Engineering of particleboards using bio-based modified starch as a sustainable alternative to conventional binders

As the wood-based panel sector seeks more resource-efficient and lower-emission products, underutilized lignocellulosic feedstocks and bio-based binders warrant systematic evaluation. This study investigated the structure and performance of single-layer particleboards (PBs) manufactured from Citrus sinensis L. and Quercus cerris L. particles using either 10% urea-formaldehyde (UF) resin or a hybrid binder containing 2% UF and 15% modified corn starch. Clear formulation-dependent differences were observed. Compared with oak-based PBs, orange-based PBs showed lower apparent density and generally inferior mechanical performance. These drawbacks were partly mitigated by using a mixed furnish containing 80% orange and 20% oak particles. The hybrid UF + MS system increased stiffness and internal bond to acceptable levels in some formulations, but modulus of rupture and water-related properties remained inferior to the UF reference. Complementary thermophysical, porosity-related, and surface-topography analyses showed that furnish composition affected internal structure and heat-transfer anisotropy, providing additional insight into structure-property relationships in the developed boards. Overall, UF-bonded PBs showed the best balance of properties and came closest to full compliance with the EN 312 requirements for P2 boards, whereas the hybrid UF + MS boards should be regarded as a promising but still preliminary route toward partial replacement of conventional binders. Further work should focus on optimizing adhesive formulation and pressing parameters and on extending application-oriented validation, including formaldehyde-emission assessment and other end-use-relevant performance tests, before broader practical recommendations are made.