Effect of expanded polystyrene content and press temperature on the properties of low-density wood particleboard

In this study, three-layer low-density (about 400 kg/m3) particleboards consisting of a mixture of wood particles and expanded polystyrene (EPS) were manufactured. EPS bead was incorporated in the core layer as a light filler. The influence of EPS content (0 %, 2,5 %, 5 %, 7,5 %, 10 %, and 12,5 %) and press temperature (110 °C and 140 °C) on the microstructure, density profile, bending properties, internal bond and thickness swelling of the panels were investigated. Results showed that incorporation of EPS beads filled in the voids between wood particles improved the core layer integrity, and generated a more pronounced density profile. Consequently, the bending properties and internal bond of panels adding EPS were remarkably improved, and the thickness swelling was decreased. However, the variation of the number of EPS from 2,5 % to 12,5 % had no significant effect on the bending properties and thickness swelling. Comparing the two press temperatures, higher temperature (140 °C) was more favourable in control panels without EPS as filler. For panels adding EPS filler, 140 °C had a negative effect on the properties of panels, especially at high EPS contents (10% and 12,5%), attributing to the shrinkage of EPS bead under press temperature that is much higher than its glass transition temperature (104 °C).