A resveratrol-based epoxy resin with ultrahigh Tg and good processability

Preparing and designing an epoxy system with ultrahigh glass transition temperature (T g  > 300 °C) is always a big challenge, which restrict its applications in some cutting-edge areas such as aerospace engineering and electrical electronics. Herein, a biomass-based epoxy resin (REEP) was prepared from resveratrol, and then curing behavior, thermal–mechanical properties, mechanical performance, thermal stability, dielectric properties and optical properties of REEP/HDDM, REEP/DGEBA/HDDM and DGEBA/HDDM were respectively studied systematically. Results suggested that the T g of REEP/HDDM was above 320 °C, higher than those of most reported epoxy systems, both derived from biomass-based and petroleum-based materials. Moreover, the tensile strength of REEP/HDDM, REEP/DGEBA/HDDM and DGEBA/HDDM were 77.8 MPa, 70.8 MPa and 63.6 MPa, respectively, and the T d5% of REEP/HDDM, REEP/DGEBA/HDDM and DGEBA/HDDM were 319.9 °C, 335.1 °C and 348.1 °C, respectively, indicating excellent mechanical performance and thermal stability of the cured epoxy system. Interestingly, the REEP/HDDM exhibited outstanding blocking properties in the range of 220–400 nm (UV-light) and low flammability with compact and continuous char residues. In short, REEP, with a well-defined chemical structure, has a stiffness conjugated stilbene structure to prevent the molecular from motioning in the crosslinked network structure and three epoxy groups, thereby increasing the crosslinked density dramatically, which endows REEP/HDDM network with outstanding comprehensive properties.