Development of lightweight particleboards using epoxidized soybean oil foamable adhesive

Abstract Lightweight particleboards have great application potential in construction, packaging, decoration, and transport industries. This study aims to develop lightweight particleboards using epoxidized soybean oil foamable adhesives. This simple strategy is expected to not only reduce the consumption of isocyanate‐based adhesives but also offer a feasible solution for optimizing the performance of lightweight panels. Green and low‐viscosity epoxidized soybean polyols (Epols) were prepared from epoxidized soybean oil (ESO) and ethylene glycol (EG) by ring‐opening reaction. Foamable adhesives with controllable properties were prepared by mixing polymeric methylene diphenyl diisocyanate (pMDI) and Epols. The results show that the optimal foam has exceptional mechanical strength, thermal properties, and a desirable pore structure. All the foamable adhesives have a synergistic foaming and curing process, which is highly matched to the particleboard preparation. Compared with particleboards with pristine pMDI as adhesive, particleboards prepared with foamable adhesive have superior mechanical properties, bonding properties, and water resistance (MOR 11.4 MPa, MOE 1900 MPa, IB 0.56 MPa, 24 h TS 6.6%) at the same density (0.55 g/cm 3 ). The microscopic results have confirmed that the cured adhesive forms a robust three‐dimensional porous cross‐linked network structure in the core layer, resulting in improved panel properties. This strategy not only reduces the consumption of pMDI but also effectively improves the mechanical properties, bonding properties, and water resistance of the panels, which provides a new pathway for developing lightweight particleboards. Highlights Foamable adhesive has been prepared using epoxidized soybean polyol and pMDI. Foamable adhesive is fully compatible with the particleboard preparation process. Foamable adhesive reduces pMDI consumption while improving panel performance. Prepared panel shows stronger specific bending strength in reported particleboards. 3D porous bonding network effectively improves the properties of panels.