International Journal of Composite Materials 2014, 4(3): 162-167 DOI: 10.5923/j.cmaterials.20140403.02 Screw Pullout Strength in Particleboards Manufactured with Waste of Eucalyptus grandis Wood Specie and Oat Hulls Amós M. de Souza 1 , Luciano D. Varanda 1 , Fabiane S. Ferro 1 , André L. Christoforo 2,* , Felipe H. Icimoto 1 , Diego H. Almeida 3 , Francisco A. Rocco Lahr 4 1 Department of Materials Engineering, Engineering School of São Carlos (EESC/USP), São Carlos, 13566-590, Brazil 2 Centre for Innovation and Technology in Composites – CITeC, Department of Civil Engineering, Federal University of São Carlos, São Carlos, 13565-905, Brazil 3 Pontifical Catholic University of Minas Gerais (PUC Minas), Department of Civil Engineering, Poços de Caldas Campus, Poços de Caldas, 37701-355, Brazil 4 Department of Structural Engineering, Engineering School of São Carlos (EESC/USP), São Carlos, 13566-590, Brazil 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. Keywords Particleboard, Strength to pullout, Eucalyptus wood specie 1. Introduction Wood is a versatile, durable and renewable material, but has variations in their chemical, physical and anatomical compositions that can occur between species and within species. So some wood uses may be limited by dimensions, anisotropy and defects of the tree [1]. To minimize these limitations, wood based products, whose properties are significantly different from solid wood, emerged. Among these several kinds of panels can be mentioned, once show a interesting alternative to lumber for various applications [2]. Particleboard panels (now called medium density particleboards – MDP) were developed in Germany in the * Corresponding author: alchristoforo@yahoo.com.br (André L. Christoforo) Published online at http://journal.sapub.org/cmaterials Copyright © 2014 Scientific & Academic Publishing. All Rights Reserved early 1940s. At the time, particleboards got importance due to the difficulty of obtaining compatible quality wood for plywood production, considering the isolation of Germany during World War II [3]. Iwakiri [3] defines particleboards as panels made of wood particles, incorporated with a synthetic adhesive, a random matrix reconstituted and consolidated by applying heat and pressure in the press hot. Other lignocellulosic materials may also be used in the particleboards manufacturing, such as the industrial and agro-industrial residues. Currently, with the growing search for sustainable products, various researches are performed aiming at the recovery of wastes. Among then, those generated by agricultural industries presents great potential in the production of this kind of panel, as observed by Ciannamea [4] and Kwon [5]. In Brazil, agro-industrial residues are available in large volume and have significant potential for employment [6]. In