Characterization of urea-formaldehyde distribution on medium density fiberboard fibers by laser fluorescence microscopy

Published: 2003

Author(s):
Riedl, B.
Cloutier, A.
Xing, C.
Shaler, S. M.

Publication Name: Proceedings of the IAWPS 2003 International Conference on Forest Products

Publication URL: https://link.springer.com/article/10.1007/s00226-005-0294-4

Research Area:
Keywords:

Abstract:

The amount of UF resin penetration into fibers, used for the production of medium density fiberboard (MDF), is unknown. To evaluate the relationship between resin viscosity and resin penetration depth, an experimental procedure involving confocal laser scanning microscopy (CLSM) and a Toluidine Blue O staining system was performed. The results indicate that CLSM in combination with a Toluidine Blue O staining system is a good way to characterize UF resin penetration into wood fibers. The main penetration direction is toward the fiber lumen. For wet fibers, whose moisture content is about 88%, the effect of resin viscosity with a range of 80 cps – 340 cps on penetration is very similar, with all adhesives reaching or almost reaching the fiber lumen after 60 min at room temperature. For MDF industrial samples, the highest depth of penetration of the adhesive was attained in the second dryer stage. After the second dryer stage, the resin penetration into the fiber did not increase.