Table of Contents
Journal of Composites
Volume 2015, Article ID 630905, 9 pages
Research Article

Visualizing the Microdistribution of Zinc Borate in Oriented Strand Board Using X-Ray Microcomputed Tomography and SEM-EDX

1Centre for Advanced Wood Processing, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
2Department of Applied Mathematics, The Australian National University, Canberra, ACT 0200, Australia
3Visualization Laboratory, Super-Computer Facility, The Australian National University, Canberra, ACT 0200, Australia

Received 30 September 2014; Revised 27 January 2015; Accepted 12 February 2015

Academic Editor: Masamichi Kawai

Copyright © 2015 Philip D. Evans et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Oriented strand board (OSB) is an important wood composite used in situations where fungal decay and termite attack can occur. To counter these threats, powdered zinc borate biocide is commonly added to OSB. The effectiveness of biocides depends on their even distribution within composites and resistance to leaching, but little is known about the distribution of zinc borate in OSB. Zinc is denser than wood and it should be possible to map its distribution in OSB using X-ray micro-CT. We test this hypothesis and chemically register zinc in OSB using SEM-EDX. Zinc borate particles aggregated at the wood-adhesive interface in OSB, creating interrupted lines of zinc oriented in the x-y plane. Zinc borate particles were also found in the lumens of wood cells. Zinc was distributed throughout OSB, although slightly less was present in the core of the composite than in surface layers. A network of zinc remained in OSB after leaching in water. The resistance of zinc to leaching may be due to its incorporation in glue-lines within OSB, in addition to its low water-solubility. We conclude that X-ray micro-CT is a powerful tool for studying the distribution of zinc in OSB and other wood composites containing zinc borate.