Recyclable and Self-healable Polydimethylsiloxane Elastomers Based on Knoevenagel Condensation

Elastomers are widely used in various fields owing to their excellent tensile properties. Recyclable and self-healing properties are key to extending the service life of elastomers. Accumulating evidence indicates that dynamic covalent chemistry has emerged as a powerful tool for constructing recyclable and self-healing materials. In this work, we demonstrate the preparation of a recyclable and self-healable polydimethylsiloxane (PDMS) elastomer based on the Knoevenagel condensation (KC) reaction. This PDMS elastomer was prepared by the KC reaction catalyzed by 4-dimethylaminopyridine (DMAP). The obtained PDMS elastomer exhibited an elongation at break of 266%, a tensile strength of 0.57 MPa, and a good thermal stability (T_d=357 °C). In addition, because of the presence of dynamic C = C bonds formed by the KC reaction and low glass transition temperature (T_g=−117 °C). This PDMS exhibited good self-healing and recycling properties at room temperature and could be reprocessed by hot pressing. In addition, the PDMS elastomer exhibits good application prospects in the fields of adhesives and flexible electronic devices.