AP1-4 - Society of Wood Science and Technology

Proceedings of the 55th International Convention of Society of Wood Science and TechnologyAugust 27-31, 2012 - Beijing, CHINAproduction of birch veneer and phenolic aldehyde was higher than the others. The initialaldehydes and ketones compounds (except formaldehyde) concentration emission fromparticleboard was much higher, but the equilibrium concentration of plywood was higherone month later. What caused the phenomenon was that hexanal and butyraldehydecompletely released in aldehydes and ketones compounds emission from particleboard,and that the two substances were both with high initial concentration and very lowequilibrium concentration (closed to zero). The aldehyde and ketones compoundsemission from plywood were acetone and benzaldehyde, with the time prolong, acetonereleased completely, we could not detect it on the 7 th day, but benzaldehyde was with alow release rate, from the beginning to ending, the concentration total decreased 35.9%.All kinds of substances emission from blockboard production of poplar substrate, peachblossom core surface layer and urea-formaldehyde were very low, TVOC equilibriumconcentration was 1.54μg/m 3 one month later, at the moment the formaldehydeconcentration was 20.33μg/m 3 (0.016ppm).100%90%80%70%60%50%40%30%20%10%0%particleboard plywood HDF blockboardaldehydes and ketonesalkanesbenzenesunknownFigure 2 the percentage of individual VOCFigure2 was the percentage content graph of individual VOC emission from wood-basedpanels, from figure2, we could see that VOC emission from wood-based panels weremain aldehydes and ketones compounds, alkanes, benzenes and some unknownsubstances, where aldehydes and ketones compounds and unknown substances accountedfor a large proportion.The main component of aldehydes and ketones were carcinogenicacetaldehyde and acetone, and aldehydes and ketones might produce in oxidativedecomposition of unsaturated fatty acid when wood chipped and dried. Some researchshowed [7] that the drying temperature and humidity seriously influent the form ofaldehydes and ketones, therefore, controlling the release level of aldehydes and ketonescompounds based on production origin, reducing the release concentration basically.Beside aldehydes and ketones compounds and unknown substances, there were alkanes(n-undecane) and benzenes emission from particleboard, and only small amount benzenesin HDF. The detected benzenes were main toluene, ethylbenzene, xylene and styrene, ofwhich the xylene release amount was the biggest. Some researches proved [8] that ifpeople inhaled higher toluene and xylene in short time, it might make central nervoussystem paralysis, and severe patients might be coma, failure in respiratory cycle anddeath. Long-term exposure in higher concentration of toluene and xylene would causechronic benzene poisoning, resulting in obstacle anaemia, fetal congenital defect,therefore, people should pay enough attention to benzenes emission from wood-basedpanels.Paper AP1-4 6 of 8