بررسي بازگشت ضخامت، دانسيته ظاهري و واكشيدگي ضخامت تخته هاي ساخته شده از خرده چوب هاي استيله راش ايراني

Investigation of springback, density and thickness swelling of boards made of Iranian Beech acetylated chips

Present research was conducted to investigate the effect of acetylation on springback, density and thickness swelling in particleboard producing by acetylated particles from Fagus orientalis. After 12 hours soaking in acetic anhydride, acetylated particles were heated in an oven at 120°C for 30, 90 and 240 minutes, to achieve three levels of acetylation, including 5, 9 and 16%. Then, particles adhesived with 10% melamine urea formaldehyde and pressed. Physical properties were determined according to EN317 standard for particleboards. Results showed increase of springback from 4.49% to 16.88%, decrease of density from 0.706 g/cm3 to 0.561g/cm3, with increasing in acetylating levels from zero to 16%. Inaddition, with increasing in acetylation levels, moisture and thickness swelling of boards decreased. After conditioning, sample moisture absorption decreased from 5.79% in untreated boards to 4.09% in boards with 16% acetylation. After 2 and 24 hours soaking in water, thickness swelling decreased from 12.2% to 3.1% and from 18.7% to 5.7%, respectively.