Visualization and numerical analysis of adhesive distribution in particleboard using X-ray micro-computed tomography

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

“…We observed the same features in our previous study of the distribution of a melamineurea formaldehyde (MUF) adhesive in the wood composite particleboard [14], suggesting that some of the zinc borate and adhesive in the OSB are located together. Zinc borate is blown onto wood flakes at the same time as aqueous adhesive and wax during the manufacture of OSB.…”

“…In addition to these individual particles, zinc borate also occurred in a more homogeneous tightly packed form, filling the lumens of some wood cells (arrowed in Figure 2(d)). Scanning electron microscopy is not very good at revealing the spatial distribution of elements in materials, as its field of view is small and it probes the surface rather than the bulk of a material, whereas X-ray micro-CT is commonly used to examine the spatial distribution of elements in rocks, polymers, and various biological materials including wood and wood composites [13,14,23,24,30]. Figure 3 shows rendered in-plane X-ray micro-CT images of unleached (Figure 3(a)) and leached (Figure 3(b)) OSB specimens.…”

“…The lack of information on the distribution of zinc borate in OSB is surprising because the distribution of other biocides in wood and wood composites has received much attention using a variety of analytical techniques including SEM in combination with EDX [11], inductively coupled plasma atomic emission spectroscopy [7], X-ray fluorescence microscopy [12], and X-ray microcomputed tomography (CT) [13]. We used X-ray micro-CT to visualize the microstructure of melamine-urea formaldehyde (MUF) glue lines in the wood composite, particleboard [14]. Wood and MUF adhesive have similar densities, and to visualize the adhesive in the composite we increased its density by covalently bonding copper sulphate to the MUF [14].…”

“…We used X-ray micro-CT to visualize the microstructure of melamine-urea formaldehyde (MUF) glue lines in the wood composite, particleboard [14]. Wood and MUF adhesive have similar densities, and to visualize the adhesive in the composite we increased its density by covalently bonding copper sulphate to the MUF [14]. Once this was done it was possible to visualize the distribution of the MUF glue lines in the composite [14].…”

“…Wood and MUF adhesive have similar densities, and to visualize the adhesive in the composite we increased its density by covalently bonding copper sulphate to the MUF [14]. Once this was done it was possible to visualize the distribution of the MUF glue lines in the composite [14]. Visualizing the distribution of zinc borate in OSB should be easier because the atomic mass of zinc is similar to that of copper, and it should contrast with wood, voids, and also the thermosetting adhesive in the composite.…”