Mechanical Properties of a Light Weight Wood Base Sandwich Panel Made From Sunflower Stalks and Poplar Layer Scrap

Light weight wood base sandwich panels have some special properties and their most important properties is high mechanical strength with its light weight. These panels can replace instead of traditional structural systems in Iran. The purpose of this paper is investigating the mechanical properties of light weight wood base sandwich panels that have made from sunflower stalk wastes and particles of poplar layers. So, Melamine Urea formaldehyde resin with ratio of (20:80, 35:65, 50:50), particles of sunflower stalk and poplar layers wastes with composition ratio of (0:100, 25:75, 50:50, 75:25, 100:0) and poplar layer with 1.8 millimeter was made for surfaces of panel and manufactured in one step press. Mechanical test such as modulus of rupture, modulus of elasticity, internal bonding, compression parallel to board plane were made according to ASTM standards. Results of tests were analyzed through the analysis of variance and classification of averages according with Duncan method tests with reliability of 95 percent was made. As a result, the mechanical strengths improve with increasing of melamine-urea formaldehyde ratio. Panels with pure sunflower and poplar obtain respectively the highest bending strength 19 and 25 MPa, modulus of elasticity 6003 and 8004 MPa and internal bond 0.31 and 0.43 MPa. In conjunction with the parallel pressure resistance, sandwich panels with a core of pure sunflower stalks with 6.9 MPa was the most resistant. Also strengths have reduced with increasing the sunflower stalks ratio to particles of poplar layers in core layers.