Self-healing, reprocessable, degradable, thermadapt shape memory multifunctional polymers based on dynamic imine bonds and their application in nondestructively recyclable carbon fiber composites

Traditional epoxy thermosets have been extensively used in many fields, including the field of carbon fiber composite materials, which is favored by a large number of researchers. But they usually cannot be recycled under mild conditions. To make matters worse, the material loses its usefulness once it is damaged. Self-healing and degradable thermosetting resins with dynamic covalent bonds offer a potential solution to this conflict. In this paper, a series of epoxy polymers named EPCN based on dynamic imine bonds were easily prepared by a one -pot method using inexpensive industrial materials terephthalaldehyde and common bisphenol A diglycidyl ether as raw materials, which were cured by D230. The results show that the materials exhibit certain self-healing, reprocessability and thermadapt shape memory properties due to the dynamic properties of the imine bonds. Moreover, EPCN epoxy polymers can be degraded due to the hydrolysis of dynamic imine bonds, and their degradation exhibit temperature and acidity dependence. More importantly, the recyclable carbon fiber rein-forced polymer composites prepared with EPCN-4 as the resin matrix can be completely degraded under weak acid conditions, leading to the ready and non-destructive recycling of its carbon fiber composite. We envision this reprocessable and degradable carbon fiber-reinforced composite material with cheap raw materials, simple process, and suitable for mass production will make it a potential candidate for sustainable structural material applications.

Automated summary

Traditional epoxy thermosets are widely used but cannot be recycled easily. This paper introduces the development of self-healing and degradable epoxy polymers with dynamic imine bonds. The polymers show self-healing, reprocessability, and thermadapt shape memory properties, and can be degraded through hydrolysis. Moreover, carbon fiber-reinforced polymer composites prepared with these polymers can be completely degraded under weak acid conditions, enabling non-destructive recycling. This material has potential as a sustainable structural material.