Bio-Inspired 3d-Printed Microstructures For Toughening Bio-Based Epoxy Matrix
Z. Xu (TU Delft - Group Teixeira De Freitas)
R. Tao (TU Delft - Group Dransfeld)
Sofia Teixeira de Freitas (Universidade de Lisboa, TU Delft - Group Teixeira De Freitas)
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Abstract
Aiming to aid the sustainable transition to fossil fuel-free epoxy materials and enhance the toughness of bio-based epoxies, here we integrate an overlapping curl microstructure consisting of coiling fiber with sacrificial bonds and hidden lengths into a bio-based epoxy matrix. Inspired by natural material, where exceptional properties are achieved at low environmental cost, the microstructure mimics the molecular structures of spider silk, known for its exceptional fracture resistance. The 3D-printed overlapping curl shows a saw-tooth mechanical response with continuous load-carrying ability thanks to the break of sacrificial bonds and unfolding of the hidden lengths. By embedding the overlapping curl into the compact-tension configuration of the bio-based epoxy, an extrinsic toughening mechanism is triggered as the hidden length unfolds. Experimental results show that a single-sided overlapping curl structure is able to improve the toughness of bio-based epoxy by 19%.