Epoxy-acrylate hybrid systems are extensively employed in adhesives, coatings, and composites; however, conventional formulations often rely on toxic monomers such as glycidyl methacrylate (GMA). This study introduces a sequentially curable epoxy-acrylate hybrid system based on novel hybrid monomers containing both glycidate and acrylate groups, synthesized via the partial oxidation of a diacrylate. Radical polymerization of monomers with a glycidate content exceeding 80% yielded viscous prepolymers consisting of epoxy-functionalized polymers and residual low-molecular-weight glycidates. These prepolymers were subsequently cured with amines at ambient temperature to form crosslinked networks. The gel fraction exceeded 90% when cured with diethylenetriamine, demonstrating efficient curing. The resulting cured materials exhibited significantly enhanced lap-shear adhesion strength (>1.6 MPa) compared to those obtained from monomeric analogs (<1.14 MPa). This improvement is attributed to the synergistic effects of polar ester groups, flexible polymeric spacers, and a loose network structure resulting from the reduced nucleophilicity of γ-keto secondary amine intermediates, as supported by density-functional-theory calculations. This two-stage curing approach provides a GMA-free, ambient-curable polymeric epoxy resins, offering a safer and more versatile strategy for the molecular design of high-performance hybrid materials.
Ochiai et al. (2026) studied this question.