Introducing rigid-flexible integrated structure and constructing sacrificial bonds to achieve mechanically robust and malleable epoxy resin

Epoxy resin (EP) is usually brittle because of highly cross-linked chemical structure , so it is necessary to carry out research on toughening of epoxy resin. Here, a modified epoxy resin with enhanced mechanical toughness and strength was prepared using a novel modifier (PEA-BA), synthesized from polyetheramine D-400 (PEA) and benzoic acid (BA). Polyether chains that represent flexible structures, and aromatic rings representing rigid structures, were integrated together into the modifier to achieve simultaneous enhancement of the toughness and strength of the resulting epoxy resin. Moreover, the aromatic rings in PEA-BA formed π-π interactions with the aromatic rings in the EP network, further increasing the ductility of the modified epoxy resin. Research results demonstrated that the modified epoxy resin exhibited significantly improved elongation at break (increasing from 6.7 % to 39.2 %), as well as higher tensile strength (from 61.9 MPa to 69.3 MPa) and impact strength (from 25.3 kJ·m −2 to 62.9 kJ·m −2 ). Importantly, the glass transition temperature and thermal stability of the modified epoxy resin were not markedly reduced. The above properties indicated that PEA-BA achieved a favorable combination of high strength and ductility of epoxy resin, providing a new idea for toughening epoxy resin.