Synchronously Improving Mechanical and Thermal Performances of Cured Epoxy Resins by Epoxidized Polyether Sulphones as Modifiers

As an effort to improve toughness of epoxy resins without scarifying their heat resistance, four novel polyether sulphones (PESs) with epoxy groups (PES-Es) are developed as efficient toughness modifiers of epoxy resins. The influences of PES-E on the mechanical property, curing kinetics, thermal, and mechanical properties of the diglycidyl ether with bisphenol-A (DGEBA) are investigated. The impact strength of PES-E/DGEBA composites is significantly improved from 16.6 to 28.9 kJ m −2 with optimal content of PES-E. Different from the composites of typical PES and epoxy which have two-phase structure, PES-E/DGEBA composites exhibit a single-phase structure owing to the participation of PES-E in the curing reaction of epoxy groups and good solubility of PES-E in DGEBA. Furthermore, the thermal stability of the PES-E/DGEBA composites is slightly increased compared to the neat epoxy resin due to the formation of crosslinked semi-interpenetrating polymer networks. The glass transitionnal temperature ( T g ) of PES-E/DGEBA composites is up to about 184 °C, 46 °C higher than the neat epoxy resin with the same hardener, which have great potential in high-performance composites. The method developed in this seminal report makes it possible to improve the toughness of epoxy resins without trading-off the T g and tensile strength.