Composite wood products
Akbar Mastouri; Davood Efhamisisi; Asghar Tarmian; AliReza Gholinezhad-Pirbazari; Mohamad Azad fallah
Abstract
Background and objectives: Surface modification and coating is one of the effective methods to increase the performance and service life of wooden structures. All kinds of super-hydrophobic techniques with a contact angle above 150 degrees and a sliding angle less than 10 degrees, in addition to creating ...
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Background and objectives: Surface modification and coating is one of the effective methods to increase the performance and service life of wooden structures. All kinds of super-hydrophobic techniques with a contact angle above 150 degrees and a sliding angle less than 10 degrees, in addition to creating high hydrophobicity, also improve the antimicrobial and other surface properties of the substrate. Nevertheless, resistance to mechanical and moisture damage are very important in connection with super-hydrophobic surfaces. Natural waxes are one of the efficient and healthy materials for creating a durable super-hydrophobic coating with high biocompatibility. In this research, nano-silica modified with non-fluorine alkyl materials in the presence of epoxy resin has been used to create superhydrophobic surfaces of birch wood (Betula pendula). Also, carnauba wax has been used to improve water repellency, self-cleaning property and durability in conditions of mechanical damage, humidity and harsh environments, comparatively.Materials and methods: Dodecyltrichlorosilane was used in the presence of toluene solvent for functionalizing and hydrophobicizing silica nanoparticles. A formulation containing 2% of modified nano silica and some epoxy resin was used by spray method to fabricate super-hydrophobic coating on birch wood. Also, the optimal amount of vegetable carnauba wax (Brazilian palm) was used as a reinforcing agent to make the nanohybrid formulation. Durability and stability to mechanical damage (sandpaper abrasion, water impact) and harsh environments (acidic, alkaline, ultraviolet rays and solvents) were investigated. Finally, the self-cleaning potential of the processed wooden surfaces was evaluated by qualitative (inclined surface) and quantitative (dropping) methods using edible liquids.Results: Both types of nanocomposite (without wax) and nanohybrid (containing wax) coatings caused the super-hydrophobicity on birch wood. The adding the optimal amount of carnauba wax to the epoxy-based nanocoating structure leads to a contact angle of 170 degrees and a sliding angle of less than 3 degrees by water drops. In addition, carnauba wax caused the stability and strength of superhydrophobic surfaces in aging and mechanical conditions. The highest level of stability in harsh environments was related to the hybrid nanocoating. The highest contact angle was observed for pomegranate juice and the lowest for milk. Also, the self-cleaning potential with various types of Fanta and Coca-Cola drinks on the superhydrophobic surface was successful.Conclusion: The use of carnauba wax increased the contact angle and decreased the sliding angle. The use of carnauba wax significantly improved the mechanical properties and water-repellency of the super-hydrophobic coating. The chemical nature and morphological structure of wax in the coating is the reason for this superiority. The super-hydrophobic surface made with nanohybrid coating in the presence of carnauba wax has the potential of self-cleaning, biocompatibility and stability in service conditions and can be used to protect all types of general surfaces in the field of food, especially lignocellulosic substrates such as wood and paper.
Farhod Firouzbehi; Davood Efhamisisi; Yahya Hamzeh; asghar tarmian; Reza Oladi
Abstract
Pyrolysis acid or wood vinegar is a dark liquid derived from the condensation of steam and smoke emitted by thermal pyrolysis of wood or any other lignocellulosic material. In this study, a heating furnace was first designed to allow a precise temperature-time program. The wood from three ...
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Pyrolysis acid or wood vinegar is a dark liquid derived from the condensation of steam and smoke emitted by thermal pyrolysis of wood or any other lignocellulosic material. In this study, a heating furnace was first designed to allow a precise temperature-time program. The wood from three different species including oak, citrus and cypress were pyrolyzed under a specific temperature-time schedule. The smoke emitted from the furnace were cooled and condensed in a 20 m pipe using the flow of cold water, and then was dumped in a container as liquid. Pyrolysis was performed at three different temperature ranges of 200, 260 and 330 ° C. The obtained pyrolysis acids had different color and acidity depending on the temperature and species of wood used. Under the heating conditions used in this study, cypress had lower pyrolysis rate than hardwoods. The weight percentage gain of the treated beech and pine wood varied from 5 to 35%, which was depended to the wood species for treatment, the temperature as well as the wood used for pyrolysis. Acid pyrolysis at higher temperatures resulted in higher weight percentage gain. The acid pyrolysis obtained at lower temperature was leached at higher rates from treated wood. Also the wood types used for pyrolysis had significant effect on the amount of lechant from treated woods.
