Performance of medium-density particleboards from Eucalyptus grandis and Triticum aestivum treated with tall oil and citric acid

ABSTRACT Background: Agro-industrial residues offer a sustainable alternative to mitigate raw material scarcity for particleboard production. Surface treatments with natural products can enhance dimensional stability. This study evaluates medium-density particleboards made from Eucalyptus grandis particles and Triticum aestivum bran treated with tall oil and citric acid. Results: Increasing T. aestivum proportions improved the compression ratio but reduced dimensional stability, modulus of elasticity, and modulus of rupture. Thickness swelling increased from 18.46% in 100% Eucalyptus particleboards to 41.31% in 100% T. aestivum particleboards. The modulus of rupture decreased from 17.86 MPa (100% Eucalyptus) to 5.37 MPa (100% T. aestivum). Citric acid improved water absorption but did not affect thickness swelling. In 100% Eucalyptus particleboards, water absorption was 64% (citric acid), 72% (tall oil), and 70% (untreated). In 100% T. aestivum particleboards, absorption was 82% (citric acid), 91% (tall oil), and 86% (untreated). The modulus of elasticity was higher in citric acid-treated particleboards (2491 MPa) than in tall oil-treated ones (1903 MPa) for 100% Eucalyptus particleboards, and the same was observed in 100% T. aestivum particleboards (784 MPa vs. 259 MPa). Conclusion: T. aestivum residues are a viable alternative for particleboards, especially in moderate proportions (≤50%) combined with Eucalyptus. Higher proportions negatively affect particleboard properties. Citric acid was the most effective surface treatment, while tall oil showed limited benefits. These findings reinforce the feasibility of sustainable particleboards and the importance of optimizing raw material composition and surface treatments.