Potential for the use of coconut husk in the production of medium density particleboard

Abstract

The use of agricultural residues in association with wood for panel production has potential to increase value, promote the adequate disposal and ensure adequate panel properties. The aim of the present study was to evaluate the potential of coconut husk in association with Pinus oocarpa wood in the production of medium-density particleboard (MDP) panels. The experimental design consisted of four percentages of Pinus oocarpa substituted with coconut husk (25, 50, 75 and 100%) and a control condition consisting of only pinus wood. The panels were produced with a nominal density of 650 kg m−3; relation face/core/face ratio of 20:60:20; 11% and 7% urea–formaldehyde adhesive (based on the weight of the particles) on the faces and in the core, respectively; and specific pressing cycle of 3.92 MPa at 160 °C with an 8 min press time. The properties of the moisture content; thickness swelling after water immersion for 2 and 24 h; water absorption after water immersion for 2 and 24 h; internal bond; and the modulus of rupture and elastic modulus in static bending were evaluated. Increasing the amount of coconut husk in the MDP panels significantly improved water absorption properties after 2 and 24 h (WA2h and WA24h), screw holding and thickness swelling after water immersion for 2 h (TS2h), increased thickness swelling property after water immersion for 24 h (TS24h), and decreased the modulus of rupture (MOR), elastic modulus (MOE) in static bending and internal bond. The use of coconut fibers provided an improvement in the physical and thermal properties of MDP panels, and although the increase in the amount of coconut fibers reduces the mechanical properties, all treatments met the values determined by standards, being allowed to state that it is possible to produce MDP panels only with coconut fibers.