Physics and Mechanical Wood
Hadi Dashti; Kambiz Pourtahmasi; asghar tarmian
Abstract
In this research, the effect of preheating in nitrogen medium on acoustic properties of walnut and white mulberry’s boards was studied. Sapwood boards of 300×20×20 mm with the green moisture content were prepared. Heat treatments were applied at 140 and 160 oC under pressure of 2 pascal ...
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In this research, the effect of preheating in nitrogen medium on acoustic properties of walnut and white mulberry’s boards was studied. Sapwood boards of 300×20×20 mm with the green moisture content were prepared. Heat treatments were applied at 140 and 160 oC under pressure of 2 pascal for 30 and 60 minutes. Following the heat treatment, the samples were dried in a convectional laboratory kiln of 8% at 50 oC, relative humidity of 50%, and air velocity of 1 m/s to the average final moisture content of 8%. Using the free vibration method on free- free bar, the dynamic modulus of elasticity and damping factor were evaluated. Results revealed that the heat-treatment at 140 oC for 30 minutes did not have a significant effect on vibration properties of the wood samples. On the other hand, the heat-treatment at 160 oC caused a significant increase in dynamic modulus of elasticity and also a reduction in the damping factor of walnut and white mulberry samples. The FTIR spectroscopy and X-ray studies showed that the degradation of cell-wall polymers and increase in the crystallinity of the walnut wood specimens occurred due to heat treatment at 160 0C.
Management and Economics wood
Seyed Mahmoud Miri Tari; asghar tarmian; Mohammad Azadfallah; Abdolkhani Ali; Davood Efhamisisi
Abstract
DOR:98.1000/1735-0913.1398.34.45.66.1.1575.1575 Mold growth resistance of Polyurethane and Diotrol coatings containing natural (Thyme essential oil) and synthetic (IPBC) fungicides in both free and microencapsulated forms was studied. Polymethyl methacrylate (PMMA) microcapsules were prepared using solvent ...
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DOR:98.1000/1735-0913.1398.34.45.66.1.1575.1575 Mold growth resistance of Polyurethane and Diotrol coatings containing natural (Thyme essential oil) and synthetic (IPBC) fungicides in both free and microencapsulated forms was studied. Polymethyl methacrylate (PMMA) microcapsules were prepared using solvent evaporation method by means of oil emulsion formation in water. Mold growth resistance against Aspergillus niger was determined by Filter Paper Disc method before and after aging process according to ASTM D 5590 Standard. Adhesion strength and surface roughness of coated samples were also measured. Results revealed that biocide-free coatings cannot provide adequate protection against mold growth, and addition of biocides, especially IPBC, significantly improved the mold growth resistance. Even after the aging process, microencapsulated biocides were able to provide better protection against mold growth due to controlled-release mechanism and shielding-effect of polymeric shell. Although the surface roughness of polyurethane coating was increased by using of biocides in both forms, especially microencapsulated ones, its adhesion strength reduced.
Management and Economics wood
asghar tarmian; Amir Sepehr
Abstract
The heat transfer through three orthotropic directions and the evolution of temperature gradient in beech (Fagus orientalis) and spruce (Picea abies) during drying were investigated. Thus, due to low capacity of dryer, small flat-sawn boards with dimensions of 80 × 25 × 40 mm (L×R×T) ...
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The heat transfer through three orthotropic directions and the evolution of temperature gradient in beech (Fagus orientalis) and spruce (Picea abies) during drying were investigated. Thus, due to low capacity of dryer, small flat-sawn boards with dimensions of 80 × 25 × 40 mm (L×R×T) were used. Then, the boards were dried at the dry-bulb temperature of 60 °C and relative humidity of 50 %. Four surfaces of the boards were coated by polyurethane-coated aluminum foil to confine the heat flux along one direction. Then, the boards were thermally insulated by 50 mm-thick Styrofoam. Some holes with 1mm in diameter were made on the board specific distances to measure the temperature using thermocouple. The results showed that the temperature of each wood increased as heating up progressed until it reached to the wet-bulb temperature. Then, it remained at an almost constant value as the wet bulb temperature until the wood moisture content reached the hygroscopic range. Furthermore, the pattern of the temperature profile for both wood species was almost identical. The surface temperature of the boards increased until it reached the dry-bulb temperature of 60 °C, while the core temperate remained as the wet-bulb temperature (48-52 °C) throughout the rest of drying period.
