No abstract

Fast‐growing plantation typically has some undesirable inherent qualities that restrict their use as engineering materials, such as dimensional instability, poor mechanical strength, and flammability (Sangregorio et al., Green Chem, 2020, 22, 2786–2798; Zhang et al., Fire Saf J, 2021, 121, 103297). In this study, a simple and environmentally friendly method was applied to improve low‐quality poplar wood by building an organic–inorganic hybrid system with a combination of biomass‐derived furfuryl alcohol (FA), ammonium polyphosphate (APP), and nano‐silica (nano‐SiO2). Different amounts of APP and nano‐SiO2 were mixed with a FA water solution, impregnated into the poplar wood followed by curing at 103°C to induce in situ polymerization of furfurylated wood (FW). The results showed that the FW/APP/SiO2 had strong self‐extinguishing properties, and passed the UL‐94 V‐0 rating with a limiting oxygen index (LOI) value as high as 49.5%. Results from cone calorimetry and thermogravimetry suggested that APP and nano‐SiO2 could have a synergistic effect, which successfully inhibited heat transfer and suppressed the smoke emission during its combustion by promoting char formation. Scanning electron microscopy shows that FA, APP, and nano‐SiO2 can basically penetrate into the cell wall and modify the wood fundamentally. FW/APP/SiO2 also enhanced the phosphorus fixation in the wood and greatly reduced its leaching into water, indicating it has long‐term fire resistance in service.

Comparative studies of the anatomy and composition had been investigated to learn about the degradation characteristics of Castanopsis hystrix wood. Its chemical degradation was analyzed with wet chemical analysis, Fourier-transform infrared analysis, X-ray diffraction analysis, and thermogravimetric analysis. Its morphology was observed with light microscopes and scanning electron techniques. It was found that the deformation and separation of cell walls have no effect on the identification of C. hystrix wood. The degradation of polysaccharides leads to the mechanical properties of C. hystrix buried wood decreased. The inclusions exist in cells of C. hystrix buried wood increased, and the dark color is related to the inclusions and ferric oxide. Furthermore, the hemicellulose was heavily degraded but there was no obvious degradation of crystalline cellulose. Large amounts of inorganic elements such as Fe and S were detected in the ash of C. hystrix buried wood.