Influence of different structural compositions of Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby and Pinus oocarpa var. oocarpa (Schiede ex Schltdl) for multi-laminated plywood production

The main goal of this research was to evaluate mechanical and physical properties of multi-laminated plywood made of Schizolobium amazonicum and Pinus oocarpa with different adhesives. Plywood panels were made with five layers, cross-lamination, and layer variation between Schizolobium amazonicum and Pinus oocarpa wood. We also evaluated urea formaldehyde and phenol formaldehyde adhesives (150 g/m(2)). The pressure used was 0,98 MPa; temperature of 150 degrees C and press time equal to 10 minutes. We have analyzed basic density and chemical composition of both wood species. For the panels, we have performed physical analyses of specific gravity, equilibrium moisture content, and water absorption. For the determination of the mechanical properties, we made tests of static bending parallel and perpendicular to the fibers, as well as glue line shear strength. Physical properties results showed that there is interference of each wood species, as well as the adhesive, over specific gravity and equilibrium moisture content of the panels. Water absorption medium values found on this work did not present statistical differences among them. Results of static bending, parallel and perpendicular to the fibers, demonstrated influence of layers structure over MOE and MOR values obtained. For perpendicular static bending, we also had significate interaction between adhesives and wood over MOE and MOR values obtained. Specifically for MOR values obtained through perpendicular static bending there was influence of adhesives utilized. Essays of glue line shear strength had demonstrated influence of layers structure, adhesive and interaction between layers structure and each adhesive. All values of glue line shear strength reached the minimum requisite of European and Brazilian Standards.