Optimization of mechanical fiber separation methods for high-quality bamboo fiber extraction from Pleioblastus amarus

Bamboo fiber is a renewable natural plant fiber with excellent antibacterial, breathable and hygroscopic properties, which has broad application prospects in textiles, composites and biomedicine. Aiming at the bottlenecks of low efficiency and unstable quality in traditional mechanical fiber separation, this study adopted Pleioblastus amarus (bitter bamboo) as raw material, and conducted a comparative investigation on four mechanical fiber separation methods: Rolling Separation (RS), Rolling-Carding Combined Separation (RC), Impact (Beating) Separation (BS) and Impact (Beating)-Carding Combined Separation (BC). All bamboo chips were pretreated via hydrothermal treatment at 170°C for 20 min. Key indicators including fiber separation degree, yield, fineness uniformity and tensile properties were comprehensively evaluated, and the defibrillation-damage trade-off rule was also discussed. Quantitative results show that: RC achieved the highest fiber separation degree of 97.00%, while RS obtained the maximum fiber yield of 60.47% (no significant difference between RS and RC, p > 0.05). Fibers prepared by BS possessed the optimal mechanical performance, with breaking force of 1397.27 cN and elastic modulus of 144.10 cN/dtex; however, its fiber diameter coefficient of variation reached 53.15%, indicating poor fineness uniformity. Carding treatment effectively refined fiber fineness but inevitably reduced fiber yield and mechanical properties. Overall, RS exhibited balanced performance in yield, mechanical properties and fiber uniformity, which is most suitable for large-scale industrial production. This work clarifies the internal relationship between processing parameters and fiber quality, reveals the matrix-shielding effect and defibrillation-damage trade-off mechanism. It provides reliable theoretical basis and technical guidance for high-efficiency and high-quality industrial production of bamboo fibers, and further promotes the application of bamboo-based sustainable materials.