High-Performance, Formaldehyde-Free Particleboard for Sustainable Housing: Process Optimization of Halloysite Nanotube-Reinforced Isocyanate Adhesives

This study aims to develop a high-performance, formaldehyde-free particleboard for sustainable housing using halloysite nanotube (HNT)-reinforced isocyanate adhesive. HNTs were incorporated into the isocyanate matrix via magnetic stirring followed by mechanical mixing, with loading levels systematically optimized from 0 to 3.0 wt%. Particleboard panels were fabricated and tested according to standard procedures. The optimal HNT loading was found to be 1.5 wt%. Compared with panels bonded with unmodified adhesive, those fabricated with the optimized HNT-reinforced adhesive exhibited significantly enhanced performance: surface bonding strength increased by 71.79% (to 2.01 MPa), internal bonding strength by 54.35% (to 0.71 MPa), modulus of rupture by 107.53% (to 19.3 MPa), modulus of elasticity by 59.95% (to 3191 MPa), and the 2 h water absorption thickness swelling rate decreased by 95.83% (to 0.1%). These results demonstrate that the optimized dispersion process and HNT loading are critical for achieving superior adhesive performance, providing a viable pathway toward high-performance, formaldehyde-free particleboard for sustainable housing.