Improving some of applied properties of oriented strand board (OSB) made from underutilized low quality paulownia (Paulownia fortunie) wood employing nano-SiO2

Abstract

In this study, effect of nano-SiO2 on some applied properties of oriented strand board (OSB) made from underutilized low quality paulownia wood employing was investigated. Nano-SiO2 at four levels (0, 1, 3 and 5phc) was added to urea formaldehyde (UF) resin and since nano-SiO2 has effect on the curing of UF resin, the press cycle time (7 and 10min) was also selected as variable. Some chemical properties of paulownia wood (holocellulose, cellulose, lignin and ash contents, pH value, hot and cold water solubility), mechanical (modulus of rupture, modulus of elasticity, internal bond strength, screw and nail withdrawal strengths), physical (thickness swelling and water absorption) properties and formaldehyde emission of the strand boards were evaluated. Mechanical properties of all panels were found to comply with general-purpose OSB minimum value requirements of EN 300 Type 1 (1997) for use in dry conditions. With incorporation of nano-SiO2 up to 3phc into UF resin mechanical and physical properties of the resulting panels improved and formaldehyde emission decreased. However, none of the panels did satisfy the WA and TS requirement of EN Standard for general purpose usage. The results of X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis confirmed the good dispersion of nano-SiO2 in the resulting OSBs. Using paulownia as a fast growing underutilized species not only can sustain the forests but also can supply raw material shortage in wood short countries.