Preparation of spherical phenol‐formaldehyde beads from phenol‐liquefied wood and the characteristics of carbonized materials

Abstract

AbstractIn this study, wood of Cryptomeria japonica D. Don (Japanese fir) was liquefied with phenol as a solvent. Phenol‐liquefied wood was mixed with formalin and spherical phenol‐formaldehyde resin (PF) beads were prepared by a two‐stage suspension polymerization reaction. The influence of the kind and dosage of polyvinyl alcohol (PVA) on the particle size distribution, mechanical strength and thermal properties of spherical PF beads were investigated. The results show that PF beads prepared with partially saponified PVA as a granulating agent are smaller than 75 μm, while the PF beads prepared with fully saponified PVA have larger diameters. However, the average diameter of spherical PF beads decreased with the increase of PVA addition. Thermogravimetric analysis (TGA) indicates that the initial thermal degradation temperature of the PF beads is around 150°C, and the main weight loss occurs between 400 and 600°C. Among them, the PF beads with BF‐04 as the granulating agent have the best heat resistance, and have the highest char yield at 800°C. The Brunauer, Emmett and Teller surface adsorption shows that the internal structure of the carbonized spherical PF beads is microporous pores. Carbonized beads prepared with high PVA adding have large absorption volume.