Volatile Organic Compound Hot-Press Emissions from Southern Pine Furnish as a Function of Adhesive Type, 1999 Environmental Conference Proceedings

Wenlong Wang & Douglas J. Gardner

University of Maine

Melissa G.D. Baumann

USDA Forest Service

Three types of adhesives, urea-formaldehyde (UF) resin, phenol-formaldehyde (PF) resin, and polymeric methylene bis(phenyl isocyanate) (pMDI), were used for investigating the effect of pressing variables on volatile organic compound (VOC) emissions. The variables examined included press temperature and time, mat moisture content and resin content, and board density. The VOCs emitted during particleboard hot-pressing with Southern Pine furnish were collected with two scrubbers filled with water and methylene chloride, respectively. The water solution of emissions trapped in the first scrubber was analyzed for formaldehyde using a colorimetric method. The other VOCs contained in the scrubbers were extracted with methylene chloride and characterized and quantified by gas chromatography/mass spectrometry (GC/MS). The measurements showed that the effects of press temperature and press time on formaldehyde emissions were significant for all three adhesives. The effect of mat moisture content was also significant for both UF and PF resins, but mat resin content and board density did significantly influence formaldehyde emissions. There was good correlation between formaldehyde and amount of water vapor collected for both UF resin and pMDI. Formaldehyde press emissions with PF resin were lower than with pMDI, due to an additive in the PF resin. Other VOC pressing emissions included terpenes and their derivatives, lower molecular weight aldehydes, ketones, and some high boiling point linear alkanes. Total VOC (TVOC) emissions were significantly affected by press temperature for all three adhesive types, and by press time for the UF and PF resin. Moisture content also had a significant effect on TVOC emissions for pMDI. While UF and PF did not significantly affect TVOC emissions, application of pMDI caused a statistically significant decrease in TVOC emissions. Changes in pinene emissions with press conditions were similar to the changes seen in TVOC.