Influence of Hardener Type on the Particleboard Properties at Industrial Scale

Influence of the two different hardeners (ammonium chloride NH₄Cl and ammonium sulphate (NH₄)₂SO₄) on the physical (density, thickness, moisture content, thickness swelling and water absorption) and mechanical (modulus of rupture, modulus of elasticity, surface soundness and internal bonding strength) properties and formaldehyde emission of the particleboard was figured out. Boards were industrially produced (at continuous press line) using urea formaldehyde resin, liquid paraffin, and a 50:40:10 mixture of Scots pine, oak and poplar chips, respectively. Except for elasticity, boards produced using ammonium chloride had better mechanical properties, but their thickness swelling and water absorption capabilities were lower (approx. 55.5% and 45.9%, respectively) than those produced with ammonium sulphate. Utilization of ammonium chloride provided 30.3% higher surface soundness. There were less than 1% differences in the thickness and density. Around 36.4% less formaldehyde emission was determined for ammonium chloride-modified boards. According to the results, only means of IB did not present statistically significant differences.