Performance of brutian pine (Pinus brutia Ten.) particles and fibers modified with low concentrations of naoh solution in board production

In this study, particles and fibers from brutian pine (Pinus brutia Ten.) were soaked in 0.25, 0.50, 0.75 and 1% NaOH solutions. The changes in the chemical and thermal properties of the particles and fibers caused by these treatments were indicated and the effects of these treatments on the physical and mechanical properties of the produced boards were evaluated. Main chemical component and fourier transform infrared (FTIR) spectroscopic analysis showed that the extractive, hemicellulose and lignin content of the particles and fibers decreased during the alkali treatments, while the cellulose content increased. Thermogravimetric analysis (TGA) indicated that the particles and fibers treated with NaOH solutions exhibited lower thermal stability than the untreated particles and fibers. Alkali treatments caused water absorption and thickness swelling increase of the produced particleboards. The mechanical properties of the produced particleboards were improved by alkali treatments. The modulus of elasticity, modulus of rupture and internal bond strength values of the produced particleboards met the requirements for general-purpose particleboards used in dry conditions, as defined by the TS EN 312 standard. Water absorption and thickness swelling of the produced fiberboards were raised consistently due to the increasing NaOH concentrations during the alkali treatments of fibers. Alkali treatments of fibers improved the mechanical properties of the produced fiberboards. According to TS EN 622-5 standard, the boards produced with control, 0.25% and 0.50% NaOH treated fibers met the requirements for load-bearing applications in dry conditions in terms of the thickness swelling, modulus of elasticity, modulus of rupture and internal bond strength.