Evaluation of the addition of wheat residues in the production of Pinus oocarpa agglomerated panels

The aim of this research was to evaluate the physical and mechanical properties of Pinus oocarpa wood agglomerated panels produced with the addition of wheat residue at different levels (0, 25, 50, 75 and 100%). For that, the materials were first reduced to particles and chemically characterized by density, moisture, ash content, lignin, extractives and holocellulose analysis. Resulting that the lignin and holocellulose content of the wheat particles showed lower values in relation to Pinus oocarpa wood, in contrast to the moisture, extractives and ash content, which were higher. Then, for the molding the particles were bonded using 12% urea–formaldehyde adhesive in relation to dry mass, and hot-pressed obtaining two panels from each treatment. Physically, the compact ratio and apparent density values obtained presented no significant changes in the different treatments evaluated, and the water absorption and thickness swelling evaluated after 24 h of water immersion showed a proportionally increase in these values in relation to the addition of the by-product however, did not met the minimum established in standards. Finally, the mechanical properties of modulus of rupture, and the modulus of elasticity and the internal bonding, presented a reduction of 78%, 61% and 67%, respectively, showing a decreasing trend with the increasing amount of wheat fibers, which had no strong influence over the improvement of these properties. Therefore, to verify the production feasibility of this agglomerated panels, further studies like chemical pre-treatment to the wheat particles are needed to improve their quality. Graphical abstract