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 0.57MPa,and a good thermal stability （Td=357℃）.In addition,because of the presence of dynamic C=C bonds formed by the KC reaction and low glass transition temperature （Tg=-117℃）.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.