Synthesis of pyrogallol triglycidyl ether: A bio-based epoxy resin monomer with low viscosity, high activity, and good thermomechanical properties

With increasing development of chip and circuit integration, the requirements regarding the viscosity, activity, and thermomechanical properties of underfill are becoming increasingly stringent. However, common low-viscosity resins are often obtained with poor thermal and thermomechanical properties. In this study, natural renewable pyrogallol was used as a raw material and preparedto prepare a high-performance polyphenol epoxy resin monomer named E3PG (pyrogallol triglycidyl ether) through employing a combination of epichlorohydrin and olefin epoxidation methods for the first time. At 25 °C, the viscosity of E3PG was only 210 cps, indicating excellent processability. Compared with traditional epoxy resin (E51), E3PG has a lower activation energy, and more importantly, exhibits excellent thermomechanical properties after curing; its glass transition temperature (Tg) reaches 164 °C, and its storage modulus (E′) reaches 3500 MPa at 25 °C. In this study, an epoxy resin monomer with excellent properties was successfully prepared using renewable polyphenols as raw materials, providing a unique and novel approach for the synthesis of epoxy resin monomers.