Preparation and Evaluation of Particleboard with a Soy Flour-Polyethylenimine-Maleic Anhydride Adhesive

A soy-based formaldehyde-free adhesive consisting of soy flour (SF), polyethylenimine (PEI), maleic anhydride (MA) and NaOH was investigated for making three-layer particleboard. The weight ratio of SF/PEI/MA/NaOH was 7/1.0/0.32/0.1. Hot-press temperature, hot-press time, particleboard density and adhesive usage were optimized in terms of enhancing the modulus of rupture (MOR), modulus of elasticity (MOE) and internal bond strength (IB) of the resulting particleboard. The MOR, MOE and IB met the minimum industrial requirements of M-2 particleboard under the following variables: hot-press temperature of 170 °C, hot-press time of 270 s, the adhesive usage of surface particles at 10 wt%, the adhesive usage of the core particles at 8 wt%, and the targeted particleboard density of 0.80 g/cm³.