Pulp and paper
Farzaneh Shiralizadeh; Sahab Hejazi; Mohammad Ahmadi
Abstract
In this research, rice straw was used as raw material. Potassium hydroxide was combined with monoethanolamine (MEA) as liquor. In another processes NaOH/Na2So3, KOH/K2So3 and KOH 14% was used as references pulp. The results showed that using pure MEA(15%) produced the highest yield and the highest kappa ...
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In this research, rice straw was used as raw material. Potassium hydroxide was combined with monoethanolamine (MEA) as liquor. In another processes NaOH/Na2So3, KOH/K2So3 and KOH 14% was used as references pulp. The results showed that using pure MEA(15%) produced the highest yield and the highest kappa number. By using potassium hydroxide as a additive agent in MEA pulping, the amount of reject, yield and kappa number was decreased and the lowest yield and the lowest kappa number relevant to MEA(15%) combined with KOH (40%). In addition, in KOH pulping observed that, with increasing concentration of MEA, as additive agent, the amount of total yield increased but the kappa number and reject content was decreased. Results showed that the highest tensile index and tear index were relevant to MEA (15%) combined with KOH (20%) and the highest burs index relevant to NaOH/Na2SO3 treatment. According to the optical properties, it was found that the highest brightness was achieved in K2SO3/KOH. The highest opacity relevant to the KOH14% .The result shows that MEA process in combined with Potassium hydroxide can be done success fully on rice straw and properties of pulp production, specially in aspect of mechanical strength, in term of combination is superior than soda and Potassium hydroxide process
Composite wood products
Ahmad Jahan- Latibari; Roozbeh Abidnejad; Mehran Roohnia
Abstract
At this research, the influence of Multi Walled Carbon Nano Tubes (Non-functionalized and functionalized) on mechanical properties of polypropylene – old corrugated container (OCC) fibers composites was investigated. OCC fibers polypropylene composites were prepared using 20% OCC fibers, 80% polypropylene ...
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At this research, the influence of Multi Walled Carbon Nano Tubes (Non-functionalized and functionalized) on mechanical properties of polypropylene – old corrugated container (OCC) fibers composites was investigated. OCC fibers polypropylene composites were prepared using 20% OCC fibers, 80% polypropylene and 3% MAPP. Three levels of multi walled carbon nano tubes (0% - 0.5% - 1%) were added. Acidic oxidation method was used to functionalize the MWCNTs. Mechanical properties were measured as defined in ASTM testing methods. The results indicated that at higher dosage of MWCNTs, the tensile strength properties of the composite were improved but the influence of the functionalizing was not statisitaclly significant. The bending strength and elasticity as wellas the izod impact were increased as the higher amount of nanotubes were added to the composite. Scanning Electron Microscopes showed the development of bonding between the composite components. Compostes without coupling agent showed lower bonding strength between polypropylene and fiber as indicated by fiber pull out. However, in the composites containing coupling agent, the fiber fracture was observed.
ّFahimeh Shabanalizadeh; Mohammad reza Dehghani firoz abadi; Abolfazl Karegarfard; Mehrab Madhoshi
Abstract
Utilization of kenaf core and stalk for the production of medium density fiberboard was investigated. Control boards were produced using poplar wood fibers and compared with kenaf boards. Urea formaldehyde resin was used. Medium density fiberboards were made at two densities of 0.55 and 0.75 g/cm3. ...
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Utilization of kenaf core and stalk for the production of medium density fiberboard was investigated. Control boards were produced using poplar wood fibers and compared with kenaf boards. Urea formaldehyde resin was used. Medium density fiberboards were made at two densities of 0.55 and 0.75 g/cm3. Six combinations of variable were tested and for each combination of variables, 3 replications and the total of 18 laboratory MDF boards were produced. The kenaf core and stalk fiber dimensions and the mechanical and physical properties of the MDF boards were measured. Factorial experimental design was used for statistical analysis of generated data. Results showed that average length of kenaf core and stalk fiber are 3.607 and 0.78 mm, and their respective diameters are 41.48 and 36.76 μm. The results of modulus of rupture, modulus of elasticity, internal bonding and thickness swelling after 2 and 24 hours immersion in water showed that kenaf core fiberboard with the density of 0.75 g/cm3 are above the required values for these boards which indicate that these properties are comparable with MDF from wood. It can be expressed that kenaf core fibers can substitute the poplar wood fiber for MDF production. The modulus of rupture, modulus of elasticity and internal bonding of MDF boards produced using kenaf core was improved as the density of the boards increased. The thickness swelling after 2 and 24 hours immersion in water was comparable to poplar fiberboard. Kenaf stalk fiberboard showed lower mechanical and physical properties due to the presence of bark fibers.