Asghar Tarmian; Marjan Ebrahimi; Reza Oladi
Abstract
In this research, the effects of vessel features, including vessel diameter, density and porosity on drying rate and casehardening of beech (Fagus Orientalis) and oak (Quercus castaneifolia) was investigated. For this purpose, flat-sawn boards with dimensions of 170×50×80 mm (L×T×R) ...
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In this research, the effects of vessel features, including vessel diameter, density and porosity on drying rate and casehardening of beech (Fagus Orientalis) and oak (Quercus castaneifolia) was investigated. For this purpose, flat-sawn boards with dimensions of 170×50×80 mm (L×T×R) were cut from the sapwood and were then dried in laboratory kiln at 50˚C and 50 % relative humidity to final moisture content of 8%. After drying, the severity of casehardening of dried boards was measured using prong test. For anatomical studies and measuring vessel features, white chalk and black marker method was used and scanned sections were analyzed using ImageJ. Pearson correlation was applied between vessel features and drying properties using SPSS software. Results showed that vessel proportion and porosity have more pronounced effect on the drying rate than vessel diameter and the latter feature can be ignored; as drying rate in the free-water domain was lower for oak having larger but fewer vessels than beech. Results also showed that correlation between casehardening and vessel diameter was significantly positive; however, a negative correlation was observed between porosity and casehardening.
Management and Economics wood
Hadi gholamian; Asghar Tarmian; Ali Abdulkhani
Abstract
In present study, the adhesion strength of polyurethane and alkyd coatings on the poplar wood (Populus nigra) was improved by nano-silane coating using sol-gel method for outdoor application. For this purpose, the boards with dimensions of 15 × 10 × 2 mm were prepared according to EN 927-5. ...
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In present study, the adhesion strength of polyurethane and alkyd coatings on the poplar wood (Populus nigra) was improved by nano-silane coating using sol-gel method for outdoor application. For this purpose, the boards with dimensions of 15 × 10 × 2 mm were prepared according to EN 927-5. The surfaces of wood specimens were modified with Tetraethoxysilane (T) sol-gel material and then, solvent-borne alkyd (AS) and solvent-borne polyurethane (PS) coatings were applied. The coated samples were placed outdoor on a platform with a slope close to Karaj latitude (36̊) for 8 months according to ISO 877 standard. In order to characterize the quality of the coatings, colorimetric, tensile adhesion (Pull off), scratch adhesion (Cross cut) and ATR-FTIR tests were performed before and after weathering. The ATR-FTIR analysis demonstrated that the wood surface was covered with silicon oxides (SiO2) attached to hydrocarbon chains. As a result of surface wood modification by sol-gel, the color and adhesion strength of polyurethane and alkyd coatings were less affected by weathering. The highest tensile and scratch adhesions were found for the combined sol-gel and polyurethane coatings.
asghar tarmian; Seaid Alireza Dehghan; Elnaz Trighnoor; Mohammad reza Pyramon; Razyeh Shamsy; Mohammad Layeghi
Abstract
In this research, the performance of a semi-greenhouse solar kiln was evaluated for dying different wood species in different season in Karaj. This study was carried out in two separate parts. In the first part, the flat-sawn boards of oak and fir with a nominal thickness of 50 mm were dried during summer ...
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In this research, the performance of a semi-greenhouse solar kiln was evaluated for dying different wood species in different season in Karaj. This study was carried out in two separate parts. In the first part, the flat-sawn boards of oak and fir with a nominal thickness of 50 mm were dried during summer of the year 2012. In the second part, the flat-sawn boards of beech and poplar with the same thickness were dried in autumn, 2014 and spring, 2015. For both parts, the boards were also air-dried. The temperature measured inside the solar kiln was 35 ºC greater than that outside during daytime and also the kiln temperature ranged from 55 to 75ºC during 10 a.m. to 2 p.m.. In both parts of research, all wood species dried in the solar kiln faster with better quality compared to those air-dried. The severity of casehardening and surface checking in the boards dried in the solar kiln was lower and more homogenous moisture profile was observed. In addition, the final moisture content was lower for the boards dried in the solar kiln.
Management and Economics wood
Reza Oladi
Abstract
One of the main reasons for low treatability of pine wood is pit aspiration during drying in free water domain or heartwood formation. In this research, for opening the aspirated pits in heartwood of loblolly Pine (Pinus taeda), biological incising modification method with bacteria was used and the impacts ...
