High-density binderless bamboo brush handles via high-consistency mechano-enzymatic pretreatment: Micro-filler effect and machinability

The resurgence of traditional culture has driven market demand for high-quality writing brushes. Natural bamboo frequently suffers from hygroscopic cracking, whereas polymer substitutes face the dual challenges of aesthetic deficiency and formaldehyde emission. While flat-molded binderless technology offers environmental advantages, it remains inadequate for addressing the high density and durability requirements of cylindrical artifacts. This study uses high-consistency mechano-enzymatic (HCME) pretreatment and cylindrical molding. It transforms bamboo processing residues into high-density binderless brush handles. Under HCME treatment, fibers fibrillate and parenchyma cells fragment. These changes induce microstructural reorganization. This reorganization constitutes a critical micro-filler effect. Porosity decreased to 3.27%, enabling a high density of 1.27 g/cm³. A thickness swelling (TS) below 5.1% effectively mitigated hygroscopic defects, while the material exhibited robust ink resistance. Attributable to micro-brittleness, chips broke cleanly during lathe turning; this eliminated fiber tearing and yielded a mirror-like surface finish. This formaldehyde-free approach achieved mechanical performance comparable to the tactile sensation of precious hardwoods but provided a potential pathway for extending binderless technology to the manufacturing of high-value cultural artifacts.