Pulp and paper
Mehrnoosh Tavakoli; saraeyan ahmad reza; hossein resalati; ali ghasemian
Abstract
The present study was carried out aiming to investigate the effect of using Deinked Mixed Office Waste Pulp (MOW) on the properties of Alkaline Peroxide Mechanical Pulp (APMP) from cotton stalk. APMP pulps was prepared using chelating agents such as Na2SiO3 and DTPA (control sample) and without ...
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The present study was carried out aiming to investigate the effect of using Deinked Mixed Office Waste Pulp (MOW) on the properties of Alkaline Peroxide Mechanical Pulp (APMP) from cotton stalk. APMP pulps was prepared using chelating agents such as Na2SiO3 and DTPA (control sample) and without these agents in two-stage pulping withL/Wratio 6:1(ml/g), 20 minutes impregnation time at 70 0Cfor firststage, 60 minutes impregnation at 75 0Cfor second stage. Also, pulp was preparedfrommixed office waste paper, whichweredeinked with conventional flotation and then each pulp was separately refined up to about 300 ml CSF. The handsheets were made from control sample pulps, APMP without chelating agents, MOW deinked pulp and mixing with 10%, 20% deinked pulp with control APMP. Physical and mechanical properties were determined using TAPPI standard methods. Deinked MOW pulp had the maximum values of density, brightness, strength properties and APMP pulp without chelating agents had the minimum values. Among mixed pulps, APMP pulp containing 20% deinked MOW pulp showed the maximum value of density, brightness, burst index and tear index.
Physics and anatomy
Maliheh Akhtari; Mehdi Arefkhani
Abstract
In this study acetylated Beech wood (Fagus orientalis Lipsky) has been subjected to a variety of artificial weathering conditions in different of times (0,150&300 h), then wood surface was analyzed for chemical changes using Fourier Transform Infrared (FTIR) spectroscopy and for structural changes ...
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In this study acetylated Beech wood (Fagus orientalis Lipsky) has been subjected to a variety of artificial weathering conditions in different of times (0,150&300 h), then wood surface was analyzed for chemical changes using Fourier Transform Infrared (FTIR) spectroscopy and for structural changes using Scanning Electron Microscopy (SEM) .Results showed that weathering process influence by the functional groups on the wood surface. Cycle of weathering (Light and water) caused the damage to the surface polymer structure and chemical and physical changes. The greatest changes caused by the functional groups and Aromatic structure of lignin. The SEM results showed that the surface of wood exposed to weathering undergoes distinct Physical changes. The surface degradation appears to be directly proportional to the time of exposure to the weathering conditions and acetylation of the wood to protect the surface from damages caused by the weathering effect of light and water.
Aliakbar Yazdi meymand; Ali Khaki; mohammad ghofrani
Abstract
Sandwich panels are one of the most advanced forms of composite structures that are widely used. The objective of this study was to investigate the effect of three types of resin: urea formaldehyde (UF), melamine formaldehyde (MF) and the combination of urea formaldehyde + melamine formaldehyde (UF + ...
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Sandwich panels are one of the most advanced forms of composite structures that are widely used. The objective of this study was to investigate the effect of three types of resin: urea formaldehyde (UF), melamine formaldehyde (MF) and the combination of urea formaldehyde + melamine formaldehyde (UF + MF) two core layer densities (400 and 500 kg/m3) on physical and mechanical properties of sandwich panels made of palm leaves waste. Pressure temperature, pressure and time for all panels were 175 °C, 35 kg /cm2 and 9 minutes, respectively. The final thickness of all panels was the same and equal to 25 mm. Physical and mechanical properties include; Water absorption (WA), thickness swelling (TS), modulus of rupture (MOR), modulus of elasticity (MOE), impact bending strength (IBS) and internal bonding (IB) were performed on the samples. The results showed that there was a significant (p<0.05) difference between the values of different treatments at the level of 95%. Physical properties (except thickness swelling) and mechanical properties with a density of 500 kg/m3 improved. The use of MF and UF + MF resins significantly improved the physical and mechanical properties of sandwich panels due to its high adhesive quality.