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One of the main reasons for low treatability of pine wood is pit aspiration during drying in free water domain or heartwood formation. In this research, for opening the aspirated pits in heartwood of loblolly Pine (Pinus taeda), biological incising modification method with bacteria was used and the impacts of different environments and strains of bacteria on the wood gas permeability were studied. Several famous and known strains of Bacillus subtilis UT B96 bacteria in collection of plant protection department of University of Tehran (22, 35, 40, and 96) were supplied in two different culture media of bacteria, namely Nutrient Broth and water bacteria solution. Optical microscopy was used to figure out the qualitative bacterial effect on the tracheid pit pairs. Data analysis revealed that bacteria strain no.22 and water bacteria solution are the most suitable selections to open the aspirated pits and improve the wood permeability. The more destructive effect of the best strain of bacteria may be due to its ability to produce more degrading enzyme. The higher impact of bacteria in the aquatic environment is probably due to their easier mobility, limited access to oxygen or lack of access to an alternative food.
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.
Seaid Masoumeh Hafezi; Ali akbar ٍEnayati; Kazem Doosthosseiny; Asghar Taremian; Ahmad Mirshokraee
Abstract
This research was conducted to investigate the effect of silane coupling agent usage to improve the bond formation of urea formaldehyde resin in wheat straw particleboard production. Three levels (0.5% and 10%; based on the dry weight of the resin) of silane coupling agent and 10% urea formaldehyde resin ...
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This research was conducted to investigate the effect of silane coupling agent usage to improve the bond formation of urea formaldehyde resin in wheat straw particleboard production. Three levels (0.5% and 10%; based on the dry weight of the resin) of silane coupling agent and 10% urea formaldehyde resin were used to produce one layer particle boards with 16mm nominal thickness. Physical and mechanical properties including MOR, MOE, IB and thickness swelling (after 2 and 24 hours immersion in water) were measured. The results of this study showed that adding silane coupling agent to the resin in wheat straw particleboard production, increased MOR, MOE and IB and dimensions stability improved. Optimum dosage for silane coupling agent to improve modulus of elasticity, internal bonding and thickness swelling was 10% and the for modulus of rupture, it was determined as 5%.
Sadigheh Daday Ghandi; Asghar Taremian; Khalil Bordi Fotouhifar; Ali kabar Enayati
Abstract
Imported lumber of Norway spruce called European spruce (Picea abies L.) from Russia have a variety of applications. However, the presence of fungal agents in this wood, their application is limited. In addition, some the fungi associated with these woods are able to cause disease in human. In order ...
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Imported lumber of Norway spruce called European spruce (Picea abies L.) from Russia have a variety of applications. However, the presence of fungal agents in this wood, their application is limited. In addition, some the fungi associated with these woods are able to cause disease in human. In order to identify the presence of such fungi in the imported woods from Russia, samples were collected from Asalem region. Isolation and preparation of pure colonies of fungi grown on woods was done using ascosporic or conidial mass suspensions and single spore method. The morphological characteristics of fungi grown on wood pieces and on culture media were studied using light microscope. The results showed that Ophiostoma piceae in sexual phase and Sporothrix sp. and Graphium spp. in asexual phase are present in these woods. In the culture, Ophiostoma sp. with asexual stage of Sporothrix sp. and Ceratocystis sp. with asexual stage of Chalara spp. was identified. The results of microscopic examination of woods in cross and radial sections showed that fungal hypha penetrated the resin canals, the ray parenchyma, tracheids, and cross-field areas
Physics and anatomy
asghar tarmian
Abstract
In this study, some anatomical, chemical and physical properties of toothbrush wood (Salvadora persica L.) of Zabol region in Sistan and Baluchestan province were investigated. Anatomical studies showed that thi s species has short vessel with intermediate diameter, simple perforation plate and alternative ...
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In this study, some anatomical, chemical and physical properties of toothbrush wood (Salvadora persica L.) of Zabol region in Sistan and Baluchestan province were investigated. Anatomical studies showed that thi s species has short vessel with intermediate diameter, simple perforation plate and alternative intervessel pits. Ray parenchyma is homogeneous and of the procumbent cell type. Axial parenchyma is storied as seen in the tangential section and resembles paratracheal confluent arrangement in the cross section. Included phloem was present in xylem. The average fiber length, total diameter, lumen diameter and fiber wall thickening were 1898.5, 19.4, 8.2 and 5.6 µm, respectively. Chemical characteristics also showed that, toothbrush wood has average cellulose, lignin, extractives and ash content about 33.5, 21.5, 6.8 and 7.5%, respectively. The results also showed that the specific gravity of the wood was 0.49 and its mean tangential, radial and longitudinal shrinkages were 7.4, 7.8 and 0.98 %, respectively.
