Produção e avaliação físico-mecânica de painéis aglomerados com resíduo reciclado de PET e adesivo estrutural

Abstract

This study investigates the production and evaluation of particleboards manufactured from Pinus caribaea var. bahamensis particles, recycled polyethylene terephthalate (PET) waste, and an epoxy-based structural adhesive as an alternative to conventional formaldehyde-based bonding systems. The proposed approach is based on the need to increase the utilisation of industrial waste, reduce the demand for conventional wood raw materials, and develop composites with improved performance and greater sustainability. Six experimental treatments were defined by combining two epoxy adhesive contents, 10% and 8%, with varying wood/PET proportions of 100/0, 85/15, and 70/30, respectively. The panels were hot-pressed at 130 °C under 5 MPa for 10 min and subsequently subjected to physical and mechanical characterisation in accordance with Brazilian, European, and North American standards. The results were subjected to analysis of variance (ANOVA), preceded by the Anderson–Darling normality test, both at a 5% significance level. When significant differences were identified, the means were compared using Tukey’s test at the 5% significance level. The results indicated high mechanical performance, with Modulus of Rupture (MOR) ranging from 28.36 to 35.90 MPa, Modulus of Elasticity (MOE) from 4,118.2 to 6,092.1 MPa, and Tensile Strength Perpendicular to the Surface (TP) from 0.88 to 1.75 MPa. Regarding physical properties, the panels exhibited densities ranging from 0.94 to 1.17 g/cm³, water absorption from 15.89% to 28.50%, thickness swelling from 14.31% to 19.92%, and moisture content from 5.44% to 8.05%. The incorporation of PET improved the physical behaviour of the panels, particularly in terms of moisture content and thickness swelling, although it affected stiffness and internal cohesion, whereas reducing the epoxy content from 10% to 8% decreased all three mechanical properties. Scanning Electron Microscopy (SEM) analyses indicated greater continuity of the bonding regions in panels containing 10% epoxy and increased morphological heterogeneity with increasing PET content. According to NBR 14810, the treatments containing 10% epoxy were classified between P4 and P6, whereas those containing 8% epoxy were classified between P2 and P4. According to EN 312, the treatments containing 10% epoxy were classified as P2, P4, and P6, while all three treatments containing 8% epoxy were classified as P2. According to ANSI A208.1, five treatments achieved the H-3 classification, whereas 30P8E was classified as H-2. Therefore, the combination of epoxy adhesive and recycled PET proved to be a promising alternative for the production of particleboards with good performance and potential for practical applications.