mona shayestehkia; Habibollah Khademi Eslam; Behzad Baziyar; Hossein Rangavar; Hamid Reza Taghiyari
Abstract
Abstract In this research, the effect of cellulose nanocrystals on the functional properties of wood cement composite panels has been investigated. Variable factors in this research are the percentage of nano in (five levels of 0, 0.1, 0.2, 0.5 and 1%), the weight of cement and also the ratio of mixing ...
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Abstract In this research, the effect of cellulose nanocrystals on the functional properties of wood cement composite panels has been investigated. Variable factors in this research are the percentage of nano in (five levels of 0, 0.1, 0.2, 0.5 and 1%), the weight of cement and also the ratio of mixing wood chips with cement in three levels (1 to 3, 1 To 3.5 and 1 to 4) dry weight of cement. In this research, poplar wood and Portland cement type 2 have been used as fixed agents. In total, 15 treatments and 3 replicates of each treatment were made. Preparation of sample in accordance with the standard (DIN / EN 634) and measurement of physical and mechanical properties including flexural modulus, modulus of elasticity in accordance with the standard (DIN / EN 310), internal adhesion in accordance with the standard (DIN / EN 319), thickness swelling after 2 and 24 hours of immersion in water was performed according to the standard (DIN / EN 317). Increased cellulose nanocrystals improved physical and mechanical strength. SEM microscopic images were taken from the samples to examine the microstructural properties of the composite. In the pictures, it was found that by adding cellulose nanocrystals, we see an improvement in the disintegration of nanocomposite materials and as a result, an increase in mechanical and physical properties
Composite wood products
Behzad Hosseini; mohammad ghofrani; Hamid Reza Taghiyari; Saman Ghahri
Abstract
In this research, Effect of soy flour addition into urea-formaldehyde resin on physical, mechanical properties and formaldehyde emission of plywood was investigated. Soy flour was mixed with urea-formaldehyde adhesive in three levels 5, 10 and 15% (based on dry weight of urea-formaldehyde adhesive) and ...
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In this research, Effect of soy flour addition into urea-formaldehyde resin on physical, mechanical properties and formaldehyde emission of plywood was investigated. Soy flour was mixed with urea-formaldehyde adhesive in three levels 5, 10 and 15% (based on dry weight of urea-formaldehyde adhesive) and three-layer plywood was manufacture from the resultant adhesive and poplar veneer. Properties of manufactured plywood including formaldehyde emission according to EN-717-3 standard, shear strength according to EN-314 standard and water absorption and thickness swelling according to EN-317 standard were investigated. The results indicated that addition of soy flour up to 15% decreased formaldehyde emission up to 29.34% and increased shear strength of panels. Moreover, delamination test (According to ANSI/HPV-HPV1 Standard) presented acceptable results. The results obtained from water absorption and thickness swelling after 2h and 24h showed that addition of soy flour increased the amount of water absorption and thickness swelling. thickness swelling after 2h and 24h showed that addition of soy flour increased the amount of water absorption and thickness swelling.
Mechanical conversion of wood and wooden fittings
Hamid Reza Taghiyari; Mohammad Ghofrani; Farzad Arbabi ghamsari
Abstract
The present research project was carried out to find out tension-carrying capacity of corner miter V-joints in tensile and compression directions to be compared with those of dovetail joints. Variables included the type of wood-composites to produce the joints (MDF and particleboard), the number of V-nail ...
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The present research project was carried out to find out tension-carrying capacity of corner miter V-joints in tensile and compression directions to be compared with those of dovetail joints. Variables included the type of wood-composites to produce the joints (MDF and particleboard), the number of V-nail in each joint (2, 3, and 4 V-nails), and the height of V-nails (7 and 10 mm). Separate sets of joints were produced with and without polyvinyl acetate resin. Results demonstrated that the tension-carrying capacity under compression tension was significantly higher than those in the tensile tension. Moreover, MDF joints showed higher tension-carrying capacity in comparison to those made from particleboard. Joints with resin were significantly stronger than those without resin. Increase in the number of V-nails resulted in an improvement in the tension-carrying capacity in both directions. Based on the results of the present research project, it was concluded that V-nails are preferred to dovetail joints from different perspectives, including their lower production expenses, lack of need for an extra step to mill the joint so that joint bits be inserted into, fast and easy installation of V-joint in one-step process, as well as higher tension-carrying capacity. Based on the obtained results indicating the maximum tension-carrying capacity of 13.7 MPa and 28 MPa for V-nails without and with adhesive, respectively, it was concluded that 4 V-nails with 10 mm in height in MDF joint-members would be recommended for joints without resin. In case of joints with resin, MDF joint-members with 3 V-nails of 10 mm would provide the highest tension-carrying capacity for craftsmen and producers of furniture and cabinets.
Composite wood products
Ghonche Rassam; Hamid Reza Taghiyari; Bratali Keshtegar
Abstract
Wood-composites are susceptible to fire due to their nature. Some research projects were therefore carried out to investigate potentiality of bentonite nanoparticles in improving fire-retarding properties in medium-density fiberboards (MDF); the present complimentary study aimed at determining the effects ...
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Wood-composites are susceptible to fire due to their nature. Some research projects were therefore carried out to investigate potentiality of bentonite nanoparticles in improving fire-retarding properties in medium-density fiberboards (MDF); the present complimentary study aimed at determining the effects of nanobentonite on physical and mechanical properties of MDF. Ten percent of urea-formaldehyde resin was used as adhesive in the matrix. Nano bentonite was added at 5 levels (%0 ,% 5 ,% 10 , %15 and %20) g/kg based on the dry weight of fibers. Bentonite nanoparticles were sprayed on the fibers after being mixed with the resin solution. Mats were hot-pressed for 4, 5, and 6 minutes at temperature of 170°C. Density was kept constant (75 g.cm-3) for all treatment. Results revealed that nano Bentonite did not improve the physical properties of water absorption, thickness swelling and mechanical properties of internal bonding (IB), modulus of elasticity (MOE), modulus of rupture (MOR). As to the other treatments, nano Bentonite consumption level of % 5 showed the lowest negative effect on the physical properties (water absorption, thickness swelling ) and treatment of 5% and %10 also less negative effect on the Mechanical properties (Modulus of rupture, Internal Bonding ). Treatment 20% is not recommended because it weakens the properties; moreover, the surface of fiberboards is not suitable. It was concluded that due to the fire-retarding improving effects, %5 of nano Bentonite is recommended as the optimum level for the industry.
Azar Haghighi; Hamid reza Taghiyari; Ali nagi Karimi
Abstract
In the present study, fire-retardant properties of nano-wollastonite in fir wood (Abies alba) was studied. Water absorption and volume swelling of the specimens were also measured. Specimens were prepared according to ISO 11925 standard specifications to measure the fire-retarding properties, and ASTM ...
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In the present study, fire-retardant properties of nano-wollastonite in fir wood (Abies alba) was studied. Water absorption and volume swelling of the specimens were also measured. Specimens were prepared according to ISO 11925 standard specifications to measure the fire-retarding properties, and ASTM D4446 -2002 standard to measure physical properties. Impregnation of wood specimens with nano-wollastonite was carried out at four consumption levels of 4, 6/3, 10 and 12%, using Bethel method (full-cell process).Five fire-retarding properties were measured; weight loss (%), ignition point (s), duration of flame after removing the burner (s), duration of glow after removing the burner (s),and carbonization area (%). The results showed that fire-retarding properties increased with the NW-content. Furthermore, the treated wood specimens showed higher dimensional stability.
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.
