Bamboo Flour Reinforced Thermoplastic Polyurethane Biocomposite Filaments and Their 3D-Printed Parts for High-Performance Additive Manufacturing

Abstract

In this study, bamboo flour (BF)-reinforced thermoplastic polyurethane composite (BTC) filaments and their 3D-printed parts were prepared through fused filament fabrication (FFF) and evaluated. Bamboo flour addition (0–15 wt%) significantly altered the aesthetic and physical properties: The filaments and 3D-printed parts exhibited darker coloration and rougher surfaces with increased BF content, which was attributed to thermal degradation and layer porosity. Thermal analyses indicated that bamboo flour induced TPU recrystallization, acting as a nucleating agent, but reduced the overall thermal stability because of the nature of the lignocellulosic flours. Mechanically, the BTC filaments and printed parts demonstrated a significant stiffness–ductility tradeoff. Although the tensile modulus and rigidity substantially improved with increasing BF content, increasing BF content also led to decreased tensile strength, elongation at break, and toughness, which were largely influenced by interfacial incompatibility and increased porosity. Additionally, dynamic mechanical analysis highlighted enhanced energy dissipation and damping properties in BTC parts with moderate bamboo flour content (10 wt%), suggesting targeted applications in vibration-sensitive environments. Therefore, the integration of bamboo flour into TPU enables the creation of stiff and lightweight composites but requires optimization of the filler content and interfacial interactions to achieve balanced mechanical properties suitable for practical FFF applications.