Tailored PLA/Chitosan/MCC composite filaments for fused filament fabrication

Abstract

The growing demand for patient-specific orthopedic implants has accelerated the development of polymer-based materials suitable for fused filament fabrication (FFF). This study aims to develop composite filaments based on polylactic acid (PLA), chitosan, and microcrystalline cellulose (MCC) for FFF applications in orthopedic implants. The composites were synthesized via melt blending and extrusion, with variations in chitosan content (1–2 wt%), MCC content (3–5 wt%), and extrusion temperature (155–165°C). Characterization included rheological testing (MFR), structural analysis (FTIR, XRD), morphological observation (SEM-EDX), thermal properties (TGA, DSC), and water absorption. The results indicate that the addition of chitosan and MCC does not alter the chemical structure of PLA but enhances interfacial interactions through hydrogen bonding. Chitosan acts as a compatibilizer, improving MCC dispersion and matrix–filler adhesion. Melt flow properties are governed by the balance between PLA content, filler composition, and extrusion temperature. All composites exhibit sufficient thermal stability for FFF; however, increasing filler content and extrusion temperature leads to higher water absorption. The optimum composition was achieved at 93 wt% PLA, 2 wt% chitosan, and 5 wt% MCC at an extrusion temperature of 155°C, yielding the most balanced performance. These findings provide mechanistic insight into the potential product innovation of composite filaments for future FFF-based orthopedic implants.