Valorizing Bamboo Culm Sheath Cellulose as Reinforcement in PLA: Mechanical Advancement, Biodegradation, and Green Cutlery Applications

Eco-friendly biocomposites are increasingly explored as sustainable alternatives to petroleum-based plastics. In this study, cellulose extracted from waste bamboo culm sheaths (BCS) was utilized as a reinforcing filler in polylactic acid (PLA) composites. The extracted bamboo sheath cellulose (BEC) was subjected to ball milling to obtain nano-sized particles. Particle size distribution and morphology were characterized using dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD) analysis confirmed a well-organized cellulose structure with a crystallinity index of 73.04%. PLA (PC) reinforced with the BEC filler at an optimized loading exhibited an increase in tensile strength (from 48.2 to 54.5 MPa), along with improved flexural strength and indentation resistance, accompanied by reduced elongation at break, indicating increased brittleness typical of PLA reinforced with non-elastic fillers. Density functional theory (DFT) analysis was employed to investigate possible interfacial interactions between them. As a proof of concept, disposable cutlery was fabricated from the optimized PLA biocomposites, demonstrating their potential as biodegradable alternatives to single-use plastic products. Cytotoxicity assessments indicated that the materials were largely safe for intended use. Additional analyses, including surface morphology and wettability, were conducted to assess suitability for product development and consumer applications.