Bio-based, robust, shape memory, self-healing and recyclable elastomers based on a semi-interpenetrating dynamic network

Fabricating materials with a combination of high toughness, and self-healing, shape memory and reprocessing properties, especially derived from renewable precursors, remains a challenge. Herein, we demonstrate a simple strategy to prepare a multifunctional elastomer based on a semi-interpenetrating dynamic network (semi-IDN) by using sustainable Eucommia ulmoides gum (EUG) as a raw material. The elastomer possessed high stretchability (similar to 876%) and high tensile strength (similar to 12.1 MPa) as well as good self-healing, solid plasticity and shape memory properties. Moreover, it can not only be reprocessed by hot pressing (tensile strength remains 92% after three times of reprocessing), but can also be recycled by dissolving with little effect on the structure and properties. In addition, a flexible electronic device is prepared by spraying hydroxylated multiwalled carbon nanotubes (MWCNTs-OH) on its surface, which exhibited good self-healing of electrical conductivity after damage. The semi-IDN concept provides a new pathway to prepare reprocessed materials, and the as-prepared elastomers have broad application prospects in new generation green rubber and flexible wearable devices.