3D-Printing of PLA-Banana Fiber Sustainable Biocomposites with Bioinspired Infill Patterns

Nature is a reliable laboratory to offer a rich variety of successful solutions to a broad array of scientific and engineering problems. The inspiration from nature has prompted the development of novel designs for high-performance materials and technologies. In the current work, 3D-printed specimens were fabricated from nature-inspired infill patterns such as gyroid and honeycomb. FDM printing filament was made from banana microfibers, a crop waste mixed with PLA to develop biocomposites favourable to the principles of the circular economy. For investigating the impact of infill density, raster orientation, and banana microfibre load, a Taguchi T9 design of experiment was adopted, offering nine different print conditions. Different mechanical characterizations, like tensile, flexural, compressive, impact, interfacial shear strength, and natural frequency, were conducted. Maximum tensile strength (62.45 ± 2.10 MPa), tensile modulus (5.04 ± 0.07 GPa), and natural frequency (60.36 ± 1.16 Hz) were achieved in the fourth print condition. Maximum flexural strength (79.78 ± 3.51 MPa) and compressive strength (60.73 ± 2.10 MPa) were observed for the seventh condition, whereas maximum impact strength (22.17 ± 0.83 kJ/m²) and elongation at break (1.82 ± 0.04%) were observed with the first condition. Inasmuch as the various conditions were best under different properties, the VIKOR multi-criteria decision analysis was utilized, and the third condition (50% infill density, 45° raster orientation, 9% banana fibre loading, honeycomb pattern) was found as the optimal overall. These banana-waste-based PLA biocomposites demonstrate strong potential to replace conventional materials in various industrial and engineering applications.