investigation on the effect of acetylation and the type of resin on the fire resistance of one and three layered poplar particleboard

this research was conducted to investigate the effect of acetylation and type of resin on fire resistance of one and three layered populus particleboard. populus particles were acetylated at three levels of acetyl content (wpg of 0, 8.39% and 17.27%). in manufacturing of one and three layered boards with acetylated particles in all thickness or surface of the boards two type of resin, urea formaldehyde and isocyanate (were used). fire resistance test was carried out in cycles 20, 40, 60 and 120 seconds. at first 20 second, flammability of boards made from isocyanate was less than that for boards containing urea formaldehyde resin, and with time passing, this effect decreased. regarding to weight loss, three layered boards showed less weight loss than single layered boards. by increasing of acetylation level, the extent length of fire extension and coal surface was increased and during distinct time, burned depth and weight loss decreased. this effect was more obvious at 120 second. indeed, acetylation not make boards resustant to fire, but retarded their combustion.