Tuning Acetal and Disulfide Network Dynamics in Dynamic Diamine‐Cured Partially Bio‐Epoxy Networks

ABSTRACT Epoxy thermosets are favored for structural applications in aerospace and automotive industries due to their high strength, chemical resistance, and thermal stability. However, their static networks prevent conventional resins such as diglycidyl ether of bisphenol A (DGEBA) from being reprocessed or recycled. To address these limitations, recent progress was made in the field of covalent adaptable networks, which combine the robust performance of thermosets with the processability of thermoplastics. This study focuses on comparing two dynamic exchange mechanisms, acetal and disulfide dynamic motifs, integrated into epoxy‐amine systems. Resins were prepared by stoichiometric mixing of partially bio‐based epoxy monomers with the respective dynamic diamines. The influence of acetal and disulfide groups on cure kinetics, thermal performance, and thermo‐mechanical behavior was analyzed alongside the effects of temperature and humidity on network performance. It was found that disulfide‐based networks offer superior hydrothermal stability and chemical resistance. In addition, phosphorus–nitrogen‐based flame‐retardant additives significantly accelerate the bond exchange rate in acetal‐based systems. Partially bio‐derived DGEBA demonstrates nearly identical thermo‐mechanical properties to its petroleum‐based counterpart, showing comparable glass transition temperature and network robustness. These findings highlight the potential of partially bio‐based dynamic epoxy systems to support circularity in composite material design.