Document Type : Research Paper
Authors
1 Assistant Prof., Wood Science and Technology Department, Shahid Rajaee Teacher Training University, Lavizan, Tehran, Iran
2 Assistant Prof., Wood Science and Technology Department, Shahid Rajaee Teacher Training University, Lavizan, Tehran, Iran.
3 Student of M.Sc., Wood Science and Technology Department , Shahid Rajaee Teacher Training University
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 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.
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