Effect of Nano-Zinc Oxide on the Physical and Mechanical properties of Paulownia Wood (Paulownia fortunei)

Present research was conducted investigate to physical (water absorption and volumetric swelling) and mechanical properties (MOE, MOR, Compression strength parallel to the grain and hardness) of Paulownia fortunei impregnated with Nano-zinc Oxide with size range from 10 to 80 nm. Specimens were impregnated with a 5000 ppm aqueous suspension of nano-zinc oxide, at 2.5 bars in a pressure vessel for 20 minutes. Results showed that modulus of rupture (MOR), modulus of elasticity (MOE) and compression strength parallel to the grain were significantly increased in impregnated specimens. The only mechanical property decreased by nanoparticle-impregnation was hardness. Highest water absorbtion and volumetric swelling took place during first 8 hours of soaking period. Results of the analysis of variance showed that the impregnation of wood with nano-zinc oxide was positive and significantly affected water absorption and volumetric swelling of Paulownia fortunei

Study on the Effect of Combined Nanosilver- Hygrothermal Treatments on Wood Properties

In this research, the combined effect of impregnation of wood with nanosilver solution and hygrothermal treatment on some physical and mechanical properties of beech (Fagus orientalis Lipskey) and spruce (Piceaabies) woods was studied. Wood specimens, Initially, were impregnated in an impregnation cylinder for 20 minutes at the pressure of 0.25 MPa, with nanosilver solution. Then, hygrothermal treatment was carried out at the temperatures of 120, 150 and 180°C for 1, 3 and 5 hours. Control specimens, without any impregnation process, were hygrothermally treated. Volumetric Swelling after 2 and 24 hours soaking in water, bending strength, impact load resistance and compressive strength parallel to the grain of specimens were measured, according to ASTM D143 and all data were analyzed statistically. The results showed that swelling and mechanical properties were decreased by increasing the temperature and duration of hygrothermal treatment. Also, nanosilver impregnated specimens which were treated at 180 ˚C had lower swelling without Not clear and not seems. Consequently or it can be concluded that with nanosilver impregnation process of wood, hygrothermal treatment would be carried out at higher temperature (180 ˚C) to obtain better dimensional stability with no more decrease in mechanical properties

Effect of Nano bentonite on Fire Retardant Properties of Medium density fiberboard (MDF)

In the present study, Fire – Retarding properties of nano-bentonite in medium density of fiberboard (MDF) was studied. 10% of urea-formaldehyde resin was used as the adhesive of the matrix. Nano Bentonite at 5 levels (0%, 5%, 10%, 15% and 20%) g/kg based of dry weight of fibers was used with the consumption of Urea-Formuldehyde (UF). Press pressure of 150 bar and temperature of 170during 4, 5, and 6 minutes were applied. Density was kept constant at 0.7 g/cm3 in all treatments. The measured properties consisted of mass reduction, inflammation time, fire-endurance, melting time and the burnt area. The results revealed that Nano-Bentonite had significant effect in approving fire retarding properties in medium density fiber board. The best properties at the level of 10% obtained and the same level recommended for industry use. The use of Nano-Bentonite more than 10% decreased the stickiness and the partly surface of fiberboards

Thermal treatment and its effect on the gas permeability of Populus nigra

In this investigation, the effect of thermal treatment on gas permeability of Populus nigra was studied. The boards with 5×5×15 cm in dimensions were steamed under average pressure 2-3 bar. The treatments were carried out at 4 temperatures of 120, 140, 160 and 180 ºC for 1, 2 and 3-hour. After thermal treatment, 2 cylindrical specimens with 18mm diameter and 10mm length parallel to grain were prepared from each board, and their transverse permeability was measured. The results showed that thermal treatment did not have any effect on gas permeability at 120 and 140 ºC but it reduced the gas permeability at 160 and 180 ºC. There was not any significant difference in %95 confidence level between different periods of thermal treatment