Effect of filler characteristics and processing route on bamboo powder-reinforced PLA composites

In additive manufacturing, there is an increasing demand for sustainable material usage; hence, biodegradable composites, particularly polylactic acid (PLA) reinforced with natural fillers, have attracted considerable attention over the last decade or so. The application of bamboo powder in PLA matrices for 3D printing applications is still underexplored, with only a few comparative studies across different manufacturing techniques conducted so far. This paper, therefore, attempts to fill these knowledge gaps by studying the effect of bamboo fibre content and particle size on the structural, thermal, mechanical, and rheological properties of bamboo-reinforced PLA composites. Moreover, composites produced via three manufacturing routes (3D printing, injection moulding, and compression moulding) were analyzed, followed by either laser or waterjet cutting. Hence, this study evaluates composite performance regarding filler characteristics and production methods. The results depicted that the composites with 125-μm bamboo powder are superior in mechanical strength when compared to their counterparts made from 250-μm fillers, while 10 wt% of the 125-μm bamboo powder increased Young's and flexural modulus by over 120 % compared to neat PLA. The injection-moulded samples had superior mechanical properties; however, 3D-printed samples with optimized filler content showed comparable strength to waterjet-cut compression-moulded specimens. The novelty of this work lies in providing the first comprehensive comparison of PLA–bamboo composites produced via 3D printing, injection moulding, and compression moulding, followed by laser and waterjet cutting, to systematically evaluate how filler size, content, and processing route influence composite performance. Such a study will identify how both the size of the filler and the manufacturing method can affect PLA-bamboo composites, providing valuable information on the optimization of material properties for the sustainable application of 3D printing and supporting the evolution of eco-friendly materials in industrial and commercial uses.