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 Physical and Mechanical Properties Medium Density Fiberboard (MDF)

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

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