Composite wood products
Ali Akrami; Kazem ِDossthoseini; Ahmad Jahan latibari; Mohammad mehdi Faezipoor
Abstract
In this investigation, the effect of paraffin content and press time and temperature on practical properties especially surface roughness of particleboard is studied. The variables such as paraffin content at 0, 1& 2 percent, press temperature at 170° and 180° C and press time of 4 and 5 ...
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In this investigation, the effect of paraffin content and press time and temperature on practical properties especially surface roughness of particleboard is studied. The variables such as paraffin content at 0, 1& 2 percent, press temperature at 170° and 180° C and press time of 4 and 5 minutes were investigated.
Modulus of rupture, modulus of elasticity, shear strength, water absorption and thickness swelling after 2& 24 hours soaking in water & surface roughness were measured.
The results indicate that there is no significant difference on the influence of paraffin content on either MOR & MOE of the particleboard. But increasing paraffin content decreased shear strength of panels.
However, addition of paraffin reduced water absorption and thickness swelling.
Press temperature had no significant influence on measured properties, but this variables increased surface roughness. Increasing press time, improved MOE, but showed no significant influence on other properties.
Composite wood products
masoudreza habibi; Hossein Hosseinkhani; Saeed Mahdavi
Abstract
In this study, particleboard was produced using Mesquite (Prosopis juliflora) called Somr wood. Oven dry density of stem and branch wood was measured as 0.92, 0.72 g/cm3 whereas the bark weight percentage of stem and branch wood determined as 13.6 % and14 % respectively. The influence of raw material ...
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In this study, particleboard was produced using Mesquite (Prosopis juliflora) called Somr wood. Oven dry density of stem and branch wood was measured as 0.92, 0.72 g/cm3 whereas the bark weight percentage of stem and branch wood determined as 13.6 % and14 % respectively. The influence of raw material mixture (stem wood, branch wood, the blend of stem and branch wood, 50/50 w/w) and resin content 10% and 12 % (based on dry weight of the particle) on particleboard properties were investigated. Properties such as MOR, MOE, IB, thickness swelling after 2 and 24 hours immersion in water were determined according to EN standard. Except for MOE, the effect of raw material type on board properties was significant. Particleboards made from branch wood, had the highest MOR. Maximum IB was observed in boards made from the blend of stem and branch wood. With the exception of bending properties, the effect of resin content on all board properties was significant. Increasing the resin content improved board properties. The lowest value of thickness swelling after 2 and 24 hours immersion in water was obtained in particleboard made from stem wood
Composite wood products
masoudreza habibi; Hossein Hosseinkhani; Saeed Mahdavi
Abstract
In this study, MDF was produced from Rice straw. Variables for Medium Density fiberboard making were as following:
- Resin content 8, 9.5, 11 (percent baced on oven dry weight of fiber)
- Press time (4, 5, 6 minutes).
There were 9 treatment conditions by combinations of the above factors and three ...
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In this study, MDF was produced from Rice straw. Variables for Medium Density fiberboard making were as following:
- Resin content 8, 9.5, 11 (percent baced on oven dry weight of fiber)
- Press time (4, 5, 6 minutes).
There were 9 treatment conditions by combinations of the above factors and three replications for each combinations which resulted in producing 27 boards.The other production variables were constant.
The anatomical properties of Rice straw such as fiber length, fiber diameter were measured respectively 810, 10.1 micron. L/D ratio of Rice straw fiber was measured 80.2. The physical and mechanical properties of MDF were determined according to DIN standard. The measurements of bending properties and IB of MDF revealed that the highest MOR, MOE, IB were obtained in variables combination of 11% resin content and press time of 6 minute and at this conditions thickness swelling of boards were the lowest.
