Technological properties of iranian cultivated paulownia wood (Paulownia fortunei)

P. fortunei was imported into Iran from China and was planted at different spacings in the forest of the north of Iran, for wood production. In this research, physical, chemical, mechanical properties and morphological characteristics of Iranian cultivated paulownia (Paulownia fortunei L.) wood were investigated. Paulownia has acceptable Runkel, flexibility and slenderness coefficients, which are in the same range as those of hardwood and softwood. In general, the results of the chemical and morphological analyses indicate that Iranian cultivated paulownia fibers are a promising fibrous raw material for paper production. The species is not suitable for uses requiring mechanical strength. The values obtained for physical properties were as follows: oven-dry density - 0.261 g cm-3, basic density - 0.242 g cm-3, air-dry density - 0.291 g cm-3, volumetric shrinkage - 7.54%, percentage of cell wall - 17.41%, porosity - 82.59%, fiber saturation point - 31.15%, and maximum moisture content - 349.72%. The means of holocellulose, cellulose, lignin and extractives were of 80.1, 51, 23.5, and 11.8%, respectively. The average values of mechanical properties were the following: modulus of rupture - 41.07 MPa, modulus of elasticity - 3.74 GPa, and compression strength parallel to the grain - 14.61 MPa. The mean value of fiber length was 996 μm, fiber width - 30.55 μm, width of lumen - 25.30 μm, and cell wall thickness - 5.25 μm.