Tannin Adhesive from Stryphnodendron adstringens (Mart.) Coville in Plywood Panels

The aim of this study was to evaluate the technical viability of using tannin adhesives derived from Stryphnodendron adstringens (Mart.) Coville barks in the production of plywood. 0, 25, 50, 75, and 100% tannin-based adhesives (TF) derived from barbatimao barks were combined with commercial phenol-formaldehyde (PF) adhesive. The properties of the adhesives were determined, and plywood was produced. The panels were produced with five crossed layers, an adhesive grammage of 360 g/m(2) (double line), and an assembly time of 10 min. A pressing cycle at a temperature of 150 degrees C, specific pressure of 12 kgf/cm(2), and duration of 10 min was used. With the exception of the parallel modulus of elasticity, panels produced with 25, 50, 75, and 100% barbatimao-derived tannin adhesive met NBR 31:000.05-001/2 standards (ABNT 2001). The tannin barbatimao adhesive proved feasible for use in plywood panels destined for both humid and dry environments.