According to Duncans, test method the effects of press times (4 & 5 minutes) and resin content (8% & 9.5%) on bending properties were not significant statistically.
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.
Physics and anatomy
Nooshin Toghraie; Abdolrahman Hosseinzadeh; Davood Parsapazhoh; Fardad Golbabaei
Abstract
To study saxaul wood properties in the various ecological regions of Iran twelve 10-22 years old sample trees (4 trees from each species) were selected and cut from three different areas around kerman. Physical, chemical and anatomical characteristics of wood samples were investigated. The results of ...
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To study saxaul wood properties in the various ecological regions of Iran twelve 10-22 years old sample trees (4 trees from each species) were selected and cut from three different areas around kerman. Physical, chemical and anatomical characteristics of wood samples were investigated. The results of this investigation revealed that the initial moisture content before felling was 38.6% and the mean specific gravity based on oven dry weight and oven dry volume (WOD/VOD), oven dry and saturated weight Saxaul saturated volume (WOD/Vs ,WS/VS ), were studied for yellow, white and black and respectively. It is concluded that saxaul wood of Kerman province is heavy. The average longitudinal, radial and tangential shrinkage were surveyed. Wood periodicity of growth was determined to be 3-4 rings per year. Anatomical features were investigated by light microscopy and papermaking factors were determined. Fiber length, fiber diameter and lumen diameter were determined. These values lead to species with short and thick fibers. Chemical composition including percentage of cellulose, lignin, extractives and ash were revealed too.
Composite wood products
Abolfazl Kargarfard; Abdolrahman Hosseinzadeh; Kazem Doosthosseini; Ahmad Jahan latibari; Amir Nourbakhsh
Abstract
In this investigation, experimental boards were produced using beech wood particle, mat moisture content gradient at 0,3 and 6%, two press temperature sat 165and 1850 C and two press times at 3 and 5 minutes. 36 sample boards produced and the physical and mechanical properties of those tested.The results ...
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In this investigation, experimental boards were produced using beech wood particle, mat moisture content gradient at 0,3 and 6%, two press temperature sat 165and 1850 C and two press times at 3 and 5 minutes. 36 sample boards produced and the physical and mechanical properties of those tested.The results indicated that mat moisture content gradient had significantly effected on modified of modulus of elasticity of boards, and with increasing mat moisture content gradient, the MOE of boards increased. Also in 0% mat moisture content gradient, increasing of press time, modulus of rupture and modulus of elasticity decreased. However with increasing mat moisture content gradient, increasing of press time caused of these properties modified.On the other hand an inverse relationship observed between mat moisture content gradient and internal bond of boards that due to of negative effect of increasing of vapor pressure were on resin bond quality in middle layer. But with increasing press time from 3 to 5 minutes, the internal bond of boards increased. The results of thickness swelling measurement indicated that with increasing mat moisture content gradient, the thickness swelling of boards increased. However, when press time increased, the thickness swelling of boards decreased.
Management and Economics wood
Habib alah Arab tabar firoz jaei; Ali Reza nezhad; Abdolrahman Hosseinzadeh
Abstract
In this study, green round poles of Populus nigra L. var. italica were treated with Celcure by using Tire - Tube method. After felling and sizing trees, thick - end of poles (about 15 cm.) were debarked and a section of tire inner Tube was fastened around the debarked end of the fresh - cut poles and ...
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In this study, green round poles of Populus nigra L. var. italica were treated with Celcure by using Tire - Tube method. After felling and sizing trees, thick - end of poles (about 15 cm.) were debarked and a section of tire inner Tube was fastened around the debarked end of the fresh - cut poles and bound tightly with rubber bands and the upper end of the tube was connected to the elevated solution container. Then the poles installed on slope and let them to absorb the solution. The results showed that sapwoods were completely penetrated but hartwood less after 8-24 hrs.
Chemical conversion
mohammad najafianashrafi; Payam Moradpour; Ahmad Jahan latibari; Hamidreza Edalat
Abstract
Poly vinyl acetate (PVAC) adhesive is one of the most important adhesives in wood and furniture industry, which has many advantages such as low cost, environment friendliness and non-toxicity. However, it has some disadvantages such as low water resistance and poor boning strength. In this study, the ...
