Effects of hardener type, urea usage and conditioning period on the quality properties of particleboard

The effects of hardener type (ammonium chloride, ammonium sulphate and aluminium sulphate), urea usage (with urea and without urea), and conditioning period (one day and one month) of the particleboard on the physical (thickness swelling), mechanical (modulus of rupture, modulus of elasticity and internal bond strength), surface properties, and formaldehyde emission of particleboard and acidity of the wood particles were investigated. The hardener type was found to be effective all of the properties of particleboard. The pH of the wood particle with the urea was slightly higher than that of particles without urea. The lowest pH value for the resinated wood particles was obtained from ammonium chloride, followed by ammonium sulphate and aluminium sulphate, respectively. The best quality properties were obtained from the particleboards manufactured with ammonium chloride, followed by particleboard made with the ammonium sulphate and aluminium sulphate, respectively. The urea usage significantly decreased the formaldehyde emission of the particleboards while it slightly decreased the mechanical properties and increased thickness swelling. Increasing conditioning period of the particleboards from one day to one month improved the quality properties. (C) 2013 Elsevier Ltd. All rights reserved.