Micromorphological studies of modified wood using a surface preparation technique based on ultraviolet laser ablation

Abstract

The objective of this paper is to demonstrate an ultraviolet (UV) laser ablation technique as a tool for sample preparation in microscopy studies of modified wood. Improved techniques for studying the microstructure of modified wood are crucial for a deeper understanding of many of their physical, mechanical and durability properties. The surface preparation technique is described in this paper. An illustration of micrographs of the micromorphology and polymer distribution in some examples of modified wood is also presented. It is clearly demonstrated that in contrast to conventional surface preparation techniques used for light microscopy and scanning electron microscopy, i.e. razor blade and microtome cutting techniques, UV laser ablation does not introduce any mechanically induced microcracks and redistribution of polymers or other mobile substances in the prepared surface. Results also show that, in particular, this technique seems to be suitable for studying polymer distribution in resin-impregnated wood, as well as detection of microcracks in modified wood cell walls.

Keywords:

• Cell wall damage
• micromorphology
• modified wood
• SEM
• UV laser

Acknowledgements

Financial support from EcoBuild Institute Excellence Centre established by VINNOVA, The Knowledge Foundation and the Swedish Foundation for Strategic Research is greatly acknowledged. We are indebted to StoraEnso, Kebony ASA and A-Cell Acetyl Cellulosics AB for providing samples of heat-treated, furfurylated and acetylated wood, respectively.