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Poly vinyl acetate (PVAC) adhesive is one of the most important adhesives in wood and furniture industry, which has many advantages such as low cost, environment friendliness and non-toxicity. However, it has some disadvantages such as low water resistance and poor boning strength. In this study, the effect of nano silica (NS) on the properties of poly vinyl acetate adhesive was investigated. The adhesive formulation with different NS contents (2, 3 and 4%) was added to the PVAC. The structure of the prepared adhesive samples was studied by FT-IR and XRD. We used the wood of Acer tree (Acer cappadocicum) to make joints in this study. Two standards of D882 and ASTM D905 were used for tensile and shear tests, respectively. Results showed that adding NS to PVAC enhanced the tensile strength of films. For example, the tensile strength of prepared films was increased by 30% after adding 4% of NS. Moreover, shear strength test showed that NS up to 3% can improve PVAC bond strength. Viscosity results showed that increasing the weight of NS up to 3% to PVAC glue lead to an increase following a decrease in the viscosity
Reza Hajihassani; Saman Ghahri; Kamyar Salehi; Fardad Golbabaei; seyedeh masoomeh
Abstract
Abstract In the current research, surface properties and failure modes of modified poplar wood (Populus deltoides) by hygrothermal treatment were evaluated. For this aim, the effect of variable factors included hygrothermal temperature (three levels: 130, 150 and 170°C) and holding time (two levels: ...
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Abstract In the current research, surface properties and failure modes of modified poplar wood (Populus deltoides) by hygrothermal treatment were evaluated. For this aim, the effect of variable factors included hygrothermal temperature (three levels: 130, 150 and 170°C) and holding time (two levels: 20 and 40 minutes) on poplar wood specimens properties (contact angle and surface roughness) prior to and after planning were investigated. The surface characteristics and failure modes were evaluated for both treated and untreated wood specimens. The results revealed that surface roughness of poplar wood was enhanced due to the hygrothermal treatment in both states of before and after planning. It was also found that the hygrothermal treatment decreased contact angle of distilled water. The bending strength of specimens was reduced by hygrothermal treatment. According to the results, failure modes of hygrothermally treated specimens were simple and compression types in bending strength test. Keywords: Surface roughness, contact angle, bending strength, failure mode
Saman Ghahri; Reza Hajihassani; Kamyar Salehi; Fardad Golbabaei
Abstract
In this study, the mechanical properties of kenaf cement composite were investigated using different amounts of kenaf particles (mixture of kenaf core and bark and kenaf core particles). Kenaf-cement composites were manufactured at different levels (10, 15 and 20%) of different kenaf particles. Also, ...
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In this study, the mechanical properties of kenaf cement composite were investigated using different amounts of kenaf particles (mixture of kenaf core and bark and kenaf core particles). Kenaf-cement composites were manufactured at different levels (10, 15 and 20%) of different kenaf particles. Also, Portland cement and calcium chloride (as cement accelerating additive) were used in this research. Calcium chloride and water were mixed well and then kenaf particles were added to the mixture. At next stage, cement was added to the prepared mixture and all component were mixed well. Prepared mixture was molded to the wooden mold and kenaf cement composites were produced. The results obtained from mechanical evaluation of kenaf-cement composites showed the highest bending strength in 10% kenaf bark-cement composites. Also results revealed that highest modulus of elasticity of 10% kenaf core-cement products were obtained. The results of this research revealed the potential of kenaf particles as reinforcement in cement composite production.
Composite wood products
Hossein Usefi; Ali akbar Enayati; Mohammad mehdi Faezi poor; Sayed hamzeh Sadat nezhad
Abstract
Canola straw as a agricultural residues has been investigated for MDF production. The variables were the steaming time of 2, 5 & 8 minutes and the resin content of 9 and 11 present. Other factors being kept constant. Some of the physical and mechanical properties such as thickness swelling (TS), ...
