ABSTRACT
This study was developed to evaluate the effects of different compositions of plywood of Pinus maximinoi, Pinus oocarpa e Pinus tecunumannii. Were manufactured in laboratory plywood composed by seven veneer with 3,0 mm thickness, with standard composition, longitudinal reinforced composition and transversal reinforced composition. Were used for veneer gluing the phenol- formaldehyde resin with the following formulation in parts of weight: resin = 100, extender = 10 and water = 10. The amount of glue spread was 160 g/m² (one side layer). The boards were pressed at temperature of 150ºC, specific pressure of 15 kgf/ cm² and press time of 15 minutes. Were realized static bending tests in the parallel and cross direction. The boards of Pinus maximinoi showed better results in MOE and MOR, parallel and cross direction in comparison to boards of Pinus oocarpa and Pinus tecunumannii. The boards made from three species showed satisfactory results of MOE and MOR, parallel and cross direction, in comparison to commercial plywood of Pinus taeda. The veneer reinforced in to parallel and cross direction not influenced significantly in the results of MOE and MOR parallel direction. The longitudinal veneer reinforced plywood affects poorly the results of MOE and MOR in the cross direction.
Keywords:
plywood; phenol-formaldehyde resin; veneer of tropical pinus