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Microstructure and Quantitative Micromechanical Analysis of Wood Cell–Emulsion Polymer Isocyanate and Urea–Formaldehyde Interphases

Part of: Micrographia Collection

Published online by Cambridge University Press:  15 March 2017

Lizhe Qin ,
Lanying Lin ,
Feng Fu  and
Mizi Fan
Lizhe Qin
Affiliation:
Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
Lanying Lin*
Affiliation:
Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China College of Engineering, Design and Physical Sciences, Brunel University, Middlesex UB8 3PH, UK
Feng Fu
Affiliation:
Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
Mizi Fan*
Affiliation:
College of Engineering, Design and Physical Sciences, Brunel University, Middlesex UB8 3PH, UK
*
*Corresponding authors. linly@caf.ac.cn; Mizi.Fan@brunel.ac.uk
*Corresponding authors. linly@caf.ac.cn; Mizi.Fan@brunel.ac.uk
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Abstract

Emulsion polymer isocyanate (EPI) and urea-formaldehyde (UF) were selected as typical resin systems to investigate the microstructure of wood–adhesive interphases by fluorescence microscopy (FM) and confocal laser scanning microscopy (CLSM). Further, a quantitative micromechanical analysis of the interphases was conducted using nanoindentation. The FM results showed that the UF resin could penetrate the wood to a greater extent than the EPI resin, and that the average penetration depth for these two resin systems was higher in the case of latewood. CLSM allowed visualization of the resin distribution with contrasting colors, showing that the EPI resin could not penetrate the cell wall, whereas UF resin could enter the cell walls. The micromechanical properties of the cell walls were almost unaffected by EPI penetration but were significantly affected by UF penetration, especially in the first cell wall from the glueline. This further confirmed that only cell walls with resin penetration can improve the mechanical properties of the interphase regions.

Keywords

interphase microstructuremicromechanical propertiesfluorescence microscopeconfocal laser scanning microscopenanoindentation
Type
Micrographia
Information
Microscopy and Microanalysis , Volume 23 , Issue 3 , June 2017 , pp. 687 - 695
Copyright
© Microscopy Society of America 2017 

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