In situ polymerization of bio-based cardanol glycidyl ether and maleic anhydride in wood: Biological durability, weathering resistance, and fire performance

Wood is a widely used sustainable construction material in North America, but it is vulnerable to fungal decay, weathering and fire risk if not used appropriately. In this study, an in situ cardanol glycidyl ether (CGE)–maleic anhydride (MA) polymer network was synthesized within the wood structure to enhance its performance. CGE and MA were premixed at weight ratios of 6:1, 3:1, and 2:1, vacuum-impregnated into wood, and cured at 105 °C to induce in situ polymerization. Microscopy revealed that most cell lumens were filled with CGE–MA networks, which exhibited strong leaching resistance, retaining over 75 % mass gain after a 14-day leaching test. Soil block tests showed that treated samples had less than 11 % average mass loss after eight weeks of fungal exposure, compared to 30–80 % for controls, demonstrating significantly enhanced decay resistance. As for surface appearance change after weathering test, the difference of total color change (ΔE) among CGE-MA treated samples and Control-W was not significant, but more micro cracks were seen in CGE-MA treated samples. However, examination of the cross sections showed that CGE6MA1-W remained comparatively intact, with fewer cracks visible. Thermogravimetric analysis (TGA) revealed lower onset temperatures and peak derivative mass loss values for CGE–MA treated wood samples compared to untreated controls, suggesting altered thermal stability. Cone calorimetry results indicated that CGE2MA1-W samples exhibited comparable fire performance to controls, whereas higher CGE-to-MA ratios increased fire risk, as reflected in elevated peak heat release rates and total heat release. Overall, we successfully applied MA and bio-based CGE to improve wood’s performance against fungal decay, but the fire performance needed to be further improved by introducing fire retardants to the system. Furthermore, compared to preservative-treated wood, this method has the potential of reducing environmental concerns of waste wood disposal. • In situ polymerization of cardanol glycidyl ether and maleic anhydride in wood was achieved. • CGE–MA networks showed strong leaching resistance (>75 % mass gain retention) regardless of wood species. • Treated wood exhibited < 11 % mass loss after 8 weeks of fungal exposure across four common wood decaying fungi. • CGE6MA1 treatment enhanced weathering resistance and dimensional stability. • Fire tests showed improved thermal stability, but higher CGE ratios increased fire risk.