The aim of current research was to investigate the effect of hydro thermo-mechanical treatment and also press conditions on the physical and mechanical properties of poplar wood (Populus deltoides). The wood blocks were initially treated hydrothermally at temperatures of 100° C for retention time of 0, 60, 120 minutes. Then, the densification process was carried out using a hot press at two phases 1-contact and 2-compression press, for temperature of 160, 180 and 200° C for 60 and 90 minutes. The wood compression set was adjusted for 40 percent based on the thickness (radial direction) of the blocks. The samples were physically and mechanically tested for density, springback after press, water absorption, thickness swelling, bending strength and modulus of elasticity. Afterward, the results were analyzed based on a complete randomized design (CRD) under a factorial experiment. Results revealed that physical and mechanical properties of samples were enhanced due to the combined hydro thermo-mechanical treatment. Results revealed that this process causes reduction of springback, water absorption and thickness (radial direction) swelling and also improvement of mechanical properties such as bending strength and modulus of elasticity.

The objective of this study was to investigate the physical and mechanical properties of glulam made from compressed poplar wood (Populus deltoides) by technique of Combined Hygro-Thermo-Mechanical Treatment (CHTMT) which is combination of two techniques of hygrothermal treatment and densification of wood. The poplar wood blocks were initially treated hygrothermally at temperatures of 130, 150, and 170° C for holding times of 20 and 40 minutes. Afterwards, the densification process was carried out under a hot press (at 160° C for 20 minutes) at two levels of compression set, i. e. 40 and 60 percent based on the blocks thickness (radial direction). For production of glulam, the blocks were jointed together by finger joint and polyurethane resin. The produced glulam were physically and mechanically tested for its water absorption, radial and tangential swelling, delamination, bending strength, modulus of elasticity and shear strength. Results revealed that physical and mechanical properties of glulam were enhanced due to the CHTMT treatment. According to the results, water absorption and radial swelling of glulam were increased due to the CHTMT, significantly. Moreover, this treatment reduced the delamination of samples after soaking-drying cycles. It was also found that the CHTMT could significantly enhance mechanical properties of glulam such as bending strength and bending modulus of the elasticity; but decreases shear strength of glue line. Generally, results showed positive effects of CHTMT in glulam production.

The current research explains an innovated technique to enhanced mechanice properties of poplar wood by combination of two modification techniques, hydrothermal and mechanical. Blocks of 50´55´500mm3 were cut from poplar wood and treated in a reactor at 120, 150 and 180°C for 30 min. Afterwards, the blocks were pressed at 180°C for 20 min at a pressure of 80 bar to achieve a compression set of 60% in radial direction. Density and bending properties (moduli of elasticity and rupture) as well as impact resistance were determined in the specimens and compared with those of the untreated one.Results revealed that the density, modulus of elasticity and impact load resistance increased as the treatment temperature rose. The highest density, modulus of elasticity and impact resistance were determined in samples treated at 150°C. The modulus of rupture was increased as the temperature was raised up to 120°C and then it was reduced as low as the untreated one at higher temperatures.

Flexural strength, modulus and tensile strength of composites made from treated baggase flour/recycled polyethylene was investigated. Baggase flour (40 mesh particles) was treated with 10% hydroxide sodium for 45 minutes. Then, the composites were manufactured using injection molding method using both treated and virgin baggase flour as filler (46 and 26%), and recycled and virgin polyethylene as matrix. Flexural strength of the composites made from treated fiber was superior to the relevant untreated fibers. Chemical modification of bagasse fiber improved the tensile strength. Increasing the fiber ratio from 26 to 46%, increased the flexural strength, modulus and tensile strength of the composite. Flexural and tensile properties of the composites produced using recycled HDPE were identical to those based on virgin HDPE.

