Particleboards produced with different proportions of Hevea brasiliensis: Residual wood valorization in higher value added products

Abstract

The use of the Hevea brasiliensis tree in latex rubber production has resulted in a consolidated role of this tree in the Brazilian economy. However, at the end of the productive cycle of the tree that lasts for approximately 25 years, the timber resulting from this venture has no added value and is usually used for the production of firewood. In order to introduce this species into the furniture and civil construction industry, the current study aimed to evaluate the quality of particleboard produced by adding Pinus oocarpa wood with Hevea brasiliensis wood in different ratios. The particleboards were produced with a nominal density of 0.60 g/cm³ and 8% (wt%) urea-formaldehyde resin and pressed at 160 °C for 8 min at a pressure of 4.0 MPa. The quality of the particleboard was evaluated by water absorption and thickness swelling, internal bonding, static bending, and screw withdrawal tests. The substitution of Pinus particles by Hevea wood resulted in decreased water absorption and thickness swelling. The boards produced with a higher proportion of Hevea had better dimensional stability due to the greater porosity of the Pinus oocarpa particles. The inclusion of Hevea brasiliensis wood resulted in a 75% increase in the modulus of rupture and a 300% increase in internal bonding compared with the particleboards produced only with Pinus oocarpa wood. The results show that Hevea brasiliensis wood could be used to obtain higher value-added products and contribute to the diversification of the raw materials used in the particleboard industries of Brazil.

Properties of Bark Particleboard Bonded with Demethylated Lignin Adhesives Derived from <i>Leucaena leucocephala</i> Bark

“…The reduction in lignin particle sizes can also impact the MOR by weakening bonding, increasing water absorption, and making it more vulnerable to defects [102,103]. To mitigate these reductions, particleboard manufacturers can consider using a well-balanced combination of different lignin particle sizes, incorporating other additives or modifiers, and conducting thorough testing and quality control [104,105]. Striking the right balance between lignin particle size, adhesive formulation, and processing conditions is essential to achieving the desired MOE, MOR, and other mechanical properties in bark particleboard.…”