Properties of birch outer bark panels reinforced with wood strands in the surface layers

Abstract

The high demand of wood as a raw material can be expected to soon lead to a severe shortage, resulting in drastic competition between various mills. This competition will be worsened by a restriction of forest cuttings in Quebec. One of the solutions to this problem would be to develop a mixed panel in which the strands of core layer are substituted by outer bark particles, and in this particular case, by particles of white birch. This type of panel could be used as siding panels and for the fabrication of boxes, bins, and commercial shelving. The objective of the present research work concerns the design, the manufacture, and the evaluation of mechanical and physical properties of this type of panel. Two manufacturing factors were taken into account: the strands orientation in the face layers and the alkali treatment made on the bark particles used in the core layer. All produced mixed panels met and exceeded almost all CAN3-0437 R-1 and O-1 property requirements. The alkali treatment of bark particles did not improve the mechanical properties of manufactured panels. The statistical analysis method that was used made it possible to choose the panel with non-oriented wood strands in the surface layers and alkali treated bark particles in the core layer as the best by taking into account only the bending strengths in both major and side axes of a panel.