A non-bisphenol-A epoxy resin with high Tg derived from the bio-based protocatechuic Acid:Synthesis and properties

A new bio-based non-bisphenol-A epoxy (PA-EP) resin was synthesized by one-pot reaction between protocatechuic acid (PA) and epichlorohydrin. This resin was cured by 4,4′-diaminodiphenyl methane (DDM) to give a cross-linked network showing a glass transition temperature (Tg) of more than 250 °C, which was much higher than that of a cured commercial bisphenol-A epoxy resin (DGEBA) (189 °C). The cured PA-EP resin also displayed the coefficient of thermal expansion (CTE) of 66 ppm/°C, which was lower than 72 ppm/°C of cured DGEBA resin. The curing kinetics of PA-EP/DDM system was also investigated, indicating that the curing process was a pseudo first order reaction (n = 0.94) and the activation energy was about 54.17 kJ/mol. Because protocatechuic acid is produced through the bio-transformation of glucose, this contribution may provide a new method for the preparation of non-bisphenol-A high-performance epoxy resins, as well as give a new way for the conversion of the bio-based protocatechuic acid.