High-Resilience Epoxy Elastomer: Dynamic Ester Bonds Enable Reprocessing and Chemical Degradability

Dynamic covalent polymer networks represent new opportunities in the design of sustainable epoxy resins due to their excellent reprocessability. However, these vitrimers typically exhibit mechanical brittleness and poor resilience performance, limiting their applications in sealing, vibration damping, and impact resistance. E44/poly(2-methyl-1,3-propanediol adipate)/glutaric acid (E44/PMPA/GA) epoxy elastomers, with high resilience, reprocessability, and chemical degradability, were synthesized through epoxy-carboxylic acid opening-ring reactions. The E44/PMPA₂/GA₈ vitrimers exhibited the highest cross-linking density (226.3 mol/m³), a T_g of 22.8°C (from DMA), and high thermal stability (T_i: 337°C). Owing to flexible chains and a moderate cross-linking density, the E44/PMPA₁₀ exhibited superior resilience (residual strain 5.6% after five tensile cycles). Meanwhile, the dynamic ester bonds within the networks endowed the E44/PMPA/GA with self-healing ability and recyclability. In addition, the vitrimers were completely chemically degradable. By regulating the synergistic effects of flexible chain segments and dynamic bonds, this work provided a promising and feasible route for the preparation of epoxy elastomers that integrate high resilience, reprocessability, and chemical degradability.