Degradable, reprocessable, self-healing PDMS/CNTs nanocomposite elastomers with high stretchability and toughness based on novel dual-dynamic covalent sacrificial system

Synthesizing materials that possesses degradability, reprocessability and self-healability simultaneously without compromising stretchability and toughness is considered a huge challenge. In this paper, a pioneering dual dynamic covalent sacrificial system is exploited for the fabrication of PDMS/CNTs nanocomposite. In the network structure, aromatic disulfide bonds and imine bonds act as sacrificial units and semi-permanent crosslinking points, respectively. The unique design endows the nanocomposite elastomers with high elongation at break (up to 1420%), high toughness (up to 5000 kJ m(-3)) and good tensile strength (up to 1.10 MPa). Moreover, these mechanical properties can be regulated by varying the chemical composition and CNTs content. Additionally, the nanocomposite elastomers exhibit excellent self-healing efficiency (12 h, 95% of toughness) at ambient temperature and the ability to be processed multiple times. More importantly, the nanocomposite elastomers can be degraded controllably by three ways, achieving the complete recycling of CNTs and PDMS. We believe that our design strategy will provide a new way for the development of green stretchable tough materials used in a sustainable way.