Investigation of Urea-Melamine-Formaldehyde (UMF) resin penetration in Medium-Density Fiberboard (MDF) by high resolution confocal laser scanning microscopy

被引：21

作者：

Cyr P.-L. ^{[1
]}

Riedl B. ^{[1
]}

Wang X.-M. ^{[2
]}

机构：

[1] Département des Sciences du Bois et de la Forêt, CERSIM/CRB, Université Laval, Québec

[2] FPInnovations-Forintek, Québec, QC G1P 4R4

来源：

Holz als Roh- und Werkstoff | 2008年 / 66卷 / 2期

关键词：

Melamine; Electron Energy Loss Spectroscopy; Medium Density Fiberboard; Wood Cell Wall; Urea Formaldehyde Resin;

D O I：

10.1007/s00107-007-0216-2

中图分类号：

学科分类号：

摘要：

A confocal laser scanning microscope (CLSM) was used to investigate the distribution and penetration of urea-melamine-formaldehyde (UMF) resin in the fiber when injected through blowline blending in a medium density fiberboard (MDF) pilot plant. Samples were prepared with respect to industrial parameters and were collected at the dryer's end. The samples were later dyed in a Dye Star-Brilliant Red solution (0.01%) and rinsed with distilled water to remove excess. The samples were scanned with the CLSM to build three-dimensional reconstructions of MDF fiber cross-sections. With proper lenses and optimized CLSM settings, it was possible to obtain fiber reconstructions with a resolution greater than the laser wave length (514 nm). The Zeiss CLSM built-in software image analyzer enabled to rebuild them in rotation on any of the three axes with up to 64 images per rotation. The resin penetration sites were identified using this software option. The penetration sites were numerous and well dispersed. The largest openings (lumen, pits and cracks) were responsible for most of the resin lost by over-penetration. The presence of resin in the cell walls (detected with the CLSM) proves their porosity without giving much information about the resin concentration. Finally, the atomic force microscope (AFM) enabled to recreate the finest surface details for these fibers samples. It was found that the fibrils aggregates orientation and size can influence the resin penetration and distribution. It was concluded that the porous structure of wood fibers and their affinity to water enable the resin to penetrate through capillary force. This phenomenon is stimulated by the high pressure, saturated steam, turbulent flow and heat. When injected in the pilot plant blowline, UMF resin was uniformly distributed over the fiber surface (22.5% coverage). The resin penetration was however important and also occurred in nanometric defaults of the wood fibers. Thus, industrial panels made out of very porous, damaged or small fibers will need more resin to fill the gaps in order to make a strong board. © 2007 Springer-Verlag.

引用

页码：129 / 134

页数：5

共 12 条

[1]

Abe K., Yamamoto H., Mechanical interaction between cellulose microfibril and matrix substance in wood cell wall determined by X-Ray diffraction, J Wood Sci, 51, pp. 334-338, (2005)

[2]

Cyr P.L., Riedl B., Wang X.M., Groom L., Atomic force microscopy of refined spruce fibers (Picea spp.)., Wood Sci Technol

[3]

Cyr P.L., Riedl B., Wang X.M., Shaler S., Urea-melamine-formaldehyde (UMF) resin penetration in medium-density fiberboard (MDF) wood fibers, Adh Sci Technol, 20, pp. 787-801, (2006)

[4]

Donaldson L.A., Lomax T.D., Adhesive/fibre interaction in medium density fibreboard, Wood Sci Technol, 23, pp. 371-380, (1989)

[5]

Gindl W., Dessipri E., Wimmer R., Using UV-Microscopy to study diffusion of melamine-urea-formaldehyde resin in cell walls of spruce wood, Holzforschung, 56, pp. 103-107, (2002)

[6]

Grigsby W., Thumm A., Visualisation of UF resin on MDF fibre by XPS imaging, Holz Roh- Werkst, 62, pp. 365-369, (2004)

[7]

Murmanis L., Myers G.C., Youngquist J.A., Fluorescence microscopy of hardboards, Wood Fiber Sci, 18, pp. 212-219, (1986)

[8]

Pakdel H., Cyr P.L., Riedl B., Deng J., Quantification of urea formaldehyde resin in wood fibers using X-ray photoelectron spectroscopy and confocal laser scanning microscopy, Wood Sci Technol, (2007)

[9]

Rapp A.O., Bestgen H., Adam W., Peek R.D., Electron energy loss spectroscopy (EELS) for quantification of cell-wall penetration of melamine resin, Holzforschung, 53, pp. 111-117, (1999)

[10]

Saariaho A.M., Jaaskelainen A.S., Matousek P., Towrie M., Parker A.W., Vuorinen T., Resonance Raman spectroscopy of highly fluorescing lignin containing chemical pulps: Suppression of the fluorescence with an optical Kerr gate, Holzforschung, 58, pp. 82-90, (2004)

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