Influence of Different UF ‐Based Resin Systems on the Mechanical Performance and Formaldehyde Emissions of Single‐Layer Particleboards

Formaldehyde emissions (FE) from urea‐formaldehyde (UF) bonded particleboards (PBs) remain a major concern due to increasingly strict indoor air‐quality regulations. This study aimed to determine how UF resin chemistry and wood raw‐material source affect curing behavior, bonding performance, and FE. UF, melamine‐fortified urea‐formaldehyde (mUF), and melamine‐urea‐formaldehyde (MUF) resins were studied, combined with Pinus pinaster and industrial recycled wood. Resin curing behavior was assessed using the Automated Bonding Evaluation System (ABES), while panel density, moisture content (MC), and internal bonding (IB) strength were determined by standard methods. Formaldehyde performance was evaluated by the perforator method (formaldehyde content—FC; EN ISO 12460‐5) and the gas analysis method (FE; EN ISO 12460‐3). UF‐bonded panels showed the highest IB strength but also the highest FC and FE values. In contrast, mUF and MUF systems consistently reduced formaldehyde‐related properties, although with a moderate reduction in IB strength. ABES results revealed differences in curing behavior among the investigated resin systems, supporting the trends observed at panel‐scale. Panels produced from recycled wood showed density and IB values comparable to pine‐based panels and, in some cases, lower FC and FE values. Overall, melamine‐modified UF systems provided an effective balance between bonding performance and formaldehyde reduction.