BEHAVIOR OF GLUED JOINTS OF EUCALYPTUS sp. SAWN WOOD

Abstract

This research evaluated eucalypt wood adhesion capacity. The material evaluated was a commercial sawn wood composed by a blend of species of the genus Eucalyptus. The adhesives used were resorcinol-formaldehyde and polyvinila acetate (PVAc). The wood was segregated in three density with  0% of moisture content: class 1; 2 and 3 that, when combined (class1 x class1; 2x2; 3x3; 1x2; 1x3; 2x3) resulted in six treatments. The performance of the adhesion was evaluated by the shear strength to parallel compression and by wood failure in the glue line. The obtained results allowed  to conclude that the adhesion of the combinations of wood/adhesive presented satisfactory performance. The average shear strength of the joints were shown equivalent to the shear strength of the solid wood with similar performance of adhesion in the two adhesives. In general, resorcinol-formaldheyde adhesive presented higher values (74.41%) for wood failure in the joints, but similar to all treatments.  The adhesion of samples of higher density presented lower performance probably when only the values of wood failure are considered. The values for the strength of glued joints, in general, were similar when analyzed the results achieved with the resorcinol-formaldehyde adhesive- base 140,56 Kgf/cm2.  To polyvinila acetate the values of wood failure decrease when the density increase (65.94%), but the resistance in the glue line was positively affected (140.25 Kgf/cm²). In general, the density influenced the adhesion of the joints for the employed adhesives.