High-Performance Epoxy Vitrimers with the Joint Action of Dual Dynamic Covalent Bonds

Abstract

Epoxy vitrimers have attracted increasing research attention owing to their stable physical properties, reprocessability, recyclability, and degradability. Among them, rapid self-healing can be achieved in dual dynamic covalent epoxy vitrimers. However, research on the performance and high-strength surface welding of dual dynamic covalent epoxy vitrimers with flexibility is still insufficient. Herein, we report a dual dynamic covalent epoxy vitrimer cocross-linked by dimer acid (DAA) and 3,3′-dithiodipropionic acid (DTDA), named E51-DAAx-DTDAy. The results suggest that the stress relaxation and selfhealing speed of vitrimers is improved and the mechanical properties can be restored by 81.2% after 24 h of healing. Additionally, significant recyclability is found in E51-DAAx-DTDAy, with a maximum recovery rate of 119.4% in tensile strength and 124.8% in elongation at break after three times of recycling. Furthermore, T v of E51-DAAx-DTDAy was above 140 °C; meanwhile, E51-DAAx-DTDAy had better insulation properties, making them more suitable for use as thermosetting materials at moderate temperatures in electronic equipment. E51-DAAx-DTDAy can be recycled by chemical reagents, and green cycling can be achieved. These are attributed to the contributions of disulfide bonds and hydroxyl ester bonds in the network topology.

Nonionic Emulsifier with Lipophilic–Hydrophilic–Lipophilic Structure for Preparing Waterborne Epoxy Coatings with High Corrosion Resistance and Thermal Stability

“…In HHPA, the characteristic bands at 1853 and 1773 cm –1 represent the antisymmetric and symmetric CO stretching vibrations of anhydride, respectively (Figure a) . The characteristic band at 913 cm –1 in E51 is attributed to the vibration of the epoxy group (Figure a) . After the reaction between PEG2000 and HHPA, the Esterification product can be obtained, which then reacts with E51 to produce the WEP emulsifier (E-PEG2000) (Figure ).…”

Oligosiloxane-Based Epoxy Vitrimers: Adaptable Thermosetting Networks with Dual Dynamic Bonds

“…These calculations serve to provide additional evidence that multiple covalent moieties are presumably active in the network. While further simulations may be able to shed additional light on the competitive nature of transesterification and siloxane exchange, we also synthesized an analogous single dynamic bond vitrimer based on 1,4-butanediol diglycidyl ether (BDDE) and PDAA to analyze the impact of multiple dynamic bonds . The BDDE–PDAA network is imbued with ester linkages but lacks siloxane moieties (Scheme S5), which limits the network to a single class of dynamic bond exchange.…”