkage and swelling after 2 and 24 hour immersion in water was 19.65%, 19.74%, 19.9%, 19.89%, 20.62% and 21.16% respectively. Mean annual diameter growth as well as mean height growth were 4.96 mm and 0.31 m respectively.
Research Paper
Alireza Kharazipoor
Abstract
Enzymatic activation of lignin on pinewood TMP (Thermo-Mechanical Pulp) fibers for MDF production was investigated using electronic microscopic technique. Two systems: laccase mediator and laccase without mediator were used. MDF was made with laccase as biological catalysts in both wet and dry process. ...
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Enzymatic activation of lignin on pinewood TMP (Thermo-Mechanical Pulp) fibers for MDF production was investigated using electronic microscopic technique. Two systems: laccase mediator and laccase without mediator were used. MDF was made with laccase as biological catalysts in both wet and dry process. Incubation of fibers with commercially available Trametes versicolor laccase was performed in aqueous solution (wet process) or the enzyme was sprayed onto the fiber (dry process). Both laccase mediator and laccase without mediator imparted major impact on the optimization of physico-mechanical properties to achieve minimum requirement of standard. Boards produced with fiber-treated with laccase were found to have higher mechanical strength than non-treated binder-free control boards. Best board properties (bending strength, internal bond strength and swelling) were observed after an incubation of 10-15 min at pH 5.6 and a concentration of 100 U/ml laccase with a mediator (4- Hydroxy benzoic acid 98%) concentration of 10 mM added at 3 min intervals . Electron-microscopic micrographs of enzyme-bonded fibers showed that the application of mediator enhances laccase reaction and, most importantly, the substrate spectrum of the enzymes broadens dramatically. Laccase (phenol oxidase enzymes) serves as an activator of lignin by radical production. Certainly it can be deduced from these studies, that enzymatic treatment altered the surface properties of the fibers. Laccase mediator treated fibers showed a marked increase in the hydrophobicity.
Research Paper
Ali akbar Enayati; Hossein Nazerani hoshmand; Kazem Dost hosseini; Ahmad Jahan latibari; Sohrab Rahimi
Abstract
In order to study the optimum manufacturing conditions of wood sawdust-cement perforated blocks, sawdust of headrige saw was mixed with portland cement type II, and then perforated blocks were molded from this mixture. The mixture ratios of sawdust to cement were selected as 28:72, 35:65 and 42:58, ...
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In order to study the optimum manufacturing conditions of wood sawdust-cement perforated blocks, sawdust of headrige saw was mixed with portland cement type II, and then perforated blocks were molded from this mixture. The mixture ratios of sawdust to cement were selected as 28:72, 35:65 and 42:58, respectively. CaCl2 (Calcium chloride) or MgCl2 (Magnesium chloride) at two levels (3%,5% based on the weight of the cement) were used as additives. The results of physical (thickness swelling after 2 and 24 hours soaking in water) and mechanical (compressive strength) properties of the blocks revealed that varying the sawdust to cement ratio imparted differences in physical and mechanical properties of the blocks. The blocks with sawdust to cement ratio of 42:58 showed the highest compressive strength and blocks with sawdust to cement ratio of 28:72 showed the lowest thickness swelling. It was observed that the type of additive did not impose any significant effect on physical and mechanical properties of blocks. Whereas the effect of MgCl2 level on the properties was significant
Research Paper
Mohammad ali Sadat nia; Ali akbar Enayati; Loeic Brancheriau; Kambiz Pourtahmasi; Farhang Honarparvar
Abstract
The acoustic behavior of reaction and normal woods, phase velocity, group velocity and attenuation coefficients in the main directions for two wood species (Populus deltoids & Picea abies), were measured and compared. The results did not show any significant difference between phase velocities of ...
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The acoustic behavior of reaction and normal woods, phase velocity, group velocity and attenuation coefficients in the main directions for two wood species (Populus deltoids & Picea abies), were measured and compared. The results did not show any significant difference between phase velocities of normal and tension wood at the same ring in poplar wood. But in compression wood from spruce, phase velocity in longitudinal direction was lower; while in transverse direction was higher compared to normal wood. Group velocity as an index of speed of wave energy in compression wood also was less than that in normal wood. In radial and tangential directions, there was no significant difference between group velocity of compression and normal woods of spruce. In poplar species, in all main directions, the measured group velocities, both for tension and normal woods were identical. The result also showed that the attenuation coefficients in reaction wood of two wood species (poplar and spruce) were less than those of normal wood in all directions. In compression and tension woods, a high correlation was observed between acoustic radiation and wood density.
Research Paper
Sayed mohammad Hosseini; Mohammad reza Mastari frahani
Abstract
Decay resistance of propionic anhydride modified Iranian beech wood against the white rot fungus (Trametes versicolor) was investigated. Iranian beech (Fagus orientalis), which is a nondurable wood was modified by propionic anhydride at different temperatures, concentrations and times without using any ...
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Decay resistance of propionic anhydride modified Iranian beech wood against the white rot fungus (Trametes versicolor) was investigated. Iranian beech (Fagus orientalis), which is a nondurable wood was modified by propionic anhydride at different temperatures, concentrations and times without using any catalyst. Propionylation was determined by calculating volume change (VC) and weight percentage gain (WPG) after solvent extraction using acetone. Different WPGs were obtained applying different treatment conditions. VC increased linearly with increasing WPG. The decay resistance of the propionylated wood against Trametes versicolor was determined according to ASTM D1413 standard test methods. Weight loss (WL) due to decay was reduced significantly when WPG increased. WPG of about 17 % was found to be the threshold level of the propionylated wood.
