Biodegradable natural polymers and fibers for 3D printing: A holistic perspective on processing, characterization, and advanced applications

The biodegradable natural polymers and fibers could be suggested to revolutionize 3D printing as sustainable, biocompatible, and unique properties in the print matrix for different applications. This review article covers the natural polymers in the form of cellulose, alginate, starch, collagen, silk, chitosan, and gelatin as printing constituents. Furthermore, it includes various natural fibers such as hemp, jute, flax, and bamboo with unique characteristics and advantages in 3D printing. Reinforcements derived from nature have provided better tensile strength, moduli, and flexural properties when infused into polymer matrices, such as PLA, ABS, and PP. Extrusion-based methods, comprising Fused Deposition Modeling (FDM)/Fused Filament Fabrication (FFF), are the most applied techniques of 3D printing for natural-polymer and fiber composites with a principal application in the medical and industrial domains. The future of natural polymers and fibers in 3D printing is becoming very promising despite uniform printability, interfacial adhesion, and mechanical property-related issues. Research in optimizing material composition, processing parameters, and post-processing techniques goes apace to attain the required properties, functionality, and performance. This review provides an outline to researchers and engineers working on 3D printing on the immense potential associated with biodegradable natural polymers and fibers for designing innovative, sustainable, and high-performance products in various applications that contribute to a greener and more sustainable future.