Ultra-lightweight foam core particleboards have been produced in a novel one-step process with resinated wood particles for the faces and expandable polystyrene (EPS) as core layer material. The mechanical and physical properties of panels were investigated in terms of the different foam core densities and press parameters (temperature, pressing and foaming time). The bending strength properties of the panels were not signifi cantly changed with increasing foam core density from 80 to 120 kg m -3 . Panels produced at a press temperature of 130 ° C (1-EPS) have an improved core-face interface and also a denser surface layer, which positively infl uences the internal bond and thickness swelling. The panels produced at a press temperature of 160 ° C (2-EPS) have smaller and more foam cells and an improved fusion of foam beads and properties, which have a positive infl uence on the edge screw withdrawal resistance and water absorption.

In this study three types of layered lightweight particleboard were produced by using different amounts of expandable polystyrene in the core layer as the filler material. The objective of this study was to compare the effect of varying amounts of expandable filler (5, 10 and 15 %) for two panel densities (450 and 500 kg/m 3 ) and two panel thicknesses (16 and 19 mm) on the panel properties. The results showed that using expandable fillers has a significant effect on the bending properties, internal bond, edge screw withdrawal resistance, thickness swelling and water absorption. The surface soundness and face screw withdrawal resistance were not affected by the usage of expandable filler, as it depends mainly on the quality and density of the surface layer. Panel density and panel thickness also have significant influence on the physical and mechanical properties of the panels produced. Physical and mechanical properties of the boards did not dramatically change when the amount of expandable filler was increased from 5 to 15 %.

No abstract

No abstract

Environmentally friendly and formaldehyde-free laminated veneer lumber (LVL) was manufactured using geopolymer constituents as binder. The main aim of the study was to improve the bonding quality between the geopolymer binder and the wood constituents. To this end, the effect of various additives (phenol flakes, conventional silica fume, and grafted silica fume with 3-aminopropyltriethoxysilane (APTES)) in the geopolymer binder features were explored via gel time and viscosity measurements, differential scanning calorimetry (DSC), and Fourier transom infrared spectroscopy. The mechanical properties (shear, bending, and compression) of LVL panels were also determined. Results showed that adding both types of silica fume had a positive impact on the geopolymer binder features. The formation of an alkaline aluminosilicate network was proven by observing the characteristics peaks of geopolymer binder at about 683 and 970 cm−1. A peak temperature of about 98 °C was determined for the geopolymer binder curing via DSC analysis. The mechanical properties were the highest for LVL panels made of geopolymer binder with grafted silica fume. It is feasible that the APTES used as grafting agent created a better bonding mechanism with superficial wood cells. In summary, the produced LVL panel showed good properties, but it still needs to be further improved to reach the required levels for use in interior and humid application.

No abstract

No abstract

No abstract