Influence of nano metals oxide treatment on medium density fiberboard properties made of sunflower straw fibers

In this study the effects of aluminum dioxide (Al2O3) and copper oxide (CuO) metallic nanoparticles, on the physical and mechanical properties of medium density fiberboard (density of 0.7 g/cm3) made with mixture of industrial wooden fibers and sunflower plant stalk fibers were studied. Two levels of raw material including industrial fibers and sunflower stalks fibers, with five levels of mixing ratios (100: 0, 0:100, 50: 50, 25: 75, 75: 25), metallic nanoparticles with concentration of 400 ppm each at two levels of 2 and 4 percent (based on dry fiber weight) were used. Physical and mechanical properties including thickness swelling, water absorption after 2 & 24 hours soaking in water, modulus of rupture, modulus of elasticity of bending and internal bonding of the samples were measured and analyzed statistically. The results showed that higher percentage of nanoparticles and industrial fibers and lower percentage of sunflower stalk fibers increased the modulus of rupture and modulus of elasticity. Applying nano-metal treatment reduced water absorption and thickness swelling after 2 and 24 h soaking in water. In overall, using 4% nano aluminum dioxide and 4% nano copper oxide at all levels of mixing ratios were resulted in producing boards with better properties, comparing to the EN 622-5 standard specifications, which are suitable for interior uses.