WS 2 inorganic nanotubes (WS 2-NT) have been incorporated into Polylactic Acid (PLA) by melt mixing to create a biodegradable , mechanically reinforced nanocomposite filament. The filament was then processed by Fused Filament Fabrication (FFF) 3D-printer, and the morphology and characteristics before and after printing were compared. We found that addition of WS 2-NT to PLA by extrusion mixing increases the elastic modulus, yield strength and strain-at-failure by 20%, 23% and 35%, respectively. Moreover, we found that the printing process itself improves the dispersion of WS 2-NT within the PLA filament, and does not require changing of the printing parameters compared to pure PLA. The results demonstrate the advantage of WS 2-NT as reinforcement specifically in 3D-printable polymers, over more traditional nano-reinforcements such as graphene and carbon nanotubes. WS 2-nt based 3D-printable nanocomposites can be used for variety of applications from custom-made biodegradable scaffold of soft implants such as cartilage-based organs and biodegradable soft stents to the more general easy-to-apply nano-reinforced polymers. Advanced manufacturing, and especially 3D printing, has attracted a lot of attention in the last decades, mostly due to its high versatility in materials and designs-including topographies that cannot be produced in traditional subtractive manufacturing, and the ease of custom-tailoring products. The latter has enormous advantage in the medical fields-especially orthopedic, dental and plastic medicine, as it allows precise anatomical design of the printed device-be it an implant, a surgical tool or a support model-to the specific patient 1,2. The most widely used printing technique is the Fused Filament Fabrication (FFF) used to fabricate thermoplastics such as Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS) and Polycarbonate (PC). In FFF, a thermoplastic filament is extruded through a heated nozzle onto a build platform as layer by layer are infused together to a final solid shape. The temperature of the extruding nozzle and build platform, as well as layer thickness, orientation, and printing speed can be tailored to control the properties of the final product. The use of thermoplastic polymers allows for fast, low-cost and relatively simple fabrication of lightweight structures, but the final product will be mechanically weak. Moreover, as the demand for multifunctional materials increases, the need for complex designs to optimize the use of such materials also rises 3-5. Polymer matrix composites, and especially nanocomposites, propose an elegant solution: the micro-and nano-additives will provide improved mechanical 6 , electrical 7 , and other desired properties, while the polymer matrix maintains ease of fabrication and lightweight structure. The choice of nanofillers and thus of properties is vast 4,8 , but the transition from a pure polymer to polymer nanocomposite is far from trivial. Issues such as adhesion, orientation and dispersion of the nanofillers within the final prod...
