Lignin Paradox: Selective Property Enhancement In Particleboard

This study investigates the effect of incorporating additional lignin powder into particleboard (PB) on its mechanical performance and fire behaviour. Particleboards were manufactured from an industrial wood particle mixture bonded with phenol–formaldehyde (PF) resin using hot pressing at 7.8 MPa and 210 °C for a total pressing time of 4 min. Three board formulations were produced: control boards without lignin addition (PB-0L), boards containing 10 wt% added lignin powder (PB-10L), and boards containing 20 wt% added lignin powder (PB-20L). Fire performance was evaluated using a cone calorimeter under a heat flux of 50 kW·m⁻². In addition, artificial neural network (ANN) models were developed to predict the carbon monoxide release rate (CORR) and smoke production rate (SPR) based on selected cone calorimeter parameters. The results demonstrate that the incorporation of 20 wt% lignin powder significantly improves fire performance, leading to an almost threefold reduction in total carbon monoxide production, from 735 to 250 g·m⁻². Simultaneously, the modulus of elasticity increased substantially, from 1855 to 2639 N·mm⁻². Conversely, the addition of lignin negatively affected the internal bond strength, which decreased from 0.48 to 0.25 N·mm⁻². The developed ANN models exhibited high predictive accuracy, with normalized root mean square errors below 6% for CORR and approximately 2% for SPR. These findings indicate that lignin powder has strong potential as a sustainable additive for enhancing the fire performance and stiffness of particleboard, although optimization is required to mitigate its adverse effects on internal bonding.