Sustainable plywood manufacturing using a sucrose-modified eco-friendly urea–formaldehyde adhesive

This study aimed to analyze the effect of sucrose addition on the quality of urea-formaldehyde (UF) adhesives and the resulting plywood performance. An experimental method was employed using UF adhesives formulated with a formaldehyde-to-urea (F/U) molar ratio of 0.8 mol, modified with sucrose at three concentration levels (0, 2.5%, and 5%). The results showed that increasing sucrose concentration reduced the solid content of the adhesive, while the pH remained stable. Viscosity decreased significantly as sucrose concentration increased, with UF-Sucrose 5% showing the lowest viscosity. Gelation time varied, with 2.5% sucrose reducing up to 9.25 min, while 5% sucrose increased up to 14.85 min. FTIR and XRD analyses indicated that sucrose interacted with the UF matrix, leading to reduced crystallinity and disruption of hydrogen bonding. TGA and pyrolysis-GC-MS results showed reduced thermal stability, as higher sucrose content caused early thermal degradation and emitted more CO2. Physical and mechanical testing showed that sucrose addition affected plywood performance, where increasing sucrose content led to higher moisture content, water absorption, and thickness swelling, but reduced mechanical properties and thermal stability. Therefore, 2.5% sucrose addition was identified as the most optimal formulation among the tested levels for plywood applications within this study.