Asghar Taremian; Zinab Frozan; Amir Sepehr; Hadi Ghlamian; Reza Oladi
Abstract
In this study, the physical and anatomical properties of old date palm wood (Phoenix dactylifera L.) and its drying behavior was studied. Four old date palm trees grown in Bam city (Kerman provenience) were felled. Then, boards with the dimension of 300 × 50 × 30 mm were cut at DBH of trees ...
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In this study, the physical and anatomical properties of old date palm wood (Phoenix dactylifera L.) and its drying behavior was studied. Four old date palm trees grown in Bam city (Kerman provenience) were felled. Then, boards with the dimension of 300 × 50 × 30 mm were cut at DBH of trees from pith to bark. After measuring the green moisture content and specific gravity, boards were dried in a semi-industrial kiln to reach the final moisture content of 8% using a mild wood drying schedule. Cross-sectional anatomical measurements were performed on the nearest boards to the bark and pith. Results showed that the green moisture content and specific gravity of date palm wood ranged between 150-260% and 0.29–0.39 and the moisture content was increased and the specific gravity was decreased from pith to bark. Anatomical observations and statistical analysis revealed that there was no statistically significant difference between average number of vessel elements and vessel bundles between pith and bark, but the mean vessel area in pith was considerably greater than bark. Results also showed that the drying rate of date palm wood was high reaching to the final moisture content of 8% within 7 days. Drying rate of bark samples was higher than those of the pith and no deformation and surface crack was observed in the dried boards.
Hamed Matini behzad; Asghar Taremian
Abstract
Poplar wood flour was spray treated with two preservative materials, (Thiabendazole or Carbamate derivatives (IPBC) with concentration of 0.9%) and then the wood/polyethylene composite samples with the composition of 60% wood, 38% polyethylene and 2% coupling agent were manufactured. The treated composite ...
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Poplar wood flour was spray treated with two preservative materials, (Thiabendazole or Carbamate derivatives (IPBC) with concentration of 0.9%) and then the wood/polyethylene composite samples with the composition of 60% wood, 38% polyethylene and 2% coupling agent were manufactured. The treated composite and control samples were exposed to weathering for 5 months using ASTM D1435 standard test method and the structural changes of the samples were analyzed using SEM microscopy. The roughness of WPCs was measured by roughness measuring device (Miyutoyo SJ 201P) before and after weathering. The SEM images showed that the highest surface changes due to weathering occurred in untreated samples. Both preservatives improved the weathering resistance of treated WPC. The differences in the roughness values root mean square roughness (Rq), mean peak-to-valley height (Rz) and average roughness (Ra) before and after weathering were measured as 7.93, 38 and 4.88µm for control samples, 1.65, 21.7 and 42.2 µm for Thiabendazole-treated and 1.2, 1.5 and 0.79 µm for IPBC-treated samples, respectively. Both preservative materials significantly improved the weathering resistance of WPCs.
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
asghar tarmian; Kazem Doosthosseini; Seeyed Ahmad Mirshokraie; Mohammadmehdi Faezi poor
Abstract
Beneficial utilization of large quantity of paper sludge from Mazandaran Wood & Paper Industry in particleboard manufacturing has been studied. Single-layer and three-layer particleboard (paper sludge as a surface layer) were produced. Urea-formaldehyde resin at two levels of 10 and 12 percent and ...
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Beneficial utilization of large quantity of paper sludge from Mazandaran Wood & Paper Industry in particleboard manufacturing has been studied. Single-layer and three-layer particleboard (paper sludge as a surface layer) were produced. Urea-formaldehyde resin at two levels of 10 and 12 percent and paper sludge content at 4 levels, 0, 15, 30 and 45 percent were studied. Other factors such as press temperature (160oC), press time (6minutes), mat moisture (12%), board density (0.75g/cm3) and etc were constant factors. Mechanical and physical properties including bending strength, shear strength, thickness swelling and water absorption after 2 and 24 hours immersion were evaluated. The results indicated that application of paper sludge reduced mechanical properties and improved thickness swelling .The particleboard produced with 15%paper sludge had the least water absorption, but by using more paper sludge, water absorption increased. Single-layer particleboard had higher bending strength. However, there was no significant different in shear strength between single and three layer particleboard. Three-layer particleboard showed lower thickness swelling.
