Evaluation of mechanical properties of laminated strand lumber and oriented strand lumber made from Poplar wood ( Populus deltoides ) and Paulownia ( Paulownia fortunei ) with urea formaldehyde adhesive containing nanoclay

In this study, the mechanical properties of laminated strand lumber and oriented strand lumber were investigated. Two species of fast growing; Poplar (Populus deltoides) and Paulownia (Paulownia fortunei) were used. Urea formaldehyde resin was used to manufacture these products and this resin was reinforced with four levels of nanoclay (0, 2·5, 5 and 7·5%) based on dry weight of resin. Press temperature, press time and press pressure were 120°C, 5 min and 11 kg cm⁻² respectively. Statistical analysis showed that the effects of species and nanoclay on the panel properties were statistically significant at 95% confidence interval. Modulus of rupture, modulus of elasticity, internal bond, shear strength and screw holding strength were analysed in boards. It was found that if nanoclay content was increased to 5 or 7·5%, all properties were significantly improved, when Populus deltoides was compared to Paulownia fortunei, the poplar panel had excellent performance.