Double-dynamic crosslinked epoxy vitrimer resin prepared using transesterification and dynamic disulfide bonds: High-performance, degradable, self-healing, environment-friendly

Abstract

Traditional thermosetting epoxy resins are widely applied in many fields due to their excellent performance. However, stable internal crosslinked networks hinder the repair of epoxy resins damaged during the operation and the recycling of decommissioned epoxy resins. Since vitrimers are epoxy resins that exhibit dynamic covalent bonding, reversible repair properties, and recyclability, they offer a potential solution to this problem. Therefore, by introducing an ester-exchange catalyst, we further introduced disulfide (S–S) bonds to the crosslinked network to construct a vitrimer resin exhibiting double-dynamic bonds, systematically investigated the basic thermodynamic and electrical properties of resins containing different S–S bond contents, and studied the self-healing properties of the possible multispecies and multiscale physical and electrical damages during device operation. Moreover, we investigated the self-healing properties of resins containing different S–S bonding contents. Results showed that the resin exhibited excellent electrical insulation, and the dynamic properties of the resin increased with the increasing number of S–S bonds in the crosslinked network, which considerably increased the repair efficiency and damage repair scale. In addition, the excellent dynamic properties rendered the resin degradable, enabling the non-destructive recycling of valuable materials from the resin matrix and specific processable remodelling and endowed the resin with thermally elastic shape memory properties. This work helps expand the class of vitrimer resins and promotes the application of vitrimers for manufacturing environmentally friendly electrical equipment.

Keywords

• Vitrimer
• Transesterification
• Disulfide bonds
• Electrical properties
• Recycling