Influence of particle size and geometry on the physico-mechanical properties and formaldehyde emissions of particleboards

Particle geometry and size distribution strongly influence particleboard performance, yet many laboratory studies still rely on simplified furnishes that do not represent industrial recycled streams. This work produced single-layer panels from virgin Pinus pinaster particles, industrial recycled wood furnish, and a laboratory-engineered pine mix (80:20 coarse-to-fine) designed to mimic an industrial-like distribution, bonded with urea-formaldehyde or melamine-fortified urea-formaldehyde resins and hot-pressed for 90, 120 or 150 s. Panels were characterised for density, moisture content, thickness swelling, internal bond and formaldehyde content and emission using European standards. All panels reached densities near 650 kg/m 3 and moisture contents of 7 %–10 %, with internal bond between ∼0.3 and 0.85 N/mm 2 and formaldehyde emission (FE) between ∼2.5 and 17 mg/m 2 h. Pressing time improved internal bond from 90 to 120 s, whereas only limited additional changes occurred beyond 120 s, indicating a practical compromise. The engineered 80:20 mix furnish improved the balance between dimensional stability, mechanical performance and FE, closely reproducing the functional response of recycled wood panels.