Sustainable Nanokaolin-Recycled HDPE Filaments for Additive Manufacturing: Optimization, Performance, and Industrial Feasibility

This review examines the progress made in the field of polymer nanocomposites for additive manufacturing. This study focuses on developing sustainable filaments from nanokaolin and recycled high-density polyethylene (HDPE) waste. Adding nanokaolin as a filler to recycled HDPE matrices created filaments with significantly enhanced mechanical and thermal properties. They achieve up to 35% higher tensile strength, 25% greater thermal stability, and 40% reduction in material costs compared to traditional biobased and virgin-polymer filaments Using the Taguchi method, a well-known optimization technique, we systematically adjusted the extrusion parameters of the filaments. This method is part of a broader strategy known as the Design of Experiments (DOE) framework. This helps to identify the best production settings. This review investigates the links between processing conditions, microstructure, and material properties, supported by advanced characterization and modeling methods. In addition to economic factors, we also detail the environmental benefits of using recycled HDPE and nanokaolin, such as reduced carbon footprint and plastic waste, compared to standard filaments. This highlights the sustainability of this method. This study establishes a scientific basis for circular material flow in additive manufacturing. This promotes the adoption of high-performance, cost-effective, and environmentally friendly 3D printing solutions.