Management and Economics wood
Reza Hajihassani; Behbood Mohebi; Saeid Kazemi Najafi; Parviz Navi
Abstract
Abstract The present research work has investigated the physical and mechanical properties of hygro-thermally modified poplar (Populus deltoides) wood. The poplar wood blocks were treated hygrothermally at temperatures of 130, 150 and 170°C and for 20, 40 minutes as holding time. The physical and ...
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Abstract The present research work has investigated the physical and mechanical properties of hygro-thermally modified poplar (Populus deltoides) wood. The poplar wood blocks were treated hygrothermally at temperatures of 130, 150 and 170°C and for 20, 40 minutes as holding time. The physical and mechanical properties were determined for both treated and untreated wood. The properties; mass loss, collapse, specific gravity changes, dimensional stability, surface roughness, bending strength and modulus of elasticity, were determined prior to and after the treatment in all wood blocks. As expected, the hygrothermal treatment significantly improved the dimensional stability of the samples. It was also found that the hygrothermal treatment could increase collapse, surface roughness and modulus of elasticity due to the treatment. However, there were decreases in wood mass, specific gravity and bending strength of the treated poplar wood. It was revealed that the mass loss, decrease in the density as well as collapse in woos is correlated with treatment temperature as well as the holding time. While, raise of the treatment temperature as the holding time caused increase of the dimensional stability.
Management and Economics wood
Mohammad Saleh Hosseini Fard; Saeed Khojasteh Khosro; Behbod Mohebby
Abstract
In this research the effect of oil-heat treatment of Fir species (Abies spp) on contact angle and adhesion strength of organic solvent based and water based coating (acid catalyzed and acrylic water based coating) were investigated. Soy oil was used for the heat treatment modification. Modification process ...
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In this research the effect of oil-heat treatment of Fir species (Abies spp) on contact angle and adhesion strength of organic solvent based and water based coating (acid catalyzed and acrylic water based coating) were investigated. Soy oil was used for the heat treatment modification. Modification process of samples were done at two time, 12 and 15 hours with temperature of 180°C. Control and modified samples were covered with acid catalyzed and acrylic water based coating. Contact angle of water was measured before and after treatment. Adhesion strength of coating was determined according to ASTM 4541 standard. Obtained results of contact angle and adhesion strength were compared with the control samples. The results showed that modification process of oil-heat treatment increased contact angle. This increase continued by increasing treatment time. Increasing contact angle reduced wettability of samples’ surface. On the other hand oil-heat treatment of wood, decreased adhesion strength of coating. The lowest value of adhesion strength was observed in the modification process of 15 hours. Results of comparing coating revealed that acid catalyzed coating had higher adhesion strength than acrylic water based coating but generally no significant differences was observed between these coating.
Delaram Drakhshandeh; Behbood Mohebi; Saeed Mahdavi
Abstract
This research was carried out to study the influence of acetylation on paper dimensional stability. Specimens from printing paper and Texon paperboard were oven dried and then treated with acetic anhydride at 120°c for 30 and 60 min without catalyst. Acetylated papers were soaked in water for 2 and ...
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This research was carried out to study the influence of acetylation on paper dimensional stability. Specimens from printing paper and Texon paperboard were oven dried and then treated with acetic anhydride at 120°c for 30 and 60 min without catalyst. Acetylated papers were soaked in water for 2 and 24 h. Afterwards, bulking effect of the acetylation and thickness swelling of the specimens as well as anti-swelling-effect (ASE) were determined in the treated specimens.
Results revealed that the bulking of the specimens were increased by reaction time. However, in case of Texon, it was slowed down after 30 min of the reaction time. The thickness swelling of the treated specimens was significantly reduced after soaking in water for 2 and 24 h compared with untreated samples. As it was expected the acetylation increased ASE in Texon and the printing papers.
Composite wood products
Yasamin Khosrevani; Ali akbar Enayati; Alinaghi Karimi; Behbood Mohebi
Abstract
The effects of different levels of wood particles acetylation and resin content on the physical and mechanical properties of particleboard were investigated. Boards were made within 6 treatments at three different levels of acetyl content (WPGs of 0%, 5.11% and 10.76 %) and two levels of resin content ...
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The effects of different levels of wood particles acetylation and resin content on the physical and mechanical properties of particleboard were investigated. Boards were made within 6 treatments at three different levels of acetyl content (WPGs of 0%, 5.11% and 10.76 %) and two levels of resin content (8 and 10 %).The results indicated that by increasing the level of particles acetylation, the density of boards was reduced whereas resin content increased this property. Equilibrium moisture content, water absorption and thickness swelling of the boards were reduced by 15.3%, 26.6% and 14.9%, respectively under optimum conditions as compared with control samples at higher acetylation levels and resin contents.MOR, MOE and IB decreased by increasing acetylation level but increasing resin content from 8 to 10 %, improved mechanical properties except for MOR which was not significantly affected by resin content. The result of this research have indicated that using 5.11% acetylation level and 10% resin content, it is possible to produce particleboard having enhanced physical properties with negligible loss of mechanical properties.