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Canola straw as a agricultural residues has been investigated for MDF production. The variables were the steaming time of 2, 5 & 8 minutes and the resin content of 9 and 11 present. Other factors being kept constant. Some of the physical and mechanical properties such as thickness swelling (TS), water absorption (WA) modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), were measured. In addition, canola straw fiber properties such as fiber length, diameter and cell wall thickness were determined. The results showed that the optimum condition for MDF production from canola straw is the treatment of 5 minutes steaming time and 11% resin content. All the tested mechanical and thickness swelling properties improved with the increase of steaming time level. Dimensional stability of the MDFs improved as resin content increased. WA and TS values of the produced boards were relatively high because no wax and no depithing were used during the board production. More over, the values of canola straw fiber length, diameter and cell wall thickness are 1215, 28, 7.43 micrometer respectively.
Composite wood products
Farhad Ghotbaldin; Habib alah Khademieslam; Amir Nourbakhsh; Mohammad Talaeipoor
Abstract
An experiment was conducted to study polymerization conditions and important production factors, the amount of resin and press temperature, on physical and mechanical properties of produced boards by urea formaldehyde (UF) and melamine urea formaldehyde (MUF) were compared. Purify UF resin (control treatment) ...
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An experiment was conducted to study polymerization conditions and important production factors, the amount of resin and press temperature, on physical and mechanical properties of produced boards by urea formaldehyde (UF) and melamine urea formaldehyde (MUF) were compared. Purify UF resin (control treatment) and its mixture with MUF at 25, 50 and 75% proportions in 170 and 180˚C temperature were used to make homogen particle boards. The proportion of resin to particles was 10 percent by dry weight. Other production factors were assumed as fix factors. Eight experimental groups (treatment) with three replications per each were studied. Produced particles were derived from species Alnus subcordata. Physical and mechanical properties measurement prepared samples were based on European EN standard. Examined Physical characteristics were water absorption and thickness swelling and mechanical characteristics were modulus of rupture, modulus of elasticity and so internal bond. The data were analyzed in completely randomized design with factorial arrangement (4*2). Statistical significances among treatment means were determined by multiple range test of Duncan. The results of this study showed that physical and mechanical properties of boards were improved by increasing the level of MUF resin and temperature. Eventually, with consideration all results and so quality and economical aspects of produced particleboard by MUF resin and its comparison with control group we have concluded that 50 percent of MUF resin and 180 degree centigrade of press temperature are optimal levels.
Management and Economics wood
Fatemeh Hasani Khorshidi; Mehdi Emadi
Abstract
In this study, effect of accelerated aging on adhesion strength of half-polyester and polyurethane transparent coatings were evaluated in maple and pine species. For this purpose, dried specimens with 12×110×550 millimeters were used. Sealer as substrate, and half-polyester and binary polyurethane ...
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In this study, effect of accelerated aging on adhesion strength of half-polyester and polyurethane transparent coatings were evaluated in maple and pine species. For this purpose, dried specimens with 12×110×550 millimeters were used. Sealer as substrate, and half-polyester and binary polyurethane as coatings were applied on wood. Coatings were implemented thereby film applicator and gun methods, and accelerated aging test of wood specimens was carried out according to ASTM D1037. Results indicated that maximum value of adhesion strength is belong to binary polyurethane in maple applied by film applicator and minimum for half-polyester in pine applied by gun method, in opposite. Due to thin film, velocity variations in gun method by painter person, and consequent rapid evaporation of thinner, adhesion decreased in comparison with film applicator method. Also it's found that accelerated aging diminished adhesion strength of coatings in both maple and pine species. It can be concluded during the accelerated aging test, the steam causes moisture absorption and swelling of the fibers near the surface and thus reduce the resistance of the coating adhesion.Long-term effect of humidity and aging makes Ecowool quickly lose their stickiness.And the effect of floating in the water samples, lignin degradation products in the process of steaming and freezing and heating washed by water And cause the loosening of the cellulosic fibers in the wood, resulting in wood adhesive strength is significantly reduced due to the accelerated aging test.
Pulp and paper
fatemeh rajabi; seyed majid zabizadeh
Abstract
The objective of this study was the evaluation of optical, mechanical properties of chemi-mechanical pulp which were bleached by one and two stage bleaching sequence of hydrogen peroxide and sodium hypochlorite. Also the environmental effects of effluents from bleached paper liquor were studied. For ...
