Screw Pullout Strength in Particleboards Manufactured with Waste of Eucalyptus grandis Wood Specie and Oat Hulls

Abstract

Eucalyptus wood species are usually found in rural constructions, civil construction, furniture and utensils, among other applications. The processing of Eucalyptus wood, which follows policies of reforestation in Brazil, generates a lot of waste, as the case of the oat hulls, which constitutes an aggravating to the environment, causing environmental impacts, which motivates the development of applications that make use of these residues, such as the case of particleboards. Among the mechanical properties commonly investigated in the characterization of the particleboards, there is the strength to screw pullout, which evaluates the bond strength of the manufactured materials. This research aimed to produce particleboards, in laboratory scale, using Eucalyptus grandis wood particles (proportions 0, 70, 85 e 100%); oat hulls particles (proportions 0, 14, 30 and 100%), both with controlled size distribution; castor oil based polyurethane resin (10, 12 and 14%, related to solid mass). These panels were evaluated concerning to pullout strength of screws (AP), from face and edge. Particle size distribution: 70 to 75% of these were found in interval ranging between 0.595 to 1.190 mm (16 to 30 mesh). Apparent density of Eucalyptus grandis and oat hulls were 0.64 and 0.29 g/cm 3 , respectively. All panels were classified as high density (greater than 800 kg/m 3 ). Compression ratio of the panels showed range from 1.25 to 3.48, remaining above the level usually recommended in literature (1.3 to 1.6), but similar to other related studies. Values of pullout strength of screws (face) met the requirements of Brazilian Standard ABNT NBR 14810:2006, for three of the twelve experimental conditions evaluated, and of pullout screw (edge), all panels met the cited requirements.