Influence of incorporating beta-cyclodextrin/essential oil-based wood preservative on the bonding strength of wood composite products

The introduction of additives during the production of wood composites may disrupt the development of bonding strength between wood and adhesive, potentially compromising the structural performance of wood composites. This study investigates the impact of incorporating a natural wood preservative into 3-ply southern yellow pine (SYP) plywood on its bonding strength. The formation of β-cyclodextrin and trans-cinnamaldehyde (βCD-tCN) inclusion complex as a natural wood preservative was confirmed by Fourier transform infrared and X-ray diffraction analyses, with an inclusion yield ranging 78 % to 120 %. The differential scanning calorimetry analysis found the curing of pMDI with wood was not significantly affected by the βCD-based additives. The influence of βCD-tCN addition on the bonding strength of a wood composite was assessed by a shear strength test of the 3-ply plywood, following ASTM D906-20. The average shear strength of all panels ranged 1.53 N/mm2 to 2.07 N/mm2, exceeding the minimum requirement of 1.00 N/mm2 for cross-layer bond lines according to EN 16351-2015. Statistical analysis indicated no significant differences between the bonding strength of pristine pMDI and pMDI containing βCD-tCN complex. The combined results suggest that βCD-tCN could be effectively implemented in the manufacturing of wood composite products. [Display omitted]