Additive manufacturing of lightweight organic-inorganic composites using amylopectin and carbon fibers

The development of sustainable and lightweight composites addresses the critical need for environmentally benign materials. The introduction of fillers, such as carbon fibers (CFs), helped the development of high-performance, multifunctional, and more mechanically efficient composites. Most CF-reinforced composites rely on heavy chemicals or permanent matrix binders to achieve the desired mechanical properties, which sacrifice their recyclability and sustainability. By leveraging natural resources, this study investigates 3D-printable amylopectin-CF composites, aiming for a sustainable and mechanically robust material system. Using an additive manufacturing (AM) method called direct ink writing (DIW), we produced a series of cellular structures with amylopectin from corn starch as a biopolymer-based matrix and milled CFs as reinforcement fillers. The composites demonstrated porous structures and well-controlled CFs alignment, leading to specific mechanical properties comparable to or superior to those of other additively manufactured materials. Scanning electron microscopy (SEM) revealed the complex crack-propagation patterns and fiber-matrix interactions that contributed to the fracture behavior of composites. These results highlighted the potential of amylopectin-CF composites as a sustainable solution for applications, such as structural engineering, food packaging, and medical devices in AM.