Morphologies and mechanical properties of polyethersulfone modified epoxy blends through multifunctional epoxy composition

Thermoplastic polyethersulfone (PES) modified multifunctional tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM) and triglycidyl para-aminophenol (TGAP) epoxy prepolymers cured with 4,4'-diaminodiphenylsulfone (44DDS) were prepared using a continuous reactor method and their reaction-induced phase separated morphologies and mechanical properties were measured and correlated with chemical compositions. H-1 nuclear magnetic resonance (H-1 NMR) and near-infrared spectroscopy (NIR) were used to quantify the chemical network formation. Atomic force microscopy (AFM) with nanomechanical mapping was employed to resolve the nanoscale phase-separated morphologies. The extent of phase separation in cured networks and resultant domain sizes were determined to be controllable depending upon the multifunctional epoxy compositions. The results obtained from mechanical studies further indicated that tensile modulus was not largely affected by multifunctional epoxy compositions while fracture toughness increased with increase of TGAP content. (C) 2017 Wiley Periodicals, Inc.