Preparation of epoxy‐terminated poly(aryl ether sulfone)s and their use as modifiers for epoxy resins

Epoxy‐terminated poly(aryl ether sulfone)s (PSE) were prepared by the reaction of epichlorohydrin with hydroxyethyl‐terminated polysulfones, which were synthesized from chloro‐terminated polysulfones (PSC) and diethanolamine. Both PSE and PSC were used as modifiers for toughening of bisphenol A diglycidyl ether epoxy resin cured with p,p′‐diaminodiphenyl sulfone. The mechanical, thermal, and dynamic viscoelastic properties of the modified resins were examined and compared to the parent epoxy resin. The effectiveness of PSC was larger than that of PSE. The fracture toughness, KIC, for the modified resin increased 45% at slight expense of its mechanical properties on 20 wt % addition of PSC (Mw 5300). These results were discussed in terms of the morphological and dynamic viscoelastic behaviors of the modified epoxy resin system.