Comparative Researcehs of the Properties of Laboratory Plywood and Some Industrial Manufactured Wood-Based Panels

The aim of the researches in the master thesis is studying the impact of the changes in plywood structure on their physical and mechanical properties. These changes are related to the change of the layer’s position in the panels’ structure along the axis of symmetry without changing the number and the thickness of the veneers. Four models of laboratory nine layered plywood were made for studying this impact. The evaluation of the models quality was made on the base of the obtained values from the tests of their physical and mechanical properties, as well as on the base of the comparative analyze of these values and the values obtained from the tested properties of comparative model of industrial manufactured plywood. The laboratory plywood models are made in controlled laboratory conditions by the method of hot dry pressing. Beech peeled veneers with thickness of 1,2; 1,5; 2,2 and 3,2 mm are used for plywood manufacturing. As gluing component for plywood manufacturing, pure water-soluble phenol formaldehyde resin with concentration of 47,10 % is used. The models are preserved with phenol formaldehyde foil, which is impregnated in the surface layers during pressing. Four panels from each model are made, as well as two additional panels without surface phenol formaldehyde foil from the second model in order to perceive the differences in physical properties between preserved and non-preserved laboratory models.