Harnessing Fly Ash as Particle Reinforcement in Nature-Inspired Multilayer Composites

Strategies for strengthening the characteristics of naturally inspired multilayer composites are being sought, including inorganic platelet alignment, enhancing interlaminar collaboration between polymeric solution and printed platelets, and optimizing soft phase materials. The former tactic is significant because a particle reinforcement can use high in-plane modulus and strength of inorganic mineral bridges and asperities as much as possible. Fly ash is an immense amount of environmental waste from thermal power plants and other industries that can be effectively employed as particle reinforcement in nature-inspired composites. Herein, the study demonstrates an anomalous phenomenon combining soft microscale organic polylactic acid (PLA) components with inorganic micro grains fly ash (FA) hierarchically designed by natural organisms through dual 3D printing technique (fused deposition modeling & direct ink writing). Our investigation of composite deformation reveals that sheet nacreous architecture exhibits the highest flexural and tensile modulus, whereas foliated structure shows better impact resistance. Remarkably, as fly ash filler increases, the mechanical behavior of composites improves as large as 882 MPa and 418 MPa, flexural and elastic modulus, respectively.