عنوان مقاله [English]
Light weight, good thermal and sound insulation, easy installation, high strength and low price are characteristics of sandwich panels that have found numerous applications in industry and construction today. In this composite two thin faces enclose a thick core layer that resists shear forces, which can be made of wood or wooden products. In this work, the improvement of the sandwich panel strength was investigated through changes on the material and cross-sectional shape of the core layer made from waste paper with square hollow shape. For the fabrication of the samples, it was necessary to design and manufacture a metal mold to form raw materials with specific ratios and hollow shaped. Different quantities of crushed paper with specified dimensions and two types of common resin in wood composites industry were used to prepare the core layers. The square honeycomb cores were sandwiched between the face layers from medium density fiber board. The first results of this study showed that compressed waste paper in the form of a core layer was an acceptable function in the structure of a lightweight sandwich panel. The density of the paper core had a significant effect on the improvement of flexural strength, which increased with increasing density. In addition, the type of adhesive had a significant effect on the flexural strength of the sandwich panel. Phenol formaldehyde adhesive further improved flexural strength, compared with the urea formaldehyde.