Influence of the oleothermal treatment as one of the thermal wood modification techniques on physical and mechanical properties of beech wood was studied in the current research work. For this purpose, beech wood samples were cut with sizes of 20×20×20 mm (r×t×l) to determine the physical properties and samples with sizes of 20×20×140 mm (r×t×l) to determine the mechanical properties. The samples were treated in sunflower oil at temperatures of 200, 230 and 260oC for 30 minutes. The wood samples were soaked in water to determine the water absorption as well as the swelling properties. Bending strength as well as the impact load resistance was determined in the treated and untreated samples. Results revealed that the Oleothermal treatment of the wood reduced the water absorption as well as the swelling in beech wood, significantly. Treatment of the beech wood in sunflower oil enhanced the water repellence effect (WRE) and the anti-swelling effects (ASE). It was also revealed that mechanical properties (bending strength as well as the impact load resistance) were reduced by increase of the treatment temperature.

The strength properties of paper produced from pulp obtained after 1, 2 and 4 weeks treatment of hornbeam chips with the Phanerochaete chrysosporium BKM-1767 fungus was evaluated and compared with control samples. After preparing fungal specimens, hornbeam chips were exposed to this fungus for one of the three periods of 1, 2 and 4 weeks at 39oC temperature and 65% relative humidity. Then CMP pulp was prepared using treated chips, chemical treatment temperature of 165oC, for either 80 or 90 minutes and sodium sulfite charge of 14, 18 and 22% (based on oven dry weight of the wood). The liquor to chips was constant at 7 to 1. The results showed that the CMP pulping yield from treated chips was lower than control sample and the reduction after treatments for 1, 2 and 4 weeks was almost 1.64, 2.84, 6.20 percent respectively. Also the strength indices of paper such as tensile strength, burst strength, tear strength and folding endurance paper prepared from treated chips were lower than control chips.

The present study was conducted to assess the effect of pre-heat treatment on the wood particle of Carpinus betulus for the manufacturing one-layer particleboard to increase dimensional stability, decrease water absorption, and improve mechanical properties. Carpinus betulus wood-particles were pre-steamed with a reactor system 160oC at 20, 40 min. The boards with 6% phenol formaldehyde were manufactured by laboratory hot press instrument. After production of particel boards, the physical and mechanical properties including water absorption, thickness swelling, MOR, MOE, and internal bonding (IB) were tested. The results of thickness swelling, and water absorption showed that pre-heat treatment boards after 24 hours immersing in water had a significant decrease from 65.65 to 77.60%, respectively, compared to untreated boards (92.31%). After two hours of immersing, only the thickness swelling showed a significant decrease. The results showed that by increasing the amount of pre-heat treatment time to 40 min, MOE reduced to 2046 MPa, although its reduction was not significant. Pre-heat treatment caused a significant increase on the internal bond amounting to values of 0.618, 0.514 MPa.

This study was carried out to assess the effects of pre-heat treatment on the wood particle Carpinus betulus marked one-layer particleboard and to increase the dimensional stability, to decrease water absorption and to improve mechanical properties. For this purpose horn beam wood-particle were with the steaming system of temperature 160° C time of 20, 40 pre-heat treatment the steam. Then the one-layer particleboard that was by 6% phenol formaldehyde was introduced by hot press one laboratory. After particleboards production, physical and mechanical properties in water absorption, thickness swelling, MOR, MOE, internal bonding (IB) panels were measured and analyzed. The results showed that physical property, thickness swelling, and the water absorption, pre-heat treatment panels in 2 and 24 hours immersing in water, effect per-heat treatment on the 2 hours water absorption was not significant. But water absorption in 24 hours was decreased to 65. 65 to 77. 60% then (92. 31%) untreatment. The results indicated effect pre-heat treatment on the MOR was significant. So, at the time of 20 min MOE 2221. 40 MPa was increased. But treatment the time 40 min 2046 MPa was decreased not significant. Pre-heat treatment was increase internal bond (IB) 0. 618, 0. 514 MPa significant.