Bio-Based Impact-Resistant Materials: Luffa Sponge as a Sustainable Solution

This paper develops low-cost, high-performance impact-resistant materials using natural luffa sponge as reinforcement for cementitious composites. It is the first to investigate the effect of temperature on the impact performance of luffa sponge-reinforced cementitious composites (LSRCC) across a wide range from − 196°C to 200°C. Addressing the brittleness of traditional materials at low temperatures, this study pioneers a sustainable, ultra-low-temperature impact-resistant material. Experimental results indicate a strong synergy between the luffa sponge and cement matrix, with the sponge’s networked fibers significantly enhancing structural integrity. Remarkably, LSRCC maintains cohesion under repeated impacts with minimal disintegration. It also exhibits low temperature sensitivity and excellent impact resistance in extreme environments. Interface properties between the luffa sponge and cement matrix were characterized using Focused Ion Beam (FIB) and Transmission Electron Microscopy (TEM), supported by Density Functional Theory (DFT) simulations. Results confirm a gradual Interfacial Transition Zone (ITZ) rather than a simple mechanical bond. Simulations reveal that hydrogen bonding within the cellulose matrix drives a gradual variation in the water-to-cement ratio across the interface, resulting in a progressive transition in interfacial strength. This transitional region enhances the load-bearing capacity of LSRCC, highlighting its superior synergistic behavior.