A highly active bio-based epoxy resin with multi-functional group: synthesis, characterization, curing and properties

A bio-based epoxy resin, triglycidyl ether of resveratrol (TGER), was synthesized based on the renewable resveratrol deriving from tannins. The structure and properties of TGER have been characterized by ¹H NMR, ¹³C NMR, FTIR, GPC and viscosity measurement. Besides, systematical investigation was carried out on the curing reaction of TGER and diaminodiphenylmethane (DDM), assisted by the characterization of mechanical properties and thermal properties of cured TGER/DDM by means of differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis (DMA), flexural and impact measurement. Non-isothermal and isothermal curing analysis showed that TGER/DDM system, deriving from autocatalytic curing reaction, possessed 40 °C lower curing temperature (84 °C) than bisphenol A diglycidyl ether (DGEBA) (124 °C) and much lower activation energy than DGEBA/DDM system calculated by Kissinger equation. DMA revealed that TGER possessed high glass transition temperature (T_g = 148 °C) and glassy storage modulus (2.391 GPa@23 °C). Meanwhile, TGER/DDM thermosets also exhibited good mechanical properties and heat resistance, illustrating that multi-phenol group and stilbene group of resveratrol endowed polymer with high cross-linking density and rigidness. Therefore, TGER could be a promising alternative to petroleum-based epoxy resin.