Research Paper
Pulp and paper
Ahmad Samariha; Jafar Ebrahimpoor kasmani; Saeed Mahdavi
Abstract
Rapeseed straw was collected from a cultivation farm in the vicinity of Babul, Mazandaran. Average fiber length, width, lumen diameter and cell wall thickness were measured as 860, 27.95, 18.86, and 4.42 µm respectively. Chemical components of rapeseed straw including cellulose, lignin, ash and ...
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Rapeseed straw was collected from a cultivation farm in the vicinity of Babul, Mazandaran. Average fiber length, width, lumen diameter and cell wall thickness were measured as 860, 27.95, 18.86, and 4.42 µm respectively. Chemical components of rapeseed straw including cellulose, lignin, ash and extractives were measured as 44%, 19.21%, 6%, and 13% respectively. Optimum pulping conditions to reach the pulp yield of 66%, were selected applying chemical charge of 20% (based on Na2O), cooking temperature of 170 ºC, and cooking time of 30 min. The pulps were refined to 350 and 400 ml CSF using PFI mill. Statistical analysis showed that mechanical properties of hand sheets with the basis weight of 127 g m-2 made from rapeseed straw NSSC pulp at the freeness of 350 and 400 ml CSF exhibited better properties compared to mixed hardwood NSSC pulp to produce fluting paper.
Research Paper
Composite wood products
Taghi Tabarsa; Sayed mohammad Hosseini; Eiman Valizadeh
Abstract
This study was conducted to investigate the potential of waste newspaper application in cement fiber board production. Cement fiber board were produced using three levels of waste paper fibers and two levels of calcium chloride as additive material. After making the boards, the Modulus of Rupture (MOR) ...
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This study was conducted to investigate the potential of waste newspaper application in cement fiber board production. Cement fiber board were produced using three levels of waste paper fibers and two levels of calcium chloride as additive material. After making the boards, the Modulus of Rupture (MOR) and thickness swelling after 24 hours immersion in water were determined based on DIN 68763. The results showed that boards made with cement:fiber ratio 90:10 and 5% calcium chloride exhibited the maximum modulus of rupture and minimum of thickness swelling (TS) after 24 hours. The results also showed that additive material had positive effect on physical and mechanical properties of boards.
Research Paper
Composite wood products
Mohammad Farajalah poor; Kazem Dosthosseini
Abstract
Effects of mat moisture content (MC) and Cu nanoparticles on heat transfer and physical and mechanical properties of poplar particleboard were investigated. Three levels of mat moisture content (9, 12 and 15%. based on oven dried wood particles) and two levels of Cu nanoparticles (0 and 15% based on ...
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Effects of mat moisture content (MC) and Cu nanoparticles on heat transfer and physical and mechanical properties of poplar particleboard were investigated. Three levels of mat moisture content (9, 12 and 15%. based on oven dried wood particles) and two levels of Cu nanoparticles (0 and 15% based on oven dried resin) were selected as variable factors. Results indicated that mechanical properties of particleboard improved as MC increases. Cu nanoparticles accelerated the heat transfer from the surface layer to the core layer of the mat and subsequently increased the internal bonding. This positive effect was evident as MC increased. Water absorption and thickness swelling increased as either MC or Cu nanoparticles content was raised. It was observed that the efficiency of Cu nanoparticles on heat transfer was superior at higher MC. Energy Dispersive X-Ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) determination revealed that the presence and very well dispersion of Cu nanoparticles in glue line.
Research Paper
Mahmood Kazemi; Hamideh Asadpoor; Shamsaldin Balapoor
Abstract
During 2008, a severe deluge in Sari caused huge damages and Cupressus sempervirens l. var. horizantalis trees in botany garden of Natural Sciences College were also fallen by the overflow. To perform the study the fallen trees disks and cores of standing trees were prepared. Using Lintab Measurement ...
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During 2008, a severe deluge in Sari caused huge damages and Cupressus sempervirens l. var. horizantalis trees in botany garden of Natural Sciences College were also fallen by the overflow. To perform the study the fallen trees disks and cores of standing trees were prepared. Using Lintab Measurement Table, the width of each growth ring per year and their average were calculated. The raw data related to rings growth were standardized by method of ARSTAN and index average of growth rings was recorded. To study the relationship between climatic variables and C. sempervirens rings growth, data of Babolsar and Tajan synoptic stations were found. The observation results of fallen trees in flat sites showed that C. sempervirens is not resistant against deluge and in the places which ground water table is raised; C. sempervirens is not suggested for planting. Numerical results also indicated that the mean growth ring is about 3.62 mm per year. Taking into account the bark width, the average of trunk diameter after 40 years was about 30 cm. Temperature increase during the Past years had caused the trend of growth width to reduce. Also the relation of index average of growth with rainfall showed that precipitation is an effective factor on C. sempervirens growth and as a result, the average of rainfall in April had a positive and significance effect on C. sempervirens growth (R= 0.61 and P<0.01).
