Reinforced, Thermal-Healing and Recyclable Chitosan/Ethylene Propylene Diene Rubber Based on Diels-Alder Reaction

Covalent adaptable networks offer a viable approach for producing recyclable rubber materials. Nevertheless, the intricate synthesis process and insufficient mechanical strength limit their commercialization applications. In this study, the reinforced, thermal-healing, and recyclable chitosan/ethylene propylene diene rubber (CEF-CS) was synthesized using a solid-phase blending process via the Diels-Alder (D-A) reaction. Furfural modified chitosan (F-CS) was included as a reinforcing filler and dynamic cross-linking point into the network formed via the D-A reaction. The influence of F-CS content on the mechanical, thermomechanical, and thermal repair characteristics of CEF-CS composites was examined. The results showed that the CEF-CS composites exhibited certain mechanical strength and dependable repair capabilities. As the F-CS content increased, the tensile strength of CEF-CS composites initially rose and subsequently declined, reaching a peak of 5.1 MPa, which was 5.1 times more than the control without F-CS. The first healing efficiency of tensile strength exceeded 70%, whereas the second healing efficiency was above 60%. Moreover, the simple preparation procedure and enhanced mechanical strength facilitate the commercial utilization of recyclable rubber materials, which is crucial for addressing the environmental pollution issue associated with rubber materials.