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The objective of this study was the evaluation of optical, mechanical properties of chemi-mechanical pulp which were bleached by one and two stage bleaching sequence of hydrogen peroxide and sodium hypochlorite. Also the environmental effects of effluents from bleached paper liquor were studied. For this purpose, unbleached CMP pulp mixed of hardwoods was prepared from Mazandaran Wood and Paper mill. Then, these pulps were bleached using P (hydrogen peroxide), H (Sodium Hypochlorite), PH (Hydrogen Peroxide and Sodium Hypochlorite) and HP (Sodium Hypochlorite and hydrogen peroxide) stages. 60 gr/m2 hand sheets were prepared and the optical, mechanical properties of hand sheets and also their effluent bleaching liquor characteristics were measured and analyzed based on TAPPI and APHA Standards. The results showed that when peroxide was applied at the last stage of bleaching, then the properties such as tear, tensile and brightness have increased and yellowness has decreased. Generally, the role of single sequence of bleaching by P and two sequence of bleaching with HP were more effective than single sequence of H or unbleached pulp. Based on results, the highest and lowest COD load is related to bleaching liquor of H and PH respectively. Moreover, bleaching liquor of hydrogen peroxide had the highest BOD load and the lowest amount of BOD is related to PH sequence of bleaching.
Composite wood products
Mohammad Ghofrani; ali mohamadi
Abstract
This study investigated the comparative tension and compression strength of detachable edge joints in MDF and particle boards. Five pieces of each samples were provides in L shape with the size of 20*20 cm according to D 1761 ASTM. Fittings were applied in three types: cross, hexagonal shape and plastic ...
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This study investigated the comparative tension and compression strength of detachable edge joints in MDF and particle boards. Five pieces of each samples were provides in L shape with the size of 20*20 cm according to D 1761 ASTM. Fittings were applied in three types: cross, hexagonal shape and plastic fitting with 2 types of counter sink and butt screw were used. The results showed that the highest amount of tension strength was in cross shape metal joints and highest compression strength in hexagonal joints. Also the lowest strength of both tension and compression was observed in plastic joints. According to results, the joints with counter sink screws had higher strength than butt screw, and the failure place in this samples was like crevice in the bottom of boards. The data showed that the tension strength of all three fittings were higher than compression strength. The highest bearing of tension stress was in MDF with glue and dowel, counter sink screw and cross shaped fitting and the lowest was in particle boards without dowel, butt screw and plastic strips. The highest bearing of compression stress was in MDF with glue and dowel joint, hexagonal metal strip and counter sink screw, the lowest was seen in particle board without dowel, butt screw, and plastic strip.
Saman Ghahri; Mohammad Reza Abde; Farshid Abdoli
Abstract
In this research, Fir wood (Abies spp.) was thermally modified by retification process. The effect of modification process on physical and mechanical properties of fir wood were evaluated. For this aim, fir wood specimens with 12% moisture were modified in the steel tank with nitrogen gas medium at different ...
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In this research, Fir wood (Abies spp.) was thermally modified by retification process. The effect of modification process on physical and mechanical properties of fir wood were evaluated. For this aim, fir wood specimens with 12% moisture were modified in the steel tank with nitrogen gas medium at different temperatures (180 °C, 200 °C, and 220 °C) and 15 hours holding time. Physical properties such as wood density, volumetric swelling, dimensional stability and mechanical properties such as modulus of rupture (MOR), modulus of elasticity (MOE), shear and compression strength parallel to grain and impact strength of different modified wood specimens were evaluated. Results showed that by increasing treatment temperature, during modification process, water absorption and volumetric swelling were decreased and dimensional stability was improved. Also, results revealed that the mechanical strength of modified wood such as MOR, MOE, shear and compression strength parallel to grain and impact strength were decreased.
Pulp and paper
Jafar Ebrahimpour Kasmani; Ahmad Samariha; Alireza Khakifirooz
Abstract
This research was conducted with the aim of investigating the effect of two-layer coating of nano-polyurethane and nano-clay on the mechanical and physical properties of packaging cardboard with brown layer. For this purpose, brown layer cardboard with grammage of 127 was prepared and tested. To coat ...
