Effect of different amino resins and different lignocellulosic raw materials on bond strength and formaldehyde emissions of particleboards

The increasing demand for sustainable and low-emission wood-based panels has prompted research into the optimization of adhesive systems and the use of alternative lignocellulosic raw materials. This study investigates the combined effects of different amino resins – urea-formaldehyde, urea-formaldehyde fortified with melamine, and melamine-urea-formaldehyde – and five biomass sources, including recycled wood, pine, vine strains, cardoon, and poplar, on the bond strength and formaldehyde emissions (FE) of single-layer particleboards (PBs). Bond strength was assessed using the ABES under varying press temperatures, over times ranging from 10 to 600 seconds, enabling characterization of resin cure kinetics. PBs were then produced at laboratory scale with a target density of 675 kg/m3 and tested according to European Standards for physical and mechanical properties – density, internal bond strength, moisture content, and thickness swelling. FE were assessed using both perforator and gas analysis methods. The results revealed that resins with higher melamine content provide superior bonding performance and lower formaldehyde release compared to urea-formaldehyde. Furthermore, raw material type significantly influenced both dimensional stability and emissions, with recycled and cardoon particles yielding higher formaldehyde levels. These findings highlight the importance of optimizing resin formulation in conjunction with biomass selection to produce PBs that meet mechanical and environmental standards.