Practical Pyrogallol-Derived Epoxy Resins via Low-Temperature Two-Step Synthesis: Unlocking High Efficiency and Thermal Stability for Sustainable Application

Abstract

As the depletion of fossil resources drives the demand for sustainable alternatives, bio-based epoxy resins (EP) face a critical challenge in balancing processability and mechanical performance. This study presents a novel low-viscosity EP, c-E3PG, synthesized from renewable pyrogallol via a two-step low-temperature method. By optimizing reaction conditions, c-E3PG achieves a high yield (65.8%) of the target compound E3PG (pyrogallol triglycidyl ether) with minimal byproducts, exhibiting a viscosity of 1500 cps at 25°C—significantly lower than conventional petroleum-based resins. Curing kinetics analysis reveals a low activation energy (70 kJ/mol), enabling efficient crosslinking, while the cured resin demonstrates a glass transition temperature (T _g) of 145°C, storage modulus (E′) of 2900 MPa, and exceptional electrical insulation properties (breakdown strength: 142.41 kV/mm; volume resistivity: 11.0 × 10¹⁵ Ω·cm). These results highlight c-E3PG's dual advantages of ease of processing and robust thermomechanical performance, positioning it as a scalable, eco-friendly alternative for high-temperature packaging and electrical insulation applications.