Bioinspired chitin/gelatin composites with enhanced mechanical property

The defensive tissues such as insect epidermis and crustacean exoskeleton in nature displayed characteristics of high strength and high toughness via multi-level structure, which shed light on the designation of natural polymer-based composites with enhanced mechanical property. Herein, a bioinspired strategy was used to prepare chitin/gelatin composite with improved mechanical property. Chitin hydrogels were first prepared by dissolution in NaOH/urea via freezing-thawing and then regeneration in sodium propionate, to form a heterogeneous nanofibrous structure. After coating gelatin on the chitin nanofibers, a hierarchical structure was obtained, leading to more compact and homogenous morphology. The coating process significantly strengthened the chitin nanofibrous structure and reduced the weak defect, which enhanced the tensile strength and toughness of the composite. The present work not only supplies a chitin/gelatin composite with high mechanical property but also offers a facile approach to prepare strengthening and toughening materials based on natural polymers. A bioinspired strategy was used to prepare chitin/gelatin composite with improved mechanical property, by coating gelatin on the chitin nanofibrous structure to strengthen the defects. image