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This research was conducted with the aim of investigating the effect of two-layer coating of nano-polyurethane and nano-clay on the mechanical and physical properties of packaging cardboard with brown layer. For this purpose, brown layer cardboard with grammage of 127 was prepared and tested. To coat the surface of the cardboard, it was first coated with nano-polyurethane and sprayed by a coating nozzle. Then the surface of the brown layer cardboard was covered with nano-clay to improve the performance of the coating material of the first treatment. Nano-clay coating was performed by a laboratory coating machine called barcoter. The coated cardboards were restrained and dried in the room for one day to stabilize the coating material on their surface. Then the samples were placed inside the freezer for 2 and 4 months and their properties were measured. The results showed that coating reduced water absorption. In the coated and frozen samples, an increase in thickness, smoothness of the surface and a decrease in water absorption and resistance properties compared to non-frozen control samples have been observed. Double coated samples showed very few pores. The thickness, smoothness of the surface and resistance to tearing in the machine cross direction of the double coated brown cardboard showed an increase of 13.7%, 75% and 3.8%, respectively, compared to the control sample. water absorption, resistance to bursting, resistance to tearing in the machine direction, resistance to tensile in the machine direction, resistance to tensile in the cross machine direction, resistance to ring crush test in the machine direction and resistance to ring crush test in the cross machine direction of the double-coated brown layer cardboard compared to the control sample, showed 107.20, 1.5, 34.3, 25.4, 24.3, and 4.7 percent decrease respectively.
Composite wood products
Amir Nourbakhsh; Taghi Tabarsa; Abolfazl Kargarfard; Fardad Golbabaei
Abstract
Laminated veneer lumber (L. V. L) manufactured from Maple and Alder wood is investigated. Three levels of layer thicknesses of 2, 3 and 4mm. were investigated. Bending strength (MOR and MOE), CompressionThe results of this investigation indicated that laminated wood strength of samples produced from ...
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Laminated veneer lumber (L. V. L) manufactured from Maple and Alder wood is investigated. Three levels of layer thicknesses of 2, 3 and 4mm. were investigated. Bending strength (MOR and MOE), CompressionThe results of this investigation indicated that laminated wood strength of samples produced from Alder layers are superior to Maple. Statistical analysis of the results showed that the effect of wood species on strength properties was significantly different at 99% level. Layer thicknesses also showed significant effect on strength increasing layer thicknesses from 2 to 4 mm. caused a reduction on MOE and improved impact properties.The results of this investigation also showed that Alder layers at 4 mm. Is superior to Maple layers in impact properties.
mohammad ghofrani; Habib Nori
Abstract
In the present study the strength of different kinds of wooden dowels, screws, and ready-to-assemble joints (RTA joints) used in medium density fiberboards (MDF) were assessed and compared for their lateral shear strength. The T-form specimens (20 cm × 8 cm) were comprised of two MDF parts in compliance ...
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In the present study the strength of different kinds of wooden dowels, screws, and ready-to-assemble joints (RTA joints) used in medium density fiberboards (MDF) were assessed and compared for their lateral shear strength. The T-form specimens (20 cm × 8 cm) were comprised of two MDF parts in compliance with ASTM D1761 standard. Five specimens for each treatment were made and a total of 20 treatments were designed; treatments in this study are as follows:Rough as well as smooth dowel joints with 8 and 10 mm diameter, using urea-formaldehyde and poly-vinyl acetate adhesives; Screw joints, sizes 5 and 6, with or without urea-formaldehyde as well as poly-vinyl acetate adhesives; And, different kinds of RTA joints.Results indicate that different kinds of screw joints show the most powerful joints in comparison with other kinds of joints; but there was no significant difference between different kinds of screw joints. Therefore, having economical points of view in mind, screw joints size 5 is recommended to be used without adhesive. The effect of dowel surface as independent variable was statistically significant, while the interaction effect of dowel diameter, adhesive, and quality of dowel surface on lateral shear strength, as well as the independent and interaction effects of two factors of combined wooden dowel along with joint, and adhesive on the strength of RTA joint (that has nuts) were statistically significant.
