Green and Sustainable Layered Chitin-Vitrimer Composite with Enhanced Modulus, Reprocessability, and Smart Actuator Function

Green and sustainable polymeric-matrix composites have recently attracted much scientific and industrial attention. Naturally derived materials (e.g., chitin and cellulose) have been extensively studied due to their abundant availability and environmental appeal. Vitrimer, combining the properties of traditional thermosets and thermoplastics, has emerged as an attractive alternative for composite matrix. Here, two hot-debated materials were combined to fabricate the layered chitin-vitrimer composite with enhanced modulus, reprocessability, and smart actuator function. We utilized an ionic liquid assisted method to prepare the chitin films with ordered microstructures. The chitin-vitrimer composites exhibited a unique two-stage stress-strain behavior, and their failure behaviors were discussed from the angle of fracture mechanics. The composites showed weldability and recyclability under the hot-pressing treatment. In addition, the welded bilayer structure demonstrated a smart actuator function on the basis of the shape memory effect. Furthermore, the simple but efficient fabrication strategy could provide an avenue to apply dynamic chemistries and natural materials in the green and sustainable industry.